Tell me why converting my Cannondale Super X is a good/bad idea

[Andrew Cohen]

Hi all,

I have this 2015 Cannondale Super X (size 56).  It is a fine bike that can take a beating.  Has disc brakes.  I sort of hate the front end handling as it has what I think are typical high trail/lots of flop handling at low-mid speeds (trail is 61/flop is 18 mm with 35mm tires).  Turns are hard to initiate, and then when turned the bike dives into the turn. Annoying.

From using an online calculator, it looks like if I just put 650b wheels on it with 38mm tires (the biggest that look like they will fit), the trail comes down to 56, flop at 16, which I think is pretty typical for a regular modern road bike and would help the issues I describe above.  Looks like the wheel radius would be 334 with the 650b versus 350 now, not sure that the 1.6 cm lower bottom bracket would be an issue or not.  I mostly ride this bike on gravel roads and pavement.

I'm no expert at this stuff, so any comments on the above would be welcome.

[Rick Johnson]

The good news is that as a cross bike it was designed with a higher bottom bracket to begin with. Comparing my own size frames (for which I have the data handy) Cannondale raised the BB height 11mm above that of the SuperSix and Synapse models (which are more road focused).
So, depending on your preference of crank length you might be just fine there.

I'd suggest you take a closer look at tire options and fitment. Personally 38mm (true size) is the least I would consider as acceptable for any use on soft surfaces. But I am a 58 frame size rider, therefore probably heavier, and live where loose sandy conditions are the norm. YMMV.

Rick

Rick Johnson
Bend, Oregon

--
You received this message because you are subscribed to the Google Groups "650b" group.
To unsubscribe from this group and stop receiving emails from it, send an email to 650b+uns...@googlegroups.com.
To post to this group, send email to 65...@googlegroups.com.
Visit this group at https://groups.google.com/group/650b.
For more options, visit https://groups.google.com/d/optout.

[Andrew Cohen]

Thanks Rick.  It has 175 cranks on now, and I am indifferent between those and 172.5 and could likley go to 170 happily, so that is good.  I have been riding 35s pretty happily on my terrain, so 38s should be good for me.  I don't think I could go any bigger in back if I wanted to, but I could probably do at least a 42 in front.

[HillDancer]

According to the spec I see when googled, size 56 has a 72.5 HTA, 45 fork offset, with 700X35 trail is 63, 650bX38 is 58 trail.  BB drop for all sizes is 67.  If a 42 is placed up front with 38 rear, HTA slackens, which increases trail. 

It would help to have details about the current tire.  If the current tire has side knobs, just changing to a domed crown tire will change steering feel. 

Hate is a strong word, if that's how negative you feel about current handling, sounds like more than a change in wheel size would satisfy.  Perhaps a wider handlebar and different turning technique might be worthwhile.

[mitch....@gmail.com]

I'm not sure how much difference you'll feel changing from 18 flop to 16. The change in trail is more noticeable--I readily notice the difference between 61 and 56mm trail when the tires,wheel diameter and head angle are the same. Depending on how the 38s actually ride compared to the 35mm tires, you may pick up just enough pneumatic trail with soft supple 38s to even out the difference in trail and not feel much overall change in handling, even if you prefer the extra cush of wider softer tires. 

My perspective is different from some on the forum since I enjoy mid-trail bikes as well as low-trail. I'm not a fan of high trail bikes on pavement and that's why I notice that 61 vs 56 trail change. 60mm trail on a typical 73 deg head angle is when I start noticing high trail behaviors I don't like--mainly over-stable and resistant to turns and tendency to dive into turns once initiated, as you noted. The resistance to turn initiation in high trail geometry can easily be overcome with counter-steering but I prefer a bike that arcs a turn without needing counter-steering. I find typical mid-trail bikes (about 56mm) with narrow tires and low trail bikes (45mm and under) with wider tires both arc turns without any need for counter steering and no difficulty initiating the turn. The thing many don't like about mid-tail bikes is they have a lot of flop like high trail so they wander at low speed if you don't focus a bit on riding straight. That's because they react, or over-react depending on your perspective, to small weight shifts. If you're used to nice mid-trail bikes and like that feel then you probably describe it as responsive because it's always ready to turn. If you don't like that feel, or if you're new to it and find a floppy-steering bike hard to ride at low speed, you might describe mid-trail as squirrelly. Both perspectives seem valid to me, but personally I find mid-trail bikes easy to ride and descend at speed but do require more attention at slow speed. 

