What is the size of a wheel?

[bstay]

I'm a bit curious regarding wheel sizes. Sometimes wheels are given in "c" sizes, i.e. 650c and 700c, whereas other times they're given in inches. I think 700c is a 28" wheel, and 650c is 27", but I'm not sure. When you get to smaller sizes there are 18, 20, 24 or 451c etc. Can anybody shed some light on the sizes and what they actually mean and how big the wheels actually are in centimeters.

 

[vlad]

Originally posted by bstay
I'm a bit curious regarding wheel sizes. Sometimes wheels are given in "c" sizes, i.e. 650c and 700c, whereas other times they're given in inches. I think 700c is a 28" wheel, and 650c is 27", but I'm not sure. When you get to smaller sizes there are 18, 20, 24 or 451c etc. Can anybody shed some light on the sizes and what they actually mean and how big the wheels actually are in centimeters.

International Standards Organisation (ISO) Rim Sizing

The ISO number is actually the bead seat diameter. This number is usually shown on the tyre wall preceded by the tyre width in mm.

Original Size Typical Designation Typical Application ISO Size
27" 27 x 1 /14" 10 Speed 630
700C 700 x 25c Road Bike 622
26" 26 x 1 3/8" Schwinn 597
650a 650 x 28a 3 Speed 590
650b 650 x 28b Tandem 584
650c 650 x 20c Triathalon 571
26" 26 x 1.5 MTB 559
600a/24" 600x25a, 24x1 3/8" Kingcycle 540
24" 24 x 1 V-Rex 520
22" 501
550a 550 x 28a 490
20" 20 x 1 3/8" Ross Bike 451
500a 500 x 28a Peer Gynt 440
20" 20 x 1.5 Greenspeed, PDQ, BMX 406
450a Italian 400
18" 18 x 1 3/8" British 399
450a 450 x 28a Kingcycle 390
17" 17 x 1 1/4" Moulton, Lightning 369
16" 16 x 1 3/8" Vision, Brompton 349
400a 400 x 47a 340
16" 16 x 1.75 BikeE 305
14" 14 x 1 3/8 Bickerton 298
350a 350 x 37a 290

(courtesy of Recumbent UK magazine)

RCO

 

[jawnn]

UNDERSTANDING DELTA TRIKE WHEELS
After having trouble with my trike wheels I dug up this information.

PIPPA GARNER (builder of quadrocycles): Well, yeah. I retightened the spokes on my canted wheels twice and finally got rid of the pinging noises, but I had the problem on 2 different cycles with canted wheels, one built by Varna in Canada, so the spokes must be tighter than what is considered conventional in wheel building. Certainly the application has something to do with it. There's no question that asymmetrically tensioned spokes are subject to more stress than wheels with the rims centered between the flanges.

HASE DELTA TRIKES: *yes, all spokes have the same length (172 mm) and so they also have the same tension. A symmetric bike wheel is the strongest solution, even with disc brakes. Both flanges on our wheels are the same size. The Ez3-usx is a cheap copy of our trike. Best regards Rüdiger Knopp Diese, hase-bikes.com

LIGHT FOOTCYCLES: Smaller wheels are much stronger in almost all respects. They would suffer less distortion from braking, as well, because of the steeper angulations and shorter spokes with less give. Rod Miner Lightfoot Cycles Inc. 179 Leavens Road, Darby, MT 59829 USA , lightfootcycles.com

GERD SHRANER (the art of wheel building): for years I worked with out a tensiometer, being under the false impression that instinct and experience were enough. When I finally started using one I discovered that even my mood on any given day gave me different result. To adjust your rim off center on the axle, just visually determine the spoke length. Then open the rim calipers on the truing stand and let only one side touch the rim. You may need some new nipples because they could disintegrate during adjustment.

BROX QUADROCYCLES: On wheels with low spoke tension on one side you may experience the disc brake pulling the tight spokes before the loose side. Centering the rim between the flanges will eliminate this action, but you still need higher tension on the spokes because of the compression factor from lateral forces. We use symmetrically dished wheels with disc brakes, and box wall rims. Brox.co.uk

KEITH BONTAGER (bicycle engineer) The disc brake side spokes should be slightly looser, yet still have the same length. However for light duty use a 20” wheel can be the same tension as the other side.

