Disc brakes on road bikes. Good idea?
Comments
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SmoggySteve wrote:If there was a stigma about discs on a road bike, I dont think Colnago and any other prestigious brand would sell bikes with them already. Only the UCI rules are preventing them being used in competition. If that were to change I am sure more manufacturers would invest more into getting weight down and balancing aerodynamics etc.
I don't think there is a stigma - consumers seem really up for it. But in my fairly long experience, a significant proportion of the bike-buying public will buy any old shite or stupid idea if it's marketed right. That's not to say discs are stupid in themselves, I'm just wondering whether they're a good idea on balance on a road-racing bike.
It seems a lot of the consumer support comes from people who's experience is in mountainbiking or commuting, where discs make a lot more sense. Or from people who are fairly new to cycling and who consider anything that looks like it makes riding a bike 'safer' can only be good. It seems to be largely these people who are leading the consumer argument here.0 -
SmoggySteve wrote:If there was a stigma about discs on a road bike, I dont think Colnago and any other prestigious brand would sell bikes with them already. Only the UCI rules are preventing them being used in competition. If that were to change I am sure more manufacturers would invest more into getting weight down and balancing aerodynamics etc.
I agree with your implication that disc brakes in their current form are not necessarily appropriate for road racing bikes and that manufacturers need to invest more in their design before they can be seen as a genuine cost-effective replacement for rim-brakes.0 -
As far as the consumer argument goes, Its not something someone is going to go out and buy and add to their bike just because its new. If anything I think consumers are likely to save money if you remove the need to change rims that are worn. Even if it takes thousands of miles to degrade them to a point of over wear a few pads and a disc are a lot cheaper than a set of wheels every year or so.
I have had a few times out in the wet where I have really wondered if my brakes are going to stop me, wet roads with dirt and oil and crap getting thrown onto the rims make stopping alot harder.0 -
I think they have a little more development needed first.
The challenges with weight and fork design could be improved with smaller twin disc systems similar to motorbikes. the challenge with boiling fluid is more about technique. The issue with maintenance etc is over rated, there really is nothing difficult about them. We'd see some big improvements in wheel design once the rim no longer needed to be a surface for friction. There is also the chance to opt for things like combined brake systems seen on some motorbikes.
Its wrong to say its easier for new riders. Its the reverse. better brakes demand better technique.0 -
I think the OP is correct in distinguishing race bikes from commuter/training/winter/CX/touring style road bikes.
Non-race bikes can really benefit from disks but I have said before, the marketing wonks at Shimano/SRAM etc are totally focussed on racing technology and trickle-down marketing: you introduce a tech for the professional peleton and if they like it, trickle it down to lower proce-points. This is totally the WRONG WAY to market disc brakes for road bikes. We (non-racers) need them in 105 grade groupsets, not Dura-Ace or SRAM RED on a daily commuter hack.
Mr Shimano, Mr SRAM and Mr Campagnolo, can you for once try trickle up marketing.0 -
MichaelW wrote:I think the OP is correct in distinguishing race bikes from commuter/training/winter/CX/touring style road bikes.
Non-race bikes can really benefit from disks but I have said before, the marketing wonks at Shimano/SRAM etc are totally focussed on racing technology and trickle-down marketing: you introduce a tech for the professional peloton and if they like it, trickle it down to lower proce-points. This is totally the WRONG WAY to market disc brakes for road bikes. We (non-racers) need them in 105 grade groupsets, not Dura-Ace or SRAM RED on a daily commuter hack.
Mr Shimano, Mr SRAM and Mr Campagnolo, can you for once try trickle up marketing.
