650b and low trail - does one necessitate the other?

[Mark Guglielmana]

This question was asked over in the C&V bike forum site - I'm sure there's a significant amount of overlap in membership here.

He asked the following question: "What does conversion to 650B change so much, trail-wise, that this is thought necessary?"

I thought about it, and wrote back that I thought they were complimentary. Any thoughts?

[Steven Frederick]

I own 650b bikes with both low trail/front loading and Rivendell/rear
loading geometries, and they're all great to ride in their own ways.
Low trail is more about where you want to carry your shtuff than
anything else, I think-though some seem to prefer the handling traits
as well. I don't find I strongly prefer one over the other--I can
adopt pretty quickly to whichever bike I choose, and get right to
enjoying the ride.

Steve

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[Brad]

The will size does not dictate the frame geometry.
The two rediscoveries just happened to evolve in parallel.
"Low trail" is a return to the geometry common before about 1979 which gradually disappeared over the course of the early 80's.
The 650B tire was used in France on sport touring and randonneur bikes that had that geometry, but there were also 700c and even 27 x 1 1/4 tired bikes that had that geometry.
Had it been in common usage on the "bike boom" imported 10 speeds it might have been hugely popular, but the only knowledge I ever had to it was a glowing description by Fred DeLong in an article in (I think) Bicycle Guide after he had ridden 650B bikes on a trip to France.  He also liked fenders on those bikes.

Over the course of the 90's many things changed in frame design.
Bottom brackets came up about a 1/2 inch to alleviate Consumer Product Safety Commission concerns about pedal strikes on turns.
Tire sizes narrowed.  The standard 27 x 1 1/4 tire which was perceived as narrow in the age of newsboy balloon tire bikes was actually 630 x 32.   Tires on road bikes moved to 28 and then 23.   Road frames chasing stiffness and style pushed the stays closer at the brakes and the bottom bracket.  Dimples disappeared from chain stays as oval round oval tubing became the norm.  Cast fork crowns were made in narrower sizes, too.

Eventually road bikes evolved into machines that did not like imperfect pavement and were thus less fun to ride  in farther away places.
They also evolved so that the barest amount of stuff could go with you on a ride.
They evolved so that fenders would not fit.   Ten years ago there were discussion on the BOB  list about how to run a piece of metal over a brake bridge so that you could make a fender fit a bigger (32 was pushing it) 700c tire.

So if it rained and you were on a bumpy road you were jostled, wet, without a rain jacket,  covered in road grime and without a camera.

Low trail lets you throw your stuff in a guidon handlebar bag and not have handling issues.
650B lets you roll over the bumps better.
Both let you be different.

[Murray Love]

While it's true that low trail and 650B aren't bound to each other out of necessity--high-trail Rivendells led the North American 650B renaissance, for instance--it's thought by many that fatter tires counteract the effects of low trail to some extent, an effect called "pneumatic trail". 

Jan has written a fair amount on the topic, and I'm going from memory here, but I think the gist is that pneumatic trail provides additional "primary stability" (that is, the perceived stability of the bike while riding in a straight line) while not interfering too much with secondary stability (the behavior of the bike under intentional steering inputs). Some people report a "sketchy" feel in low-trail bikes: the steering feel is light, and you can move the handlebars around a fair bit while not altering the line of the bike. Pneumatic trail may reduce the sketchy feel somewhat, while preserving the ease of maintaining a straight line, and the greater controllability of low-trail bikes in cornering.

Or I may have gotten it completely wrong. The point is that 650B and low trail are too some extent complementary.

Murray

Victoria, BC

--

[Nick Favicchio]

I dig low trail, sounds like a number of folk like something more in the mid-trail range (a la Rivs).

Correct me, but low trail being in the 25-40 range, mid being 40-55 and high being above that. Super ish numbers, but that's the ballpark, right?

This is handy...

http://yojimg.net/bike/web_tools/trailcalc.php

Between the "pneumatic" trail and the awesomeness that is needle bearing headsets, I think most people would be just fine with a bit (or more) of front load on a 650b puffy tire bike with mid trail.

I like the more stable feel and light input of low trail but I'd say no right or wrong answers.

[Mark Guglielmana]

Between the "pneumatic" trail and the awesomeness that is needle bearing headsets, I think most people would be just fine with a bit (or more) of front load on a 650b puffy tire bike with mid trail.  

I like the more stable feel and light input of low trail but I'd say no right or wrong answers.

Good points, the "pneumatic trail" of fatter tires is complementary to low trail, it would seem. Someday I'll put some narrow tires on my Competition and see if I can tell any difference in handling.

[Mike Schiller]

most experts would consider low trail in the 30 to 45 mm range and mid trail 50 to 65 mm.  I have 3 custom low trail bikes ( 2 are 650B and 1 700c) and think the positive traits of low trail work well in both  sizes.

I think on the 650B list there are more low trail devotees than mid trail. 

~mike

Carlsbad Ca.

[Steve Palincsar]

On 06/01/2015 08:01 PM, Mike Schiller wrote:
> most experts would consider low trail in the 30 to 45 mm range and mid
> trail 50 to 65 mm. I have 3 custom low trail bikes ( 2 are 650B and 1
> 700c) and think the positive traits of low trail work well in both sizes.

What constitutes "low" varies by wheel size. 30-40 is "low" for
650Bx42; 45mm is "low" for 700x32.

[Joe Broach]

I haven't kept track of the most recent models, but past Rivs including my Romulus almost always hit right around 60mm, or the low end of "high" trail. 

Best,

joe broach

pdx or

[satanas]

I'm basically hating the handling of my Soma GR after two months or so. 32mm trail is not enough for me to be comfortable, whatever I'm doing. I might try building a fork with horizontal dropouts to experiment, but have never been unhappy with normal trail handling...

later,

Stephen

[Mark Guglielmana]

It would be interesting to know what it is about the handling that you don't like. Doesn't steer quick enough? Riding with handlebar bag or without? Saddlebag? Have you ridden another low trail bike that you like? 

[Gary Jacobson]

Seems that for 650  the sweet spot is commonly becoming around 39 mm with 42 mm tires, which according to those who seem to know about these things is towards the upper limit of "low trail". At least that's what I have concluded after reviewing people's posts on their experiences. If my conclusion is inaccurate then I'm sorry for stating it. People interested in low trail 650 b should do their own research and need to trust the manufacturer of their frame. I never even engaged my builder around trail number during the planning stage of the project, as I trusted his judgment, and my input would be based only on posts like this and a low trail 700c that I own. He was told that I wanted a mixed surface front load carrying frame, and I knew him to be experienced with low trail design.

