bike with disc brake more advantages or disadvantages?

[winkybiker]

A bit of a sidebar here. Just purchased a Tandem with a rear Mechanical disk. You can actually stop the bike with only the rear disk. You could not brake this hard on a road bike rear wheel as it would slip. The front is a dual pivot POS with enough reach to accommodate the tires and clearance for fenders but this has to be replaced eventually. Di2 with a broader gear range and Hydro disk upgrade with front wheel and fork with through axle. Wow, Brakes on a tandem that really work great. We used to have a tandem with just Vee brakes and it was awful braking.

They put a disc on the rear but not the front? That's just weird.

 

[OffTheBackAdam]

Tandemsve had rear disc brakes for many,many years.
They're on the rear, because you're likely to lock the brake up whilst cornering. Lock up the front & you'll be down, lock up the rear & you've a chance to recover.

 

[winkybiker]

Tandemsve had rear disc brakes for many,many years.
They're on the rear, because you're likely to lock the brake up whilst cornering. Lock up the front & you'll be down, lock up the rear & you've a chance to recover.

I thougt one of the advantages of discs was that they were easier to modulate. I'd always want my best brake on the front, both in terms of power and modulation. Modulation on cantilevers is appalling and I'd do pretty much anything not to have one of those evil things on the front.

I would think that tandems, due to their length, are a bit more balanced in terms of front-to-rear stopping power than regular bikes which can't stop effectively with the rear brake alone. But I don't see why a tandem would be more likely to lock the front (or rear) brake in a corner.

 

[9000ft]

When I got my first full suspension mountain bike it also had disk brakes. The thing that really made me say "holy s**t, how did I live without this?" wasn't the full suspension, it was the disk brakes. Anyone who says disks offer only slightly better braking performance over rim brakes either hasn't ridden them or is overly invested in their opinion.

Disk brakes offer a LOT more stopping power, much better modulation, less wear on the rims and can be made very light - very comparable to the total weight of rim brakes when you include the weight savings to not having to build the rim for rim brakes. Someone mentioned complexity, but actually, a hydraulic disk brake is a very simple device. I spend much less time farting around with my disks than I ever did with rim brakes. I suppose the areo penalty would be an issue on a time trial bike, but for general riding and racing I'd say it's negligible

There are many times I wish I had the power and modulation of disks on the road.

 

[9000ft]

I'd say rim brakes win this one by a long shot on the road bike. On the MTB, it's a different story, obviously.

Why would it be a difference on an MTB? Don't all the issues you mention also apply to mountain bikes?

 

[winkybiker]

Why would it be a difference on an MTB? Don't all the issues you mention also apply to mountain bikes?

MTB riding uses a lot more braking. It is just more important. Technical downhill sections are ridden with LOT of braking, so the advantages of better modulation of discs are realised much more of the time. The disadvantage of aerodynamics don't matter on MTBs.

Road biking only involves the very occasional use of brakes (crits and switchback descents would be the exceptions) so although the discs might be better, the disadvantages (ugly (SRAM levers make me want to puke), heavy, expensive, non-aero, incompatible wheels, rotor rub etc...) far outweigh the very occasional advantages. This won't stop the Freds buying them buy the container-load this summer, though.

Riding regularly in the rain where rim brakes scarcely work at all is another exception, perhaps.

 

[Master50]

They put a disc on the rear but not the front? That's just weird.

This is an interesting problem as I was always of the mind that disks are the answer for Tandems. Santana who is definitely a leader in the tandem world definitely was not speaking well of mechanical disks available even a few years ago. the most common Avid brakes would melt plastic parts in big Euro mountain rides. Mechanical systems are not as effective as rim brakes because f the heat. Further caliber brakes like Dura ace are not considered adequate for Tandems. At the time this opinion pice was written very few Hydraulic disk brakes were available. In a nutshell Mechanical disk brakes are considered a step down from cantilever brakes by Santana.
I have hade the tandem out 3 times now and the disk rear / caliber front is perfectly fine for the hills and terrain here but I have already noticed the disk warp after a long application. It feels about as powerful when cold as V brakes were on the Tandem we had 15 years ago. I can stop the bike with just the rear brake.

