Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

General Cycling Discussion Have a cycling related question or comment that doesn't fit in one of the other specialty forums? Drop on in and post in here! When possible, please select the forum above that most fits your post!

User Tag List

Reply
 
Thread Tools Search this Thread
Old 09-25-11, 06:09 PM   #1
jtdickie
Junior Member
Thread Starter
 
Join Date: Jun 2011
Location: Sun City Hilton Head Island, SC
Bikes: Raleigh Sojourn, Cannondale Super V-500
Posts: 12
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
road bikes and disc brakes

Why is it I don't see disc brakes on road bikes?

Thanks,

Jim
jtdickie is offline   Reply With Quote
Old 09-25-11, 07:00 PM   #2
mulveyr 
Senior Member
 
mulveyr's Avatar
 
Join Date: Feb 2010
Location: In the wilds of NY
Bikes: Box Dog Pelican, Raleigh Sojourn, Specialized Secteur, 1991 Cannondale tandem
Posts: 1,479
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Quote:
Originally Posted by jtdickie View Post
Why is it I don't see disc brakes on road bikes?

Thanks,

Jim
Not looking in the right place?

More and more touring and utility bikes have them. But people who weigh components to fractions of grams would never tolerate the additional weight over caliper brakes.
__________________
Knows the weight of my bike to the nearest 10 pounds.
mulveyr is offline   Reply With Quote
Old 09-25-11, 08:31 PM   #3
BarracksSi
Bike ≠ Car ≠ Ped.
 
BarracksSi's Avatar
 
Join Date: Jul 2007
Location: Washington, DC
Bikes: Some bikes. Hell, they're all the same, ain't they?
Posts: 13,858
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
They're coming.

Race bikes have already been loaded with ballast to meet the UCI-mandated minimum weight. Some people have said that it would make sense to put that extra weight to good use -- such as, say, disc brakes so they don't have to cook wheel rims on 50-mph downhills.

I can't remember its name, but there's a new one with two small rotors on the front, giving plenty of braking force without adding any twisting forces to the fork.
BarracksSi is offline   Reply With Quote
Old 09-25-11, 09:44 PM   #4
tsl
Plays in traffic
 
tsl's Avatar
 
Join Date: May 2006
Location: Rochester, NY
Bikes: 1996 Litespeed Classic, 2006 Trek Portland, 2013 Ribble Winter/Audax
Posts: 6,955
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
It's because they don't sell well.

Trek debuted the Portland in 2006 as the first production road bike with disc brakes. They discontinued it due to poor sales after the 2011 model year.

I don't have many pics of the non-drive side of mine (a 2006 model). Here's the only one I could find fairly quickly.



Other than four-seasons all-weather commuters who are willing to drop some serious coin on a bike to ride in the rain and snow, there's no compelling need for disc brakes on a road bike.

Part of it too is that dealers couldn't figure out how to sell them. I own the only one sold in my area. There are six Trek dealers just on my side of town. Five of them have never even seen one in real life, until I ride in the door, then we're instant celebrities. They all think it's cool, but they don't have a clue as to who they'd sell one to.

Last edited by tsl; 09-25-11 at 09:56 PM.
tsl is offline   Reply With Quote
Old 09-25-11, 10:03 PM   #5
tsl
Plays in traffic
 
tsl's Avatar
 
Join Date: May 2006
Location: Rochester, NY
Bikes: 1996 Litespeed Classic, 2006 Trek Portland, 2013 Ribble Winter/Audax
Posts: 6,955
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Quote:
Originally Posted by BarracksSi View Post
Race bikes have already been loaded with ballast to meet the UCI-mandated minimum weight. Some people have said that it would make sense to put that extra weight to good use -- such as, say, disc brakes so they don't have to cook wheel rims on 50-mph downhills.
The problem with that argument is that the wheels weigh a ton, (well, okay, 2100 grams or so). Sure, disc brakes are nice on mountain descents, but you have to pedal the damned things up the mountain first.

I've done it, so I know it can be done,

but it was neither fun, nor pretty.

