Anybody riding a disc ROAD bike?

[eBAUMANN]

Thoughts?

Good decision? Bad decision?
- No more burning through rims! Consistent braking in any weather condition! Hooray!

Is the "weight penalty" a bummer?
- Im not a weenie but I do like my road bikes somewhere in the 16-18lb range, depending on the frame material.

Hydro v mechanical?
- Although hydro offers superior performance, I'm a bit concerned about its field serviceability should something sh*t the bed 50mi from home.


I always said it was silly, but I'm loving the whole disc cx-bike thing...enough to get me considering other things that I once thought were silly...

[Matfam]

I'm riding a disc cross bike on the road, with 28 gatorskins. As a superclyde, in the Pacific Northwest, I have better modulation and braking. There is no fade, grabbing or inconsistencies in braking. I'm glad I made the change and won't ever go back to rim brakes. I have Diamondback Haanjo comp, with mechanical TRP, Spyres


Sent from my iPad using Tapatalk

[fogrider]

yeah, this has not been discussed here at all...lets see, disc if you're going to ride in wet weather.

[DrSpoke]

It's not a pure road bike, but have been riding a Ridley X-Trail (C30) for about 2 months and more than 1,000 miles. Lately it's been a combination of road/trail so I've been using larger tires - Schwalbe S-Ones in 30c. But before that I put on a lot of road miles using Vittoia Open Paves in 27c. The bike is a bit over your weight limit but, I think, most of it is in heavy components, especially the crankset as well as the wheels & tires. That said, I love it on the road. It's probably comparable to a fondo/touring geometry so is very comfortable. It has Shimano hydraulic flat mounts and stops effortlessly from 50mph. A fun bike to ride on the road and pretty awesome off road.

[ofcounsel]

I'm riding a Cannondale Synapse Disc. I love it, and I'm super happy with the brakes. Much better modulation and confidence inspiring on long descents.

Mine weighs in a 17 lbs 13 oz as shown (with pedals, cages and accessories):
http://i150.photobucket.com/albums/s81/ofcounsel/Focus/A3D92445-88A4-43D5-84DC-4B4DB8F4E990_zpskp8se17u.jpg
http://i150.photobucket.com/albums/s81/ofcounsel/Focus/8A27823C-3ACB-4476-9822-A10763F3E7CF_zpsdnutolmg.jpg

Not super light, but not a total porker either. Tires are 28mm, but grow to about 31.3 on my rims.

Admittedly, I don't have a lot of miles on my road hydros road, but in my (and my riding buddies) years and tens of thousands of miles of experience with MTB hydros, reliability/servicability is not an issue at all. Really, no reason (other than to save a bit of money) to choose cable brakes over hydro. One thing you need to keep track of and check, from time to time are your pads. That's the service issue, in that disc pads are not as easily inspected as rim brakes. You actually have to bend down (or put the bike on the stand) give them a good look. But that issue is the same, whether it's mechanical or hydro.

[joosttx]

I ride my cross disc bike on the road. discs are great. they do perform better in the wet no question. And I would give them a slight edge under normal conditions. With that said I have no intentions upgrading my road bike to discs as calipers are just fine and the improvement of disc brakes is minimal . I am really sold on campy bora ultras as being the best wheel available. I don't think I will go to discs until campy makes a disc wheel.

I would get disc brakes if your option was them vs canti's.

[ofcounsel]

I ride my cross disc bike on the road. discs are great. they do perform better in the wet no question. And I would give them a slight edge under normal conditions. With that said I have no intentions upgrading my road bike to discs as calipers are just fine and the improvement of disc brakes is minimal . I am really sold on campy bora ultras as being the best wheel available. I don't think I will go to discs until campy makes a disc wheel.

I would get disc brakes if your option was them vs canti's.

Curious. Are yours cable or hydro?

[ajhapps]

Descending the backside of Hawk Hill in the rain here in SF (-18% grade) last week, I got to the bottom and thought, "I need some f'ing disc brakes"

[joosttx]

Curious. Are yours cable or hydro?

Hydro... shimano rs685 to xtr's.

[ofcounsel]

Hydro... shimano rs685 to xtr's.

Nice!

[Lionel]

I ride my cross disc bike on the road. discs are great. they do perform better in the wet no question. And I would give them a slight edge under normal conditions. With that said I have no intentions upgrading my road bike to discs as calipers are just fine and the improvement of disc brakes is minimal . I am really sold on campy bora ultras as being the best wheel available. I don't think I will go to discs until campy makes a disc wheel.

I would get disc brakes if your option was them vs canti's.

This.

[cinema]

hydro disc brakes were seriously the greatest thing to ever happen to mtb, for me the single most important upgrade. i'd rather ride rigid with hydros than fs without.

i have no doubt they'd be awesome on a road bike but i'm not in the market, if i was i would consider it. but aesthetically i think it's a blight on a nice road bike. with time we'll come to accept it.

