650B Conversion Tire Clearance Repository

What bike(s) have you converted to 650B? What tires fit?

Make Model Year (or era)/ serial number/ distinguishing feature(s)/ color Frame Size Largest 650B tire that fit (stock) Try anything that didn’t fit? Brakes used to convert Other comments Contributor
Centurion Turbo 1983 58cm Col de la Vie 38mm fenders Tektro R559 Rory!
Katakura Silk Full chrome, ca. 1984 61cm CTC 38mm with fenders none Tektro R559 Easiest conversion I’ve ever done…this bike fit the tires/wheels almost as though it were designed to do so. Fork was medium trail though. Azorch
Nishiki Comp II 1986 56cm 42mm Tektro R559 Bruce
Torelli from Cinelli Corsa factory 1983-4 57cm 38mm Too tight to safely run 42s Tektro R559 Bruce
Trek 420 1989 58cm 42mm fenders Tektro R559 (maxed out in back) Here is a slightly older one that fits Hetres & fenders: http://brazenbicycles.com/Trek-650b-Town-and-Country

Also this looks like a 1986 400: http://brazenbicycles.com/Trek-400-650b-Sport-Touring


Have you converted a bike? Comment below with the following and I will update the table:

  1. Make
  2. Model
  3. Year (or era)/serial number/distinguishing feature(s)/color
  4. Frame size
  5. Largest 650B tire that fit
  6. Any 650B tire(s) that you tried that didn’t fit
  7. Brakes used in conversion
  8. Other comments



Tire Size and Air Volume


Wheel Tire Volume Increase over 700x23C Example Tires
700C 23mm 3.5 L 0% The old standard
700C 19mm 2.4 L -33% Oh, dear!
700C 21mm 2.9 L -17% Eek!
700C 26mm 4.5 L 29% Grand Bois Cerf Blue (222g, 184g), Compass Cayuse Pass (248g)
700C 27mm 4.9 L 39% Challenge Parigi-Roubaix (285g)
700C 28mm 5.3 L 50% Compass Chinook Pass (229g)
700C 30mm 6.1 L 74% Challenge Strada Bianca (355g)
700C 32mm 6.9 L 99% Compass Stampede Pass (291g, 254g)
700C 33.333mm 7.6 L 117% Jack Brown (435g, 295g)
700C 35mm 8.4 L 140% Compass Bon Jon Pass (355g, 303g)
700C 38mm 10 L 185% Compass Barlow Pass (390g, 359g), Soma C Line (400g)
700C 42mm 12.3 L 252% Soma Supple Vitesse (380g, 340g)
700C 44mm 13.6 L 289% Compass Snoqualmie Pass (378g, 329g)
700C 50mm 17.8 L 411% Schwalbe Marathon (1.0T)
700C 55mm 21.9 L 527% Schwalbe Marathon (1.125T)
650B 32mm 6.6 L 88% Hutchinson Confriere (320g), Grand Bois Cypress (285g, 261g)
650B 38mm 9.4 L 170% Compass Loup Loup Pass (354g, 333g), Panaracer Pari Moto (340g, 300g)
650B 42mm 11.6 L 233% Compass Baby Shoe Pass (390g, 362g), Grand Bois Hetre (412g)
650B 48mm 15.5 L 343% Compass Switchback Pass (478g, 413g)
26″ 32mm 6.3 L 81% Compass Elk Pass (178g)
26″ 38mm 9.1 L 159% Compass McClure Pass (366g)
26″ 44mm 12.4 L 254% Compass Naches Pass (350g, 300g), Compass Slumgullion Pass (447g)
26″ 50mm 16.3 L 366% Schwalbe Big Ben (1.5T)
26″ 54mm 19.2 L 450% Compass Rat Trap Pass (454g, 418g)
26″ 55mm 20.0 L 473% Schwalbe Big Ben (2.0T)

Air volume was calculated in MS Excel with the following formula (this example is for 650B/584ISO with 38mm tires):

This will give results in cubic millimeters. Volumes above have been convert to liters (dividing by 1 million), rounded to the nearest tenth.

Some variances may be introduced from rounding, unit conversions, and other factors.

This is all white coat, clean room, armchair nerdery stuff only. Real life measurements of tires can vary based on many factors including miles, rims, tubes, production batch, etc.

Tire weights are manufacturer published weights, except for Schwalbe which were 100% fabricated for my own amusement.