You probably already know all about the traits of low, high, and mid trail.

I converted a favorite mid-trail bike (56mm with 25mm tires, 73 head angle) to 584-42mm BSP EL tires and loved the ride. The outer wheel diameter stayed almost identical so it was a lesson for me on pneumatic trail which I had only known in abstract before. With 25mm tires this bike easily initiates turns and never needs counter-steering unless I have to change line significantly mid-arc. But with the same trail figure and same flop figure with 42mm tires this bike needs counter steering to initiate arced turns at speed and needs small counter-steering input all through the turn to maintain the arc. My conclusion was enough pneumatic trail had been added by tire width that it now acted like a high trail bike even with just 56mm trail. Someone who knows this topic more may have a different take. For anyone who likes mid-trail (and the vast majority of performance bikes are designed for mid-trail) it's worth considering that narrow tires work better with mid-trail (in my opinion). I hope that the big makers who are now making wider tire performance bikes decide to adjust trail down from 56 to 45 at least. 

By comparison my best bike has 30 or 31mm trail with a 73 head angle and with the same BSP EL tires it arcs through the same turns at speed with no perceptible need to initiate the turn other than leaning over--so easy and smooth and no counter-steering input needed. 

--Mitch. Nothing wrong with counter steering but I consider it coping with something not ideal. Unless riding a motorcycle and then it's how all motorbikes initiate all turns. 

[Max]

Have you tried, say, a 28 mm tire on a shallow (classic) profile rim?.. In my experience, a combo like that can feel as nice on rough roads / dirt paths as a 650b x 35 or 38 mm combo, and the steering might get closer in feel to where you'd like it.

[Andrew Cohen]

Thanks for the input Mitch, my experience mirrors yours.  It seems like I might like the poster below's suggestion to try this bike with some narrower tires, or, in the best world, try it with some 650b wheels an dnarrower tires like 32s or 35s to minimize the pneumatic trail.  

[Andrew Cohen]

Hi HillDancer,

Current tires are 35mm Compass Bon Jon pass, run tubeless.  OK, maybe I don't "hate" the front end handling, it is more like "pretty annoying".  It sounds like maybe 650bX32 or 35 might be a good place to go with this bike as an experiment.

[J-D Bamford]

My 2-cents is that spending much money on a bike with "pretty annoying" traits only means you're not saving that money for a more suitable bike for your preferences. I totally know how doing just one more thing to a bike in the stable is always less painful than considering a new ride. I've done it more times than I care to admit. But in retrospect, it's nearly always a waste of money...

[Jim Bronson]

I agree with this post that it would be hard to fix all your handling quibbles with a change to 650b.  A new or new to you bike may be what's needed.

It becomes a more worthwhile experiment if you can borrow a wheelset, or if you'll reuse the wheels on a different bike if it doesn't work out.

Or if you just have excess money burning a hole in your pocket ;)

[Andrew Cohen]

These are words of wisdom, thanks for the input.  I only have one bike i've gone down anything like this path before on (less drastic upgrades) and I don't like it much better than where it started.

[Andrew Cohen]

I don't know anyone else even remotely interested in 650b, so no borrowing in my future.  I did just get a custom dream rando type bike that is 650b (Shimano discs), so a 2nd set of wheels wouldn't be the worst thing to have around.  That said, I am not in a hburry to spend $$ on wheels that may be used quite infrequently.

Still, the smart thing is probably just to keep riding my custom and see how things shake out.  I think the only time I would likely choose this cross bike (even with improved wheels or a fork switchout for better geometry) over my rando machine would be events (like a gravel race I am doing this weekend in Michigan) that will involve potentially severe bike abuse in transport and at the event.  In other words, I like having a beater when necessary, but I'm not sure how often that will be.  Could end up being 2x/year, could end up being 15X/year depending on how often I end up traveling for work stuff.  

All the input is appreciated!

