Designing a XXL Porteur - 650b or 700c ?

[Kieran Joyes]

Hi All,

I'm starting to think about having a very large Porteur/City Bike made for me. At a lanky 6'4", most classic steel 64cm frames are too small, and finding something in the appropriate size, along with proper front end geometry, chainstay length, fender clearance and modern features is challenging, to say the least.

I've begun to think about having a 65-66cm c-c low-trail frameset made, mated to a porteur-style rack for front-loading. The finished product would have the swept-back bars and the wide-range 1x9spd drivetrain that I have come to prefer on my current bikes.

But what about the wheels? 700c or 650b? I'm tempted to design the bike around Hetres, but there are fat 700c tires on the market now too. Anyone out there have thoughts on proportionality of big frames and 650b? Have other tall folks been down this path, and have anything to report? 

This J. Bryant porteur is vaguely close to what I envision. Mine would be even larger!

KJ

Toronto, Canada

[Jim Bronson]

I'm 6'7" and if I was starting from scratch with a custom I would design around the Compass Barlow Pass 700c.  But for converting existing bikes, 650b has worked great for me.  I'm running Loup Loup Pass 650Bx38 on my 69cm custom Rivendell.

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Keep the metal side up and the rubber side down!

[David Banzer]

I'm working on a 67cm c-c Shogun 500 frame that I picked up recently that will be built up almost exactly as you describe. It'll be built up around 650b and has a fork with quite a bit of rake, haven't measured exactly though (appears to be the same or more than 80s touring bikes)
Potential drawbacks on the frame:
1 set of water bottle bosses
No dt shifter bosses
No canti bosses (obviously even if there were wouldn't fit 650b
Rear spacing is 126mm

On a city bike, for me, 1 water bottle cage is enough. I'll probably get canti's brazed on eventually, and the rear spacing can be cold set to 130mm.

So... there are options for larger older steel framesets out there, they're just kinda rare to find. Luckily I paid $40 for mine with a buncha parts still on it.
Getting braze ons added to a frame that fits right works for me. Plus, you get to make sure the bike fits before investing a little more.

That being said, if I had the money I'd get a custom made I'd do that instead.

David
Chicago

[Jan Heine]

The choice of wheel size has little to do with the rider height. It's about the handling. If you want the nimble handling of a good performance bike, 650B wheels are your choice. You do need wide tires on a porteur, especially if you plan to carry a real load on the front rack.

My friend Ryan is 6'4", and he loves his 650B randonneur bike.

If you prefer your bike to corner "as on rails", settling on a radius and not budging from it no matter what you do, then a big 700C wheel will give you that extra stability.

Jan Heine
Editor
Bicycle Quarterly
www.bikequarterly.com

[Daniel]

Kieran,

I'm 6'2" and just had a 62cm custom built around 38mm 700c tires (plus fenders): https://www.flickr.com/photos/coopercycles/14433655436/in/photostream/

In my opinion, the C Line is a very nice tire, but not quite as cushy as the Hetre.

A big driver in my decision was to be on a common wheelsize for the sake of commuting.

Given the appearance of the bike (the red Soma tires, fenders and large frame), I've been asked a few time if it's "650" (please say, "650B," folks, but that's a rant for another day).

I wouldn't say it does "not budging from it no matter what [I] do" I feel like with the 73* HTA and 65mm (IIRC) rake, it handles very nicely and can I correct/change its line mid-turn.

Daniel

[Jim Bronson]

Frankly i don't notice that much if any difference in handling on my Rivendell going from 700x32 Grand Bois to 650Bx38.  Going from my Rivendell to my other bikes is much more noticeable.

I have noticed that for whatever reason the 650b tires give me less problems with tire defects like sidewall bulges than did 700c tires, although i don't think my sample size is big enough to draw any conclusions.

Btw i need more LoupLoups for 3CR, do you have them in stock for shipping today?  (Reply off list.  Or not, if Loup Loup availability is an area of general interest)

[Christopher Grande]

KJ,

I vote 650b. I'm 6'6" with one frame that is a 65cm and another that is a 67cm, both are a little small on me. One is 650b and the other is 700c, and I can't say that there are any advantages that the 700c bike has over the 650b because of the increased diameter. In fact, the 650b being able to take larger tires has that major advantage, and I'm guessing you aren't a feather-weight at 6'4". If anything, I would say increase tire size for larger riders, not wheel size.

