Roadbikes - disk brakes = why not?
Discussion
The contact area on a road bike tyre is so small that a decent caliper can overcome it, discs are overkill and add weight and complexity. They also mean that you have to cross lace a front wheel and add more spokes to transfer the braking force from hub to rim, and that's a traditional weight saving area for Road bike wheels, as well as dishing on the spokes needed to fit a disc onto the hub making them weaker weight for weight. Calipers are also lovely and aerodynamic, sitting tucked at the crown of the forks or even integrated inside the fork blades themselves on top level TT bikes.
swerni said:
They work far better in the wet.
Is this not a massive benefit?
Not really. Tyres work far worse, so it's nice to have brakes that auto adjust and get a bit worse in the wet soas not to overcome the available grip.Is this not a massive benefit?
Seriously, disc brakes + wet road + 23mm tyre = instant lowside on brake application. You just can't modulate them well enough to not snatch a front wheel IMO.
whlist i am not sure squeezing rubber agaisnt an alu/carbon rim is the best solution to braking on road bikes, i dont think disc brakes are the answer either, certainly not at pro level. the pads are changed as and when required so consumables arent an issue and they dont go through a pair of pads before the end of a single stage even on a mountain stage with some big descents. on those stages in particular, the stage is often won on the descents with big risks meaning big rewards so the ability to brake better is a false asset in some circumstances?
If a pro rider punctures, its simply a case of open the caliper (done on the bike) and stop, then a mechanic comes along and does the rest. disc alignment is a bit harder and getting a wheel on quickly without a disc rubbing or having to have adjust the caliper or run sufficient travel between pads and disc that its not an issue, but then does that impact power?
I dont think weight is the issue, most pro tour bikes are already underweight and the use of strategic placed weights are added or they use alu bars/stems to make them legal so adding discs wont affect them too much.
the aero issue is an interesting one but surely the obvious solution is to add a fairing to the calipers like some rear mechs have on TT bikes?
If a pro rider punctures, its simply a case of open the caliper (done on the bike) and stop, then a mechanic comes along and does the rest. disc alignment is a bit harder and getting a wheel on quickly without a disc rubbing or having to have adjust the caliper or run sufficient travel between pads and disc that its not an issue, but then does that impact power?
I dont think weight is the issue, most pro tour bikes are already underweight and the use of strategic placed weights are added or they use alu bars/stems to make them legal so adding discs wont affect them too much.
the aero issue is an interesting one but surely the obvious solution is to add a fairing to the calipers like some rear mechs have on TT bikes?
The main reason is that they are not allowed when racing as they are against UCI regulations.
That is changing though and there is significant development in hydraulic road bike shifters.
Personally I think they will be a very good idea, so long as they can alter what is needed from the MTB brakes.
More modulation, less snappy brakes. Very good heat handling and effective braking from the hoods.
To me the biggest plus will be not having to rebuild wheels every few months. Wet weather just eats rims!
That is changing though and there is significant development in hydraulic road bike shifters.
Personally I think they will be a very good idea, so long as they can alter what is needed from the MTB brakes.
More modulation, less snappy brakes. Very good heat handling and effective braking from the hoods.
To me the biggest plus will be not having to rebuild wheels every few months. Wet weather just eats rims!
On many Cyclocross bikes, mechanical (cable-pull) discs are already standard fodder for the mass market. From what I've read on the net and in print, there are some hydraulic systems already available to 'convert' a road bike to hydraulic discs, but so far no-one seems to have perfected an integrated hydraulic brake lever that would work with the current crop of groupsets.
I'm well aware, from the cycling press, that Shimano, Tektro, et al, are all working on solutions, but since most road riders don't see the lack of hydro discs as a problem, the manufacturers aren't working on it as their highest priority. They probably won't bother unless the Pro-Tour boys come to the conclusion that disc brakes will win them a Grand Tour, and since most Tours seem to be won on the climbs, this probably won't happen.
Like most things, we , if we want them, will have to wait until the Pro-Tour teams have hydraulic discs perfected, and declared legal for competition by the UCI, before we can specify them for our new bikes. If they do make it onto the market, you can bet that, like any shiny new tech, the first to break ranks and convert will be charged a premium. Eventually, as the initial buyers pay off the R&D costs, the rest of us will pay a lower 'premium' in order to specify them on a new groupset. From there, "trickle down" will mean that in a few years time, we will all be able to ride the brakes that the Pros were using just a season earlier.
The 'PROS' would seem in this case to favour the 'mixed surface' rider, on the cyclocross or touring bike. They already ride heftier frames, generally, when compared to 'pure road' bikes, and weight/aero advantage is not the Holy Grail to them. The 'CONS' have already been mentioned by others further up the thread: after years of designing lighter, more 'delicate', and aerodynamic wheels, road frames and especially forks, the manufacturers will have to have a massive rethink, in order to come around to the idea of building road wheels more like MTB wheels, and redesigning the front fork completely to resist the additional stresses involved with governing deceleration at the hub rather than the rim.
