Replies to This Discussion

Permalink Reply by Bill W. on November 7, 2013 at 3:56am

Hi,

I think to answer this question you need to focus on geometry, specifically your geometry. 650's will definitely allow for larger diameter tires and if you get the right 650 tire can be equally as spirited as any racing grade tire (Review compass bicycle article on this subject). A custom built frame or a purpose manufactured 650b frame can accommodate for larger  riders, though typically you may find these frame types (less custom built) on the small size. Custom built frame would render this issue obsolete.You can compensate by fitting the bike for your body, but you may have to make some sacrifices.

650b's can be strong but the difference in quality, strength, durability is no better or worse than a 700c built and constructed by a professional. Another consideration is the serviceability of the wheels. If your touring, long solo riding etc, and you experience a mechanical with your wheel, chances are your going to have to go to a LBS for assistance. If you need to replace a wheel and the shop has either 700c or 26' mb rims then you'll have some issues. Something to consider.

Permalink Reply by Duppie on November 7, 2013 at 4:18am

Bill, that is some great info. I subscribe to BQ, so I am familiar with Jan Heine & friends beating the drum about the advantage of wider tires.

I am 6’1” with a disproportionately large torso and short legs (inseam of 32”) and shorter than expected arms. Because of that, I ride a 56cm LHT (although it probably would have been better to go with a 58cm).

I am planning on buying a purpose built frame, but a custom frame is probably outside my budget. I plan on getting a professional fitting before purchasing the frame. Would I bring the geometry of some candidates to that fitting and make a choice based on the fitting results?

I think the main question is whether the smaller wheel size and the resulting impact on the frame geometry leads to a noticable different handling, or is this more of an academic debate and an average rider like myself would not notice the difference when riding these bikes?

Permalink Reply by Mike Jenkins on November 7, 2013 at 5:41am

The main advantage of 650B in a purpose built bike is to mount lightweight, large diameter road tires.  Examples would be Grand Bois Extra Leger or Pacenti Pari-Motos.  The desirability of the tires is their ability to work well on a wide variety of surfaces while giving a comfortable, less tiring ride.

On an existing frame that was designed to use narrow 700C or 27" tires, 650B has been used successfully to mount a wider tire.

The geometry of the bike needs to be matched to the rider (duh!) and also to where the load is to be carried.  Replacing a high trail fork with a low trail fork on my first 650B bike resulted in more stable low speed handling and much greater stability in gusting cross winds.

An additional consideration for a new bike is a more flexible tube set.  The LHT is fairly stiff to accommodate a full load of touring gear.  You might find a more flexible frame easier to pedal.

If you wanted to try a 650B bike, arrangements could be made.

Mike 

 

Permalink Reply by pistola on November 7, 2013 at 5:49am

The smaller the wheel's diameter, the quicker it will rotate, and the smaller it's rotational interia will be, given that the 2 rims compared have the same mass.  Here's a great article on the subject, but beware there's a lot of physics involved:

http://velonews.competitor.com/2008/07/bikes-and-tech/calculating-a...

 

There's a couple of things to consider while choosing between wheels.  The 700C wheel has better rim and tire selections at the time.  As the previous poster mentioned, this might be important if you break a spoke or need a new tire, or need a whole new rim/wheel in the middle of nowhere.  Tires on a 650B wheel will wear out slightly more quickly.

 

The 700C rim will ride over bumps/potholes more smoothly than a 650B wheel.  The 650B wheel will be more agile and quicker to accelerate than the 700C wheel.  I have numerous wheels, including 27.5" (the old 650C standard) and 20" wheels on my folding touring bike and you can definetly tell the difference between the 20" wheeled bike's handling and the 700C wheeled bike.  The 650B wheel will give you more clearance for fenders and help you avoid clipping your feet when you turn as well.

 

However if I were building up a new bike to be used on really long rides, I'd go with the 700C wheel standard mainly for comfort reasons, with availability of parts and tires as a secondary reason.  

Permalink Reply by David P. on November 7, 2013 at 10:07am

If you don't plan to use tires larger than 32mm or so, I wouldn't use wheel size as a primary determinant. I am a fan of 650b, but that is because of some really, really nice tires available in that size, all of them fairly large-volume. My daily-driver Rawland (650b frame) uses Hetres, and my go-fast Vendetta (a conversion) uses Cypres. The GB Cypres is also available in 700c, so if you don't want to use a tire any bigger than that, 700c is as good as 650b, I think. But if you do want to use larger tires, like Pari-Motos or Hetres, then I'd go with 650b, since while there are some nice larger 700c tires available (mostly Schwalbe, I think) those are really nice. Not sure I'd do credit card tours on event tires, though. There are plenty of good frames available for your purpose in either wheel size (Rawland Stag or Nordavinden, Boulder Bicycles offererings, Soma Grand Randonneur, Ocean Air, VO, etc.

You're welcome to try either of my bikes if you'd like to, and if you fit them (Vendetta is 57cm square, Rawland will fit a wide range of people due to the sloping top tube), though I don't think my Rawland will be representative of anything you want - it is many things, but one thing it is not is sprightly. My enjoyment of the Vendetta went up by like a factor of two when I put 650b wheels on it.

Permalink Reply by Bill W. on November 7, 2013 at 12:55pm

As an aside,  I rode the grand bois extra leger tires this year (700c/32mm) and was very very happy with there performance. They were more prone to flats but I treated them as little rest stops.

Permalink Reply by ilter on November 7, 2013 at 2:19pm

Duppie,

Production 650b bikes tend to have lower trail than 700c bikes. That is probably the only issue you should consider regarding geometry. Otherwise you can probably find a production 650b bike that fits just as good as your LHT. Soma's new randonneur, for instance, comes in several sizes, as far as I recall. (another non-critical difference is that 650b bikes may have shorter seat tube due to less bb drop, so top tube length might be a better measure for comparison).

Permalink Reply by Duppie on November 8, 2013 at 9:37am

Lots of great feedback. Haven't really decided what size wheels, but I did book an appointment with a bike fitting studio. I think I will discuss with them if my specific measurement would point me in one specific direction.

David P.,

I will PM you to see if we can arrange a test ride.

Mike J.,

Thanks for the offer as well. I do live in the city without a car, so getting out to your place may be hard.

Permalink Reply by Duppie on November 18, 2013 at 5:06am

I did have a change to ride a 605B bike owned by David P. That bike was an absolute joy to ride.

 

My concern is around tire availability. Most 650B tires seem to favor speed over flat protection.

Does anyone know of 650B tires that have a good amount of flat protection and still are reasonably fast? I am thinking of tires like Schwalbe Marathon Supreme. I have that one multiple bikes and find it to be fast, while flats are really a no-issue.

Permalink Reply by ilter on November 19, 2013 at 4:49pm

I remember reading somewhere that non tour guard pasela is good, both in 650b & 700c.

Also, you can try searching for an answer in here: https://groups.google.com/forum/#!forum/650b