Next time I go to Colorado, I'm taking my Litespeed with its 1400 gram wheelset.
tsl is offline   Reply With Quote
Old 09-25-11, 10:30 PM   #6
Nermal
Senior Member
 
Nermal's Avatar
 
Join Date: Jan 2006
Location: Farmington, NM
Bikes: Giant Cypress SX
Posts: 2,067
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
BarracksSi, That's a problem I had never considered, and already there's a solution waiting to go.
__________________
Some people are like a Slinky ... not really good for anything, but you still can't help but smile when you shove them down the stairs.
Nermal is offline   Reply With Quote
Old 09-25-11, 10:48 PM   #7
gbiker
Senior Member
 
Join Date: Aug 2010
Location: Denver
Bikes: Secteur, Camber, Trek 930
Posts: 459
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I've ridden in downpours and down mountains (Mt. Evans even) and have always found rim brakes good enough.
gbiker is offline   Reply With Quote
Old 09-26-11, 07:44 AM   #8
BarracksSi
Bike ≠ Car ≠ Ped.
 
BarracksSi's Avatar
 
Join Date: Jul 2007
Location: Washington, DC
Bikes: Some bikes. Hell, they're all the same, ain't they?
Posts: 13,858
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
http://www.bikerumor.com/2011/04/20/...ights-details/

They say its wheelset is 1490g.
BarracksSi is offline   Reply With Quote
Old 09-26-11, 09:00 AM   #9
idc
Senior Member
 
Join Date: Oct 2009
Location: Virginia/DC
Bikes: GT road, Kona Jake disc, Wabi Special FG, Swift Folder, beater 26" MTB, Genesis Day 00, Salsa ElMar, Raleigh RXS
Posts: 1,451
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by BarracksSi View Post
Nice. $1 per gram.

The next bike I buy will probably be a CX with disc brakes. I have a good, light (enough) road bike for decently dry conditions but I've ridden through enough rain showers now to want something with disc brakes. Fortunately UCI has now legalized disc brakes for cyclo cross so more and more 2012+ models should come with disc brakes. And the CX will also double duty for the times I want to ride a bit of off-road.
idc is offline   Reply With Quote
Old 09-26-11, 09:28 AM   #10
tsl
Plays in traffic
 
tsl's Avatar
 
Join Date: May 2006
Location: Rochester, NY
Bikes: 1996 Litespeed Classic, 2006 Trek Portland, 2013 Ribble Winter/Audax
Posts: 6,955
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Quote:
Originally Posted by BarracksSi View Post
That's claimed weight, not measured. And I doubt it includes rotors (and possibly not rim tape). Rotors count as rotating weight, just so you know. Mine are 120g each, plus let's say 5g each for the six mounting bolts and a drop of blue Loctite. So that's another 300 grams to your 1500 for 1800. Still nowhere near a "climbing" wheel.

I don't see Alberto trading in his Zipps in the near future.

Last edited by tsl; 09-26-11 at 09:33 AM.
tsl is offline   Reply With Quote
Old 09-26-11, 10:40 AM   #11
BarracksSi
Bike ≠ Car ≠ Ped.
 
BarracksSi's Avatar
 
Join Date: Jul 2007
Location: Washington, DC
Bikes: Some bikes. Hell, they're all the same, ain't they?
Posts: 13,858
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
All I'll want is for the Pro Tour to start using them. Then maybe us mortals will have more options available (not that the current offerings aren't good, 'cuz they are). I can't say that I'll give up my road bike anytime soon, but even after converting my commuter to drops -- which the general public perceives as a "road bike" -- I'd like to build up another that includes disc brakes.

Why the pros? Well, where d'ya think they developed integrated shift/brake levers?
BarracksSi is offline   Reply With Quote
Old 09-26-11, 10:59 AM   #12
chasm54
Banned.
 