 

[winkybiker]

This is an interesting problem as I was always of the mind that disks are the answer for Tandems. Santana who is definitely a leader in the tandem world definitely was not speaking well of mechanical disks available even a few years ago. the most common Avid brakes would melt plastic parts in big Euro mountain rides. Mechanical systems are not as effective as rim brakes because f the heat. Further caliber brakes like Dura ace are not considered adequate for Tandems. At the time this opinion pice was written very few Hydraulic disk brakes were available. In a nutshell Mechanical disk brakes are considered a step down from cantilever brakes by Santana.
I have hade the tandem out 3 times now and the disk rear / caliber front is perfectly fine for the hills and terrain here but I have already noticed the disk warp after a long application. It feels about as powerful when cold as V brakes were on the Tandem we had 15 years ago. I can stop the bike with just the rear brake.

Tandems used in mountainous areas where braking is an issue need at least three brakes. If I had one, and rode it in the mountains, I'd have four. V-brakes front and rear and discs on both wheels. Cantilevers are the spawn of the devil and should be killed with fire.

 

[9000ft]

MTB riding uses a lot more braking. It is just more important. Technical downhill sections are ridden with LOT of braking, so the advantages of better modulation of discs are realised much more of the time. The disadvantage of aerodynamics don't matter on MTBs.

Road biking only involves the very occasional use of brakes (crits and switchback descents would be the exceptions) so although the discs might be better, the disadvantages (ugly (SRAM levers make me want to puke), heavy, expensive, non-aero, incompatible wheels, rotor rub etc...) far outweigh the very occasional advantages. This won't stop the Freds buying them buy the container-load this summer, though.

Riding regularly in the rain where rim brakes scarcely work at all is another exception, perhaps.

You might not use your brakes much on flat or gently rolling terrain but I live in the Rocky Mtns and you use your brakes plenty hard on sharp turns on long mountain descents. There have been plenty of times I've worried about my rims overheating on long steep descents.

Another thing to consider is safety. I've been pretty lucky with cars on the rode but having the extra power of disks for that panic stop that might save your life after a car pulls in front of you might change your mind.

 

[Master50]

Tandems used in mountainous areas where braking is an issue need at least three brakes. If I had one, and rode it in the mountains, I'd have four. V-brakes front and rear and discs on both wheels. Cantilevers are the spawn of the devil and should be killed with fire.

I understand Arai is not making their rear drum brake. I too hate cantis and have seen a pair or two in the spokes with a bloody face accompanying it.

 

[ustabe]

You might not use your brakes much on flat or gently rolling terrain but I live in the Rocky Mtns and you use your brakes plenty hard on sharp turns on long mountain descents.

After failing to roll tubulars cemented with Tubasti on a few canyon descents, I stopped worrying about heat. I did switch to a better cement, though.

It's interesting that in other discussions, objections to road disc brakes focused on the misconception that they could not dissipate heat as well as rim brakes. I found myself defending them, or at least Shimano's products, citing their extensive R&D and use of cooling fins and alloy-steel sandwiched rotors. I am impressed, but I'm not compelled. That may change, but not for now.

If you find compelling reasons to ride road disc, by all means, make the investment. If you don't, don't worry, you aren't going to die.

 

[winkybiker]

You might not use your brakes much on flat or gently rolling terrain but I live in the Rocky Mtns and you use your brakes plenty hard on sharp turns on long mountain descents. There have been plenty of times I've worried about my rims overheating on long steep descents.

This overheating simply doesn't seem to be an issue with rim brakes (some carbon clinchers notwithstanding, apparently). I've also ridden lots of long, steep, switchback descents in Europe with rim brakes and had no issues at all. The pros race down these sorts of descents wthout overheating issues.

 

[King Boonen]

They stop marginally better than my rim brakes on alu rims, in exchange for a significant cost difference. That's a disadvantage to me.

Carbon rims? I have one set of carbon tubs. All my other wheels are alu. As far as fluid is concerned, taking the bike to the shop and waiting/paying for brake bleeding is a huge disadvantage vs. fixing the brakes yourself with a simple allen key.

So, we have more weight, extra cost, extra cost of maintenance vs. nearly identical performance, lower cost, ease of maintenance.

I'd say rim brakes win this one by a long shot on the road bike. On the MTB, it's a different story, obviously.

Sorry, late reply.

Bleeding is hardly ever required, I know guys who have been running the same set of brakes for over 5 years and have never bled them. It's also a simple process. Yes, it's more of a faff than adjusting a cable, but there are huge benefits.