Hope that helps!

Chris G.

[Kieran Joyes]

I like the idea that the bike would be easier to handle in traffic and at lower speeds. I also want the most cushy, floaty, air voluminous enjoyment I can reasonably get, and going by today's variety of good quality rubber - and the Hetre's apparent track record - I'm tempted to lean towards 650b. Plus, I have other 700c bikes that go fast, so something altogether different appeals.

I'm actually a lightweight, you might say - about 170 lbs. So increased stoutness/rigidity of the frame to accommodate me is not particularly applicable, aside from it's structural ability to carry a load and not show it.

KJ

[John Clay]

On Thursday, July 24, 2014 11:49:56 AM UTC-4, Kieran Joyes wrote:

Hi All,

I'm starting to think about having a very large Porteur/City Bike made for me. At a lanky 6'4", most classic steel 64cm frames are too small, and finding something in the appropriate size, along with proper front end geometry, chainstay length, fender clearance and modern features is challenging, to say the least.

With the caveat that beauty is in the eye of the beholder, bicycle aesthetics (including wheel diameter to frame size proportions) are as important to me as function. I'd be in terrible trouble if asymmetrical wheel sizes or extremely small/large wheels improved performance in meaningful ways; I wouldn't be able to build, or probably even ride, frames that weren't pleasing to my eyes. But there are plenty of choices in wheel and tire sizes to support performance and aesthetics over a wide range of frame sizes (human and bicycle). Again, this is all to my eyes; others may see and evaluate things differently.

By my quick coffee break calculations the 650x42 has about 15% more volume than the 700x38. A little more cush and a skosh wider, but with good design is the bike really giving up meaningful handling and utility for your purposes? I haven't ridden either of those tires yet; both of my bikes are 650b, one in 32mm Cypres and the other in 36mm CdlV. Neither does deep southern sand worth a darn (nor would a 42), both are fine on reasonably consolidated trails, turf, packed gravel, etc. In that context I'd be hard pressed to identify a surface where the Cypres yields meaningful capability to the CdlV. I ride both offroad a lot, more than on road actually. In back to back tests by the same riders, same roads, with razor sharp analysis and sustained attempts at differentiation I can believe that differences can be found. That's all good stuff for which I am truly grateful, but perhaps it makes this case: If that's what it takes to find these very, very small differences on the ragged edge of bicycle performance then perhaps you could flip a coin over these two tires/frames and suffer nothing in performance, comfort or utility.  

If I were 6-4 I'd select 700c because the proportions are more harmonious to me than an overly tall 650b frame.

John Clay
Tallahassee, FL
   

 

[Jon Doyle]

Look at my friend's 67cm Boulder 650b: https://flic.kr/p/kUdXvX

I suppose you could pick either wheel size and be happy. I would personally go with 650b because Hetres and Babyshoes are the best tires, ever.

Jon

Watertown, MA

On Thursday, July 24, 2014 11:49:56 AM UTC-4, Kieran Joyes wrote:

[Steve Palincsar]

On 07/25/2014 10:58 AM, John Clay wrote:

On Thursday, July 24, 2014 11:49:56 AM UTC-4, Kieran Joyes wrote:

Hi All,

I'm starting to think about having a very large Porteur/City Bike made for me. At a lanky 6'4", most classic steel 64cm frames are too small, and finding something in the appropriate size, along with proper front end geometry, chainstay length, fender clearance and modern features is challenging, to say the least.

With the caveat that beauty is in the eye of the beholder, bicycle aesthetics (including wheel diameter to frame size proportions) are as important to me as function. I'd be in terrible trouble if asymmetrical wheel sizes or extremely small/large wheels improved performance in meaningful ways; I wouldn't be able to build, or probably even ride, frames that weren't pleasing to my eyes. But there are plenty of choices in wheel and tire sizes to support performance and aesthetics over a wide range of frame sizes (human and bicycle). Again, this is all to my eyes; others may see and evaluate things differently.

