Road Caliper Brakes on MTB bridge
 

Is it possible to install road caliper brakes on a mtb's bridge? My oldish aluminum Trek mtb with V-brakes has a hole in the bridge between the seatstays. Is it possible to install a road brake there and will it match up with a 700c wheel? Or is that hole there for some other reason?

I think that hole is for rack mounting, but can not swear to it. If you have a spare rear caliper, try it for fit. An 'oldish' MTB is probably 26" wheel frame, so do not know if 700c wheel is a go for it. Again, if you have a spare, try it for fit. Good luck.

a Brake needs a decent solid flat surface to bolt against, but if you can arrange that .. .

I've seen it done several times. It always seems a little odd to me, but it's your bike.

it is something you need to try. back in the early '90s I saw some guys do just this (with steel frames) for a cheap cross bike. it is just a matter of wether the wheel fits the frame then the correct reach brake caliper. you will likely need an older style 'nutted' brake with a pair of concave washers to help hold it steady.

the hole was likely intended for a rack, as noted, or fenders

Thanks for the input. A 700c wheel with 32 tires fits on the frame. I haven't tried just installing the brake on the bridge (because it would be a bit of work), but I will.

Measure from the center of the bridge hole to the center of the brake track on whatever size wheel you plan to use. That will tell you the "reach" you need.

The hole was likely intended for a reflector.

FWIW, my fixed gear conversion started life as a Raleigh mountain bike. I built a 700c wheelset for it. The distance between the reflector hole on the fork and the front wheel's brakeing surface was exactly right for an ordinary, standard reach, 105 brake caliper. I don't use a rear brake on that bike but it looks like a standard reach road caliper would fit the seat stay bridge too.

Just out of curiosity I measured the distance from the fork and brake bridge holes to the brake tracks on my 700C wheel Surly Cross Check. They measure about 78 mm so only BMX-type very long reach caliper brakes would work. Apparently these holes are really intended for fender, reflector or rack mounts.

I have a set of Tektro 800A long reach calipers which are good for 61-78mm reach applications. Do a google search for "Tektro 800" to find a source of good pricing.

Did this actually work? I am considering something similar for an old Trek 930.

Those tektros are basically designed for this application. They're meant to replace old long-long reach sidepulls or come OEM on utility bikes that come with fat tires and fenders.

1995 Trek 930 has the proper dimensions for a standard reach road caliper. As noted before, get a nutted one, with washers to fit the brake bridge's tube.

This isn't a Trek 930, but its dropout-to-brake bridge measurements are only 1/16" off.

https://farm6.staticflickr.com/5538/...41743ddb_b.jpg

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P1010092 by Lester Luallin, on Flickr

Tektro 800A's are great for this. ~$23 online.

They have two drawbacks, however:
1) No quick release. Best paired with levers that have a quick release built in. You could retrofit a quick release stolen from another brake.
2) They're backwards! Compared to any other (american market) sidepull, the cable enters on the opposite side. These are made for the Japanese home market, where they may be the correct orientation for whatever bikes they go on (city bikes?). This is only a problem if you have brake cable routing along the left side of the top tube; you'll have to cross the brake cable over somewhere.

Otherwise, decent dual pivot, long reach brakes for cheeeep.