This is an existing technology which has had plenty of development from MTB to motorbikes. It is not something new to the bike market that is uber expensive to the masses.0 -
Anyone is doubt about the tech and development of discs, go ask someone in the MTB section about their effectiveness going downhill cross country. This is a sport where you dont just need to slow down for a corner. you need to slow down to stop wile e coyoteing into a tree at 50mph. They work, yes they are heavy but not so heavy that weight can not be reduced significantly with other materials. The only reason it hasnt so far is cos weight is not a buzz word so much in MTB. Staying on your bike while you crash down the side of a mountain is. making sure you stop when you get there is not something you take lightly.0
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But to make a disc brake suitably ultra-light for DuraAce/RED groupsets, you have to push the technology to the edge of safe, with small calipers, small fluid resevoirs, non-conductive carbon fibre mounts etc.SmoggySteve wrote:This is an existing technology which has had plenty of development from MTB to motorbikes. It is not something new to the bike market that is uber expensive to the masses.
Internal-frame cable routing means re-flushing the system after mounting, adding to assembly costs.
MTBers dont do the kind of 30 minute descents at high speed with drag braking that road riders can do in the Alpes. MTB downgill bikes have far more metal and 180mm rotors. Road brakes are being made for small rotors cut down to the bar min of weight.
A less ultralight, more conservative mid-level groupset would remove lots of these risks and make a better product.0 -
MichaelW wrote:
But to make a disc brake suitably ultra-light for DuraAce/RED groupsets, you have to push the technology to the edge of safe, with small calipers, small fluid resevoirs, non-conductive carbon fibre mounts etc.SmoggySteve wrote:This is an existing technology which has had plenty of development from MTB to motorbikes. It is not something new to the bike market that is uber expensive to the masses.
Internal-frame cable routing means re-flushing the system after mounting, adding to assembly costs.
MTBers dont do the kind of 30 minute descents at high speed with drag braking that road riders can do in the Alpes. MTB downgill bikes have far more metal and 180mm rotors. Road brakes are being made for small rotors cut down to the bar min of weight.
A less ultralight, more conservative mid-level groupset would remove lots of these risks and make a better product.
If they can make a bike frame that weighs 700g safe to ride they can afford the weight brought on by disc brakes. Dont forget race bikes still have a lower weight limit in races and if you can afford it or if the teams need it, they will make it happen.0 -
My last set of rear pads only lasted 800 miles, not that long really. But a new pair only cost me £3. My choice would still to stick with callipers.Daddylonglegs wrote:True about the cost of rims. Anyone know how much life you can expect out of a pair of rotors and a set of pads?
Having said that, I went for a ride recently when the snow started to come down thick and fast, and my stopping distance changed dramatically - I got a fright as to how poor it had become. But this was the only time I have experienced this. Even in the wet I've never had too much of a problem. I think it was the cold and wet combination.0 -
bernithebiker wrote:Just to further muddy the waters;
Carbon rims - braking is mediocre at best, downright shabby in the wet.
If I could improve braking power whilst keeping a lightweight tubular carbon rim, I would be interested.
This is it for me. Discs hold the promise of consistent braking irrespective of rim or conditions AND should enable weight to be removed from rims where it really matters. We are already starting to see the weight penalty being eroded, I'd be surprised if they aren't mainstream in next five years.0 -
I'm ambivalent about disks. The problem is that for some types of road bike usage they would offer a lot of advantages, while for others they would just add a lot of unnecessary weight, expense and complication. I do most of my summer riding in southern Finland, where I can get out of town on a cycle path in 15mins and then be on quiet, rolling country roads with no major hills. I hardly use my brakes at all. I have had brake pads on bikes that have lasted years. For that sort of riding, disk brakes would be a complete nonsense. I'm also only 63kg on a 6.7kg bike, so even on hills my stopping power requirements are not in the same league as for someone a lot bigger and heavier. On the other hand, I can see how the power and modulation offered by disks could be great for long descents in hilly areas. I'm a pretty rubbish descender and anything that can potentially increase my confidence to allow me to push my speed up on descents would be welcome. For descending in wet conditions, +1000... Rim brakes in the wet on steep descents are just a nightmare. Yes, it's the tyre traction that is the main worry in these conditions, but in order to have control over that you need to be able to finely modulate your braking, and modulation is the first thing that goes with rim brakes in the wet, especially on carbon rims. Similarly, if you do a lot of riding in busy roads and heavy traffic, the extra confidence offered by disks (again, especially in the wet) is going to be welcome, although arguably this is commuting rather than recreational/sports riding.