My cheap Deore disc brakes stop better than any rim brakes I've ridden except a friends Dura Ace in the dry and with much less force. In the wet it's no contest, disc brakes are orders of magnitude better than alu rim brakes and even more so than carbon rims. So near identical performance is just wrong. Under a certain set of conditions the performance might be similar, but vary the conditions and disc brakes win by a long way. The other thing is the braking hardly changes. Disc brakes work almost identically in the wet as they do in the dry, the only difference is tyre grip. Now, if you have a shed full of bikes or only ride in the dry then that's fine, but for those of us with 1 road bike brakes that operate consistently well under all of the conditions we ride in are much, much more preferable. I can ride through four seasons in one day up here...

At the moment they are heavier, but once they are allowed in the peloton there will be more development and we could see significantly lighter rims developed as there is no longer a need to take rim wear into consideration. This will result in less rotational weight and make for much faster wheel sets. As for overall weight, unless the UCI change the limit it's only an issue for weight weenies anyway (I ride a steel frame so I'll admit my biases here).

They are more expensive. I can't say if prices will come down, but the latest Deore brakes are good enough for downhill so I would expect they would. It's going to take a while though.

Less aero? Most likely although with more development of caliper mounting and there no longer being a need to mount rim brakes on the top of the forks we may actually see more aerodynamic designs due to this (they will probably be ugly though....) both for forks and rims.



At the current state of development/market, yes there are lots of disadvantages. But 5 years or so down the line once they are properly introduced I can see them out performing rim brakes in every way. It's a pain for people who have lots of rim brake compatible kit (I ride rim brakes on the road and no doubt will for a long time yet) but rim brake parts are going to be around for a long time yet. It's also very early in road bike disc brake development, the current brakes are likely to be very different from those of 5-10 years down the line, and I won't be buying in for a good while, but that's how development works. Some people will pay the premium for new developments and years down the line we all benefit.

 

[9000ft]

This overheating simply doesn't seem to be an issue with rim brakes (some carbon clinchers notwithstanding, apparently). I've also ridden lots of long, steep, switchback descents in Europe with rim brakes and had no issues at all. The pros race down these sorts of descents wthout overheating issues.

I should have also mentioned that overheating is only one issue. Power is the main advantage. Anyone who says rim brakes are anywhere near in the league of disks for braking power and modulation hasn't ridden a bike with disks. Hauling down a road at 40-50 mph into a sharp turn (I have 2010 Dura Ace so I have top of the line build), I've often wished for the power and one finger modulation of disk brakes.

Like others have said, if you're OK with rim brakes that's fine, but don't fool yourself that they have any performance advantages. IMO, disks will become more and more common on road bikes over the next 2-4 years.

 

[winkybiker]

I should have also mentioned that overheating is only one issue. Power is the main advantage. Anyone who says rim brakes are anywhere near in the league of disks for braking power and modulation hasn't ridden a bike with disks. Hauling down a road at 40-50 mph into a sharp turn (I have 2010 Dura Ace so I have top of the line build), I've often wished for the power and one finger modulation of disk brakes.

Like others have said, if you're OK with rim brakes that's fine, but don't fool yourself that they have any performance advantages. IMO, disks will become more and more common on road bikes over the next 2-4 years.

I never said that discs didn't work better. I just think they solve a problem that doesn't exist for most people. Except when riding in the rain, I never wish my brakes were more powerful.

 

[42x16ss]

I never said that discs didn't work better. I just think they solve a problem that doesn't exist for most people. Except when riding in the rain, I never wish my brakes were more powerful.

Agreed. The only time I can think of discs being a major advantage is when racing and descending in the wet on deep carbon wheels without an alloy braking track.

 

[VeloFidelis]

All the ridiculous hair splitting aside, here's a prediction for you: The UCI will approve the use of disc brakes in road cycling before the start of the 2016 season. And the conversion in the peloton will be unanimous by the end of the Spring Classics. When you show a pro that he can descend faster, and brake later, more safely, with more confidence, in all conditions, do you seriously think they won't go there? Why not?... the weight thing? Bahh!... minor details soon to be worked out.

I worked for a ski binding manufacturer in 1985 that came up with a clipless pedal that was 2.5 times heavier, with way less cornering clearance than the toe clip/strap pedals that any pro was using at that time. What kind of pedals do you use?

Disc brakes work better... prepare to evolve.