Tom Matchak built this 650b with 39 mm trail and I use it with low riders and/or just a handlebar bag. I like the handling very much at the low to medium speeds that I ride at. I'm no longer comfortable flying down hills, so I can't comment on handling at speeds 30+ mph.

Keep in mind that riding surface and tire choice bears on experience and handling. 32/33 mm is a common trail for 650b it seems, and I wonder if speed demons would favor that. Those in the know say that many factors affects the rider's experience. 

In a Bicycle Quarterly review of many bicycles with many geometries a 650b Routens with 38/39 mm trail was found to be good on soft surfaces but not as good as lower trail  650b bikes on harder surfaces. 

All I know is that I have ridden many bikes, and still own too many. I am enthralled with my new Tom Matchak built 650 b low trail bike. It feels like the wind is always behind me. Uncanny and weird. I suspect that tube choice plays a large role in my perceptions.

Gary Jacobson

Rosendale, NY

[Steve Palincsar]

On 06/02/2015 10:01 PM, Gary Jacobson wrote:
> Seems that for 650 the sweet spot is commonly becoming around 39 mm
> with 42 mm tires, which according to those who seem to know about
> these things is towards the upper limit of "low trail".

I fear you are confused. Tire width and trail are both measured in mm,
and tire width and trail are related. But tire width is not trail.

[Gary Jacobson]

I thought that the effects of (geometric) trail on handling characteristics are related to tire width, or pneumatic trail.  My assessment of people's experience using 42 mm tires is that 39 mm of trail is a sweet spot.

Gary Jacobson

Rosendale, NY

[Steve Palincsar]

On 06/03/2015 06:57 AM, Gary Jacobson wrote:
> I thought that the effects of (geometric) trail on handling
> characteristics are related to tire width, or pneumatic trail.

They are. Basically, trail is made up of geometric + pneumatic trail.
Wider tires have more pneumatic trail; as tire width increases, if one
wishes to retain the same "handling feel" (i.e., overall trail) you need
to decrease geometric trail. This is why "low trail" geometric trail is
higher for 700Cx32mm bikes than 650Bx42mm bikes.

As for a "sweet spot" -- there's a range in which there are minor flavor
variations, and some will prefer the low end of the range and some the
high end.

> My assessment of people's experience using 42 mm tires is that 39 mm
> of trail is a sweet spot.

What was your methodology in conducting this assessment? I currently
have 3 650B bikes and sold another, and I don't recall having been surveyed.

[Bill Romano]

Agree with you Gary and Stephen. My Polyvalent has, I believe, 38 or 39 trail and is very pleasant and stable with 42s. My GR on the other hand at 32 trail with a needle bearing headset was still most twitchy and shimmied with my hands off the bars. The GR fender less and with 2" Big Bens no longer possesses these traits. Is that pneumatic trail correction? -Bill

[satanas]

On Tuesday, 2 June 2015 19:50:52 UTC+1, Mark Guglielmana wrote:

It would be interesting to know what it is about the handling that you don't like.

Everything. Total lack of stability at all speeds, loaded or not. Very twitchy without a bar bag, but doesn't shimmy then - so far. With a bar bag shimmy is a problem. Part of this may be bump steer from the massive fork offset, coupled with non-flex of the fork blades. Then there's not enough trail to correct things. Top tube/head tube flex may be a factor too. 

Riding in a straight line requires significant concentration - I don't like this at all, especially for long events with pacelines, like PBP. (I might be building another fork before then.)

With front panniers it doesn't quite shimmy, probably because the extra weight damps things.

Doesn't steer quick enough?

Unstable, see above. I'd much prefer slower steering; I can make the bike turn and would prefer to put a little more effort in doing that (occasionally) than have to work *all the time* to go straight.

 

Riding with handlebar bag or without?

No good either way.

 

Saddlebag?

Yes, sometimes (Revelate), but this doesn't appear to affect handling.

Have you ridden another low trail bike that you like?

No - only an AM; this has different issues, but shimmy isn't one of them, presumably due to the suspension and extremely stiff frame and fork.

"We are not amused."  :-(

Later,

Stephen

[Mark Guglielmana]

Stephen,

Thanks for the detailed reply. It points out that low trail isn't a magic bullet for everyone. There's a significant school (cult?) of low trail disciples that believe this to be a panacea for everyone. As always, YMMV.

 I haven't seen any good "first principles" analysis or dynamic modeling to be able to quantify handling characteristics. If someone reading this knows of any, please post! If not, there's got to be some Mech Engr. grad student out there looking for a thesis subject. 

Having said that, it works extremely well for me. If we were close to the same size and lived close enough to each other, it would be interesting to go riding and swap bikes for a bit. Has anyone else tried riding your low trail bike? This would help determine if the problems you've encountered are inherent to the bike or if its the bike/rider dynamic relationship that's the issue?

I remember my first encounter with shimmy. After riding over the Golden Gate bridge with a friend on a Ron Cooper, we were flying down Alexander Blvd when his handlebars started to shimmy. It got so bad he almost crashed before slamming on the rear brake. We stopped at Bicycle Odyssey and talked to Tony Tom, he admitted he had no good explanation as to why some bikes/riders did this on occassion. I mention the shop and the owner to assert his "bona fides", those that don't know - Tony has been around a long time, sells a lot of high end bikes, was one of the top Ron Cooper dealers in the country,  and is very C&V knowledgable. If he didn't know the answer, I figured it was still a mystery.

I've read that low trail has been associated with shimmy, fat tires seem to alleviate this, which circles back to my original post.

Mark

[Kieran Joyes]

Have you tried high trail and a front load, for comparison purposes?

KJ

On Thursday, June 4, 2015 at 11:10:03 AM UTC-4, satanas wrote:

Riding in a straight line requires significant concentration - I don't like this at all, especially for long events with pacelines, like PBP. (I might be building another fork before then.)

Unstable, see above. I'd much prefer slower steering; I can make the bike turn and would prefer to put a little more effort in doing that (occasionally) than have to work *all the time* to go straight.

 

Riding with handlebar bag or without?

No good either way.

 

[Steve Palincsar]

On 06/04/2015 12:32 PM, Mark Guglielmana wrote:
> Stephen,
>
> Thanks for the detailed reply. It points out that low trail isn't a
> magic bullet for everyone. There's a significant school (cult?) of low
> trail disciples that believe this to be a panacea for everyone. As
> always, YMMV.

To be fair, the handling Stephen describes isn't at all typical of low
trail bicycles, although it may perfectly describe his Soma. Also, I'm
not sure about the "panacea for everyone" part -- usually, it's the
answer to questions like " how do I retain normal-feeling handling while
increasing the width of my tires," and "how do I retain normal handling
while carrying weight up front in a handle bar bag."