[livingminimal]

Rode my Stinner di2/disc daily for about 18 months before it broke. Getting it replaced by warranty right now and I seriously can't wait to get back on disc. So incredibly confidence inspiring.

Things I don't give a ···· about:
Nominal weight "penalty". At my size this is a joke.
Nominal aero "penalty". At my size this is a joke.

I love hydro disc. It works amazing. I am not as into mechanical. Doesn't have the same consistent or power hydro does. I've had 685 and 785. Both are amazing g.

[Duende]

Descending the backside of Hawk Hill in the rain here in SF (-18% grade) last week, I got to the bottom and thought, "I need some f'ing disc brakes"

+1 Came to the same conclusion on that decent! No joke that one...

[Neil]

Been running the R785's from the moment they were released - recently built a bike for my girlfriend with the R685's, and have cleaned out my stash of rim braked (modern) wheels, I can't see myself buying/making a rim braked modern bike again.

That said, I have the Klein and the Serotta, neither of which I plan to get rid of and both of which are of course rim braked.

Rim brakes will fade away over the next couple of years until they are the preserve of the supermarket $100 special.

[oldpotatoe]

Thoughts?

Good decision? Bad decision?
- No more burning through rims! Consistent braking in any weather condition! Hooray!

Is the "weight penalty" a bummer?
- Im not a weenie but I do like my road bikes somewhere in the 16-18lb range, depending on the frame material.

Hydro v mechanical?
- Although hydro offers superior performance, I'm a bit concerned about its field serviceability should something sh*t the bed 50mi from home.


I always said it was silly, but I'm loving the whole disc cx-bike thing...enough to get me considering other things that I once thought were silly...

Only if you wear a helmet and use tubulars..are discs a good idea. :eek:

I get a kick out of those around here, on dry days, on the road, riding a flat 20 miler up to Hygiene and back..that gotta have disc brakes...:confused:

I think it depends on what, where, conditions of your ride, period. Pluses and minuses..no such thing as a free lunch.

I predict 4 pages..

[David Tollefson]

I've got both. The road bike is rim calipers, but it's also running 23mm tires max and no accommodations for fenders. I've got two gravel bikes that also double as road duty and can accommodate fenders nicely. All cable-actuated discs (TRP Spyre one one, Avid BB-7's on the other).

[redir]

I'm getting a Synapse soon and on the fence about disk or not. Problem I have is I'd have to abandon some pretty nice wheelsets if I go with disk. If slowing down in the rain is all they are really one up on then i don't care, I don't ride in the rain and in fact if I am in a race and it starts raining the first thing I do is try to get away and if that doesn't stick then I drop out.

[ergott]

I think it depends on what, where, conditions of your ride, period.

You're getting soft.;)

:beer:

[AngryScientist]

i won't say never, but i'm pretty sure the answer for me is never.

[alancw3]

i would think that disc brakes would put a lot more stress on spokes/nipples/ ilets on the wheel. i am not an engineer but if you apply stopping pressure to the center of a mass doesn't that create more pressure than applying it to the outside circumference? think about applying the brakes aren't those spokes like absorbing a lot of energy i.e. like bending? different with a car as it does not have spoked wheels, well at least not modern cars.

can old potato and ergott comment on my observation?

[fa63]

For road bikes, I think the tire width is still a major limiting factor for disc brakes. You can have all the braking power you want, but you are still limited by the traction that the tires offer.

[oldpotatoe]

You're getting soft.;)

:beer:

Not soft enough to EVER have a disc brake on one of my bikes tho..:rolleyes:

[oldpotatoe]

i would think that disc brakes would put a lot more stress on spokes/nipples/ ilets on the wheel. i am not an engineer but if you apply stopping pressure to the center of a mass doesn't that create more pressure than applying it to the outside circumference? think about applying the brakes aren't those spokes like absorbing a lot of energy i.e. like bending? different with a car as it does not have spoked wheels, well at least not modern cars.

can old potato and ergott comment on my observation?

Absolutely true and why in the shop we saw a lot of stoopid light, thin spoke, low spoke count disc brake wheels on MTBs go south early on..Great for selling not great for riding. Why, IMHO, less than 28h disc wheels are kinda asking for trouble.

[yummygooey]

i got my first mtb with hydro disc this year and it's amazing

getting my first (all) road bike with hydro disc any day now... i'm very excited to ditch the cantis and hang the remaining skinny tire rim brake bikes up as sunny sunday drivers

[ergott]

i would think that disc brakes would put a lot more stress on spokes/nipples/ ilets on the wheel. i am not an engineer but if you apply stopping pressure to the center of a mass doesn't that create more pressure than applying it to the outside circumference? think about applying the brakes aren't those spokes like absorbing a lot of energy i.e. like bending? different with a car as it does not have spoked wheels, well at least not modern cars.

can old potato and ergott comment on my observation?

