arimajol

Hey gang, I've got an 80's trek touring bike. I am running modern 700c wheels rather than the original 27" set. I have been able to set up the original cantis for the 700c wheels, but stopping power isn't awesome. Is there a more modern set of calipers that will work better than the old ones? Maybe even a non-canti option like mini-Vs or something? I mostly run traditional road bike rim brakes and haven't messed around with these much. Thanks a bunch y'all

tcs

The time honored starting point is top quality brake pads and new, quality cables and housing.

cyccommute 

Best place to start is with good brakes. There are none better than Paul’s cantilevers. Good and solid, easy to set up, and far better than anything I’ve ever used. Expensive but worth it. I happen to have a spare set that I might be willing to let go.

dddd

Changing to 700c rims significantly increases leverage/power, but also increases the "pad dive" angle to the extent that wider 700c rims are not used.

Some Trek's have dark-anodized Matrix rims that challenge the original brake pads getting any grip, and any Shimano pads seem to harden early on and provide doubly poor braking power.

The straddle cable can be shortened for increased power, but it's been 25 years since I went looking for them (in cases where the straddle cable wasn't adjustable at one end).

My Trek 720's braking power increased quite dramatically when I fitted 700c Module-4 rims and premium brake pads, almost too strong with RSX STI levers!!!

Velo Mule

The difference is 4mm between the 27" wheel and hte 700C wheel with the 70C being 4mm smaller diameter. That should get you more leverage. Since you are not feeling like you have enough stopping power here are the things to do in order of simple and cheap to expensive.

- Remove the brake pads and sand them. Enough to remove the top layer of rubber and get down to softer rubber.
- Buy new brake pads and install them. Consensus here is that Kool Stops are the best. I have also had good luck with Jagwire brand pads.
- Replace both the caliper and the brake levers with Linear pull. Since the linear pulls have a different pull ratio, you will need new levers to go with them.
- If you want to keep the canit brakes and Levers, I have heard good things about Paul canti brakes. But they are expensive and there are other alternatives. That also assumes that the calipers on your Trek are inadequate, which may not be the case. Even Trek's low end bikes had good canti brakes. They may have been made of steel, but they work.

PugRider

One thing I find helps with cantilever brakes is dialing in some "squish" by fooling around with the straddle cable. It will seem like more lever travel than you might be used to, but I find you can really get some bite out of the brakes that way, with less squeezing force. Some sort of mechanical advantage thing going on, similar to the suggestions to lower the straddle cable.

Jeff Neese

Cantilever brakes have plenty of stopping power when properly set up, so no need to swap brakes. Start with better brake pads and also make sure your straddle cable is the correct length. Show us a picture of your brake setup.

The Golden Boy 

It seems people have varying opinions on what works for cantilever brakes on "vintage" bikes. ...and I suppose there's differing opinions on what the word "works" actually means.

Short story long, on "vintage" bikes, cantilever brake studs are generally MUCH closer together than the modern standard- and there was no standard back in the day. According to Velo Orange- the modern standard is between 77-85mm. The front posts on my 1985 Schwinn Voyageur SP are 50mm apart. Because modern brakes are built around the premise that bosses are going to be between 77-85 mm apart AND the brake posts will be set for 700C rims, there's no need for them to be adjustable enough to cover 10, 20 or 35mm of distance between the posts AS WELL AS 4mm down. Old brakes had to be adjustable enough to be used on a bike that may be spaced at 60 in the front and 78 in the rear.

Since you say you have an old Trek and the stock brakes aren't working well, I'm going to guess that you're using DC960s. Some people say they work great- and that they've worked on 27-700C conversions... I've only used them on 27" wheels and I didn't like them.

I'm not a Shimano fan, BUT- they did their Deore series cantilever brakes really are the best. The AT50, MC-70, MT-60, MT-62 and M732 are all good- IMO, in ascending order with the M732 being the best. I also had good luck with Suntour XC Pro brakes. I've also heard a lot of successes with the DiaCompe 981s. I was completely SURE M900 XTR brakes would work- because they're SO similar to the XC Pro brakes... Nope.

There's thousands of people that hate cantilever brakes- either they don't have them set up correctly or they're using the wrong levers or brakes with the wrong geometry for what they want... they can be difficult to set up to begin with. Add on to having the pads diving at some goofy angle or wearing into the tires or pulling the pads against the stays or fork legs even though you used some fancy pants top of the line expensive brakes...

I would greatly encourage you google things like "modern cantilever brakes work for 27 to 700c conversion" and "vintage cantilever brakes work for 27 to 700c conversion." I think you'll find that, while there are outliers, the old brakes work better, and it's really only a certain subset of old brakes that work really well.

I am currently riding a 1985 Trek 720 with Suntour XC Pro brakes and a 1985 Trek 620 with M732 brakes.

Miele Man

You might be interested in what the Late Great Sheldon Brown had to say about setting up cantilever brakes.

https://www.sheldonbrown.com/cantilever-geometry.html

Cheers

tcs

Magura hydraulics.