>
> I haven't seen any good "first principles" analysis or dynamic
> modeling to be able to quantify handling characteristics. If someone
> reading this knows of any, please post! If not, there's got to be some
> Mech Engr. grad student out there looking for a thesis subject.
>
> Having said that, it works extremely well for me. If we were close to
> the same size and lived close enough to each other, it would be
> interesting to go riding and swap bikes for a bit. Has anyone else
> tried riding your low trail bike? This would help determine if the
> problems you've encountered are inherent to the bike or if its the
> bike/rider dynamic relationship that's the issue?
>
> I remember my first encounter with shimmy. After riding over the
> Golden Gate bridge with a friend on a Ron Cooper, we were flying down
> Alexander Blvd when his handlebars started to shimmy. It got so bad he
> almost crashed before slamming on the rear brake. We stopped at
> Bicycle Odyssey and talked to Tony Tom, he admitted he had no good
> explanation as to why some bikes/riders did this on occassion. I
> mention the shop and the owner to assert his "bona fides", those that
> don't know - Tony has been around a long time, sells a lot of high end
> bikes, was one of the top Ron Cooper dealers in the country, and is
> very C&V knowledgable. If he didn't know the answer, I figured it was
> still a mystery.

And some will say that's not even the sort of "shimmy" people talk about
when they complain that they can't ride their bikes no-hands; that's
"speed wobble." Any bike can do it, the rider is a big part of it
("death grip" or shivering can induce it) and a bike can have it and
then with a few minor changes in rider position, not have it -- as was
the case with my 1972 P15 Paramount.

I recall one mailing list discussion thread with a guy who complained of
shimmy with every single bike he'd ever ridden, including all the major
brand carbon racing bikes; I specifically asked if other riders riding
his bikes had the problem and he said no. And he's the only one I ever
heard complain about shimmy on a Trek Madone.

[Harold Bielstein]

Found this article yesterday on Facebook. Interesting take on low trail, skinny tubed bicycles. Might be interesting to some.
http://www.gonesouthblog.com/new-frame-first-impressions/

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5211 Meadowlark Dr
Rapid City, SD 57702
605-341-0315
hkbie...@rap.midco.net

[Mark Guglielmana]

Good points all. 

Since this is the 650b Group (which has a large intersection with low trail), we should all be open to the fact that there's different strokes for different folks, and that a new take on an old wheel size and geometry may not be for everyone. 

The guy with the shimmy problem only had it on that bike, and had been through maybe a dozen bikes in his life. He used to race, can still do a track stand, and I doubt he had a death grip on the bars-we even discussed his grip that day. 

[Stephen Poole]

Interesting take; maybe 40mm trail is significantly better than 30-ish(?). I don't believe higher trail impedes low speed handling at all, otherwise MTBs wouldn't be able to go uphill.

Later,

Stephen

[Marc Pfister]

On Saturday, June 6, 2015 at 7:31:42 AM UTC-6, satanas wrote:

Interesting take; maybe 40mm trail is significantly better than 30-ish(?). I don't believe higher trail impedes low speed handling at all, otherwise MTBs wouldn't be able to go uphill.

MTBs balance higher trails with wider handlebars. If you look at the change in head angle and bar width over time they actually correlate quite well. I think that's also reflected in the return to narrower drop bars on low trail rando bikes.

Also on MTBs weight distribution comes into play. The trend these days is long front centers and short back ends, which means less weight on the front wheel and therefore less wheel flop at a given trail value.

- Marc 

[satanas]

Yes, on several occasions, but the geometry weren't at all intended for a bar bag. IMO there are things that can be done to improve without resorting to low trail. And these were attached-to-the-bar type bags in any case..

So, yes, but no.

Later,

Stephen

[satanas]

FWIW, I've ridden numerous bikes over the last few decades, having worked in various bike shops and written magazine tests. The bikes with odd handling were very few:

1. 531ST touring bike with low mounted rear bags. This shimmied, due largely to the rear bags "wagging the dog".

2. Various Moulton bikes. These have low trail plus small, light wheels so are not stable in a straight line. They don't shimmy though as the frames and forks are very stiff.

3. Slingshot, with cable as downtube and hinge in headtube. This fitted me perfectly and I expected to like it, based on reviews. In reality handling was vague due to deflection of the head tube over bumps, and a varying head tube angle - in multiple dimensions.  :-) I rode the same loop on my own road bike just after to be sure I wasn't imagining things; I wasn't.

4. A production touring bike with heavy gauge tubing, plenty of trail and *very* heavy 700c wheels and tyres. This had serious wheel flop when climbing; the frame may not have been to spec.

5. The Soma GR

In the same period I've ridden many, many road/touring/MTBs with normal-ish geometry and had no handling issues with any of them, however stiff or not. (Comfort is a different matter.)

For me, shimmy has been a non-issue, apart from #1 above, which handled okay with a normal rear rack and bags. The interesting thing is how many varied bikes all handled basically okay. Of these only a few really pedalled really well, but that's another matter. And then there's ride comfort, another issue again.

Later,

Stephen

[satanas]

On Saturday, 6 June 2015 14:40:45 UTC+1, Marc Pfister wrote:

MTBs balance higher trails with wider handlebars.

Recently yes, in the early 1990s not so much. Very narrow bars were all the go for racing then.

 

If you look at the change in head angle and bar width over time they actually correlate quite well.

Maybe.

 

I think that's also reflected in the return to narrower drop bars on low trail rando bikes.

Dubious IMHO. I think narrow bars are used more by older cyclists (rando bike buyers) as that's what they're used to and like, myself included. 

Also on MTBs weight distribution comes into play. The trend these days is long front centers and short back ends, which means less weight on the front wheel and therefore less wheel flop at a given trail value.

^ Have to think about that one; doesn't immediately make sense to me.

Later,

Stephen

[Guy Washburn]

What size GR do you have?

On Tuesday, June 2, 2015 at 10:11:52 AM UTC-4, satanas wrote:

[Ryan Watson]

> On 2015/06/06, at 8:27, satanas <nsc.e...@gmail.com> wrote:
>
> 3. Slingshot, with cable as downtube and hinge in headtube. This fitted me perfectly and I expected to like it, based on reviews. In reality handling was vague due to deflection of the head tube over bumps, and a varying head tube angle - in multiple dimensions. :-) I rode the same loop on my own road bike just after to be sure I wasn't imagining things; I wasn't.

I rode a slingshot for a bit, a cyclocross model I guess? I had 37mm paselas on it. I didn't notice anything unusual about the handling at all. It definitely planed for me, but once the novelty wore off it didn't really offer a better ride than a nice flexy conventional frame.