BOB BRYANT (RCN magazine): In a hard turn most of the weight goes to the out side spokes so they should be at least as tight as the inside spokes, because after all the axle does stand on the spokes. The reason that Sun bicycles built the wheels like bike wheels is simply that they couldn’t afford to build a new wheel-building machine and still keep the price down. If you paid $265 for your wheels they should be willing to build them correctly.

 

[daveornee]

I'm a bit curious regarding wheel sizes. Sometimes wheels are given in "c" sizes, i.e. 650c and 700c, whereas other times they're given in inches. I think 700c is a 28" wheel, and 650c is 27", but I'm not sure. When you get to smaller sizes there are 18, 20, 24 or 451c etc. Can anybody shed some light on the sizes and what they actually mean and how big the wheels actually are in centimeters.

Good answers to your questions:
http://sheldonbrown.com/tire-sizing.html
You will see various charts at the bottom of the article that should answer you questions.
ISO andBead Seat Diameter is the key.

 

[jawnn]

700c is a stupid american in·ter·pre·ta·tion of 70,0 centameters or 700mm. and this is the O.D. with a 23mm? tire, the rims are less. see the Hostel shoppe cataloge.

one inch is 2.54 centimeters.

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I just cant understand how americans deform so many words, like cog! use your dictionary. the word sprocets is the correct term.

cog1 ( P ) Pronunciation Key (kg, kôg)
n.
One of a series of teeth, as on the rim of a wheel or gear, whose engagement transmits successive motive force to a corresponding wheel or gear.
A cogwheel.
A subordinate member of an organization who performs necessary but usually minor or routine functions.

sprock·et ( P ) Pronunciation Key (sprkt)
n.
Any of various toothlike projections arranged on a wheel rim to engage the links of a chain.
A cylinder with a toothed rim that engages in the perforations of photographic or movie film to pull it through a camera or projector.

 

[jawnn]

700c is an interpretation of 70,0 centameters or 700mm. and this is the O.D. with a 1.5" tire, the rims are 622mm. see the Hostel shoppe cataloge.

one inch is 2.54 centimeters.

 

[Scotty_Dog]

700c is a stupid american in·ter·pre·ta·tion of 70,0 centameters or 700mm. and this is the O.D. with a 23mm? tire, the rims are less. see the Hostel shoppe cataloge.

one inch is 2.54 centimeters.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

I just cant understand how americans deform so many words, like cog! use your dictionary. the word sprocets is the correct term.

cog1 ( P ) Pronunciation Key (kg, kôg)
n.
One of a series of teeth, as on the rim of a wheel or gear, whose engagement transmits successive motive force to a corresponding wheel or gear.
A cogwheel.
A subordinate member of an organization who performs necessary but usually minor or routine functions.

sprock·et ( P ) Pronunciation Key (sprkt)
n.
Any of various toothlike projections arranged on a wheel rim to engage the links of a chain.
A cylinder with a toothed rim that engages in the perforations of photographic or movie film to pull it through a camera or projector.

This "stupid American" is trying to in·ter·pret why you are answering a posted question that is almost two years old..............

Considering your rant, the misspelled word (in bold) is especially precious.

 

[jawnn]

This "stupid American" is trying to in·ter·pret why you are answering a posted question that is almost two years old..............

every-one has the opportunity to learn from clear definitions, even if misspelled.

stupid:

adj 1: lacking or marked by lack of intellectual acuity [ant: smart] 2: in a state of mental numbness especially as resulting from shock, or over work; "he had a dazed expression on his face"; "lay semiconscious, stunned (or stupefied) by the blow"; "was stupid from fatigue" [syn: dazed, stunned, stupefied, stupid(p)]

 

[jawnn]

OK now.... so the information is not so correct .... I found an article in an old RCN magazine that explains the history of the wheel sizes....

they used to be messures by the out side diameter... so that 700c is the arcaic french term for o.d. in milimeters with a 1.75" tire. (All the wheels were 70cm o.d.)

so at some point they thought it better to put smaller tires on the 700c rim. and forget the rest of the rim sizes.

so now the 700c is smaller than 700mm

even this stupid american learns.......