To each their own: many people think the Alex Moulton bicycles look marvelous, and they have tiny wheels (17 or 20")

By my quick coffee break calculations the 650x42 has about 15% more volume than the 700x38. A little more cush and a skosh wider, but with good design is the bike really giving up meaningful handling and utility for your purposes? I haven't ridden either of those tires yet; both of my bikes are 650b, one in 32mm Cypres and the other in 36mm CdlV. Neither does deep southern sand worth a darn (nor would a 42), both are fine on reasonably consolidated trails, turf, packed gravel, etc. In that context I'd be hard pressed to identify a surface where the Cypres yields meaningful capability to the CdlV.

I have bicycles with both 32mm Cypres and 38 & 42mm 650B tires.  You may be hard pressed, but I have no difficulty whatsoever identifying road surfaces where the latter are superior to the former: two include gravel roads and cracked, alligatored pavement.

I ride both offroad a lot, more than on road actually. In back to back tests by the same riders, same roads, with razor sharp analysis and sustained attempts at differentiation I can believe that differences can be found.

Trust me, ordinary people like me have no difficulty at all identifying differences without razor sharp analysis or sustained attempts at differentiation.

That's all good stuff for which I am truly grateful, but perhaps it makes this case: If that's what it takes to find these very, very small differences

No, these are gross, obvious differences.  Nothing small or subtle about them.

on the ragged edge of bicycle performance then perhaps you could flip a coin over these two tires/frames and suffer nothing in performance, comfort or utility.  

If I were 6-4 I'd select 700c because the proportions are more harmonious to me than an overly tall 650b frame.

As I said, to each their own.

[Jim Bronson]

I've been looking at those Boulder Bikes with desire.  Is it 67cm center-top or center-center?  Was that a custom tig?  I'm assuming yes.  I would be interested in one like that, with the caveat that I'd like my bars to be level with the seat, so maybe I'd want the head tube extension to be longer, mostly for aesthetics.

I would probably take the $75 option for the cream headtube also.

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[Jim Bronson]

That sort of bike would make packing up for PBP a lot easier!

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[Kieran Joyes]

These are most definitely two conditions in my riding reality that are shaping my demands of this future bike. Some of the roads here in Toronto are horrendous, and the more pillowy the ride, the better!

KJ

[Steve Palincsar]

On 07/25/2014 11:56 AM, Jim Bronson wrote:
> That sort of bike would make packing up for PBP a lot easier!

Many Moultons have been ridden in PBP.

[Oliver Smith]

I'd much prefer a full custom, but the 65cm Soma Grand Randonneur seems like it would make an nice porteur for a 6'2"-6'5" (give or take) rider and is designed around 650b wheels. 

And I'll be very curious to hear about your new bike, whatever it is!

- Oliver Smith

[mitch....@gmail.com]

Still catching up on this thread, but I had a similar decision to make and discovered I just didn't like wheel diameters much more than a 700x28. I ride 58-to-60cm frames and can easily fit larger 700c tires but didn't enjoy riding them. Maybe it's just me and my preferences but above 28mm I start to notice the little extra inertia required to get them moving and turning and they start to feel a little ponderous (and I much prefer a 25mm over the 28mm). But 650B 42mm Babyshoe Pass feels feels easy to get rolling or turning, even in a few cases compared on the same frame after conversion.  I have come to the conclusion I have a preference for wheels/tires in about the diameter of a 650B 42mm. All the wheels/tires I really like at about the same diameter, 700C 25, 650B Babyshoe Pass, 26"x2.25". I've decided it may not be coincident that all the wheels I like to ride best are about the same outer diameter. Maybe it's the inertia sweet spot?  --Mitch

[Kieran Joyes]

Thanks Mitch. I have wondered about the inertia sensation you describe, especially on a city bike that sees a lot of stop n' go traffic, and lower cadence riding. I only have 700c bikes right now, and the 700x40 tires on the Cross Check feel good, but not overly zippy or precise.

KJ

[Christopher Grande]

In response to John C.'s point that the smaller wheel diameter will impact the aesthetic harmony of large bike, I think it's worth pointing out that any frame over 65cm doesn't have much hope of maintaining the same idea of harmony that say a 52cm - 58cm would. Type in '68cm bicycle' in google image search and most of the bikes will have 700c's or 27's on them. Still look goofy as all hell, unless you spend a lot of time looking at them like I do.