So I guess ideally we might all want to have bikes with and without disks for different conditions, but in practice may end up choosing one or the other depending on where and how we do the majority of our riding.0 -
neeb wrote:I'm ambivalent about disks. The problem is that for some types of road bike usage they would offer a lot of advantages, while for others they would just add a lot of unnecessary weight, expense and complication. I do most of my summer riding in southern Finland, where I can get out of town on a cycle path in 15mins and then be on quiet, rolling country roads with no major hills. I hardly use my brakes at all. I have had brake pads on bikes that have lasted years. For that sort of riding, disk brakes would be a complete nonsense. I'm also only 63kg on a 6.7kg bike, so even on hills my stopping power requirements are not in the same league as for someone a lot bigger and heavier. On the other hand, I can see how the power and modulation offered by disks could be great for long descents in hilly areas. I'm a pretty rubbish descender and anything that can potentially increase my confidence to allow me to push my speed up on descents would be welcome. For descending in wet conditions, +1000... Rim brakes in the wet on steep descents are just a nightmare. Yes, it's the tyre traction that is the main worry in these conditions, but in order to have control over that you need to be able to finely modulate your braking, and modulation is the first thing that goes with rim brakes in the wet, especially on carbon rims. Similarly, if you do a lot of riding in busy roads and heavy traffic, the extra confidence offered by disks (again, especially in the wet) is going to be welcome, although arguably this is commuting rather than recreational/sports riding.
So I guess ideally we might all want to have bikes with and without disks for different conditions, but in practice may end up choosing one or the other depending on where and how we do the majority of our riding.
I agree with a lot of this. I think it's true that the need for discs on a road bike changes depending on the riding people do and the terrain they inhabit. The problem we have is there's a danger there will eventually be no choice.
We'll see the pro teams all picking and choosing depending on the nature of the race (although no doubt the manufacturers will only be telling us about the riders who are using them). Meanwhile the public get the second-rate kit because the seriously light stuff will cost a ransom and we won't even get to choose between discs and rims anymore. Last year's Vuelta was a case in point. If I was having to race up those insane climbs the last thing I'd want is a pair of discs bolted to my bike. The pros won't use them to climb the Pyrenees, but we'll all have to.
I remember we had one of Marco Pantani's Tour de France-winning Bianchis on display for a while in the bike shop I worked. It was the bike that had taken him through most of the Alpine stages and had been built and assembled specifically for getting him over the climbs. It was extremely light for that time - or even now come to think of it - titanium everything. They had even replaced the left hand STI lever with a standard brake lever and fitted an old-style front mech lever to the downtube to shave off weight. I'm not convinced that Pantani would have had a pair of discs on that bike, because no matter how light they get a disc set-up, it will still be substantially heavier than a pair of rim brakes.0 -
I kind of agree with you - but there is a massive difference! We will never have the same kit as the pros (unless we spend thousands) also the weight you keep referring to will be a few grams - to us mere mortals it will make very little difference.Daddylonglegs wrote:If I was having to race up those insane climbs the last thing I'd want is a pair of discs bolted to my bike. The pros won't use them to climb the Pyrenees, but we'll all have to.0 -
TheFD wrote:
I kind of agree with you - but there is a massive difference! We will never have the same kit as the pros (unless we spend thousands) also the weight you keep referring to will be a few grams - to us mere mortals it will make very little difference.Daddylonglegs wrote:If I was having to race up those insane climbs the last thing I'd want is a pair of discs bolted to my bike. The pros won't use them to climb the Pyrenees, but we'll all have to.
I'm not sure the difference is that massive right now. at the moment I'd say the difference in weight and performance between an average pro bike in the peleton and a good quality shop-bought one is minimal and I think road-racing-bike riders really like this state of affairs whether they actually race or not.
