Drill 650 to 700C?
 

Is there some reason that if I have a carbon fork with 650 dropouts that I shouldnt just drill it to 700 size for use on 700 wheels?

thanks

Gene

Huh? The axle diameters for almost all front hubs are 9 mm diameter no matter what the rim size is so "drilling the dropouts" doesn't do anything. A 650 rim is smaller in diameter than a 700 rim so you would have to lengthen the fork blades to make it fit. I really don't understand what you are proposing.

WHAT???
:crash: :crash: :crash:

Run for cover. They coming!!!

This is not a trick question.

I wouldn't take a drill to any fork, regardless of the reason. Forks take a lot of stress and a structural failure is almost always painful.

It would be interesting to know what the OP is proposing to do. The question, as stated, doesn't seem to make any sense.

But you must admit, we have some pretty trick answers. :D

<Scratches head>

Show me some reference to a dropout on a bike ever being referred to as having a size like 650 or 700....

....I'm not saying it's impossible, but after 25 years fixing bikes, it's the first time I've seen it....

<still scratching>

OK well if you drill the top of the fork so the wheels fit into the drop out- would that work?

Sure, right up to the first time you tried to ride the bike.

Heck yeah, I'z wit' y'all. I don't know's where da' all be comin' from but it sho' 'nuffs scarin' the bejesus outa' me.

A mod should lock this thread as soon as possible, this is utter nonsense. I doubt the OP is serious.

I understand what he's trying to do.. He doesn't have enough clearance for a 700c wheel on his 650 fork and wants to know if he can remove material from the bottom of the crown (I believe this is the right word) so that it'd fit.

I think the only way this would be an acceptable solution is if the fork were steel, had an actual crown, and you only needed to file 2mm or less for it to fit. Framebuilders actually do this kind of thing all the time on track bikes.. see the photo

http://velospace.org/files/pogb.jpg

But all this about drilling? I don't think that'd be a good idea. At least use a dremel.. if you don't have much to take off, use a hand-file.

Well, a 650c wheel is an ISO 571 rim and a 700c is an ISO 622. Assuming similar tire heights, the radial difference is 25.5 mm. Do you think anyone could file/Dremel/saw/etc. over an inch of metal from under any fork crown?

He might have 5/6" of clearance already, so he'd only need to remove 1/6" (random numbers..). Who knows. One of my road bikes has... (measures)... 7/8" clearance between the tire and the bottom of the crown.

But I did re-read the original post, and turns out the guy has a carbon fork. My advice is definitely a bad idea in that case.

it would be less than 1/16th it looks like- they nearly fit now-

Even if it does work (which I highly recommend against, especially with carbon) the brake will probably not line up (assuming this is for a bike with front brake).

buying the proper frame or fork is a lot less expensive than having your jaw surgically reconstructed after the fork fails because you modified it to work with something that it wasn't supposed to work with. don't be an idiot.

Yeah, if it were steel, id tell you to go for it.

Carbon. Hell no.

Yeah, once you cut the carbon fibers while grinding out the crown, you substantially weaken key tensile bearing elements. With carbon, the cutting is a problem is substantially worse than other bike materials. It would also be a bad idea on aluminum-though substantially less than carbon.

Since carbon is what you have, consider getting a 700c fork and putting in there if you want to go to larger wheels.

PM makeinu. I'm sure he has lots of inexpensive ideas that would work.

Bob

A question like that leads me to believe that you shouldn't even HAVE a bike...

Maybe you could try a smaller tire? If it's just 1/16, then you probably shouldn't have a problem..

And yes, make sure your brake would line up (you can test this without a tire).

I think if you can get the wheel to fit that the brakes wouldn't align with the rim.

also, on a bike designed for 650c, going to 700c will probably make toe overlap a lot worse.