Measuring Brake Drop [?]

Hi all,

I'm very new to road bikes and have got myself in a bit of a mess. I recently bought a nice singlespeed bike which needed a bit of work, namely new brakes, cables, etc.

Now that I come to try and find some brakes I'm struggling to find some that I'm confident will actually fit. I've measured the vertical distance from the central boss to the wheel rim and it's around about 90mm at the front and 70mm at the back. I can't find anything online that would fit this but might well be measuring it wrongly!

The back brake is currently a seized up u-brake, with the front being a central pull cantilever. Ideally I'm looking to fit u-brakes on both front and rear but think I may have to settle for some v-brakes on the front.

Any advice would be very appreciated!

You need to measure from the centre of the caliper retaining bolt diagonally to the centre of the rim. As long as the measurement falls within the specified reach of the caliper, it will fit.

Nice one, very clear.

Thank you very much.

Surely that pic is relevant to sidepulls pulls not V's and U's. U's were of the same period as Cantis' and had gone by the time V's came about. (There may well be exceptions but these will be rare.)
U's don't fit Canti/V bosses. and of course the opposite.

U's on a road bike. Very odd. Are you sure they are not old centre pulls? Mafac/Weinmann or similar. If thats the case then just buy more. Having said that most centre pulls had a bolt through the fork rather than fork bosses.
Does your bike have bosses on the fork and seat stays? If no I bet you have centre pulls. Send a pic and you will get a much clearer answer as we will now what you have. .

Thanks again, I'll try and put some photos up tonight.