Ryan

[Joe Broach]

​

On Tue, Jun 2, 2015 at 7:11 AM, satanas <nsc.e...@gmail.com> wrote:

I'm basically hating the handling of my Soma GR after two months or so. 32mm trail is not enough for me to be comfortable, whatever I'm doing. I might try building a fork with horizontal dropouts to experiment, but have never been unhappy with normal trail handling...

What was it you were looking for from the new low trail geometry, Stephen? Hopefully you can saddle up on a different bike to figure out if the GR's just a lemon or you're just incompatible with LT. For what it's worth, my first low trail experience was on a Nordavinden with similar geometry to the GR (but flexier tubing). I was surprised at how nicely it handled even unloaded. I preferred it to my Romulus for everything except no hands stability. In the end, it was a bit too small for me to keep long term, but it convinced me to experiment further with lower trail bikes. Hope you figure things out and still enjoy your PBP!

Best,

joe broach

pdx or

--

[Alistair Spence]

Have you verified that it is in fact 32mm? I re-raked a fork on one of my bikes to give 27mm or trail and didn't care for it at all. This was back in the days before VBQ's work on the matter that showed us all the light. At that time, I assumed that there was a linear relationship between load carried and trail required. I wanted to carry heavy (up to 40 lbs) front loads so I figured I'd get the trail number really low. It  ended up being skittish and tiring to ride. This was exacerbated by the fact that I was running wide city style bars on the bike. No beuno.

I built an improved version of that bike from scratch with 38mm of trail, and some other tweaks here and there. Night and day. Big improvement in the handling. 

Also, I'd look at how much weight you have over the front wheel ie. chainstay length and front center dimensions and where your c of g is w.r.t the axles. In my experience the pneumatic trail part of the equation especially is influenced by the weight distribution, although obviously the geometric trail is too.

Alistair Spence,

Seattle, WA.

 

On Tue, Jun 2, 2015 at 7:11 AM, satanas <nsc.e...@gmail.com> wrote:

--

[Nick Payne]

I've never noticed anything lacking with the handling of normal trail bikes. We've done extensive amounts of touring on them - both tandems and single bikes - sometimes with *all* the load up front, sometimes with just saddlebags, and had zero problems with the handling whether we were going 7kph up a mountain pass or 100kph down the other side. Here's one photo taken midway through a three week tandem tour of Tasmania. The huge front panniers are home made and mounted on a Bruce Gordon lowrider rack built with 3/8" CrMo tubing:



And here's a photo taken when we were touring Switzerland equipped with just a pair of Carradice saddlebags:

[Mark Guglielmana]

On Saturday, June 6, 2015 at 4:49:55 PM UTC-7, NickP wrote:

I've never noticed anything lacking with the handling of normal trail bikes. We've done extensive amounts of touring on them - both tandems and single bikes - sometimes with *all* the load up front, sometimes with just saddlebags, and had zero problems with the handling whether we were going 7kph up a mountain pass or 100kph down the other side. 

Great pics!

This obviously fits in the "if it ain't broke, don't fix it" category. Who needs low trail and/or 650b is you're happy with what you've got?  

On the other hand, it's nice to have alternatives. 

Hey, who let you in the 650b group anyway?

:-)

[Nick Payne]

I do ride 650b - I just grabbed those old photos to show a point. I have three 650b bikes, and they probably get the majority of my saddle time these days. They're all normal trail as well - a Bleriot and two customs. And I load them up in the same manner as I did the 700c and 27" wheel bikes I used to tour on. Here's the Bleriot about 80% of the way up Mt Hotham while saddlebag touring in the Victorian Alps:

[Steve Palincsar]

--

And that's the totally Rivved-out approach to loading a Rivendell, too.  That's exactly the configuration the bike was designed for.   Just don't try that with a bike with 30-38mm trail.

There is one use case where that amount of trail and that load configuration may come to bite you in the rear end: if that grade in the photo is steep enough for you to be grinding up at 4-5 mph you may find you're constantly correcting the steering to keep it on a straight line, because at low enough speed that design can get unstable and start to zig and zag from side to side by itself, and to keep to a straight line the rider may have to work hard sawing the bars back and forth to keep the bike from veering off on its own.  I've been there, on a green and cream big brother of your Bleriot, the one Tony now owns, and also on an orange-and-cream cousin (with a lot narrower tires).

[Matthew J]

> And that's the totally Rivved-out approach to loading a Rivendell, too.  That's exactly the configuration the bike was designed for.   Just don't try that with a bike with > 30-38mm trail.

Much as I like Rivendells, I went away from them because I prefer most of the weight up front rather than in the back with most of my riding.  

I disagree with comments above that there is no difference in ride and handling with heavy load up front on a mid trail bike.  I've notice a significant difference since going to low trail. 

[Nick Favicchio]

Alright no no and no. I love my Soma GR. Begrudging love, its got a little give but does not plane. However, I feel like it puts everything in a lovely spot.

For the Oregon Outback with 18lbs in a Carradice and 15lbs in a boxy bag and 51mm tires (so 32mm trail) it was BOSS BOSS APPLE SAUCE! I'd ride the same set up again.

I've been riding it with Pari Motos so 29mm trail with almost nothing over the front wheel on forest roads and around town and such and if it only worked with me like the Old Motor Bacon does I'd never need another bike.

But if I go full custom, I think 30-35 range. 73 head tube and 65mm offset seems like the thing.

[satanas]

I'm not convinced that very low speed handling is better with low trail. Seems to be the same - or worse - to me. I am becoming convinced that huge fork offsets mean heavy steering at low speed, whatever the trail.

Re the comments on c of g: no easy way for me to measure or change this, although I am convinced the GR chainstays are at kedt 1cm too short, if only since there's no room for a triple FD plus fenders. Chain angles would be significantly better with 10-20 mm longer stays too.

I agree with Nick P though: normal trail works fine, so why change things and then have to deal with shimmy, more bump steer, etc???

Later,
Stephen

PS: I'm intending to build a few prototypes once home to make sure I understand what's going on.

[Nick Favicchio]

Yea, I can dig it. Why such short chain stays? What's it GET you? What's the advantage? B/c it was fashionable in the early fifties, b/c most bikes before the war had awkwardly long chain stays? I dunno.

The idea that low trail is "better" doesn't make sense to me, but it's different and I have a preference. It makes me happier and the bike more forgettable on long lovely rides. Or so I've convinced myself :).

My Motor Bacon had 40mm or so of trail and I felt the front boxy bag trying to "fall away", sort of drag the front end around. I like the feel of the GR better with regards to weight up front and feel. I think it's trail related.

