bsyptak

I'm thinking that disc brakes will start showing up in greater numbers on lower end bikes because lower end bikes are heavier to start. It will take some technology to get the weight down enough to get them on a 15 lb bike. Maybe tiny calipers and smaller rotors since less braking force is required? Ti and AL rotors are already in use.

I will say that hydraulic disc brakes are hands down better than any rim brake out there. The buttery soft pull of a lever with a single finger on a steep downhill is more than enough to slow you down and ease you down at a crawl without locking up the wheels.

One could say that putting disk brakes on a mountain bike was an attempt to solve a problem that did not exist. I mean, v-brakes do work. But disc brakes are light years ahead in performance. Good luck finding v-brakes on any high end mtb these days. Expect the same in the road world.

simplyred

How fast are you going that you need disc brakes on a regular basis?

umd

I stand corrected, but my point still applies.

Banzai

It appears that no one has perused the article I linked.

Please do so, then start shot-gunning speculation on the board.

bsyptak

It's not the speed necessarily though disc brakes are better in that regard too. It also saves your [insert $ value] wheelset from dying due to brake surface wear. Wheels conceivably last forever, well until the chain/cassette goes the way of the doodoo bird in favor of some sort of internal transmission. Wet riding doesn't gunk up the wheels & braking surfaces. Pads last longer.

Another reason is that manufacturers are always looking for ways to encourage/prod you to replace your bicycle with a shiny new one. The best way to do that is to make your current one 'obsolete'. Disc brakes don't work on rim brake equipped frames, though they could on the front with a hub/fork switchout. Who bought a new bike because their old one was steel or their old one had a quill stem or downtube shifters or a 5-6-7-8-9 speed drivetrain or center-pull brakes or single pivot brakes? Downtube shifters are over a half pound lighter than brifters. 10 speed is unnecessary.

Fast forward X years: marketing and forced obsolescence killed the rim brake

umd

Never say never. I had similar debates with people when digital photography was just getting started. It was a common belief that digital would never replace film for most people. I won't take the other side of the never debate, but I will say that given the present state of the technology and market, rim brakes are adequate for my needs.

waterrockets 

Zinn has forgotten more about bikes than I'll ever know, but he loses credibility with me when he claims there's an appreciable benefit to lower rotating mass.

Most of the article talks about getting the technology blessed by the UCI.

There's just not as much braking in road biking as in CX, XC, or DH racing. Descending is an obvious exception, but most of the races in the US are crits, in which we barely even touch our brakes for the entire race.

If they can make a disc-braked road bike within 1/2 lb of a D/A calipered bike, for maybe $100 more, I can see them starting to take over. I just can't see the weight and price getting that low.

bac

If weight is not a BIG issue, why would anyone consider rim brakes?

For me, there really is no comparison between rim and disc brakes. Discs are better idea in just about every circumstance. With the exception of weight (ex: if you're racing), there is no good reason to use a rim brake over a disc brake - none.

... Brad

simplyred

I can see carbon fibre disc brakes coming out - inspired from car racing applications. Heck - I can even see the Tour riders using them if they were light enough when descending a mountain pass...

That being said - they still make V-brakes and linear-pull brakes. I don't see how rim brakes will end in production - but definitely in popularity...

waterrockets 

Well, don't forget aerodynamics. And price.

bac

I'll buy those reasons.

... Brad

DiabloScott

Bike makers could completely solve this by putting the brake mount on the other side of the fork but they're too afraid of admitting the problem even exists.

I'd favorably consider disc brakes for a muddy MTB or cyclocross bike or winter commuter but there just aren't enough downsides to rim brakes for me to consider them on a regular road bike.

sac02

I doubt you will see carbon rotors on bikes. Those kind of brakes require extreme heat to function properly. Not "One time I touched my rim after a descent and it burned me" hot, but "glowing red or hotter" hot. We experimented with some on our FSAE car and couldn't get them hot enough, and for cold stops they were just scary. We couldn't get them hot enough with a 55hp, 375lb car stopping from 80mph - I doubt they'll get hot enough on a 200lb rider-and-bicyle combo.

Mac

MichaelW

ISO mounts of front of fork: Cotic road rat
and on chainstay rather than seatstay: Simpel Dailybread
The non-standard brake location solves a couple of issues:
Front axle popping out under braking when the QR is not 100% tight. You cant use this improved location with a disk dynohub.
In the rear, it solves issues with rack and fender mounting.
Both these frames are general-purpose doitall road bike for commuter use, not road race bikes.

Jerseysbest

I don't think there's a big argument to put disc's on all road bikes, just where they're useful.

I don't want them on my road bike, but on my touring bike, yes. There are, however, a few hills I've been down where the brakes on my roadie weren't doing the job and I'd wish I had some better brakes, but those are far and few between wouldn't never justify the cost.

