Why don't road bike have disk brakes?
 

Seeem to me that disk brakes on a road bike would be a better solution and create less wear on the wheels. Who don't they use them? Is it a weight issue?

Weight for one, and for another you don't need the stopping power in the mud and such because (hopefully) you aren't riding through the mud and through streams on a road bike.

some road bikes do. giants touring bike for one http://www.giant-bicycle.com/us/030....h_text=touring

as to why most don't, cydewaze got it.

mine does

http://gallery.roadbikereview.com/sh...&ppuser=246067

Sorry You May Not Link To Images Consumerreview.com

My bike has them. The manufacturers haven't given us discs on road bikes yet because the technology is still MTB technology, where strong downhill brake performance is more important than everything else, including weight.

Eventually, manufacturers will come up with a "road bike disc brake standard," probably with 3.5" rotor diameters and ultra-light hubs & calipers. When this happens, almost all road bikes will have disc brakes.

Needless to say, this is just my opinion - time will tell where the market goes. I think that the eventual technical superiority of discs will win out.

http://members.cox.net/younggg/Bike1.jpg

http://members.cox.net/younggg/Bike.jpg

You need a much heavier fork to handle disk brakes. They have to be stiff but with no suspension they are not as comfortable.
You can also have problems integrating rack and fenders with disks.
On a race bike you really dont need them.
On a touring bike or winter commuter they might be useful.

I must politely disagree with some of your statements:

1. "You need a much heavier fork to handle disk brakes." I've seen retro 70's touring bikes with lots of flexible fork rake fitted with disc caliper mounts. They work fine.

2. "They have to be stiff but with no suspension they are not as comfortable." Almost all of the MTB style bikes have both suspension AND disc brakes, so the comfort argument fails.

3. "You can have problems integrating rack and fenders with disks." I disagree - mounting tabs are mounting tabs - either the frame has them or it doesn't. If the tabs are there, the mounts are there.

4. "On a race bike you really dont need them." I partially agree with this statement. In the current generation of disc brakes, the hubs, rotors, and calipers are too heavy for race bikes. Once discs are designed specifically for race bikes, they'll take over because they're better.

5. "On a touring or winter commuter they might be useful." Agreed.

Thanks for your comments.

I just bought a Redline Conquest Disc-R which is one of a handful of road bikes with disc brakes. I use it for commuting, and I'll never again buy a bike without disc brakes, the braking is that much better.

Perfectly adjusted rim brakes are probably just as good as perfectly adjusted disc brakes. The difference is that rim brakes go out of adjustment much faster, and are trickier to adjust when they do. It's not a big deal if you're Lance Armstrong and have a team of technicians to rebuild your bike after every ride, or if you hardly ever have to brake, but I ride every day in stop-and-go city traffic, and my brakes take a beating.

Anyone know why Giant discontinued the OCR with disc brakes?

Not a clue.

I'm running a Salsa Las Cruces Cyclocross bike with disk brakes for my commuter. Last winter I trashed a set of rims from riding in the rain. The brakes dug deep grooves in the rims. I should have wiped down the rims more often and picked the junk out of the pads. If the rotors wear down they are a lot cheaper than lacing up a new set of rims. Avid makes roadbike specific disc brakes that have the proper pull for roadbike levers. They work really well once dialed in and they are not too graby. The weight penalty is at least 1lb.

I don't think you can put disc brakes on carbon forks and carbon forks are all the rage.

http://specialized.com/bc/SBCBkModel...d=05Crossroads

The specialized crossroads is sort of a road bike... not entirely though. More of a commuting bike I guess.

here's one:

http://store.yahoo.com/phattire1/recafiroandc.html

The top of the line specialized sirrus has a carbon fork with disc brakes.

I'm glad I snagged my giant OCR touring though. I want a thin and light steel frame (the sucker is currently 27lbs stock), a 22-23lb roadie with discs wouldn't be too bad. With a couple of tweaks, the OCR touring would be just about the perfect bike for long distance commuting or touring.

I can see the use with loaded touring, especailly in the mountians, but not for road racing. Too much brake, too much weight, too expensive. I think UCI banned disc brakes in cyclocross.

Marketing and demand mostly.Most road race bikes arent ridden in the rain or bad weather.Most people with road bikes that are rec riders hide from bad weather like its the plague.

I have a feeling discs will gradually start getting mainstream though, they arent hard to retrofit, and they do work much better.I know 3 guys that ride for a living and have done exactly that.

I have seen it on some cycle cross bikes but I don't think it'll ever catch on as a main stream trend.

The reason? Professinal racers don't use them. The day Lance and Jan start using it, all other reasons against the disk brake people talking about will disappear. Start showing up from the top models in the catalogs and eventually fades out the caliper brakes. It's not which one is better but which one peple buy.

Rim brakes are "integrated" disk brakes.

ROTFLMAO!

Rim brakes don't work if the rim is bent.
Rim brakes generate heat that can (and has) caused tires to explode off the rim.
Rim brakes wear away at the soft aluminum of the rim.
Rim brakes work poorly in wet weather.
Rim brakes often work not at all in ice and snow.
Rim brakes quit working once they're hot (this is why the MTB world went disc).
Rim brakes can interfere with fender mounting where desired.
Rim brakes require opening to remove tires wider than the rim.

I could go on, but why???

If you don't "get" disc brakes, that's fine. Please don't claim that rim brakes are "integrated" discs :p

No they dont work is the rim is bent, but it depends on what you mean by bent. If its out of a true maybe 3mm it will work. I like to keep decent spacing between pad and rim, i use my speed dial to adjust the leverage.
Maybe my bike is different, but i have never seen a tire explode from heat generated by rim brakes. Disc brakes generate far more heat.
Lets not kid outselves about the soft metal of rims. It isnt so soft it gets eaten away in a few thousand miles, yes rims have to be made from a somewhat soft metal to avoid cracking from tension but...with machined sidewalls i dont see it as such an issue. You will have to replace them, but in my opinion by the time the rims seriously need replacing most people will want to change wheels anyways.
Rim brakes do degrade performance in very wet weather, but there are good pads which counter this reasonably well.
If you get water on the rims it can freeze in which case there is no stopping power, this is true.
Maybe its just be but i have noticed my rims getting very hot.
If using V brakes, installing/removing a wheel only requires you to lift the little bridge thing from the noodle, its as easy as a SRAM powerlink

Disc brakes would not only add more weight, but also more polar moment. People who ride road bikes probably don't brake as much as people who ride MTB's (because of terrain differences), so discs are not necessary. I would assume if you're racing a road bike, you would brake even less because you're trying to minimize wasted energy and maximize speed.

I recall reading a couple of bits over on SheldonBrown.com about DOCUMENTED problems with disk brakes pulling the front wheel free of the fork, despite the QR being properly closed. Seem that the directional loading with disks is a LOT higher than with rim brakes. As for me, I'm more the touring type, I could see the advantages of disk brakes, there was a tandem 'bent at the local Memorial Day Ride that had hydraulic disks front and rear, and a "bail out Brake", a rear caliper break controlled by a converted bar-end shifter on the strokers handlebar. I forgot what company made the brakes, but the guy said that model was only made for a couple of years. If it's any help, it was a RANS recumbent.

Just my .02 worth

Steve W.

also you would not be able to use 2.0/1.5/2.0mm spokes for your wheels. You want a heavier guage spoke for discs and it makes a fairly substantial weight difference

Saying "rim brakes are good enough for road bikes" is like saying "drum brakes were good enough for cars." In the end, the superior technology (disc brakes) will win out.