[J-D Bamford]

I think I see where you're at here. You've got a pretty nice (on paper) recent vintage Cannondale cross bike that would appeal to the typical roadie/cx guy. Since you bought it new, or perhaps nearly so, it felt somewhat expensive, and you want to stay committed to it. But you just got a "dream" custom randonneur, which in comparison makes it easy to spot the weaknesses of the CX. If that's the case, it's somewhat analogous to my situation. It took me 4-5 years to admit to myself that my previous nice bike just didn't meet my needs once my truly nice, custom bike was in hand. You're at a good milestone to challenge yourself about whether that CX is really any good to you at all.

Perhaps you'd be better off selling that CX for whatever you can get, and building up a beater/travel bike for the purposes you described. Build yourself a "mule", in Bicycle Quarterly parlance. I bought a used VO Polyvalent frame here a year or so ago - it started as a singlespeed city bike (flat bars, 650b x 38) and is about to morph into a road/hooligan bike (drop bars, 650b x 48 Compass tires, perhaps 1x drivetrain if not SS). The used frame was relatively cheap, but solid quality and reputation. While it rides smooth and stable like a champ, I have no hesitation abusing it and wouldn't have any qualms about airline travel or heavy gravel riding duty...

[Ryan Watson]

> On 2016/04/13, at 6:27, Andrew Cohen <dogr...@gmail.com> wrote:
>
> I don't know anyone else even remotely interested in 650b, so no borrowing in my future.

You might be surprised. A guy I work with, previously not even a cyclist, recently showed me his new bike. He just went to a local shop, tested a few and picked one. It just a low-end MTB/hybrid looking bike with flat bars, but the darn thing is 650B!
Things sure have changed :-)

Ryan (currently riding 650A in Tokyo :-)

[desmond...@gmail.com]

Yes, buy a new bike done correctly.

Sent from my iPhone

[DanielYorbaLinda]

Heck, even Walmart bikes can be had in 650B now!

This is a sub $250 Mongoose. There's some 650B bikes for as low as $120.

This sweet, sweet cruiser is even belt drive and 650B:

I'm crying...but I don't know if I'm happy or sad.

Daniel

PDX

[Jan Heine]

I remember when the detractors of 650B said that you wouldn't be able to buy tires for your bike at Walmart, if you destroyed a tire on a tour. They underestimated the power of a good idea!

More seriously, the tire argument is pretty flawed for my riding. If I slice a tire at the top of Babyshoe Pass at 3 a.m., it doesn't matter which size it is. If I don't carry a spare, I'll have to fix it myself. In fact, my routes are carefully planned to avoid places with Walmarts and similar stores.

Jan Heine

Editor

Bicycle Quarterly

www.bikequarterly.com

[Andrew Cohen]

Hi all, again thanks for the input.  Update: I decided to get a 2nd set of 650b wheels built.  I will try them out on the Cannondale cross bike.  If I don't like that setup any better than the Cannondale with 700c, it will be an easy bike to sell and I'll still have the 650b wheels for N+1, plus to use as spares for my main bike.  For the community benefit, I'll post impression of changes to the cannondale's ride when I get the wheels and have some time on the setup.

On Saturday, April 9, 2016 at 11:18:00 AM UTC-5, Andrew Cohen wrote:

[Andrew Cohen]

To revisit this thread:  I got the wheels a couple months ago and have a number of good rides on the conversion.  I'm using the 38mm Compass extralight Loup Loup Pass tires.

The wheels are rock solid - some Giant-branded 27.5 mtb XC rims laced to White Indus CLD hubs.  I'm really happy with them.

Mounting the tires is pretty hard, the bead is TIGHT on these rims and takes some muscle with a lever to get on there.  Easy to destroy tubes in the process, but I'm getting better at it.  Got some Schwalbe G1 in 40mm on order because I want tubeless and I'm not willing to run a non-tubeless tire like the LLPs without a tube.  My dream setup would be the Compass Babyshoes with a tubeless rated bead (unexpectedly, it seems that I could clear 42s comfortably due to the way the smaller rim pulls the wides part of the tire back a bit on the stays).

