Can anyone list the measurements for a 650cc frame
a) from center of the fork dropout to the brake hole and
b) rear dropout to brake bridge hole?

OR, if you know of a source for this information online could you please point me in the right direction? I'm trying to figure out what size wheel a frame will accept but I don't have access to a set of 650cc right now. I know for a fact it does NOT accept 700cc.

I've measured the distance to be aproximately 340-345 mm front and rear on my 650c bike.

Regards, Anthony

Thanks very much Anthony! If you don't mind, a couple follow up questions...

Is there any room left between the wheel/tire and the fork crown and brake bridge? For instance, if you wanted to install fenders, would you be able to? I realize most bikes built for 650c (NOT "cc", sorry about that) are racing machines so probably can't fit fenders.

Finally, if there is not enough room for fenders is there enough room to fit slightly larger tires? Traditionally 650c are thin racing tires but I recently read about the Terry Tellus tire:

https://www.sheldonbrown.com/harris/tires/571.html

In your estimation, do you think you'd be able to fit these on your 650c bike?

Actually, I'd have a question about 650C vs 700C frames and wheels, because I admit I am fuzzy about the 650C wheels: I understand they must be a bit smaller than a 700C, but.. would a frame for 650C accomodate a 700C wheel? Would normal V-brakes work, on a 650C frame with a 700C wheel? And what if I put a 26" wheel on a 650C frame, would that work?

I have never seen a 650C wheel in my life, I think.

Depends on the frame. Some frames will take it, otherwise just won't even with the smallest tire imaginable.

My frame doesn't have super tight clearances. You could easily fit 650x28c tires and you could probably fit realy petite fenders if you could find mounting points although on my frame there are none.

Regards, Anthony

There's no way you are going to fit a 700c wheel in a 650c frame. 650c is ISO size 571 mm and 700c is ISO size 622 mm. That's a 51 mm difference in diameter and about 25 mm difference at the brake surface. A bike built for 650c wheels won't have a v-brake/cantilever brake mount that I've ever seen.

A 26" mountain wheel is ISO size 559 mm which is only slightly smaller than 650c but the wider build of 26" mountain wheels is going to be too wide for narrow racing forks used on 650c and actualy although the rim is slightly smaller in diameter I don't think the wider 26" tires are going to fit anyway.

Actualy this is all a bit academic anyway because why in the world would you want to fit the wrong wheels anyway?

Regards, Anthony

Thanks a lot, Anthony!

To answer your question: because I saw an excellent deal for a frameset on eBay (and the dude actually ships to Europe, for a change), and was considering my options.

Even if you could get 700c wheels to fit it would be an odd sort of a bike to ride and probably wouldn't be what you were looking for. Apart from small bikes where the use of smaller wheels is more obvious the use of 650c wheels in larger frames alows for an effectively VERY short head tube. This has the handlebars being very low. Good for aerodynamics when using TT/TRI bars but too low for road bikes.

So you would end up with a bike with VERY low handlbars, a high centrebracket height and quirky handling because the steering geometry is affected by wheel size! Not what you were expecting.

Regards, Anthony

Not the mysterious 650cc wheel again. Wheel sizes aren't measured as volume.

While we're on the subject of 650 wheels. Someone asked me on a group ride why tri bikes had 650 wheels? Did not have a good answer.

The OP already admitted that mistake.

650c wheels help with rider aerodynamics. They provide an effectively lower head tube allowing for lower placement of the handlebars. Its not realy about wheel aerodynamics. They have gone a little out of fashion with larger frames because in the larger sizes you can get the head tube low enough with 700c wheels so there is no need for 650c wheels.

Regards, Anthony

Thanks DieselDan! Please feel free to search my username "geedubbayoo," inspect all my posts and publicly correct any misspellings, typos, grammatical errors and technical gaffes you might find. It's nice to have someone looking out for me.

(I thought it might be worth having the subject line edited to correct my mistake but a search for "650c" returns this thread, so no harm done.)