In general you have a higher spoke count with disc wheels. Also, I cross all the spokes, no radial. It's not difficult to build a wheel that can handle the stresses. Think mountain bikes.

[livingminimal]

Absolutely true and why in the shop we saw a lot of stoopid light, thin spoke, low spoke count disc brake wheels on MTBs go south early on..Great for selling not great for riding. Why, IMHO, less than 28h disc wheels are kinda asking for trouble.

Having actually used disc brakes on road...

...I will corroborate your theory :) I broke quite a few spokes early on. They were craptastic superlight bladed spokes and not laced up 3x in the back, and for a guy my size, that was a poor choice.

[Willy]

I have a Trek Domane 6.5 with hydro disk brakes. I couldn't be happier with it. In order of greatness - brakes, electronic shifting and ride comfort.

[eBAUMANN]

Some good thoughts here, one thing nobody has mentioned yet is how disc helps preserve your wheels (by not braking on the rim) which is something that's very attractive to me, as you can spend a lot of money on nice wheels to help keep the overall bike weight down. It's particularly nice for cx because of the course conditions that can exist (and will destroy a carbon braking surface) but I have had similar things happen on road bikes (dirt roads, rain) that I'd love to avoid in the future.

A friend once wore down his pads so low in the rain that the little fins on the bottom of the carriers actually machined a groove into his carbon rim, ruining the wheels. Sure you can burn through disc pads in the right conditions but if you do you won't be braking metal-on-rim.

[livingminimal]

Some good thoughts here, one thing nobody has mentioned yet is how disc helps preserve your wheels (by not braking on the rim) which is something that's very attractive to me, as you can spend a lot of money on nice wheels to help keep the overall bike weight down

I mean, I sort of feel like this goes without saying, no?

I am probably racing these next cx season http://nextdevo.com/ (unless something I like more comes along in the next 7 months) and I wouldn't even consider it if I were on cantis. I would consider getting a set for my road disc bike too.

I like carbon wheels a great deal, I still toy with getting a set for my Pegoretti or my Focus, but really, I wouldn't commit those kinds of dollars to a carbon wheel at this point unless it was for a disc bike.
(unless I took a shot at something like this, which I just stumbled on: http://www.nextie.net/road-25mm-clincher-tubeless-NXT50C07)

[eBAUMANN]

I mean, I sort of feel like this goes without saying, no?

well, yes, there are a lot of things that seem obvious but don't occur to everyone for whatever reason.

the reason i mention it is because people will spend $3k on a set of carbon rim brake wheels without really considering (or maybe caring) about their relatively limited lifespan, due pretty much exclusively to the method of braking used on them.

personally I'm more ok spending big money on a set of disc wheels because i know that they will last as long as i keep them safe (no crashing or pot holes).

maybe thats obvious to everyone, but maybe not, and i think its a bigger factor when moving to disc than people give it credit for. sure, stopping power is all well and good, but there are a host of other benefits that sometimes seem to fall by the wayside in the debate.

[Fatty]

Currently running caliper brakes on my road bikes.

Looking forward to the day when I build up a full hydro road bike.

With tubeless tires.

[livingminimal]

maybe thats obvious to everyone, but maybe not, and i think its a bigger factor when moving to disc than people give it credit for. sure, stopping power is all well and good, but there are a host of other benefits that sometimes seem to fall by the wayside in the debate.

Maybe I am just sounding like a dick about it, in that case, all apologies, but yeah you're exactly right. I think I just did so much damn searching/reading/discussing about disc before I ordered a custom steel disc bike I take that wheel-preservation business for granted.

The arguments are always about disc vs rim over actual stopping power, really, no one can ever argue against rim longevity (I don't think anyone can argue braking performance either, but that's a whole other topic entirely)

[livingminimal]

With tubeless tires.


That's the other jump I'm about to make, I think. Not buying new sets of wheels unless they're tubeless-ready.

[redir]

I don't know, I've got wheels from the 1970's on my vintage bikes that have seen an awful lot of ride time and they are still going just fine. I can see the argument for cross and MTB with the dirt and grit that could damage rims but I don't see that as a viable justification for road or at least it's reaching for straws.

[Pelican]

The arguments are always about disc vs rim over actual stopping power, really, no one can ever argue against rim longevity.

Carbon wheels are the main reason why I would go to road disc. The other nuance is people talk about increased stopping power, when it is really about improved braking feel (modulation) and control for big/fast descents (less heat on those carbon rims). On skinny tires, I think most discs will have plenty of power (I've tested a bunch).