The difference to the 700c setup is pretty significant.  The 650b wheels definitely have calmed down the "high trail, high flop" feeling I was looking to get away from.  It turns much more evenly and "road-bikey" now, much more predictable and no more 50-pencing around fast corners on the pavement.  Haven't had any issues with more pedal strike (as anticipated)  on the road or on XC mtb trails and dirt roads.  I also am now using a Revelate tangle frame bag which is great and doesn't seem to alter the handling of the bike at all, even when stuffed with stuff.

What a success!

On Saturday, April 9, 2016 at 11:18:00 AM UTC-5, Andrew Cohen wrote:

[Greg Achtem]

Pictures are always encouraged. Glad you found a good, and comfortable solution.

What is 50-pencing?

[Andrew Cohen]

"50-pencing" is an old motorcycle racing term meaning to make multiple course corrections in a corner when the bike falls in too fast and you have to stand it up repeatedly to correct.  I guess that the old 50-pence piece in the UK had cuts in its circumference to give it texture, hence the name.

Hope pic comes through.  Doesn't look that different from a 700c with a moderately large tire!

[url=https://flic.kr/p/HZUKyo][img]https://c3.staticflickr.com/8/7287/27565960114_586195e079_b.jpg[/img][/url][url=https://flic.kr/p/HZUKyo]Untitled[/url] by [url=https://www.flickr.com/photos/141839770@N04/]Andrew Cohen[/url], on Flickr

On Saturday, April 9, 2016 at 11:18:00 AM UTC-5, Andrew Cohen wrote:

[mitch....@gmail.com]

On Tuesday, July 19, 2016 at 1:41:07 PM UTC-6, Andrew Cohen wrote:

"50-pencing" is an old motorcycle racing term meaning to make multiple course corrections in a corner when the bike falls in too fast and you have to stand it up repeatedly to correct.  I guess that the old 50-pence piece in the UK had cuts in its circumference to give it texture, hence the name.

Glad you had a good result. It's great when a conversion not only lets you explore a different wheel/tire option but also makes a known bike better.

Love the term 50-pencing. I wonder if that is what I described in my post way back in this thread where on a conversion I found I had to do multiple counter-steering corrections throughout a fast turn? It may not be what you're describing but what I'm thinking of is where the bike repeatedly stands up in the turn and I counter-steer to lay it back down into the turn again, and again. 

Usually a motorbike falls into the turn after only one initial counter-steer to start the turn, and you stop noticing those after you get used to it. Same with high trail road bikes in my experience--I have to initiate a fast road sweeper with a counter-steer. But not on mid- or low trail bikes. They only need one if you have to significantly change your radius mid-turn. 

--Mitch 

[satanas]

This has been a really interesting thread, and Mitch's comments have been very thought provoking. I haven't really noticed any difference between 55 & 61 mm trail on road bikes with 23-622, and 72-74° head angles (with similar trail) all feel about the same to me too. Still, I'm coming to the conclusion that I don't much like very low trail (<45mm), or lots of fork offset.

To me, both of these things impact handling negatively. Low trail feels twitchy/iffy/too sudden to me and I didn't find adjustment took place; for me theres was no advantage at any speed or with any load condition, low speed climbing included.

More offset helps the fork to flex more - and to reduce trail if that's desired - but IME *less* offset helps steering with front panniers at low speed as one has more leverage that way. It also seems that having more offset and less trail makes it easier for the bike to "bend in the middle" at the headset, between the tyre contact patches, particularly with anything behind the rear axle or attached to the frame in front of the head tube.

Re pneumatic trail, I'm inclined to think the effect is fairly small, though detectable. For me, 28-451 with ~63mm trail feels much the same as 23-622 with 55-61mm trail, with 42-584 and 46mm trail a bit less directionally stable, but not by much. With 42-584, 31mm trail and 74mm offset things get ugly though, IMHO.

There are way too many variables to be able to wrap one's head around all this easily, plus people's ideas of what is good or bad vary massively too, as with food, fashion, music, etc. If there's time I'll try to build a few frames and/or forks so I can figure out what suits me; that appears to be different to what many others have reported here.

