paulapart

I've had my Trek 7100 for over a year now and love it, but I recently replaced
-the stock flat handlebars with bullhorns (which I much prefer),
-the stock direct-pull cantilever brakes with side-pull single pivot caliper brakes (which are apparently a more compatible brake design for bullhorns).
-and the stock brake levers with Shimano levers that make sense for bullhorns



I love how this setup fits and rides, but no matter how tight I calibrate the pads and cables, I just don't have the same stopping power at all. This inability to stop isn't even safe. Do you think it's the brake mechanism, levers, or the setup of all these new components? One mechanic suggested dual-pivot calipers but I'm just not convinced it's solely a matter of having fancier brakes. If these brakes work on other bikes, why aren't they working here?

I appreciate any and all advice you've got! Cheers.

FMB42

Are you sure that your brake levers are compatible with caliper brakes?

It sounds like you might have installed linear-pull ("V") brake levers (which will not work with caliper brake systems).

xenologer

judging by the photos, those caliper brakes have rather long arms -they look pretty weak
I'd say its the new brakes that's the problem.

assuming your previous brakes were the centerpull type?cable goes straight up the center to a hanger on the headset? -yeah, cable routing difficulty aside those are actually pretty strong brakes

Easiest thing to do would be to put them back on

alternatly, go with the dual pivot sidepulls as your LBS suggested; these are in fact stronger than single pivot calipers. -having one arm on a separate pivot mean shorter effective brake arm and more leverage; the 'fancy' is not just for looks. google for in depth explanation/math/diagrams/physics

lastly, buy extra grippy brake pads of the salmon colored variety; really though, do this last, it better to have good brakes to begin with....



p.s. why are there apparatly 2 different bikes in your photos of the caliper brake install? assuming the 2nd photo is the current one; the brake pad visible is upside down -the little wing/tab should face down

HillRider

Frankly the brake you fitted appear very cheap and poorly made along with being flexy and single pivot and having poor pads . I recommend replacing them with decent quality double pivots and, for sure, replace the brake pads with much better ones. Kool Stop Salmon pads are the class act and well worth the cost.

dsbrantjr

+1 on FMB42's brake lever question.

What kind of brake pads are you running? Changing to something like Kool Stop Salmon might help.

Those look to be rather long reach calipers which will have poorer leverage, thus less braking power than the regular calipers.

Also, the cable going into the front caliper seems to be going into the adjuster at rather an angle; this might add friction due to the cable rubbing in the bore of the adjuster. I wonder if a little shorter cable housing or a ferrule might be in order.

FBinNY 

There's a reason that bikes like yours are equipped with cantilever brakes. Long arm side pull brakes will never perform as well as cantis will which cost the maker much more than side pull calipers, plus the added cost of brazing on the bosses. If Trek was willing to spring for the canti's, rest assured that they felt they had little choice.

I suggest you go back to the original brakes. Depending on the levers you bought you might have cable travel issues, but take it one step at a time.

Airburst

OP says "direct pull" cantilevers, which I assume means V-brakes or something of a similar design. OP, there are levers available for drop bars (which is what your bullhorns are, for the purposes of lever selection) that will operate direct-pull cantilevers. You could also use "mini V-brakes", which work the same as most direct pull brakes, but are compatible with standard-pull brake levers.

Old-fashioned centrepull cantilevers are also an option.

FMB42

My research seems to indicate that the 2010 and 2011 Trek 7100 was equipped with "V" (linear pull) brakes. I could be wrong tho...

cyclist2000

I would go back to the original brakes (assuming V-brakes). Or get cantilever brakes.