Having said that, I've got a Synapse similar to the one on the first page, but with regular caliper brakes it weighs in at 14lbs 13oz. As a certified weight weenie, there's no way in hell I'm adding 3lbs to the bike for a bit better braking.

[Mark McM]

i would think that disc brakes would put a lot more stress on spokes/nipples/ ilets on the wheel. i am not an engineer but if you apply stopping pressure to the center of a mass doesn't that create more pressure than applying it to the outside circumference? think about applying the brakes aren't those spokes like absorbing a lot of energy i.e. like bending? different with a car as it does not have spoked wheels, well at least not modern cars.

Disc brakes do put more stresses on the spokes, but not much more. The stresses due to (vertical) weight bearing are far higher than the stressed from the torques from hub breaks. Here's why: Most of the stresses due to vertical (weight bearing) loads are concentrated on just a few spokes in the LAZ (Load Affected Zone) at the bottom of the wheel. However, torque loads from braking are distributed nearly equally to all the spokes. The peak stresses due to braking torque are only a fraction of the peak stresses from radial weight bearing. Also to be considered is that weight bearing load cycles occur during every revolution of the wheel, whereas braking stresses occur only during braking.

Merely crossing the spokes on a rim brake wheel is generally sufficient to handle the extra spoke stresses from braking. Consider: Peak pedaling torques can sometimes be high enough to lift the front wheel off the ground (i.e. "pop a wheelie"), yet crossing only the drive side spokes on the rear wheel is sufficient to handle even these peak torque loads on the spokes. Crossing the spokes on both sides of the wheel should be enough for any torque loads the wheel will ever see, whether from pedaling or braking.

[Mark McM]

For road bikes, I think the tire width is still a major limiting factor for disc brakes. You can have all the braking power you want, but you are still limited by the traction that the tires offer.

Actually, no. The limit of braking on a road bike is actually the pitch over point. A road bike has a relatively high center of gravity for its wheelbase, so it will pitch over (i.e., the rear wheel lifting and bike starting to go end-over-end) at a fairly low deceleration rate. The pitch over point on a road bike is generally between 1/2 to 2/3 g-force, which is much less than the traction coefficient of a road tire on clean dry pavement. A good rim brake (in dry conditions) can bring a bike to the pitch over point.

Keep in mind, that as braking increases, weight is shifted from the rear tire to the front. This actually increases the front tire traction. This is why road racing motorcycles often have two large brakes on the front and only a single small brake on the rear - they brake so hard that there is virtually no traction left on the rear for braking, and the majority braking force is provided by the front tire. But while the rear tire is decreasing its traction, the traction on the front tire increases so much that, when riding in a relatively straight line on clean dry pavement, the front tire can not be skidded before the pitch over point is reached. The same is true for bicycles, but even more so, because the ratio of C.G. height to wheelbase is higher than on motorcycles.

[beeatnik]

^so, in dry pavement, on a straight line, under 2/3 g-force, it's more difficult to unweight a rear wheel on a bika with, um, superior stopping power up front (disc instead of rim)? but do disc brakes provide that much more stopping power than good rim brakes for there to be a measurable difference? say over 5%

[fa63]

I was thinking more about wet pavement conditions, where disc brakes are often claimed as superior.

[eBAUMANN]

I was thinking more about wet pavement conditions, where disc brakes are often claimed as superior.

its not so much about the wet on the road as it is the wet on your rim vs the wet on your rotor.
there will generally be less wet on the rotor because its further from the wet transference units aka tires.
less wet on your braking surface = better braking regardless of road surface conditions.


Also - just to clarify, im talking about ROAD BIKES, not "gravel bikes" not "cx bikes," ROAD bikes, tour de france, big mountains, fast descents, ROAD riding. ya digs?
Even on high-end carbon wheels with top of the line brake pads, there were absolutely times when i would have loved not necessarily more POWER, but more consistent/even braking while decelerating from 50+mph into a switchback.
Its just a piece of mind thing I guess.

[livingminimal]

Its just a piece of mind thing I guess.

and therein is your answer.

the peace of mind thing with disc is very real, very tangible, and for me, very much wanted and appreciated if I am going to spend any time in the mountains locally. There are honestly rides I've been putting off doing lately simply because I am waiting for my Stinner to arrive.

[ofcounsel]

Having said that, I've got a Synapse similar to the one on the first page, but with regular caliper brakes it weighs in at 14lbs 13oz. As a certified weight weenie, there's no way in hell I'm adding 3lbs to the bike for a bit better braking.

Yeah, my Synapse is definitely not a weight weenie bike. But I think you can get significantly lighter wheels/tires. I know DT swiss has off the rack wheels in the 1325g range, pretty easily. Custom wheels might go lighter. At that point, I'm guessing if you went with lightweight wheels/tires, you would be closer to 1.5lbs penalty, assuming you're using an otherwise similar component/cockpit set up.