[Mike Schiller]

It's too bad, Stephen, that your 1st experience on a low trail bike was with the GR.  IMO it's a mediocre version of a low trail bike esp. for your weight.  I think a trail no. around 40-45 works best and longer chain stays ( 440 mm or so) and a lighter tubeset would have given you a much better impression.  

Personally I'll never go back to mid/high trail bikes. The front loading capability, steering geometry and overall ride quality are so much better. I love  the high speed steering and slow speed stability when they are  properly executed.  

~mike

Carlsbad Ca.

[Murray Love]

It's been several years since I last rode a low-trail bike, but I preferred their handling characteristics on balance, even with a moderate saddlebag load (I never used low trail with a front load). On the other hand, I'm perfectly fine with the mid-trail on my Sequoia, though it's more prone to veering than I'd like. And I love the mid-trail handling on my Vitus, with its short wheelbase and steep angles.

The two main reasons I preferred low trail were the following, both related to the lower wheel flop of low-trail geometries:

- Lower sensitivity to steering inputs meant less veering under unintentional steering inputs: crosswinds, bumps, shoulder-checking, or a tired, weaving rider. The flipside of this is the light steering feel and the initially disturbing tendency of the front end to wander without affecting the straight-line trajectory.

- By the same token, the lower sensitivity allowed me to more easily alter my line while cornering, providing a higher level of control.

On the other hand, I experimented with trails between 30-43mm, and found that 30mm was a little too light and wandery. The 40-45mm range seems to provide a good balance of low sensitivity and self-centering.

Murray

Victoria, BC

[Steve Palincsar]

On 06/10/2015 08:57 AM, satanas wrote:
> I'm not convinced that very low speed handling is better with low trail. Seems to be the same - or worse - to me. I am becoming convinced that huge fork offsets mean heavy steering at low speed, whatever the trail.
>

That's just plain contrary to most everyone's experience.

[Murray Love]

I wondered about that too. I mean, it seems to me that the steering "heaviness" on a bicycle is due to the steering input force required to a) overcome high self-centering, and/or b) recover the front end from a "dive" resulting from high wheel flop (which is directly proportional to trail). But both of these effects should be reduced on low-trail bikes.

On the other hand, bikes at low speed can tolerate large steering inputs. And since low-trail bikes have reduced steering sensitivity, it stands to reason that you'd have to move the handlebars more on a low-trail bike to get the same direction change as on a higher-trail bike. Perhaps this additional steering action lends itself to an unstable, wobbly feel.

Murray

Victoria, BC

[Ken Freeman]

For a while at least most 650 fans liked trails in the upper 30s with wide donuts, like the Hetre.  Colleagues and compatriots on "that Granty list" spoke up in favor of low 40s/mid 40s for 700c, with in both wheel types tire width and softness being significant variables.

In one issue, BQ/Jan spoke up about 40's containing the sweet spot for a sample 700c wheel, and 30s containing the sweet spot for 650.

I wonder if in this thread we are all comparing apples with red skin to apples with red skin.

--

Ken Freeman
Ann Arbor, MI USA

[Steve Palincsar]

On 06/11/2015 08:31 AM, Ken Freeman wrote:
> For a while at least most 650 fans liked trails in the upper 30s with
> wide donuts, like the Hetre. Colleagues and compatriots on "that
> Granty list" spoke up in favor of low 40s/mid 40s for 700c, with in
> both wheel types tire width and softness being significant variables.
>
> In one issue, BQ/Jan spoke up about 40's containing the sweet spot for
> a sample 700c wheel, and 30s containing the sweet spot for 650.
>
> I wonder if in this thread we are all comparing apples with red skin
> to apples with red skin.
>

To some extent we are comparing Red Delicious to Macintosh -- taste
preference -- and to some extent, apples with pomegranates. Some prefer
handling on the low end of 30, some on the higher end: purely a matter
of taste, and both can taste good, provided your load is a handlebar bag
with a total load somewhere between 2 or 3 lb on the low and and 10 lb
on the high end. Unloaded, handling can feel WEIRD make you yell out
loud WEIRD.

On the other hand, put over 20 lb load on the front end of such a bike,
trail in the 30s, and you can under some circumstances get the feeling
that steering has "locked up." "Heavy" doesn't begin to describe the
feeling that the bars just do not want to turn at all. Jan wrote a BQ
article about this, and I experienced it on tour in South Dakota, solved
by removing something like 4 lb to the rear bag. Cause, per the BQ
article, insufficient wheel flop to help augment the steering, and the
weight on the front had so much inertia ordinary steering movements just
didn't move the wheel at all.

For such heavier front loads, trail in the 40s worked out better.

Also for riding with or sometimes without any front load -- which,
amazing as it might sound, some people actually want to do -- trail in
the 40s works out better.

[Ken Freeman]

I still haven't found a decent decaleur for my Terraferma, so I haven't ridden it yet with front load.  But it has Hetres, bbdrop around 8 cm and about 35 mm trail and it's not a bad ride at all.  It's fine with about 10 lb of saddlebag load.

[Evan Baird]

It's interesting to hear people's perspectives on this. I've ridden quite a few low trail bikes now, both purpose built and conversions, and I currently own the Rawland Stag, but people's feedback is all over the place. When we were developing the Grand Randonneur we basically copied Rene Herse (Mike Kone's bike). Some people thing it's too stiff (mike/jan) but lots of people complained that it's too flexy. The smaller frames have slightly higher trail due to toe overlap, but with a front load I can't tell the difference. I did find that lightweight tires can contribute to shimmy, but chaning the tire pressue seems to help. I don't know what to make of it, considering it was probably the first low trail bike that many people have ridden, and lots of people used porteur racks and rear racks, which it's not really designed for.

[satanas]

^ It's the first non-Moulton low trail bike I've ridden. IMHO,the BB, forks and seatstays are too stiff, but the top tube and thus headtube is not stiff enough. I will be building a less stiff, lower rake fork on Wednesday, which might solve a few problems; I will report back after it's been ridden a bit.

Later,
Stephen

[Ken Freeman]

Steve, I think you are a lot more sensitive than I am, or experienced.  What symptoms are you seeing that mean the TT is not stiff enough?

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[Stephen Poole]

With front panniers it's possible to feel/see the head tube twisting during tight, low speed turns, I.e., on bike paths. I suspect this is happening at high speed too, and contributing to the shimmy. I've had a couple of other frames that "did the twist" like this in the past. It's not a good thing.

Later,
Stephen

[Evan Baird]

I get the sense that the overwhelming reaction from "normals" when they first try a low trail bike is they either don't notice a difference, or they hate it because it feels twitchy and makes the brakes feel less responsive. The only people who actually like it are nerds who've already convinced themselves that it's what they want (myself included) and know more or less what they can expect with or without a front load. There's a reason why long haul truckers are the most popular touring bike of all time.