Pepper Grinder

You had direct-pull cantilevers aka V-brakes. You should have switched to regular cantilevers, not sidepull calipers. Keep the brake levers you have if they work for you (I prefer reverse levers/tt levers on bullhorns, though that's not an option with bar-end shifting), and install some regular cantilever brakes. My LBS charges $18 for a set, entry level Shimano Altus. They work fine.

mconlonx

The better way to have gone would have been to keep your V-brakes and got the proper road brake levers to work with them. If you still have them, you could just opt for new, long-pull levers; or since you have the bars set up and wrapped, the easier route might be as others have suggested: dual pivot road calipers or cantilever brakes.

Even more arcane: keep your current bar setup, re-mount your V-brakes, and use a Problems Solvers Travel Agent to make up for the brake/lever incompatibility.

LarDasse74

Yeah, the brakes you have on there are pretty craptacular... the type of thing you might see on an inexpensive BMX or an entry level MTB from 1985.

Centre-pull cantilever brakes (often just called 'cantis'), when properly set up, will give far superior stopping power - similar to the direct pull cantis (also known as V brakes) that you removed. THese would be my first choice for use with road-style levers, although you need to figure out some way to mount a cable-stop or cable-hanger above the brake - either on the fork's steerer tube (some hangers act as a headset spacer under the stem) or bolted tot he hole in the fork where you now have the brake mounted.

The other options are: Use the original brakes with some sort of cable-travel multiplier (often called a 'travel agent), or get some 'mini-vs', which are short-armed V brakes that will work with road levers like yours, although they don't allow a lot of clearance for wide tires and/or fenders.

dsbrantjr

"install some regular cantilever brakes."

+1 While you are at it put in a fork crown mounted cable hanger for the front, there's plenty of room. This will help eliminate brake shudder which can occur with headset or stem mounted hangers and canti brakes. I like the Specialized Tricross Fork Hanger.

onespeedbiker

I would not agree that going with (center pull) cantis is a good idea. While I have cantis on several of my bikes, I have never found them to be nearly as strong as V-brakes and are much harder to set up. The best bet is what mconlonx first recommended These are levers you would use https://www.jensonusa.com/Brake-Lever...o-Brake-Levers This is the setup I had with my tandem before I went to a dropbar (still using the same levers).



BTW I tried using the similar side pull cantis like you installed and they couldn't lock up the rear brake even when I was just pushing the bike! As you said, using these brake calipers are dangerous!

LarDasse74

They are much more difficult to get working at top performance, but I assure you, with proper setup, cantilever brakes are as strong as (or stronger than) V brakes. Depending on the brakes and hardware used, 'proper' setup may be difficult or impossible, though.
V brakes are a superior design simply because it is much harder to set them up improperly - If you have a decent cable, decent pads, and a V-brake compatible lever, and the brake pads don't touch the tire, they will have good stopping power.

Now that I think about it, for the OP, a set of V-brake compatible levers and re-installing the old brakes is likely the simplest solution.

hueyhoolihan

i'll just relate my experiences...

i've got a couple of vintage mtbs with cantis, both shimano. i have removed rear brake and use only the front. stopping is not a problem, but they have to be adjusted properly.

i also have four road bikes, all with single pivot caliper brakes. also using only the front. again, i have not had problems with braking. the single pivot sidepulls are a mix of shimano and dia-comp. all high end or middle level quality.

brake pads are important, i guess, but i just buy those inexpensive ones they have been making for sidepulls for 40 years. they are about 1.50 a pair.

one thing i can say is that the sidepulls work better if the arms are adjusted properly on the pivot bolt (mine hold their adjust similar to that of a loose bearing hub. a double nutted arrangement) and that the pads and or rim have not been contaminated with grease or oil. if so they will never work very well.
OTOH if the sidepull arms are too flimsy (and those brakes do look to be low quality) they too will never work very well.

edit: i forgot. you might want to check that your brake blocks have full converage on the rim.