Later,
Stephen

[Mike Klaas]

satanas, I think I end up in the same camp as you after ~8 months on my first low-trail bike (Boulder All-Road, 2.89cm trail).  It's subtle, but I find it takes noticeably more concentration to keep the bike going where I want it to go.  I also feel "resistance" from the bike to leaning over going into sharper turns.  As a result, I tend to bike more conservatively—slower in descents; more space between my wheel and the edge of the road.

Perhaps slightly larger tires to increase pneumatic trail would help (currently running 38mm).  It might be that low-trail just isn't for me.  (650b wheels/tires OTOH, are very much for me.  My next bike will almost certainly be 650b and mid-trail).

-Mike

[Steve Palincsar]

On 07/20/2016 03:13 PM, Mike Klaas wrote:
> satanas, I think I end up in the same camp as you after ~8 months on
> my first low-trail bike (Boulder All-Road, 2.89cm trail). It's
> subtle, but I find it takes noticeably more concentration to keep the
> bike going where I want it to go.

Not me. I have three, and I've been riding them for years now, and many
tens of thousands of miles and I absolutely don't see any of this.

[Stephen Poole]

On 21 Jul 2016 5:13 am, "Mike Klaas" <mike....@gmail.com> wrote:
>
>It's subtle, but I find it takes noticeably more concentration to keep the bike going where I want it to go.  

Totally agree except I'd say really obvious, not subtle at all. For me that was a major problem when drafting others on group rides; on a normal road bike I've never had issues here.

> I also feel "resistance" from the bike to leaning over going into sharper turns.  As a result, I tend to bike more conservatively—slower in descents; more space between my wheel and the edge of the road.

Hmm, my problem was more that leaning and turning, once started happened more suddenly than I was comfortable with. Perhaps this comes down to a) how you like the bike to handle and/or b) how you typically initiate turns. My biggest problem on descents was shimmy, which I detest; some say it's easy to control(!) but I don't want any shimmy tendencies, ever.

> Perhaps slightly larger tires to increase pneumatic trail would help (currently running 38mm).  It might be that low-trail just isn't for me.  (650b wheels/tires OTOH, are very much for me.  My next bike will almost certainly be 650b and mid trail.

I'm heading in a similar direction, but "mid trail" and similar terms seem to have different numbers attached, depending on who's talking. I currently have a frame with (actual, accurately measured) 72° head angle, and have ridden it 1000s of km with each of two forks, one with 74mm offset (31mm trail), the other with 60mm offset (46mm trail). Effective fork length is the same; head angle does not change. The 60mm fork is also a bit lighter and more comfy, but the main difference for me is that handling is much better, with and without a load.

Directional stability is better at all speeds, and cornering is pleasantly unsurprising(!), plus shimmy is dramatically reduced, though not totally eliminated; only one instance with the new fork. I suspect a bit less offset again would fix that, but I was trying to avoid excessive foot overlap with fork #2.

Next frame (#2) will be almost totally different regarding fit, geometry and which bits are how stiff so I'm thinking that at worst #3 should be dialled - I hope.

Later,
Stephen

[Stephen Poole]

Like I said, tastes vary. IMHO, there are few acceptable "one size fits all" solutions for anything, unfortunately.

The bottom line is that each individual needs to figure out what works for them *themselves.* And yes, this takes time, money and effort.

Reviews can help, but are much more useful if one can "calibrate the reviewer" first. A local newspaper music reviewer had tastes that were diametrically opposed to mine, and I confidently bought anything he panned, and avoided  like the plague anything that got glowing reviews. His reviews were really helpful to me, just not in the intended manner.   :-)

Later,
Stephen

[Rick Johnson]

On 7/20/2016 1:03 PM, Stephen Poole wrote:
> Reviews can help, but are much more useful if one can "calibrate the
> reviewer" first. A local newspaper music reviewer had tastes that were
> diametrically opposed to mine, and I confidently bought anything he
> panned, and avoided like the plague anything that got glowing
> reviews. His reviews were really helpful to me, just not in the
> intended manner. :-)

I like to refer that as "contrarian opinion". It can be a solid
indicator. For instance I have narrow feet so when I shop for footwear I
use the phrase "too narrow" in my Google search. That yields a lot of
complaints about shoes that often leads to ones that are perfect for me.


Rick Johnson
Bend, Oregon