My concern is that manufacturers could decide to push the disc brake idea so hard we all end up riding bikes with them on anyway, or anxiously contemplating our two-grand-plus 16-17lb carbon bikes and wishing they weren't so old-fashioned. Market forces which won't apply to the pros will be left to remove choice from the recreational rider. It might be this that is causing the hesitation with manufacturers in introducing discs to the road-bike market more aggressively. Because, they suspect, in the end the disc brake is not in fact, a good universal solution to the issue of brakes on a purpose-built road-racing bike and too many consumers, like the pro-teams, will remain unconvinced.0 -
Maybe I have missed something on this thread, but just so you are aware: -
I used to race SuperMotards Motorbikes, we had lovely big 320mm discs on the front and 270mm on the rear, braking was fantastic even in the wet, however they generate a massive amount of heat.
If someone crashed in a race and the disc touched a fallen rider then there was no major problem as the leather suits and helmets would protect them from being scarred for life.
Can you imagine in the middle of the peleton that a load of riders went down on a haripin descending a mountain, if the discs were hot it would go through Lycra like butter and would cheese wire any helmet :roll: :shock:
The only way to prevent such injury would be to encase the disc so that if it did touch a rider, then the risk of harm would be reduced, I'm sure that a Carbon ventilated cover could be made weighing less than 50g that would prevent this, so until such time as this could be created then I don't think they should be allowed in races or for that matter on group rides.
I know that they are allowed in Cyclocross, but do the brakes ever get really hot on fast descents?
Just my opinion, I'm all for progress as long as it doesn't increase the risk of injury, if I crashed and a hot disk landed near me eye, then I wouldn't be a happy chappy :shock:0 -
I’ve been riding my mountain bike to work all winter (I’m counting now as winter btw) and one thing I’ve discovered is disk-brakes aren’t as good on the road as everyone seems to think they are (or will be).
I had to change my pads recently because of the horrendous squealing and lack of stopping power; this was after only 3 months of use on the road.
My local bike mechanic told me this is a common problem as the pads get ‘glazed’ from continually braking while being in contact with oil picked up from the road, they end up looking like mirrors and stop working.
I’m not sure if the brake pads designed for road bikes are different but the ones designed for off-road certainly have issues.0 -
The heat thing is all about technique.
In MTB for long gradual descents you alternate braking to allow them to cool or simply go on hard and come off for a second or 2. They really do cool down quite quickly.
Wrt hot things touching flesh. I personally would be more concerned about the tarmac cleaving flesh from body than getting burned by a disc that may touch me for a split second. Then when you look at the general improvements gained from stopping quicker, there is an argument that a crash avoided is worth the risk.0 -
Velonutter wrote:Maybe I have missed something on this thread, but just so you are aware: -
I used to race SuperMotards Motorbikes, we had lovely big 320mm discs on the front and 270mm on the rear, braking was fantastic even in the wet, however they generate a massive amount of heat.
If someone crashed in a race and the disc touched a fallen rider then there was no major problem as the leather suits and helmets would protect them from being scarred for life.
Can you imagine in the middle of the peloton that a load of riders went down on a haripin descending a mountain, if the discs were hot it would go through Lycra like butter and would cheese wire any helmet :roll: :shock:
The only way to prevent such injury would be to encase the disc so that if it did touch a rider, then the risk of harm would be reduced, I'm sure that a Carbon ventilated cover could be made weighing less than 50g that would prevent this, so until such time as this could be created then I don't think they should be allowed in races or for that matter on group rides.
I know that they are allowed in Cyclocross, but do the brakes ever get really hot on fast descents?
Just my opinion, I'm all for progress as long as it doesn't increase the risk of injury, if I crashed and a hot disk landed near me eye, then I wouldn't be a happy chappy :shock:
This is a far bigger issue than weight IMO, so long as they keep the 6.7 kg limit, I reckon discs won't present any actial weight penalty, if they are introduced to the pro Peleton. Also, it's going to be hard to convince most proper roadies to use them if the pros aren't.You live and learn. At any rate, you live0 -
The weight of the brake itself isn't the only consideration, you have to also consider that road bike forks/frames are not designed to accept the sorts of forces applied by slamming on a disc brake.