Join Date: May 2010
Location: Uncertain
Bikes:
Posts: 8,657
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
As has been pointed out, it's not just the weight of the wheels, it's the forks. They need to be beefed up to withstand the strain, and that both adds more weight and compromises handling. And there really isn't any need for them, if you're riding on the road you don't get the crud that CX or mountain biking has to deal with, and my rim brakes work fine. Moreover, while discs certainly stop you, they also require more maintaining and are more vulnerable to damage. So for the moment I can't see that the pros outweigh the cons for road cycling.
chasm54 is offline   Reply With Quote
Old 09-26-11, 11:12 AM   #13
mulveyr 
Senior Member
 
mulveyr's Avatar
 
Join Date: Feb 2010
Location: In the wilds of NY
Bikes: Box Dog Pelican, Raleigh Sojourn, Specialized Secteur, 1991 Cannondale tandem
Posts: 1,479
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Quote:
Originally Posted by chasm54 View Post
Moreover, while discs certainly stop you, they also require more maintaining and are more vulnerable to damage. So for the moment I can't see that the pros outweigh the cons for road cycling.
I see people claim this all the time about disc brakes, and I have no clue whatsoever about where this idea comes from.

I have a touring bike with discs, and a road bike with dual-pivot calipers.

When I do my yearly complete tear-downs that include brake maintenance, after I've taken them off and cleaned them, I can install, align, and adjust my disc brakes in literally less than five minutes.

When I do my dual-pivots, it takes a good 15 minutes to get everything perfectly centered and aligned.

When I need to change my disc pads, I drop the wheel, pull the retainer clip, install the new pads, back off the dial, and I'm done.

When I need to change my dual-pivot pads, I need to deflate the tire, drop the wheel, install the new pads, fiddle with height and toe-in, tweak the barrel adjuster, reinstall and reinflate the wheel... and I'm done a lot later than the disc pads.
__________________
Knows the weight of my bike to the nearest 10 pounds.
mulveyr is offline   Reply With Quote
Old 09-26-11, 11:28 AM   #14
chasm54
Banned.
 
Join Date: May 2010
Location: Uncertain
Bikes:
Posts: 8,657
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by mulveyr View Post
I see people claim this all the time about disc brakes, and I have no clue whatsoever about where this idea comes from.

I have a touring bike with discs, and a road bike with dual-pivot calipers.

When I do my yearly complete tear-downs that include brake maintenance, after I've taken them off and cleaned them, I can install, align, and adjust my disc brakes in literally less than five minutes.

When I do my dual-pivots, it takes a good 15 minutes to get everything perfectly centered and aligned.

When I need to change my disc pads, I drop the wheel, pull the retainer clip, install the new pads, back off the dial, and I'm done.

When I need to change my dual-pivot pads, I need to deflate the tire, drop the wheel, install the new pads, fiddle with height and toe-in, tweak the barrel adjuster, reinstall and reinflate the wheel... and I'm done a lot later than the disc pads.
Fair enough. I take it you don't bend any discs, then? And I've seen plenty of my MTB-ing friends struggling with jammed discs. But ymmv, and anyway I'm not arguing against discs for tourers, merely saying I don't see that they have any particular advantages for road bikes at present.
chasm54 is offline   Reply With Quote
Old 09-26-11, 11:44 AM   #15
njkayaker
Senior Member
 
Join Date: Sep 2007
Bikes:
Posts: 9,513
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 83 Post(s)
Quote:
Originally Posted by tsl View Post
Rotors count as rotating weight, just so you know.
That weight is nearer the hub than the rim (and the axis is an important part of the "rotating weight" issue).

This says that "inertial" (ie, rotational) weight of the wheels is negligible.

http://www.biketechreview.com/review...el-performance

I haven't seen any source that indicates to what amount the rotation weight contributes to effort expended moving the bike.