[Steve Palincsar]

On 06/23/2015 01:47 PM, Evan Baird wrote:

I get the sense that the overwhelming reaction from "normals" when they first try a low trail bike is they either don't notice a difference, or they hate it because it feels twitchy and makes the brakes feel less responsive. The only people who actually like it are nerds who've already convinced themselves that it's what they want (myself included) and know more or less what they can expect with or without a front load. There's a reason why long haul truckers are the most popular touring bike of all time.

My immediate reaction riding my Kogswell P/R around the bike shop parking lot without a load was to shout something like "Holy Crap!!!" out loud.  It felt amazingly weird and strange.  However, as soon as I put a handlebar bag on the bike, even with next to nothing in it, it felt completely normal, and I really liked the way it steered.

[Stephen Poole]

Well, I've had the GR for some months now, and still don't like the handling at all. I'd probably say I was a nerd, and had an open mind about low trail, but it just doesn't work for me.

Today I found that the frame and fork are out of spec; fork has 74mm offset (measured very carefully on an Anvil fork jig several times) and the head angle is actually 72 degrees, not the 72.5 specced. Trail comes in at close to spec at around 31mm, but is not enough IMO. I was planning an making a new fork today/tomorrow, but now the offset will have to be rethought as I'd like to minimise overlap, and this is now more difficult. The new fork will probably increase trail to about 45mm; hopefully this will be enough to prevent things feeling weird and shimmying.

NB: IME the barbag needs to have 1-2kg in it before it changes handling - then the bike shimmies.  :-(

Later,

Stephen

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[mitch....@gmail.com]

On Monday, June 1, 2015 at 6:16:05 PM UTC-6, joe b. in portland wrote:

I haven't kept track of the most recent models, but past Rivs including my Romulus almost always hit right around 60mm, or the low end of "high" trail. 

 

Bridgstone made very nice mid-trail bikes but I agree that Rivs seem to all be high trail.

 

I also see the break-over from mid-trail to high trail is around 60mm. (Like Steve says, this varies by tire size so my observation is based on narrower tire and applies to 23-32mm tires.)

Low trail is 45mm and below where a bike becomes noticeably less sensitive to weight shifts and it's easier to ride straight going slowly. Also at 45mm the bike likes a front load.

 

Above 45mm a bike starts to flop around a bit with a front load, and you're in mid-trail territory till you get to 60mm. A vast number of sporty road bikes are delivered with a 56mm trail and they're thought of as responsive because they go off-line easily. You can turn them with the slightest weight shift. At speed they feel very stable but you can still initiate a turn very easily by weight shift. At slow speeds you have to keep your body movements calm or a mid-trail bike wanders around responding to small weight shifts. You can ride a mid-trail bike straight as you want (I do) but you have to pay more attention to it than to a low trail bike.

 

Above 60mm you start to get high trail characteristics where a bike resists turning, even with weight shifts, even with pulling on the bars, and this increases the faster you go. This is why mtbs were always fine with high trail--at speed descending on dirt you wanted as much stability and resistence to the wheel being knocked off it's course as you can get, but then at the noodling slow speeds of much trail riding you could turn just fine, especially with the wider bars mtbs developed with.

 

This high-trail characteristic of resisting going off-line can feel stable (Murray may have a better term for this and I hate to call it stable because so many very different cycle traits are described as "stable"). This is why almost all turning you do on a motorcycle (all very high trail) is initiated with counter-steering. You almost can't turn a motorcycle without countersteering, so stable is it on its line, and I've ridden a few high trail bicycles that need counter steering to initiate turning. It's almost never necessary for mid-trail which responds so quickly to weight shift (over-responds some would say) but can still be useful deep in a sweeping turn if you have to change your line.

 

This stability also means high-trail bikes are ok with front loads because even if there's a lot of geometric wheel flop, the stability is so high that it prevents the bag's weight from flopping the front end around like it does on mid-trail.

 

45mm for a traditional road bike is a sweet spot because it feels as "responsive" "easy-to-turn" as a mid-trail race bike and doesn't feel vague without a front weight like some lower trail bikes can. But it will ride straighter and easier on the climb than a 56mm trail race bike and it will carry a loaded front bag neutrally with no bad behaviors. If I were still wanting to ride 700C road wheels I'd prefer a 45mm trail bike every time because there is nothing it doesn't do well.

 

But I prefer to riide supple 42mm tires now, so I'm learning to re-adjust my perception of this to what Steve and Murray described.

 

This is all what I've observed from riding actual bikes and I've ridden a quality 45mm trail road bike since 1976 and quality mid-trail 56mm bikes since the early 80s. I like them both equally but the 45mm trail just doesn't have any drawbacks. I like high trail too but mostly for motorcycles or mountain bikes. (Track bikes have high trail too and I don't undestand why they feel just like mid-trail bikes on the track, even as they measure out at 68mm.)

 

I've done a couple mid-trail conversions and have one 56mm mid-trail bike that is a joy to ride with Babyshoe Pass tires. Wierdly it even is fine with a 10 lb front load in a GB bag set up low over the front wheels and close to the head tube. I've noticed though that on fast descents it feels different transitioning from turn to turn than the same bike does with 26mm 700C tires, and isn't as comfortable leaning over into a higher speed turns with 42mm tires as my 45mm trail bike is (and 45mm is still fairly high trail for 42mm tires). This may be an example of why low trail complements wider tires as has been suggested. It may that 35mm trail and 42mm tires descends the way 56mm trail bikes do with 23mm tires, but with all the extra grip of the wider tire. Many people report that their fastest descending bikes are built around 42mm tires and I bet that has something to do with the trail being optimized for the 42mm tires as well as the grip and margin the wider tires provide.

 

--Mitch

 

 

[Evan Baird]

Do you have any thoughts on the affect of head tube angle given the same geometric trail? I have some ideas based on my experience, but I dont have a large enough sample pool to say definitivly what Ive observed.

[mitch....@gmail.com]

On Thursday, July 2, 2015 at 4:25:43 PM UTC-6, Evan Baird wrote:

Do you have any thoughts on the affect of head tube angle given the same geometric trail? I have some ideas based on my experience, but I dont have a large enough sample pool to say definitivly what Ive observed.

Playing around with Jim G's trail calculator, you can see that comparing the same trail, the steeper head angle results in slightly less geometrical flop. For example it shows that for a 33mm trail bike that uses a 72 deg head angle with 73mm of rake flop=10, while for a 33mm trail bike that uses a 74 deg head angle and 61mm of rake flop =9. I doubt I'd feel that difference. But I wonder what the difference between 73mm and 61mm of rake feels like. 