I'm using Ultegra and Alu bars. My wheels weighed in at about 1580g, and I'm using 28mm tubeless tires.

[livingminimal]

Yeah, my Synapse is definitely not a weight weenie bike. But I think you can get significantly lighter wheels/tires. I know DT swiss has off the rack wheels in the 1325g range, pretty easily. Custom wheels might go lighter. At that point, I'm guessing if you went with lightweight wheels/tires, you would be closer to 1.5lbs penalty, assuming you're using an otherwise similar component/cockpit set up.

I'm using Ultegra and Alu bars. My wheels weighed in at about 1580g, and I'm using 28mm tubeless tires.

I don't think the difference between say, 785 and DA 9070 is 1400 grams all-in, but I could be wrong.

[ofcounsel]

I don't think the difference between say, 785 and DA 9070 is 1400 grams all-in, but I could be wrong.

Agreed. I can't imagine it is. My bike, at 17lbs, 13oz, isn't a weight weenie bike. But if I had chosen some lighter weight components, such as lighter wheels, lighter tires, carbon bars, it could easily be 1.5 lbs lighter.

[Bostic]

I have over 9000 miles on my Volagi Liscio road bike that turns 4 in a couple of months. BB7 (and for a few month Spyres) mechanical discs. I've used it on many double centuries over that time including three years of the Alta Alpina 8 pass 21k climbing and descending. In the rain I've ridden down 16 miles of Mt. Rose highway in Reno. In San Francisco, every steep 25% + grade including the ones covered in Eucalyptus leaves. When wet the BB7's squeal like crazy for a few seconds then they are quiet. 160mm front, 140mm rear.

When I set aside some wheel money I'll get an 11 speed 130mm rear disc hub and convert the bike to hydro. I haven't decided on Sram or Shimano for that one yet.

The amount of disk brake road bikes on the road has grown a ton in the last year. I see them everywhere now in Silicon Valley.

[fa63]

its not so much about the wet on the road as it is the wet on your rim vs the wet on your rotor.
there will generally be less wet on the rotor because its further from the wet transference units aka tires.
less wet on your braking surface = better braking regardless of road surface conditions.


What I meant to say is, wet roads = less tire traction.

[DrSpoke]

It's a bit dated but here is a link to a good analysis re road disc bikes including weight differential. He puts the increase in wheels weight at about 1 lb. And I would suppose there is a bit more in the lever assembly as wells as the calipers.

http://intheknowcycling.com/2015/01/08/why-and-when-to-buy-a-road-disc-bike/

[austex]

My next (road) bike will be disc for one primary reason - the ability to switch wheel sizes among 700C, 650B and 559, each running different profile tires (25/42/54mm respectively, same steering geometry) depending on the predominant expected surfaces of the day's ride.

Nothing against rim brake bikes that I have ridden for nearly 50 years, but I like the tire-volume flexibility. Not parting with the PX-10 nor the Tommasini Super (though several others will be on the block), but even a curmudgeon can grow with the times.

Oh, and probably Velo Orange Pass Hunter Disc...w/ down-tube shifters (DuRaCe 10-sp indexed) and TA Pro 5 Vis crank.

[Black Dog]

A friend once wore down his pads so low in the rain that the little fins on the bottom of the carriers actually machined a groove into his carbon rim, ruining the wheels. Sure you can burn through disc pads in the right conditions but if you do you won't be braking metal-on-rim.

OK, a serious question here, not trolling. Are the disk pads able to handle long descents (i.e. long mountain descents) where there will prolonged periods of braking? Will the pads wear out quickly; within one ride? Also is brake fade and issue as the rotors heat up, and along this line is there a risk of boiling the fluid? I really have no experience with disks and am genuinely curious about these aspects of road disk tech. There are descents that require a lot of prolonged braking; think steep and twisty mountain roads.

[livingminimal]

OK, a serious question here, not trolling. Are the disk pads able to handle long descents (i.e. long mountain descents) where there will prolonged periods of braking? Will the pads wear out quickly; within one ride? Also is brake fade and issue as the rotors heat up, and along this line is there a risk of boiling the fluid? I really have no experience with disks and am genuinely curious about these aspects of road disk tech. There are decent's that require a lot of prolonged braking; think steep and twisty mountain roads.

····s been tested everywhere, including that 20+ mile descent in Hawaii. The bottom line is, hydro disc works so well from a modulation standpoint, overheating anything is moot. rotors are designed to dissipate heat as soon as you let off, and the hard-force that you could be breaking at is really neutralized by the nuanced modulation. Things like boiling the fluid are truly of no concern.

[Black Dog]

ï½·ï½·ï½·ï½·s been tested everywhere, including that 20+ mile descent in Hawaii. The bottom line is, hydro disc works so well from a modulation standpoint, overheating anything is moot. rotors are designed to dissipate heat as soon as you let off, and the hard-force that you could be breaking at is really neutralized by the nuanced modulation. Things like boiling the fluid are truly of no concern.