 

[VeloFidelis]

Gee... that didn't take long at all.

http://cyclingtips.com.au/2015/08/eight-worldtour-teams-to-begin-using-disc-brakes-in-the-peloton-this-month-mass-rollout-likely-in-2016/

 

[Master50]

Re:

A LBS mechanic told me never use a radial spoke wheel with disc brakes.

That's a tricky "never." Hub bodies have to be manufactured to different tolerances for radial builds anyway. People, including me, would build and ride them anyway.

It's been a long time, but one used to have to find hubs that specifically supported radial spokes. I don't know if hub manufacturers are specifying this anymore or not. A disc hub *definitely* needs to specify supporting a radial build.

That fork better be a thru axle if you are going to buy a bike with disc brakes.

Nothing tricky about this never. a radial spoked wheel is no good for disk braking nor for the rear wheel for the same reasons torque and wind up. this has been well explored for all sorts of wheels including motorcycle and MTB wheels. I won't do the research for you but radial spoking for any wheel with torque at the hub. Radial spoked wheel only brake at the rim.
Cycling news has several videos now with test of disks and the latest show that in terms of distance that disks always stop shorter than rim brakes. the distance to stop improves as the roads and conditions get better but even dry docks are better. Both CN tests used SRAM brakes.
The first time road racing has permitted disks is right now. August and September races are permitting the use of disks in road races. So far only a few teams are using them. Maybe the Vuelta will be the first big race test ground?

 

[lemon cheese cake]

Re: Re:

A LBS mechanic told me never use a radial spoke wheel with disc brakes.

That's a tricky "never." Hub bodies have to be manufactured to different tolerances for radial builds anyway. People, including me, would build and ride them anyway.

It's been a long time, but one used to have to find hubs that specifically supported radial spokes. I don't know if hub manufacturers are specifying this anymore or not. A disc hub *definitely* needs to specify supporting a radial build.

That fork better be a thru axle if you are going to buy a bike with disc brakes.

Nothing tricky about this never. a radial spoked wheel is no good for disk braking nor for the rear wheel for the same reasons torque and wind up. this has been well explored for all sorts of wheels including motorcycle and MTB wheels. I won't do the research for you but radial spoking for any wheel with torque at the hub. Radial spoked wheel only brake at the rim.
Cycling news has several videos now with test of disks and the latest show that in terms of distance that disks always stop shorter than rim brakes. the distance to stop improves as the roads and conditions get better but even dry docks are better. Both CN tests used SRAM brakes.
The first time road racing has permitted disks is right now. August and September races are permitting the use of disks in road races. So far only a few teams are using them. Maybe the Vuelta will be the first big race test ground?

The Eneco Tour had disk brakes, and so will the US Pro Challenge. So the Vuelta wont be used as a testing race, as the Teams were asked to select two races that they wanted to test the brakes and that went to the ET and the UPC.

 

[wendybnt]

I don't ride discs but I think it may be a bit like Di2. Totally unneccessary....but once you've used them you will never go back. I think the weight issues will get more marginal as the development takes place, but also weight isn't everything. I'm not sure they are of benefit to actual pro riders, but we will have to see if they change their descending style because of them.

I think they would be of great help to your average rider on long descents, where hands get tired, particularly in the cold. And if you live in a rainy country it will be good to actually have some braking power Rim design will evolve as well, and people may be more willing to invest in a component that will largely cease to be a consumable.

 

[42x16ss]

Re:

I don't ride discs but I think it may be a bit like Di2. Totally unneccessary....but once you've used them you will never go back. I think the weight issues will get more marginal as the development takes place, but also weight isn't everything. I'm not sure they are of benefit to actual pro riders, but we will have to see if they change their descending style because of them.

I think they would be of great help to your average rider on long descents, where hands get tired, particularly in the cold. And if you live in a rainy country it will be good to actually have some braking power Rim design will evolve as well, and people may be more willing to invest in a component that will largely cease to be a consumable.

Good point. I see it in a similar light as well. Electronic shifting, compact cranks, endurance geometry, disc brakes, wide profile wheels, they don't add a real performance benefit, but they do make a bike that bit nicer (or easier) to ride.

 

[avanti]

One top cyclist I know thinks disc brakes would be useful in a time trial since he could brake later and harder going into a corner.

 

[hulkmolly]

Benefits: disc brake braking and the cooling effect is better than v brake!
Inadequate: disc than v brake weighs a lot! And for some oil disc and the phenomenon of oil spill, as avid juicy 3 and hayes!