2WheelFury

Disks could potentially do two things:

1. put more of the rotating mass towards the inside of the wheel, rather than the perimeter (less moment of inertia, meaning easier to speed up/slow down rotational speed)

2. much thinner/lower profile rim sidewalls (related to #1). Rim sidewalls wouldn't have to be tall enough to provide a contact patch area for brake pads anymore.

So yes, I think there's some potential gain to be realized here.

UT_Dude

I'm going to contest your bit here, but only somewhat.

Wheel changes are (I think) faster with discs (from experience with MTBs).

Yeah, you need a somewhat stronger frame/fork, but I don't think that's as much of a penalty as you think, because I don't think you have to put that much more strength in them. If you can endo a road bike (put all the weight on the fork for a few seconds at least), then it should be strong enough to withstand the force of stopping the bike.

You'd lose some spacing, yes, but well worth it for the benefits. Or they could just adapt a slightly wider hub. It's not really that much spacing. Considering that it's now the norm on Mountain Bikes, I can't see it having been a big penalty to lose the spacing -- those wheels are plenty strong.

If you're locking up your tires that easy, maybe it's time for new tires? Yeah, it can be done, but it's not *that* easy (for me).

I think the real benefits aren't so much increased stopping power, but rather better modulation, lower maintenance (no new pads for carbon rims, etc), ability for the brake to actually grab in the wet (my MTB brakes work fine in the rain because they're discs, my road brakes work, but lose considerable useability). Plus, you don't run the risk of overheating rims and blowing tires, I still think you'd have faster wheel changes, and plus they just look cooler!

malpag3

+1 to braking predictability.

My g/f has a Novara Big Buzz with Avid BB5 Disc Brakes. It's a great commuter/city bike for sure.

Cone Wrench

Disc brakes could be dangerous in a group ride crash. A disc, specially a rotating one, could really cut into flesh.

malpag3

Yeah aren't they forbidden in some kind of racing? I forget, but I recall hearing something like that and the reasoning was exactly that, they're sharp and nasty.

Rutnick

The bike pictured is a more of a city commuter bike. The Portland is actually a great bike. All weather. I have the LeMond Poprad version that is steel with a carbon fork. Min has it too. It has BB7 disc brakes. Wheel changes? Well, they are just as fast or faster than standard brakes. I don't have to flip open the brakes to remove them. Open the skewer and well...there is the wheel. The skewer issue? What skewer issue? What issue about the front wheel coming off? I've never had to retighten the wheel on this bike. For whatever reason, I put the skewer on the front wheel on the drive side. Probably because it was a PITA to get off the other way. ZERO issues. Zero issues just like my disc MTBs.

MTB had the same issue with early disc brakes. They were junk and rim brakes were still superior. Fast forward and the BB7 is the TOP mechanical disc brake. That has the ROAD BB7 disc brake and they are awesome.

Now, waterrocket is talking about weight....jeez...HE'S talking about weight saving? HIM? The steel bike rider who's bike is what? 19lbs? Min's poprad is 18.5lbs WITH discs. Mine is right at 20lbs.

slow? umm...yeah, my Poprad is a X bike but it is NOT slow. Slower on the climbs maybe but not overall. I ride it in the winter months when it is cold, raining, snowing or whatever it is. 800 miles of riding in rough weather. The discs came in handy. When I did 3S3M in the rain this year, I wished I had the discs descending off the mountains.

You need to look at the engine more than the bike weavers.

Another great application for road discs is tandem and touring.

If you guys think those 6" rotors are just too much, you can alway ride my XC bike with 8" rotors.

Personally, I think road discs are a fabulous addition to my stable. It give me better wet weather options.

Water, have you even ridden or raced with disc brakes in ANY fashion? I have in MTB and have done tube or wheel changes during a race. unless you are a bonehead with hydros and grab the brake with the wheel off, it is fast to change the wheel. The BB7s pictured are fine because the pad is already spread apart and is mechanical.

As far as the front wheel flying off while riding, never happened. I look at what I have and use the proper skewer the FIRST time. Shaving weight with a skewer is a bonehead move anyway.

Rutnick

you roadies need to HTFU.

You don't ever think the dirt guys wreck or draft off each other? I've never seen anyone ever cut with a rotor.

Hell, I run serrated rotors on my race MTB. Good thing I haven't killed anyone with them yet. Especially in that 25 person group I rode with. Hell, we probably rode closer than most of you guys in a paceline.

Rutnick

The poprad and portland both already have both of those features. The rear brake is already on the chainstay.

Both bikes already have ISO mounts.

Kastnerd

Since Disc brake hubs are 135mm most of them have better spoke angles than 130mm hubs.

Do you think its possible to spec out a 14lbs disc brake road bike?

sfcrossrider

Paging MIN.