To ensure the rear stays or the fork blades or the fork steerer and headtube don't bend & crack under these forces, substantial strengthening is required, thus making a frameset much heavier; we're talking a few hundred grams, which in the road world is a huge amount of extra weight.0 -
Maybe what's needed is just more research and innovation on rim brakes. Better braking surfaces and pad compounds, better heat dissipation to allow lighter rims, hydraulic calipers for better modulation, etc.
You can scoff that rim braking is a suboptimal solution and that everything has been tried before, but braking on carbon rims has come on in leaps & bounds in the last couple of years and continues to do so. Also, as Paul Lew says in the recent interview in Cyclist magazine, the rim is effectively a big disk that is already there - why not use it?
Look at how much better rim brakes are than they were 30 years ago... Who's to say there isn't still much more potential for improvement?0 -
neeb wrote:Maybe what's needed is just more research and innovation on rim brakes. Better braking surfaces and pad compounds, better heat dissipation to allow lighter rims, hydraulic calipers for better modulation, etc.
You could always take the same approach that trial adopted back in the 90's and cover the braking surface of your rim in tar!0 -
Just thinking... One problem with current rim braking on clinchers is that the braking surface is also holding the tyre on, so weight needs to be added to the rim to make it up to handling both tasks. Pros don't have this problem to nearly the same extent because they run tubulars, which allows very light rims that can still handle braking forces (all the more reason for them to resist disk brakes compared to amateurs).
Why not design clincher wheels with rim braking surfaces slightly nearer the hub? Deep section wheels are already very common, why not put the braking surface nearer the spokes and have longer reach calipers?0 -
because the forces on the mounts would be a problem.0
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You mean on the mounts for the callipers? There must be a sliding scale though. How much more reach would they have to have before it became a serious practical problem? I was just thinking of moving the braking surface maybe a centimeter to 15mm further down, just to take the stress of the tyre clinching part of the rim.diy wrote:because the forces on the mounts would be a problem.
If someone has already done the maths and it wouldn't work, I will take their word for it.0 -
could work with mtb style vbrakes. but for a road bike you have more force required to stop the wheel and more leverage being applied to the mount.0
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If you want an additional braking surface radially inside the tyre-holding part of the rim, how about hydraulic rim brake calipers (Magura style) integrated into the fork blades. You could position them at any height to meet any braking surface you want without he deep drop required of rim callipers. The smaller radius braking surface would stay clear of puddles compared to current versions.0
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richymcp wrote:I’ve been riding my mountain bike to work all winter (I’m counting now as winter btw) and one thing I’ve discovered is disk-brakes aren’t as good on the road as everyone seems to think they are (or will be).
I had to change my pads recently because of the horrendous squealing and lack of stopping power; this was after only 3 months of use on the road.
My local bike mechanic told me this is a common problem as the pads get ‘glazed’ from continually braking while being in contact with oil picked up from the road, they end up looking like mirrors and stop working.
I’m not sure if the brake pads designed for road bikes are different but the ones designed for off-road certainly have issues.
Just de-glaze the pads with Emory paper on a flat surface.Condor Super Acciaio, Record, Deda, Pacentis.
Curtis 853 Handbuilt MTB, XTR, DT Swiss and lots of Hope.
Genesis Datum Gravel Bike, Pacentis (again).
Genesis Equilibrium Disc, 105 & H-Plus-Son.
Mostly Steel.0 -
rubbing them down wont help if they are contaminated. wont hurt though. Most mtbers run winter/wet pads and summer/dry. I use kevlar in the summer and sintered in the winter. i have even mixed and matched without problems.
Don't forget to clean the discs too a washing up pad and a bit of soapy water is all you need to get off any burned on crud.0