Altbark

V brakes or dual pivots with compatable levers if you want worry free, easy to adjust stopping power. Cantis if you like picking scabs, enjoy listening to squealing brakes and really don't like having decent stopping power. Yes quality cantis can be set up but why bother? Al

LarDasse74

This post reminded me that the OP's brake assembly doesn't look quite right - you can see there is only one nut holding the brake together on the main pivot bolt, where normally you would expect to have two - one tightened just enough to remove play between the arms and another to tighten against the first and act as a locknut. If these brakes were indeed meant to have two nuts, the one nut will be constantly readjusting itself and will never be correct... either too tight or too loose will greatly affect braking power. Unless someone has done some magic with that brake in the past (like adjusted it perfectly and put locktite on the nut) then I would bet adding a cap nut or acorn nut and properly adjusting will make a big difference.

paulapart

Thanks for such a thorough and speedy response, y'all. You've taught me so much so fast.
Before these cantis I tried out the stock V brakes with the new setup and found they also didn't perform well (worse, even). Maybe they just weren't calibrated right.
Sadly I don't have the V brakes anymore. This all happened longer ago than I would like to admit. Other confessions: yes, the front pads are upside down in the image. and yes, I lost the 2nd nut(s) because, well, I'm dumb.

I'm looking into dual pivots with good pads. salmon! As for dual pivots, what would y'all recommend on a budget? I recall someone saying that I'd need "long reach" calipers, that right? How do I know whether or not brake levers are compatible with dual pivots?

fietsbob

you should look in to short arm direct pull , but they cost more , and match brifters for cyclocross setups

or buy the right V brake compatible lever with the longer arm brake.

did you go down a 26" frame to 650b or 700c wheel change road, it' s a fool's errand.

FastJake

As everyone has pointed out, you replaced excellent V-brakes with super-long reach single pivot sidepulls. The problem is the new brakes

No, don't get dual pivot calipers. Use the bosses the frame has provided and get another set of V-brakes (and the correct V-brake drop bar levers) or a set of traditional cantilever brakes.

Cable routing on the bike also looks pretty poor. Cable setup on a bike matters a LOT. Almost as much as the type of brakes you are using, and certainly MORE than the level of shifting components you're using. Read this the next time you set them up: https://sheldonbrown.com/cables.html

LarDasse74

FastJake is right -

Not only is your bike designed for V-brakes, but it will likely be cheaper and easier, and not look like a kludged-together stolen bike, if you us V brakes and the proper levers.

In my experience, V brakes beat the stopping power of even the best dual-pivot calipers.

The simplest solution is to use mini-v brakes, if they will give you enough tire clearance.

paulapart

Okay, it all makes sense now. This bike comes with V-brakes for a reason, and V-brakes it shall have.
So the question: what arm length do I need/how do I measure it? I see Tektro's got 926a's (80mm), RX5's (85mm) and RX6's (90mm). It's about 75mm from the center of the post on the brake mounting post to the top of the wheel (going straight up the fork). I assume the shorter the arm length I can manage, the better off I'll be? I just don't want to end up with ordering brakes that don't fit and all that jazz.
Lever-wise, will the Shimano Super SLR lever I've got on there now work with mini-Vs?
Finally I'll be sure to reroute the cables properly next when I install the new setup.

I really appreciate all the thorough feedback. You definitely saved me from some real danger. Danger that no mechanics have been quick to give me a real explanation on. I'll post results when they come in.

Airburst

Mini v-brakes will work with the standard road lever you've got at the moment - that's the point of them.

With V-brakes, if you get V-brake levers, the precise arm length doesn't really matter, in my experience, they all work. Basically, longer arms will give more braking power, but will require more cable pull to operate.

frantik

you can use cantilever brakes with a bullhorn..? as long as you have the cable stop on the stem or a fork mounted one it will work fine

Cantilever brakes are far and away better than single pivot caliper brakes

actually, seeing other posts in this thread, you probably used to have V-brakes which typically feel even more powerful than cantilever brakes. you can get road levers for vbrakes. or use older style cantilever brakes with the existing brake levers

whatever you do, ditch those single caliper brakes