I get the improved modulation, however, there are still roads where prolonged and constant braking are needed. Not, a case of release brake, release and repeat. There is no nuanced braking involved, you are on the brakes or off the road. I have done a lot of technical descents like this on roads in the mountains, not making this up. Is this an issue for road disks? I really am curious, as I am sure that they have been used under every conceivable road condition by now, there must be an answer.

[Mark McM]

ï½·ï½·ï½·ï½·s been tested everywhere, including that 20+ mile descent in Hawaii. The bottom line is, hydro disc works so well from a modulation standpoint, overheating anything is moot. rotors are designed to dissipate heat as soon as you let off, and the hard-force that you could be breaking at is really neutralized by the nuanced modulation. Things like boiling the fluid are truly of no concern.

Huh? What does modulation have to do with heat? Very little, I'm afraid. And road disc rotors are so small that wheel rims actually dissipate heat much faster than disc rotors do.

There have been some tests of disc brakes at very high loads (such as with tandems) that have resulted in fluid boiling. Disc brake designers have gotten better at designing brakes to operate at higher temperatures, but it is still a concern.

[livingminimal]

Huh? What does modulation have to do with heat? Very little, I'm afraid. And road disc rotors are so small that wheel rims actually dissipate heat much faster than disc rotors do.

There have been some tests of disc brakes at very high loads (such as with tandems) that have resulted in fluid boiling. Disc brake designers have gotten better at designing brakes to operate at higher temperatures, but it is still a concern.

I'm probably wrong then but I was always under the impression that being able to more casually ease into/out of braking with less applied force meant pads and rotors were not as likely to heat up quite as much as expected? and that the damage possible in overheating brake tracks on carbon wheels was more problematic?

[bfd]

Huh? What does modulation have to do with heat? Very little, I'm afraid. And road disc rotors are so small that wheel rims actually dissipate heat much faster than disc rotors do.

There have been some tests of disc brakes at very high loads (such as with tandems) that have resulted in fluid boiling. Disc brake designers have gotten better at designing brakes to operate at higher temperatures, but it is still a concern.

If you believe Santana, they don't recommend front disc brakes for tandems as they say it is only the third best brake option behind v-brakes and dual pivot brakes! They claim that for a 700c wheels, the rim brake has a 3:1 advantage over an 8" disc brake, unless your brake has flat-bar brake levers:

http://santanatandems.com/Techno/BrakePower.html

Good Luck!

[jwess1234]

I'm not interested in the jump anytime soon for road (on an upcoming cross bike yes). In either case, I would exclusively go with a quality hydro setup so the pistons consistently go back to place and there is no rub on the rotor.

On that same irritant of not wanting any rub/noise, I would also make sure the fork is especially stiff to withstand deflection of the rotor. I cant remember the thread, but someone mentioned the new Enve GRD (prototpe?) with the thru-axel and its construction was good at controlling for this--I could be imagining things, but I thought the final spec will be direct-mount should help with the same.

My eventual cross/road capable build by Rock Lobster will be based around the fork's dimensions and its purported strength.

Goodluck with the build--hope we see pics soon.

[oldpotatoe]

Maybe I am just sounding like a dick about it, in that case, all apologies, but yeah you're exactly right. I think I just did so much damn searching/reading/discussing about disc before I ordered a custom steel disc bike I take that wheel-preservation business for granted.

The arguments are always about disc vs rim over actual stopping power, really, no one can ever argue against rim longevity (I don't think anyone can argue braking performance either, but that's a whole other topic entirely)

I guess and if you ride in wet, sloppy road conditions with rim brakes, yes you can wear out rim sidewalls. I have replaced more than a few in the shop BUT in 35 years of riding, I can say I have never worn out sidewalls of any of my wheels. I wack the rim way before the sidewalls are a problem, it seems. I have a set of non machined sidewall, Campag tubie rims that are about 20 years old and the side walls are fine.

With uber light rims, not enough spokes, on disc wheels..wacked rims are an issue.

[Mark McM]

I'm probably wrong then but I was always under the impression that being able to more casually ease into/out of braking with less applied force meant pads and rotors were not as likely to heat up quite as much as expected? and that the damage possible in overheating brake tracks on carbon wheels was more problematic?

Braking converts the kinetic energy of motion into heat. Kinetic energy of motion is proportional to the mass and the square of velocity. The amount of heat generated in braking will always be equal to the amount of kinetic energy removed (due to the change in velocity), regardless of how well modulated the braking is. If you slowed down by dragging your feet on the ground, the heat generated at your feet would be same as the heat generated in the best modulated hydraulic disc brake.

