Disc brake on front only = stupid?
 

As a geek, I can't help but see the superiority of disc brakes. Of course, I'm not a cycling geek, so maybe I'm missing the reason why discs aren't more common. Regardless, to indulge my fetish, I've either got to get a new bike, or add a disc-compatible front fork. In cycling parlance, is this ********? The bike in question is a Kona Jake.

Not stupid at all, in fact probably much smarter than getting a new bike just for the discs.

Why not? I've thought about doing that to an older Giant mountain I have that I really like otherwise. I am worried my current fork might dive too much with a disc even though it is "disc ready", so think about that a little.

Alot of cars have a similar setup...disc brakes up front, drums in the rear. Some small motorcycles don't even have a rear brake :).

You're no more of a geek than the rest of us. A replacement fork is an excellent solution to your problem of rim brakes. The kona p2 disc fork is an excellent option.

There're also disc brake adapters for cantilever frames, e.g., DDG disc mount.

http://www.supercycles.co.uk/images/...ke_adaptor.jpg

I thought of this option too. It's just that I'd rather not stick a fork that's not a Miyata on my Miyata :)

I've been giving it a lot of thought. I've been riding an older hybrid POS (Specialized Crossroads) and justify (rationalize?) each upgrade with the idea that I'm probably going to get a Surly Karate Monkey to build up for trail riding and foul weather commuting. It's the foul weather bit that has me thinking disc for the front--I'll almost certainly go with canti or V brakes for the rear...

Go for it. I'm about to do it myself.

Is your front hub disc compatible? If it is then you should be all set. I'd recommend mechanical disc brakes, they work just as well as hydraulic disc brakes on the road, they're cheaper, and easier to service. I'd say different if you were riding a dh bike though.

I want a fixie with a front disk. Like a cross check with a diff. fork or something.

No it's not stupid. When I go disc on my 4300 the front will be the first one.

Is just a rear disc helpful or would it be a waste of money because the front brake does most of the work (as the fronts do in cars)? I have a Cannondale F500 which came with mounts for a rear disc, but not for a front disc. I always thought it was kind of weird that if they only provided one it would be the rear mount. But that's because of my car experience.

Skip Montanaro

I built my current bike out of a Nashbar cyclocross frame and fork. Front brake is the Avid BB7. No brake on the rear yet. Rims are disc brake only. Haven't felt compelled to get the rear brake. Commute with a moderately loaded rack. I weigh nearly 200lbs.

I like to ride fast and have to stop and start a lot to get to and from work. Round trip 22 miles, five days a week. Bike is now one year old. One disc brake is serving well.

I did just what you are thinking about. I commute on an old Surly 1x1 that did not have disc mounts. I bought a Kona P2 disc fork, a used disc wheel set and Avid BB7's. I can't believe how good disc brakes are compared to V's. I'd like to have a rear disc brake too, but would rather weld on the mount instead of using the DDG mount.

I'd be fine with just a rear disc on a MTB, as I ride slow but often go through mud. Road bike, front would be just fine since that's where the majority of braking power is. Although, if I were towing a trailer, I might like to have both, as I think even on a bike you'd notice the rear brake being able to do more work with the extra load.

I put disc brakes on my front last fall. They're great. I don't see any point in putting them on the back for two reasons:
1) the rear brake is hardly ever used anyway
2) the rear brake is a lot more work and more complicated to put in.

It took about 20 minutes total to put the brakes on the front (I already had a compatible fork) if you don't count that I had to build a new wheel for it. The existing rim was getting about worn through from the grinding that the rim brakes gave it so it needed replacing anyway. The only extra cost due to the disc brake conversion was that I had to buy a new hub, and nobody had the cheap ones so I wound up paying $55 for the hub (and $60 for the brake; Avid BB7). All I bought apart from that was a new cable.

I have a Jake the Snake where I put on a front disc. I got the carbon cross fork from Nashbar, they have it on sale every few months. Bought a disc hub, rebuilt the wheel and got an Avid bb7 road disc. was a huge difference in stopping downhill in the rain at 6:30 in the morning. Compared to the canti brakes the difference was dramatic, ymmv.

The pictures below are crappy because its in my messy garage, it was raining :)

Woops, put in same pic twice, how do you delete attachments? ahh well, consider it stereo !

Discs are common on nearly all bikes. Any bike that uses a hand activated caliper brake is a disc brake...they just have really large rotors.

Is it worth it to retrofit to hub mounted disc brakes? Only you can determine that. Do you ride a lot in the rain or are your current brakes lacking in stopping power? If you ride in the rain a lot, they might make sense. If your bike lacks in stopping power, try adjusting the brakes first. Here's a good place to start.

If you want them just because they are sexy, consider the cost. A new fork will cost you from $70 and up. You'll need a caliper for around $70. You'll need a new wheel for $70 up. That's $210 minimum to do the conversion, not including the cost of labor (if you don't do your own work). That's a lot to put into a $850 bike unless there is something really wrong with the bike.

Jarery, how's the tire clearance on those forks? Can it fit up to 45c?

There are lots of reasons they are not more common, chief among them they don't stop any faster than a $19 dual pivot caliper. The do work better in the rain, snow, and don't wear the rim though. If they could be made to sell for $19, and not weight much, I'd consider them.

Not a complete waste if you commute in muddy, rainy weather and road conditions. Ever notice how the rear rim and brake is always so much muddier than the front? The front seems to kick up the spray onto the BB and rear rim or it disturbs the mud so the rear can them swim in it. Take your pick. Either way a disc on the rear would help avoid the far more rapid wear of the rear rim from the abrasive rubbing of the brakes.

But in terms of stopping power you're right. Most of the stopping power comes from the front. Especially when you're trying to stop as hard as possible. Ever notice how the rear locks up so quickly when you're really squeezing on the front? That's the weight transfer to the front taking away load from the rear so it locks with less pressure. It's counter intuitive but in a serious panic stop as you squeeze harder on the front you should be easing off the rear to where it's not quite locking up. But that's a hard thing to think about when an ugly big SUV just drove across your bow.



Back to the front disc topic.... A few years back when discs were a must have and the frame makers had not quite caught up with the designs it was common on the mid priced bikes to find a disc front and V brakes on the rear. So your frame will not implode or anything like that if you do this and your braking ability will be enhanced.

45C? No idea. The Nokian cross tires it originally came with are the widest I own. Those we 32's i think. I ride on 25's for my commute. I think 45's would be pushing it for a cross fork though.

Yes, I'd like to know this too.

True, there's nothing really wrong with the bike, but when it comes to toys, it's hard to define a "Need" versus a "Want." I didn't say it was supposed to make sense!

Seconding the "only in the rain/wet" replies. I run this setup on one of my MTB's - I ran v's until I got caught in a freak thunderstorm during a ride. I had no stopping power and lots of ups and downs to negociate, it was hairy.

http://www.geocities.com/hobartlemagne/GoldieRims1.JPG

I customized my fixie with a front disk brake. I added a cyclocross fork to do it.