Last edited by njkayaker; 09-26-11 at 11:48 AM.
njkayaker is offline   Reply With Quote
Old 09-26-11, 12:10 PM   #16
Hippiebrian
Senior Member
 
Join Date: Apr 2011
Location: Long Beach, Ca.
Bikes: Raleigh Sojourn, '67 Raleigh Super Course, old Gary Fisher Mamba, and a generic Chinese folder
Posts: 576
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
I have disc brakes on my touring bike and love them. I have no need for speed, however, so weight isn't an issue with me. I understand why roadies don't like them as the extra weight would definately slow down a good cyclist (however most aren't good enough to notice the weight difference, but that's a topic for another thread...).
Hippiebrian is offline   Reply With Quote
Old 09-26-11, 05:34 PM   #17
tsl
Plays in traffic
 
tsl's Avatar
 
Join Date: May 2006
Location: Rochester, NY
Bikes: 1996 Litespeed Classic, 2006 Trek Portland, 2013 Ribble Winter/Audax
Posts: 6,955
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 26 Post(s)
Quote:
Originally Posted by njkayaker View Post
That weight is nearer the hub than the rim (and the axis is an important part of the "rotating weight" issue).

This says that "inertial" (ie, rotational) weight of the wheels is negligible.

http://www.biketechreview.com/review...el-performance

I haven't seen any source that indicates to what amount the rotation weight contributes to effort expended moving the bike.
Not saying it does or it doesn't. Just saying it's not reasonable to compare one set of wheels with a braking surface to another set without.

Unless the second one is a fixie.

Since you can't remove the braking surface from a set of rim brake wheels for a valid comparison, then you must add the braking surface--the rotors--to the disc brake wheelset for a valid, apples to apples comparison. Anything else is disingenuous.
tsl is offline   Reply With Quote
Old 09-26-11, 08:03 PM   #18
Thor29
Senior Member
 
Thor29's Avatar
 
Join Date: Aug 2005
Bikes:
Posts: 757
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
There's at least one company betting that discs on road bikes are worth doing: http://www.volagi.com
The only thing I don't like about the Volagi is that it has 130mm spacing. That really limits the number of hubs you can use on the rear.
I have a Salsa La Cruz cyclocross bike with disc brakes. I really like the extra stopping power. I personally would like to see a lighter version of the BB7 brakes and more options for road frames that use disc brakes.
Thor29 is offline   Reply With Quote
Old 09-26-11, 08:06 PM   #19
Thor29
Senior Member
 
Thor29's Avatar
 
Join Date: Aug 2005
Bikes:
Posts: 757
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by chasm54 View Post
Fair enough. I take it you don't bend any discs, then? And I've seen plenty of my MTB-ing friends struggling with jammed discs. But ymmv, and anyway I'm not arguing against discs for tourers, merely saying I don't see that they have any particular advantages for road bikes at present.
I also ride mountain bikes and so far nobody in my group has ever managed to bend a rotor. Bending rims happens sometimes, which makes disc brakes an even better option since you don't have to worry about a bent rim hitting the brake pads. (I once tried to ride my Surly Cross Check on a mountain bike trail and bent the rear rim so severely that I had to disconnect the rear brake to finish the ride).
Thor29 is offline   Reply With Quote
Old 09-26-11, 08:35 PM   #20
dscheidt
Senior Member
 
Join Date: Jul 2008
Bikes:
Posts: 1,373
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by chasm54 View Post
As has been pointed out, it's not just the weight of the wheels, it's the forks. They need to be beefed up to withstand the strain, and that both adds more weight and compromises handling. And there really isn't any need for them, if you're riding on the road you don't get the crud that CX or mountain biking has to deal with, and my rim brakes work fine. Moreover, while discs certainly stop you, they also require more maintaining and are more vulnerable to damage. So for the moment I can't see that the pros outweigh the cons for road cycling.
There are some advantages for racers: the rim doesn't need to withstand the heat or abrasion of the brakes, which are big problems with plastic rims. That, in theory, should let the rims be a bit lighter, and longer lasting. Theres' also the possibility of some (very small, I suspect, but that doesn't matter to the people who buy this stuff) aerodynamic improvement from not having to have a brake track.
dscheidt is offline   Reply With Quote
Old 09-26-11, 08:41 PM   #21
prathmann
Senior Member
 
Join Date: Nov 2008
Location: Bay Area, Calif.
Bikes:
Posts: 6,095
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Quote:
Originally Posted by mulveyr View Post
When I need to change my disc pads, I drop the wheel, pull the retainer clip, install the new pads, back off the dial, and I'm done.

