27" to 700 wheels

[derrick]

Been asked to put together an old bike, the frame is for 27" wheels ,is it possible to fit 700c wheels, the problem is the brakes, are there long drop brakes that would fit? it has to be a flip flop wheel so could be ridden as a fixie, but still needs brakes, Cheers for any advice.

 

[Sharky]

According to Sheldon, you would need to move the brake shoe 4mm closer to the centre of the wheel, so very little difference. Just depends on the current calipers and if they would be ok.

Might have more of a problem with the rear wheel, if going for new wheels. The width of the rear stays are probably 126mm, whereas new replacements are 130mm or wider .

 

[Ajax Bay]

This sort of deep drop (normal drop is circa 49mm but that's too little for my C20 531 frame):
https://www.sjscycles.co.uk/brakes/...per-brake-5573-mm-very-deep-drop-nut-fitting/
May be overkill.
Note external (to seatstay bridge/fork crown) nut fitting versus the 'normal' long 'internal' nut.
'Normal' nutted: https://www.merlincycles.com/tektro-r539-long-drop-brake-calipers-pair-60603.html (57mm drop max)
https://www.sjscycles.co.uk/brakes/black-tektro-r539-long-drop-caliper-brake-set/
The 27" rims are ETRTO 630 v '700c' at 622, so the additional drop needed is only 4mm.
Edit: Measure the distance from the seatstay bridge brake 'ole to dropout c-c and subtract 313mm (I have taken account that the rim radius is 311 and the hypotenuse is therefore 317mm, and that the brake pads are 8mm wide). That should give you an estimate of the minimum length you need for the brake drop.

 

[Dogtrousers]

Been asked to put together an old bike, the frame is for 27" wheels ,is it possible to fit 700c wheels, the problem is the brakes, are there long drop brakes that would fit? it has to be a flip flop wheel so could be ridden as a fixie, but still needs brakes, Cheers for any advice.

I've done this. I got some long drop brakes. I can't remember where I bought them, possibly SJS. TBH they aren't all that long. You might get the impression from the name that they are great long wibbly callipers and will be rubbish at brakinng but they're fine. They're just a few mm longer. The ones I have are "Tektro Quartz" calipers. Bought about 10-12 years ago.

As @Ajax Bay points out, on an old frame you may have to get nut fit brakes or be prepared to drill out the hole for recessed fittings.

The other tricky thing I encountered was that modern wheels with 622mm rims have really wide rear hubs - too wide for the frame. But the fact that you're setting it up as SS/fixed with a flip flop hub should (I think) mean you won't have that concern. I resolved that problem by bending the frame.

 

[Sharky]

SS/fixed with a flip flop hub

Agree, that won't be a problem. Should be 120mm oln.