[ergott]

A metal rotor and the compounds used in a disc brake pad are better suited for managing the heat generated than a metal or carbon rim and rubber pad. It works, but it's not better than disc.

[Mark McM]

I guess and if you ride in wet, sloppy road conditions with rim brakes, yes you can wear out rim sidewalls. I have replaced more than a few in the shop BUT in 35 years of riding, I can say I have never worn out sidewalls of any of my wheels. I wack the rim way before the sidewalls are a problem, it seems. I have a set of non machined sidewall, Campag tubie rims that are about 20 years old and the side walls are fine.

With uber light rims, not enough spokes, on disc wheels..wacked rims are an issue.

I'm a little surprised to hear that you haven't worn out any rim brake tracks. It takes quite a few miles, but I've worn out a few, even on wheels ridden primarily in dry conditions.

Rear wheels typically get whacked out of shape from road damage more frequently than fronts, for a variety of reasons (they carry more weight, they are dished and have more uneven spoke tensions, it is easier to unweight and avoid obstacles with the front wheel than the rear wheel, etc.). Conversely, front wheel braking is more effective, so front rims usually get more brake wear than rears. For these reasons, most of my rear rims get retired from impact related damage, but more often my front rims get retired from brake wear.

[Mark McM]

Well, now that we've discussed disc brakes and heat, how about disc brakes and cold? The Latest Velonews Tech FAQ (http://velonews.competitor.com/2016/01/bikes-and-tech/394007_394007)article discusses the problems experienced by hydraulic brakes at cold temperatures, and references an earlier article in which the consensus was that cable operated brakes were more reliable in extreme cold. And let's not forget that SRAM's recall of all their road hydraulic brakes (both rim and disc) in 2013 was due to low temperature failures.

[ergott]

Well, now that we've discussed disc brakes and heat, how about disc brakes and cold? The Latest Velonews Tech FAQ (http://velonews.competitor.com/2016/01/bikes-and-tech/394007_394007)article discusses the problems experienced by hydraulic brakes at cold temperatures, and references an earlier article in which the consensus was that cable operated brakes were more reliable in extreme cold. And let's not forget that SRAM's recall of all their road hydraulic brakes (both rim and disc) in 2013 was due to low temperature failures.

I've been on my disc bike down to 13F. No noticeable difference at all.

[branflakes]

All this talk about braking! I spend the majority of my time worrying about form, speed and power. Braking is essential, but I don't plan on riding them constantly. Sure, fade can be unpleasant on long descents, but I've never felt so unsafe as to need to add weight and greater maintenance (re: hydraulic).

Having said all that....
I purchased a Wilier GTS Disc last summer and rode for a bit. It had TRP Hy/Rd hydraulic with mechanical pull. I will suggest the brakes didn't inspire any greater confidence in my riding (mind you I am Cat6).

Long story short - I sold the bike last week. Looking forward to my 'old fashioned' calipers again.

[branflakes]

Oh yeah, forgot, good call OP! You were right, four pages. ;)

[eBAUMANN]

Generally speaking, I have never really felt the need for better braking on my road bikes, which all have high-end caliper systems in place that work just fine.
That said, there are times (rare as they might be) when there is definitely something left to be desired.

Now, when I say "better braking" i dont so much mean MORE POWER as I mean how consistently and smoothly that power is applied.
THAT, is where I think disc brakes hold a distinct edge over most rim brake systems, particularly of the carbon rimmed persuasion.

In my experience, even a crappy disc brake will feel smoother and more even in its actuation than a crappy rim brake, just by virtue of how a pad and rotor interface vs a pad and rim.

Now, scale this up to high-end rim and disc brakes. Think about the amount of variables in play that can effect the smoothness/consistency of a rim brake (pad condition, braking surface condition, pad ALIGNMENT, toe in if applicable), the importance of each of these things is magnified on a carbon braking surface and magnified again as speed/load increases.

I spent 2 weeks this summer going up and down some very large mountains. Going up was all fine and dandy, not much braking there, but coming down...thats another matter altogether. Lots of hard braking from very high speeds into very tight turns. While I am clearly still here to tell the tale, the braking performance I experienced was not exactly pleasant or confidence inspiring. It was more often than not ear-splitting and inconsistent. These were high-end rims with the latest and greatest in braking technology, as were the pads and brakes. They were set up properly with a compression-less housing system, etc etc.

My take-away from this was that carbon wheels wheels on big mountains are a bit of a double edged sword. Great going up but potentially a nightmare coming down.

With disc brakes, I see the potential for a more consistent and reliable braking system regardless of rim/pad material or terrain.

THAT is the main appeal to me, as someone who enjoys both going up and coming down large mountains as quickly as possible ;)

[crankles]

^. I second all of this...
I too switched to hydro disc for CX this season and very quickly wanted it on my road bike for the reasons listed above (plus a few other like arthritic wrists). If I was back living in Indianapolis where the biggest hills were highway overpasses, rimbrakes would be just fine. Here in NorCal though, every lunchtime ride involves a 1500 ft drop.