When I need to change my dual-pivot pads, I need to deflate the tire, drop the wheel, install the new pads, fiddle with height and toe-in, tweak the barrel adjuster, reinstall and reinflate the wheel... and I'm done a lot later than the disc pads.
I'm a little puzzled. When I replace my sidepull brake pads I just screw in the barrel adjuster, take off the old pads, attach the new pads, and I'm done. I don't see the need to do any fiddling with the wheel or tire.

The main maintenance problem I see with rim brakes is that they eventually wear down the rim surface and replacing the rim takes a significant amount of time. Since I live in a climate where we have a limited rainy season this is only needed every 50 - 80 kmiles and therefore isn't a major burden. But I'd welcome a switch to a separate (and easier to change) disc if I frequently rode in wet conditions that wear out the rim's braking surface. I'd opt for just having the disc in the front since that's where you need the most effective braking and retain the lighter rim brake in the rear (I have yet to wear out the brake surface on a rear rim).

One other consideration is that the current disc brake designs make the 'lawyer lip' retention of the front wheel an essential feature. With a front rim brake I prefer to remove the lawyer lips to provide for more convenient wheel removal and replacement.
prathmann is online now   Reply With Quote
Old 09-26-11, 08:58 PM   #22
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 19,716
Mentioned: 7 Post(s)
Tagged: 0 Thread(s)
Quoted: 465 Post(s)
Yea there are road bikes for racers .. weight weenies ... Titanium and carbon-fiber land.

then there are road bikes for commuters and the rest of the Lumpen Proletariat .
Put the BB up a half inch or so and you got the Cross bike thing going on too .

something for just about everyone.

FWIW, On my V brake posts I have Magura hydraulic rim brakes , pad changes are literally a snap.
fietsbob is online now   Reply With Quote
Old 09-27-11, 07:32 AM   #23
jtdickie
Junior Member
Thread Starter
 
Join Date: Jun 2011
Location: Sun City Hilton Head Island, SC
Bikes: Raleigh Sojourn, Cannondale Super V-500
Posts: 12
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks all for your input.

Jim
jtdickie is offline   Reply With Quote
Old 09-27-11, 04:33 PM   #24
BarracksSi
Bike ≠ Car ≠ Ped.
 
BarracksSi's Avatar
 
Join Date: Jul 2007
Location: Washington, DC
Bikes: Some bikes. Hell, they're all the same, ain't they?
Posts: 13,858
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by dscheidt View Post
Theres' also the possibility of some (very small, I suspect, but that doesn't matter to the people who buy this stuff) aerodynamic improvement from not having to have a brake track.
Although I think it's silly, not only does Zipp put little dimples in their wheels, they even sell tires with dimples on them. I'll bet that they'd love to dispense with the brake track altogether.
BarracksSi is offline   Reply With Quote
Old 09-28-11, 02:47 PM   #25
dynaryder
PatronSaintOfDiscBrakes
 
dynaryder's Avatar
 
Join Date: Apr 2005
Location: BicycleSPACE warehouse in SW Washington DC
Bikes:
Posts: 6,983
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Quote:
Originally Posted by chasm54 View Post
Fair enough. I take it you don't bend any discs, then? And I've seen plenty of my MTB-ing friends struggling with jammed discs.
Apples to oranges. MTBing causes all kinds of damage you don't regularly see on street bikes. When was the last time you bent a hanger on a rock?

I've had to straighten the discs on two bikes;one got damaged in shipping from eBay(wheel also needed trueing) and one took a hit playing bike polo. Never had an issue just riding around town.
__________________

C'dale BBU('05 and '09)/Super Six/Hooligan8and 3,Kona Dew Deluxe,Novara Buzz/Safari,Surly Big Dummy,Marin Pt Reyes,Giant Defy 1,Schwinn DBX SuperSport,Dahon Speed Pro TT,Brompton S6L/S2E-X
dynaryder is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 09:32 AM.