forresterace

Generally, is it possible to convert a frame that is set-up for center-pull cantilever brakes to direct-pull V-brakes. In other words will the brake mount studs be in such a position on the frame and fork to allow pad adjustment on the V-brake arms to match the rims.

thanks

Monster Pete

The mounting points for cantilevers are exactly the same as those for V-brakes, so generally you can mount either to a frame/fork without difficulty. However, you will need different brake levers for v-brakes compared to cantilevers. In some cases, you might have to ignore frame-mounted cable stops and just run a single length of housing from the lever to the brake. Once set up well, cantilevers can give just as good performance as v-brakes though..

HillRider

Mechanically, Pete is correct but I've found that good quality V-brake (Avid Single Digit 7 in my case) coupled with the matching levers do indeed give better feel and require less lever effort than cantilevers, even those "properly" set up.

AEO

there is one measurement that is often overlooked and it's the distance between the two studs.
Some older canti equipped bikes have this on the narrow side, which makes them unsuitable for V-brakes.

HillRider

Interesting point and I wonder how narrow is too narrow? I installed the Avid Single Digit 7's mentioned above on a Surly Cross Check with what appears to be a road-type fork and seat stays and had no problems at all. The Avids have several spacers between the pads and the arms that can be arranged as needed to allow for a fair range of stud spacing.

Admittedly the Cross Check is designed to fit wider tires than most true road bikes so the spacing may be larger but I expect it's no wider than most canti-equipped touring or cyclocross frames.

AEO

cross check is relatively new.
I'm talking about 80's and 90's touring frames which can have them around 58mm to 75mm range. It's quite impossible to get things mounted properly when they are on the narrow 58mm side.

HillRider

OK, that's good info. My Cross Check measures 75 mm center-to-center of the mounting posts both front and rear.

Retro Grouch 

One issue that frequently has to be overcome is lack of cable housing stops. A linear pull brake needs cable housing to function and canty brakes are pulled by the bare cable. The simplest solution is to run a continuous cable housing from the lever to the brake and zip tie it to the top tube.

fietsbob

by contrast, I measured .. My older fork has a 65mm boss spread, another , a 60.

rear is wider on both,,

HillRider

All of the bikes with cantis I've dealt with had top tube housing stops for the rear brake just like calipers. For the cantis there was a section of bare cable between the stops, a short run of housing from the rear toptube stop to the rear anchor and then bare wire to the straddle cable. Substituting V-brakes just required removing or bypassing the rear anchor and running continuous housing from the rear toptube stop to the noodle. Noi zip-ties or other jury rigs required.

fietsbob

dont know, as OP didn't offer, but some frames brazed a tube along side the seatpost,
for the cable and it acts as a hanger. last housing stop is on the front of the bike, then.

QBP solves that sort of situation, with a clamp on,machined, alloy housing stop.

FastJake

Speaking of cable stops.. I had to do some weird routing when I put V-brakes and gears on my 95 Tassajara. As you can see, the bike was meant for cantis and has a braze-on to run a bare wire to the brake. There was no way I could run housing from that stop so I used the front derailer stop for the brake. Then when I put gears on I used the rear derailer stop for the front derailer cable. Leaving only the RD cable to be strung through the canti stop. It looks goofy but it is the only way it would've worked and everything works just fine.

bradtx

forresterace, Unless you have a bicycle designed for roller cam brakes the linear pull brakes will swap in, along with a set of matching ratio levers no problem. The bosses/studs for roller cam applications are much closer to the rim's level than a cantilever's position.

Brad

PS I forgot that you could use a Travel Agent https://problemsolversbike.com/products/travel_agents/ or similar product.

gyozadude

+1 on that. The older touring bikes with narrow braze-ons (e.g. bridgestone T500/T700 models mid-80's) were designed around a tiny fulcrum cantilever like the older DiaCompes. Even normal Cantis, like most of the Shimanos will not work on these guys. 58mm reach? Really? Mine on the T700 are even less clearance than that. The braze-on posts are literally, just too high. They need to be down 4mm. (and these bikes were designed for ISO 630/27 inch wheels!) The only ones I found other than the stock Dia Compes, were the first gen DeoreXTs using a narrow pad with the canti-studs fully retracted so the brake shoes are touching the canti-brake. Then there's enough room to brake and still allow a gap. The newer tektro oryx or nashbar equivalents and newer shimano cantis all are no-good (and I have sets in the spare parts bin that were tried). Bummer. The Dia Compes were okay back in the day, but compared to the stopping power of even low-end Acera V-brakes, there just is no comparison. But I live fine with my old DeoreXTs with modified low-pro canti-shoes.

But one trick I use with linear pulls where the canti-posts are brazed on far enough down from the rim, many come with brake shoes that have thicker and thinner spacer washers on the threaded post itself that also work with a curved washers that allow you to toe in the shoe. Usually, the thicker washer is on the inside of the shoe and pushes the shoe closer. If you have close-spaced canti-posts, try swapping with outside set which should be thinner. This will push out the shoe 2mm outward on each side, and may get around the issue of the cantilever posts being too close to the rim. You can also try to swap to a thinner rim as well. The combination might give you more working gap to allow the shoe to be properly gapped between rim and brake. The only thing that might bug you is the closeness of the V-brake arms where the accordian boot that slides over the noodle might get pre-squeezed.

TurbineBlade

+1. V-brakes are nothing magic, and I personally don't like them. They're basically just a cantilever brake "stuck" in the high-leverage, low travel adjustment. They require very little hand pressure to get extremely high leverage, but as a result the pad travel sucks ass. I prefer cantilever brakes, which are adjustable for the mechanic.

Plus - are you running a bare cable from that seat tube braze-on to the rear derailleur guide? if so, that's not a great idea -- just run full housing from your right shifter along your top tube and then to the right side and down the right seat stay. Just leave the seat tube braze-on unused. I have a frame almost identical to yours and I also didn't use the seat tube braze-on.

CharleyGnarly

That is kinda funny.
I have an old Gary Fisher Mamba that I put Vs on and did something similar. I am running a 1x7 setup so I have no front der, so I was able to use those stops.
And I have bare cable exposed as well, and it works fine. I will have to check it out later and take a pic of it.

alex jb

I just took a bike the other way.I had a Scattante R330 with mini V brakes and mountain flat bar levers. I went drop bar and although the short travel/high leverage of the 105 road shifters with V's made for powerfull brakes, it left poor clearance and any sign of the wheels being out of true and the brakes would rub.Problem solvers travel agents fixed the ratio's back, but I went to canti's for better debris clearing.If you want brake power and have tough wheels that stay very true, I think V's can be better than Canti's but it is very application dependant.

TurbineBlade

Given that it's for a shift cable and not a brake cable, I still can't see how having a metal cable rubbing on the frame in at least one location is good practice for routing cables on a bicycle. An exposed cable traveling in a staight line from stop to stop is one thing, but that's not what this picture shows.

I remember NYC bike snob had a few pictures of "housing-less" brake cables that kind of reminds me of this. This gets the "Seal of disapproval" man. And you don't want that.

CharleyGnarly

I see what you mean now. Didn't pay close attention that early. That is weird, and will eventually rub right through that tubular guide by the seat tube clamo. Those things are pretty soft.
And my rig is in a straight line. I gotta pay closer attention....