--Mitch

[Evan Baird]

I think the relationship between wheel flop and trail is pretty well understood, however Im trying to get a better understanding of how the position of the bag in relation to the tires contact patch affects steering with or without front panniers. I dont see very many people wanting a dedicated brevet bike at Soma's price point. Lets face it, that type of shit is for people with money to burn. However a bike that can handle loaded touring, unloaded rides after the gear gets dropped off as well as light trail duty is much broader. The issue with most of the super light custom rando bikes Ive seen is theyre really not speced for any real offroad riding. Anybody who's taking those on single track better have some really good dental insurance.

[Mark Guglielmana]

It all gets down to what type of riding one does. Just because I don't ride single track doesn't mean I don't/won't ride dirt roads. My low trail bike with a handlebar bag (yes, call it a rando bike if you want) gets me where I want to go with comfort, and is optimized for the type of riding I do. And I can get that type of bike by modifying a 70's-80's steel bike without burning through a lot of cash. It works well as a credit-card tourer as well. Loaded "expedition" touring with tent, bag, etc., panniers front and rear? It could do that, but I'd rather have a mid-trail, stouter frame. It won't ride better than my theoretical "modified" bike when I drop the gear off, however. Real offroad riding requires (for most) ~2" tires, not many frames can handle that, but we're starting to see frame builders design around that paradigm. An old, steel MTB can be used to create something like that, but it sure as heck ain't optimized for fast road use. 

So there is no single "one size fits all" bike that excels at all types of riding. If you want to ride single track one day, do a brevet the next, and go on a long expedition tour for a few weeks later on, a single bike could do it-heck, any bike could theoretically do it, but each type of riding suggests an optimal type of bike, I would think.

On Fri, Jul 3, 2015 at 9:04 AM, Evan Baird <vanst...@gmail.com> wrote:

I think the relationship between wheel flop and trail is pretty well understood, however Im trying to get a better understanding of how the position of the bag in relation to the tires contact patch affects steering with or without front panniers. I dont see very many people wanting a dedicated brevet bike at Soma's price point. Lets face it, that type of shit is for people with money to burn. However a bike that can handle loaded touring, unloaded rides after the gear gets dropped off as well as light trail duty is much broader. The issue with most of the super light custom rando bikes Ive seen is theyre really not speced for any real offroad riding. Anybody who's taking those on single track better have some really good dental insurance.

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[Ryan Watson]

> On 2015/07/03, at 10:29, Mark Guglielmana <mark.gug...@gmail.com> wrote:
>
> The issue with most of the super light custom rando bikes Ive seen is theyre really not speced for any real offroad riding. Anybody who's taking those on single track better have some really good dental insurance.

The Rawland rSogn is a nice exception. While not "super light" in terms of weight, it's a much livelier ride than any of the super light bikes I've ridden and can take huge knobby tires when you want to hit the trails. (I'm taking mine up to the San Juan mountains in Colorado in a couple days, WooHoo!)
Rumor is that a new version is in the works.

Ryan

[Ed Braley]

Yes, it really does come down to what type of riding you plan to do.

 

The thread in this dialog reminds me of a conversation I had a while back with one of the LBS guys. They'd just built a Soma GR for one of their customers - full rando rig; fenders, dynamo hub, lights, rack bag, etc. I rode in on my Pacer with the carbon fork. The Pacer didn't fit the mold. it's not a rando bike, not low trail, no bag, no lights.  So why did I make it 650B? Because I can go places on the 650x38B setup that I wouldn't ride on tires that fit 700C wheels in that frame. And it still felt like a Pacer sport touring bike.

 

I told the guy to look at all the 700C bikes on the shop floor; carbon Di2 race bikes, aluminum cyclocross bikes, steel single speeders, hybrids, etc. They're all different, but they're all 700C, right?

 

Most of us on this list started on 650B bikes modeled after the classic randonneuring bikes, but 650B wheeled bicycles can and should be as diverse as bikes on 700C wheels. It's all good!

 

 

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[WMdeR]

>The issue with most of the super light custom rando bikes Ive seen is theyre really not speced for any real offroad riding. Anybody who's taking those on single track better have >some really good dental insurance.

Dear Evan,

It isn't like superlight frames just fold up offroad if ridden with a bit of care. I rode my all-standard-diameter, all-7/4, superlight fork Allroad for three years as my mountain bike. Now, I'm not hucking big drops on it or anything, but it did fine--once I pulled the fenders.

I did find that fenders were a pain for true offroad (bang the front on enough rock drop offs, and it'll eventually crack; fly through a slash pile and pick up a big enough stick, and the front fenders fold and yard sales happen, etc), and that a superlight fork is probably not crash-durable enough even for my relatively tame usage, but the frame has been fine. I had to set the fork after a friend got caught in a rut at high speed and flew off of the bike--a third fender, now that I think of it--but the frame was as true as it was from Waterford when I unboxed it. I eventually wanted to raise the handlebars to level with the saddle (descents on 2 1/2" of drop were a bit disturbing--no brakes on the tops..), and, rather than swap the bike 'round once a week, I ended up getting Kelpie to put together a dedicated offroad machine.

The V-brakes and 55mm tires are an improvement. I can't say the difference is transformative to my riding.

Best Regards,

Will

William M. deRosset

Fort Collins, CO

[mitch....@gmail.com]

On Friday, July 3, 2015 at 5:24:09 PM UTC-6, WMdeR wrote:

>The issue with most of the super light custom rando bikes Ive seen is theyre really not speced for any real offroad riding. Anybody who's taking those on single track better have >some really good dental insurance.

Dear Evan,

It isn't like superlight frames just fold up offroad if ridden with a bit of care. I rode my all-standard-diameter, all-7/4, superlight fork Allroad for three years as my mountain bike. Now, I'm not hucking big drops on it or anything, but it did fine--once I pulled the fenders.

I did find that fenders were a pain for true offroad (bang the front on enough rock drop offs, and it'll eventually crack; fly through a slash pile and pick up a big enough stick, and the front fenders fold and yard sales happen, etc), and that a superlight fork is probably not crash-durable enough even for my relatively tame usage, but the frame has been fine. I had to set the fork after a friend got caught in a rut at high speed and flew off of the bike--a third fender, now that I think of it--but the frame was as true as it was from Waterford when I unboxed it. I eventually wanted to raise the handlebars to level with the saddle (descents on 2 1/2" of drop were a bit disturbing--no brakes on the tops..), and, rather than swap the bike 'round once a week, I ended up getting Kelpie to put together a dedicated offroad machine.