[campy man]

Rim brakes will fade away over the next couple of years until they are the preserve of the supermarket $100 special.

Put down that Kool Aid :no:

[thermalattorney]

Built a steel disc road up this past fall.

Generally I would say that discs are unnecessary for flat terrain and aren't worth the weight penalty. Hydro discs deliver powerful one-finger braking and low-effort two finger braking, similar to CX8.4/SRAM levers but without the need to constantly true the rim.

As flat as NYC is, there is a lot of traffic to dodge on the way to open road and I really appreciate how easy one-finger "oh ****" braking is. This build comes in pretty heavy at 20.3lbs, but I only notice the weight when I'm carrying the bike up 4 flights of stairs.

http://www.pedalroom.com/p/steel-di2-disc-road-money-pit-26308_2.jpg

[JayBay]

I won't buy another rim-brake bike again, unless it's to pick up something cool and vintage. But for new bikes, be it cross, gravel grinder, or pure road race I'm all for discs.

http://s27.postimg.org/uzyc0o7oj/IMAG1250.jpg

[Charles M]

I won't buy another rim-brake bike again, unless it's to pick up something cool and vintage. But for new bikes, be it cross, gravel grinder, or pure road race I'm all for discs.

http://s27.postimg.org/uzyc0o7oj/IMAG1250.jpg


Same here...

I'm on my 5th disc road bike and unless it's a review bike that comes without disc, Everything I do for me will be disc.

It's not about wet or dry, it's great feel and performance in any condition. I don't notice the weight at all.


https://scontent.fphx1-2.fna.fbcdn.net/hphotos-xta1/t31.0-8/1483635_10205061632874510_6648805849432581569_o.jp g

https://scontent.fphx1-2.fna.fbcdn.net/hphotos-xtf1/t31.0-8/11118114_10205061632794508_3057289776186398915_o.j pg

https://scontent.fphx1-2.fna.fbcdn.net/hphotos-xaf1/v/t1.0-9/10940415_10204401406689268_1982327750288062026_n.j pg?oh=211b014053dd77140ad7d8f56a26f623&oe=573BFB78\

https://scontent.fphx1-2.fna.fbcdn.net/hphotos-xat1/v/t1.0-9/11223791_10205999899490589_8030567686786449743_n.j pg?oh=7f9a01b640a1a087eecdca40dd3f7c40&oe=572B9AFB

https://scontent.fphx1-2.fna.fbcdn.net/hphotos-xpf1/t31.0-8/978067_10202557772519566_7663230674172522943_o.jpg


Loads of opinion out there...

But I've not spoken to anyone that has significant time on a disc bike that doesn't prefer the function and ease of use...

One condition... Hydro.

The make-do cable actuated calipers are at a notable disadvantage (but still better than virtually all rim brakes and especially so with carbon rims).

[David Tollefson]

I've got significant time on disc brakes, off-road and on, and my preference for a road bike is still rim calipers (single pivot, at that). But I'm not racing any more, and when the weather is iffy, I'm on my all-road bike (groad bike, gravel grinder, whatever you like to call it) that sports disc brakes, on the road. That road bike, 23mm tires max, is for the dry days only.

[cpamplin]

Built a steel disc road up this past fall.

http://www.pedalroom.com/p/steel-di2-disc-road-money-pit-26308_2.jpg

That's a nice bike, can you share details of the build?

[54ny77]

all those exposed cables looks awful.

and more hassle to clean.

my opinion only, of course.

incidentally, i felt the same way when di2 came out--sure it's neat, works awesome, but seeing glorified electrical tape and zip ties everywhere on otherwise beautiful frames to make it function...blech. it's nice to see some builders doing hidden routing and integrating it all under 1 package.

thermalattorney--that's a really nice lookin' rig.




https://scontent.fphx1-2.fna.fbcdn.net/hphotos-xat1/v/t1.0-9/11223791_10205999899490589_8030567686786449743_n.j pg?oh=7f9a01b640a1a087eecdca40dd3f7c40&oe=572B9AFB

[DrSpoke]

Here is a couple pics of my new Ridley X-Trail. It's mostly gravel and mixed pavement/trail but I also have a set of pure road wheels. If or when I ever get a new road bike it will surely be disc. Of course by then there will likely be a multitude of options as well as improvements in the technology.

[thermalattorney]

That's a pretty bike, can you share details of the build?

Thanks, you can read the updated build thread here (http://forums.thepaceline.net/showthread.php?p=1856796).

/threadjack

The R785 hoods have a shape unlike anything else Shimano makes. They fit OK on my Easton SLX3 bars but the angle isn't ideal.