Flying_Pigeon

Hi everyone, first post here!

I have an old'ish bike (Cannondale Killer V500) and would like to upgrade some of the equipment on it, mainly upgrading to disc brakes.

The problem is that I only have the necessary brackets for disc brakes on the front, due to having replaced the original (hard) forks with Rock Shoks.

I would like to know if it is worth fitting a disc brake on the front only (the front brake seems to provide the most stopping power) or, if not, are there brackets available to retrofit disc brakes on older style frames?

Any help is much appreciated

Stacey

And its the ubiquitous "disc brake question" too.

You'll get the maximum ROI by doing a front only conversion. If you have linear pull brakes then the job is really straight forward.

To try to add rear disc, you're just not gonna get the bang for the buck.

Flying_Pigeon

Didn't realise, my initial search was maybe not thorough enough.

Thanks for the reply, are you saying it's possible to convert to disc brakes at the rear of an old style frame?

tsl

I think she's saying that in general terms, from a cost-effectiveness standpoint, going to front disc only makes the most sense. My guess is that since the front does 90% of the stopping, spending the same money on the rear, gets you only 10%. See?

As for converting an old frame, anything is doable if you throw enough money at it. Custom re-fabrication of the dropout is technically possible, but very expensive.

Flying_Pigeon

Thanks for the advice, I guess I'll look into front disc brakes only...

tsl

Don't forget to include a new front hub plus wheel rebuild labor, or a whole new front wheel into your budget. Earlier in the year I thought I'd convert my commuter rig to discs. It seemed cheap enough until I factored in the new wheels. I bought a new commuter rig with disc brakes instead.

wroomwroomoops

While I mostly agree, I'd like to point out that there are legitimate ecceptions to the rule; for example, one of my winter bikes (which I have now deconstructed) had a diskbrake in the rear. Why? Because in the winter, when you cycle on uneven, bumpy ice, sometimes covered with loose snow, or on very hard-packed (and very uneven) snow, or down a hill on ice (this is Finland), you'll notice that your safety is better served by a rear brake you have good control of, and is dependable regardless of snow, rain or other precipitations.
V-brakes in front were all I needed for emergencies. This setup was the fruit of many experiments and a longtime experience. You might disagree, but if you were in my shoes (that means, going through the finnish winters cycling), you would come to the same, or similar, conclusions.

JonathanGennick 

With respect to the original post, I'll point out that the new Kona Ute is designed with disc-brake in front and v-brake in back. So there is at least one off-the-shelf bike available in the configuration that the original poster is thinking of.

spinninwheels

The convertion is well worth the money in my books. But then again I did it to my T2000 frame. If you're mechanically inclined at all and you have the tools, you will save some money. My convertion was just under $300 for a BB7, fork, Deore hub and A719. I did all the work myself except for cutting the steering tub on the fork.

The biggest advantage is your stopping ability in rain. I live in Vancouver - it rains a lot here. Plus, it saves my rims. The [rim] brakes are hell on your rims in wet conditions. I would normally be changing rims about every year and a half (front and back) otherwise.

The convertion will pay for itself in that time period.

Flying_Pigeon

I think I'm pretty much set on a disc conversion for the front....

....now the next question would be the additional advantages of using a hydraulic type over cable activated.

HillRider

My experience is that rear rims fail from rim brake wear much sooner than fronts even though the fronts have much more stopping power and are (or should be) used more. I believe it's because the front rims live in a cleaner environment but they throw road grit and spray up onto the rear rim which lives in a much more abrasive world. So a rear canti or V-brake will cause rim wear on the most vulnerable rim.

JiveTurkey

Mechanical would allow you to use your current brake levers (if just for symmetry's sake) and it will be cheaper. Hydro is better, yes, but decide if you need it.

Portis

I wouldn't do it. The front wheel is MUCH easier to stop for ANY brake, including v's. On top of that, how much of your normal braking is done with the front wheel? My guess is not that much.

HillRider

If it's not, it should be. The front brake is much more effective.

wroomwroomoops

With the ecceptions I noted.

Portis

Yeah that is often said, and i won't disagree. But ride long enough and often enough using more front brake than rear and you will grab too much of it some day and realize an unpleasant result.

I only use my front in conjunction with my rear. I see the point that the assertion here is that adding a disc to the front will be worthwhile because it provides more stopping power. My belief is that it provides no real benefit because a finely tuned set of V-brakes will stop just as well on the front, maybe on the back for that matter.

spinninwheels

I agree. My rear rim would always look concave, while my front rim would look somewhat better, though still showing signs of wear.

However utilizing a disc brake on the front of my bike, saves my back rim because I don't use my rear brake in wet conditions now.

CdCf

On my SS commuter bike, I have a disc front and V rear.

To avoid wearing down the rear rim, I almost exclusively use my front brake only. If I anticipate a hard brake coming up, I lightly touch the rear brake to get a feel for the point of contact and stay prepared.

I'm doing a pretty good job, as my rear rim is very clean (something it never was for more than a day or two when I used it all the time).

So yes, all you need is a front disc, unless you're a downhill racer or if you want to use a rear disc to avoid rim wear (which is wise).

Sheldon Brown

Going downhill on ice you would use a brake?!...?!

Sheldon "Whoooooooosh" Brown

wroomwroomoops

Yes, I have in my mind a very specific place where I don't have more than 1.5m to stop on the road after the hill (the hill is not paved, just frozen). The road is perpendicular to the movement of the bike, and the inclination is terrible. Then the road is a sudden flat surface. If I don't brake I'll kill myself.

Michel Gagnon

It probably depends on your brake use. I replaced a front rim one or two years ago and have two front rims (on different bikes obviously) that show definite signs of wear. Rear rims on those bikes still look like new. And I also replace brake pads once or twice a year on the front brake of each bike whereas I hardly ever replace pads on the rear brakes.

MudPie

See this to convert your frame to handle disc brakes. Seems like a slick idea.

https://www.therapycomponents.com/BRAKETHERAPY.htm

HillRider

I use both brakes pretty evenly and I've had several rear rims fail from brake track wear over the years while front rims last much longer on the same bikes. Also, my rear brake pads wear down significantly faster than the fronts.

My only explanantion is that the rear rim gets sprayed with a lot more grit and dirt than the front so it lives in a much more abrasive environment even if it does less of the actual braking work. This disparity is particularly obvious on my rain/beater bike which is used only in wet, dirty conditions and the rims and brake pads wear faster on it than on any other bike with the rears being particularly wear prone.

Portis

I'd say the rear does plenty of work, it just has a LOT of work to do.

Sixty Fiver

When people come into the shop to have their bikes serviced I always note the brake wear and if their rear brakes are unusually worn (in relation to the front) I often give a quick talk on proper braking technique as if you are using your rear brake as your primary then you're not doing it right.

Proper use of the front brake will stop you faster and with practice one can use their front brake for hard stops in complete safety.

The rear brakes on my bikes look pretty fresh as they don't see much use at all while my front brakes get replaced on a pretty regular basis.