The V-brakes and 55mm tires are an improvement. I can't say the difference is transformative to my riding.

For the dedicated off-road machine, what changes did you make besides higher bars? Low trail or high trail? Did you size down for more stand over? I think this is related to what Evan was asking, if you have a "rando" bike that works almost just fine for offroad and then you make an offroad bike to get all the way there, what does that look like. Ravn is one answer. Jones is another.  

[Murray Love]

I thought this question was interesting enough to whip up a quick CAD drawing to see what it looks like when you vary the HTA while holding trail constant. 

In the center is a fairly standard 73° HTA/50 mm offset front end, flanked by two extreme cases. All have Trail (T) = 50.4 mm.

Clearly, there's a huge difference in wheel flop (F) between the three configurations. As the HTA slackens, more steering input will go into rolling the wheel from side to side, and less into yawing--and I assume yawing of the wheel at the contact patch is the primary method of changing direction, whether through steering or countersteering. Conversely, at the very steep HTA, most steering input is yaw with very little roll.

How would this work out in the real world? I expect the very shallow HTA would cause the wheel to dive from side to side at the slightest twitch of the bars, but without causing much change in direction. On such a bike, the rider would be constantly engaged in a wrestling match with the front end in order to keep it upright. The turning radius would be large.

On the steep front end, it seems that even very small steering inputs would cause a change in direction. On such a bike, maintaining a straight line would require constant vigilance and small adjustments, but with little effort. The turning radius would be small.

At least I think that's how it would go. I do prefer HTAs toward the steeper end of the normal spectrum because of the sharper, more responsive steering, and I now avoid bikes with 72° or below. But the analysis above is all just intuition.

Murray

Victoria, BC

--

[Brad]

Excellent point. 
A 650B conversion allows for what an LBS owner described when he road my bike as "a high tech comfort bike."  If you are not into a guidon front bag then low trail is not critical.
If you need bigger tires for
- a bigger person
- roads that gobble 700 x 28 into cracks
- occasional gravel or off pavement
- or just to be different
then go for it.

Mudguards aka fenders similarly are not necessary if you live where it doesn't rain, or you don't care if you get covered by mud.

Racks are not necessary if you never haul anything you cannot put in a jersey pocket or a tiny pouch under your seat.

[WMdeR]

>For the dedicated off-road machine, what changes did you make besides higher bars? 

Dear Mitch,

Not sure if this fits readily in this thread, but:

It was a totally different design, one done in concert with Kelpie Cycles (Colin Pinney) as a trial for drop-bar mountain bikes. We were kicking around ideas for a 650B mountain bike, and we did a bit of design by committee.

Colin is pretty comfortable in the Colorado ss 29er tradition, and builds a mean "Don bike". He also does an integrated machine built around 50mm tires (29er or 650B depending on frame size) which was rooted in his (extended) experiences with my Boulder Bicycle Allroad machines, and that bike does its job well.

This wasn't either of those design patterns. It turns out I ended up pretty close to "norba" geometry, though closer to Charlie Cunningham's front ends (i.e. more rake, steeper head angle).

I should note that the mountain bike is intended primarily for off-road use and very limited time on roads. This one doesn't climb really well for me on the road when geared (8/5 oversized tubes + pretty stout rear end+ 55mm knobbies @18psi = slug on pavement). I'm the princess with the pea on paved climbs. On the other hand, I find moderate to fairly dramatic differences in tube spec are just not noticeable offroad (uphill, anyway; and once the main triangle doesn't noticeably flex on switchbacks it is "stiff enough" as far as I'm concerned). 

It has a sloping top tube, designed around heavier O/S tubes (This bike was built in part around what was cheap in Nova Supply's catalog. It has been a learning tool for both of us--a proof of concept, after all. I have successfully dented it--heat treated top tubes are indicated for production).  

I'm planning to do a second iteration once a slot opens up in Colin's queue. That'll have 

1. a heat-treated top tube, probably in a lighter gauge (though still O/S); 

2. a bit less rake/more trail. The bike rides beautifully with 2lb on the front, but feels a bit too light at low speed without a load, and I turn out to really like a touch heavier steering offroad);

3. probably a heavier-gauge fork. That's just FUD so far. The bike really does soak up shock offroad well for an unsuspended machine, but the fork deflects, a lot, on dropoffs, and it disturbs my off-road designer friends;

4. a shorter top tube (the current design has a looong top tube, and fits me best with straight bars. I have found I still prefer dirt drops;

5. I may go to a slightly shorter chainstay length, which would probably necessitate a curved seat tube for a design 60mm tire;

6. I don't know yet whether I'd do another horizontal dropout machine (versatility raises its head, and has been successful so far on this one) or admit I really want gears (vertical drops). I'd definitely go with a 1X10 if geared; and

7. Paint. This one is a true test mule, built inexpensively to try out ideas, but the mad-max chic of an unpainted or clear-coated frame doesn't really appeal to me.

I find having a only single gear pretty limiting so far for OYB riding, as I've got ten miles of being hugely undergeared before I get to the trailheads, but I worry less about killing a derailleur/dropout on rocks, and the lack of chain slap has been nice. 

Best Regards,

Will

William M. deRosset

Fort Collins, CO

[Stephen Poole]

On 5 Jul 2015 03:15, "WMdeR" <wmder...@gmail.com> wrote:
>
> >For the dedicated off-road machine, what changes did you make besides higher bars? 

> 3. probably a heavier-gauge fork. That's just FUD so far. The bike really does soak up shock offroad well for an unsuspended machine, but the fork deflects, a lot, on dropoffs, and it disturbs my off-road designer friends;

^Agree it's FUD! Have plenty of offroad miles on light gauge road forks with no problems so far. Some people just cannot stand visible flex, but I quite like it.

> 4. a shorter top tube (the current design has a looong top tube, and fits me best with straight bars. I have found I still prefer dirt drops;

Will, what drop bars do you use on road and off road, and how much difference in reach and bar height? Thanks.

> 6. I don't know yet whether I'd do another horizontal dropout machine (versatility raises its head, and has been successful so far on this one) or admit I really want gears (vertical drops). I'd definitely go with a 1X10 if geared;

Why not 1*11 with XT? None of the bits are too horribly expensive, and one doesn't have to use the ones less suitable (cranks?).

>
> I find having a only single gear pretty limiting so far for OYB riding, as I've got ten miles of being hugely undergeared before I get to the trailheads, but I worry less about killing a derailleur/dropout on rocks, and the lack of chain slap has been nice.

FWIW, I agree re chain slap, and have recently built a 650b+ Rohloff frame. Won't be able to test before October, but hopefully it will work.

Later,
Stephen