Working on a '98 trek that came with cantilever brakes. Putting on generic shimano v brakes that the shop owner said would fit front and back. I successfully installed and tuned the fronts, but the back cable won't keep tension. I confirmed the cable isn't slipping from the pinch bolt by marking it. The levers are correct for v brakes. My suspect is the small cable routing running along the side of the seat tube. Seems like the angle it's running the cable is keeping me from getting it tight without bending it. Any ideas? different angle noodle or would this require frame modifications. I pull the cable until the brake pads are almost on the rim, then tighten the pinch bolt there. After one brake pull, the cable is slack and the housing comes out of the brake handle
by tx_longman
12 Comments
You need to run the cable housing all the way to the noodle.
It looks like a piece of cable housing is missing – from the frame to the brake noodle.
That stretch needs brake-specific cable housing; and needs to snug firmly into the end cap attached to the noodle. Then recalibrate the brakes.
this will never work, unfortunately. that cable guide that’s brazed onto the frame is meant only for cantilever brakes, and will only work with cantilever brakes. sorry! you can run full-length housing from the brake levers to the brake, holding it down with zip-ties or whatever. it’s ugly but will work.
The way you have it will not work. The brakes need cable housing routed into the noodle in order to work.
You can use a clamp on cable stop to bypass that little brazed on steel macaroni cable guide. Problem-solvers makes these, I believe Origin8 does as well.
The cable routing you are using is intended only for cantilever breaks.
Some people have found ways to mount cable housing into that little cable guide, but it requires some ingenuity, like using a step down ferrule that will fit into the cable guide.
I’ve converted a bunch of these to v-brake and the best solution I’ve found is a clamp-on cable stop that sits on the top tube against the seat tube. I’ve seen a bunch of attempts to repurpose the little tube and none of them work that well in my opinion.
https://preview.redd.it/j397efgwi42g1.png?width=624&format=png&auto=webp&s=0dc79faa0c6fcabba0cb4608bc7201e9fe872e22
Yeah you need to find a way to run brake cable housing from the braze-on cable guide at the seatpost clamp to the noodle. Right now when you pull the brake cable you’re just pulling the slack out of the cable without moving the brake arms enough. The little coffee straw is just to keep that spot from rubbing metal on metal. If the cable guide is too small to accommodate housing you might need to modify it or run full length housing past the seat post on the other side to the lever with zip ties or something. Or just run cantis if you don’t absolutely need to do this conversion.
If you don’t want to buy anything else to make this work then you just have to run housing all the way from the brake lever to the noodle. Bypass all of the housing stops on the frame and zip tie the housing to the top tube.
Funny i love the cantilevers on my 98 trek multitrack 700, are you gonna swap the grip shifters? That’s my next project
Why are you downgrading from cantilever brakes to V-brakes? You said the bike came with cantis. Do you not know how to install them?
Just take the V brakes back and get cantilever brakes. The V brakes work in that they will melt on the same bosses but the thing you need most is a straddle cable and or cable hanger. You should be able to get brakes front and back for that thing for $40.
I’m unable to edit this post, but I’d consider this solved thanks to all who recommended clamp on cable guide!