In my opinion, it is pretty likely that road riders will, in the event that Hydraulic Discs do take off, find that they split into two distinct camps - much like the Shimano/Campagnolo split, there'll be a Disc/Rim split when it comes to brakes too. Many of us, and I count myself as one, like the way our skinny-forked bikes ride too much to countenance swapping to a heavier, more uncomfortable, less flexible, bulky eyesore of a front fork to take advantage of a performance gain(?) that we didn't want, nor ask for. It's horses for courses for me. If I decide to go down the Cyclocross route in the future, I'm sure that a nice Disc brake system will be high on my priority list. If I'm looking for another road bike (and I always am, if I'm being honest) I'll be after something lighter, or more aero (or both?) than my current steed, or there's not a lot of point. I can, as someone else rightly pointed out, already lock up my 23/25mm tyres in the wet, using my (terribly inefficient?) Ultegra rim brakes and quality after-market blocks, if I'm not careful, so what would I need with a stronger set of brakes that meant I would have to ride a heavier, less chuckable bike?
Anyone else like Status Quo?
As for a simple solution - buy the lightest, skinniest Hybrid you can find with hydraulic brakes already fitted, nip down the LBS and pick up a decent set of Alu drop bars and a road cassette, and swap them for the straight bars and climbing cassette on your Hybrid. Voila!!! your very own front suspension/hydraulic disc brake 'racing' bike. The only drawback will come when you are tucked in on a fast decent, and you suddenly need your brakes, as they'll still be on the top of the bars, not where you are used to them.
Disclaimer:That's not a serious suggestion, by the way, and no correspondence will be entered into, regarding personal injury or death claims sustained as a result of taking up this (very) flawed suggestion.
I'm well aware, from the cycling press, that Shimano, Tektro, et al, are all working on solutions, but since most road riders don't see the lack of hydro discs as a problem, the manufacturers aren't working on it as their highest priority. They probably won't bother unless the Pro-Tour boys come to the conclusion that disc brakes will win them a Grand Tour, and since most Tours seem to be won on the climbs, this probably won't happen.
Like most things, we , if we want them, will have to wait until the Pro-Tour teams have hydraulic discs perfected, and declared legal for competition by the UCI, before we can specify them for our new bikes. If they do make it onto the market, you can bet that, like any shiny new tech, the first to break ranks and convert will be charged a premium. Eventually, as the initial buyers pay off the R&D costs, the rest of us will pay a lower 'premium' in order to specify them on a new groupset. From there, "trickle down" will mean that in a few years time, we will all be able to ride the brakes that the Pros were using just a season earlier.
The 'PROS' would seem in this case to favour the 'mixed surface' rider, on the cyclocross or touring bike. They already ride heftier frames, generally, when compared to 'pure road' bikes, and weight/aero advantage is not the Holy Grail to them. The 'CONS' have already been mentioned by others further up the thread: after years of designing lighter, more 'delicate', and aerodynamic wheels, road frames and especially forks, the manufacturers will have to have a massive rethink, in order to come around to the idea of building road wheels more like MTB wheels, and redesigning the front fork completely to resist the additional stresses involved with governing deceleration at the hub rather than the rim.
In my opinion, it is pretty likely that road riders will, in the event that Hydraulic Discs do take off, find that they split into two distinct camps - much like the Shimano/Campagnolo split, there'll be a Disc/Rim split when it comes to brakes too. Many of us, and I count myself as one, like the way our skinny-forked bikes ride too much to countenance swapping to a heavier, more uncomfortable, less flexible, bulky eyesore of a front fork to take advantage of a performance gain(?) that we didn't want, nor ask for. It's horses for courses for me. If I decide to go down the Cyclocross route in the future, I'm sure that a nice Disc brake system will be high on my priority list. If I'm looking for another road bike (and I always am, if I'm being honest) I'll be after something lighter, or more aero (or both?) than my current steed, or there's not a lot of point. I can, as someone else rightly pointed out, already lock up my 23/25mm tyres in the wet, using my (terribly inefficient?) Ultegra rim brakes and quality after-market blocks, if I'm not careful, so what would I need with a stronger set of brakes that meant I would have to ride a heavier, less chuckable bike?
Anyone else like Status Quo?
As for a simple solution - buy the lightest, skinniest Hybrid you can find with hydraulic brakes already fitted, nip down the LBS and pick up a decent set of Alu drop bars and a road cassette, and swap them for the straight bars and climbing cassette on your Hybrid. Voila!!! your very own front suspension/hydraulic disc brake 'racing' bike. The only drawback will come when you are tucked in on a fast decent, and you suddenly need your brakes, as they'll still be on the top of the bars, not where you are used to them.
Disclaimer:That's not a serious suggestion, by the way, and no correspondence will be entered into, regarding personal injury or death claims sustained as a result of taking up this (very) flawed suggestion.
WeirdNeville said:
Not really. Tyres work far worse, so it's nice to have brakes that auto adjust and get a bit worse in the wet soas not to overcome the available grip.
Seriously, disc brakes + wet road + 23mm tyre = instant lowside on brake application. You just can't modulate them well enough to not snatch a front wheel IMO.
Yep, totally with all of this.Seriously, disc brakes + wet road + 23mm tyre = instant lowside on brake application. You just can't modulate them well enough to not snatch a front wheel IMO.
pablo said:
If a pro rider punctures, its simply a case of open the caliper (done on the bike) and stop, then a mechanic comes along and does the rest. disc alignment is a bit harder and getting a wheel on quickly without a disc rubbing or having to have adjust the caliper or run sufficient travel between pads and disc that its not an issue, but then does that impact power?
The motorcycle world endurance championship teams have to change the front wheel on their motorcycles and they have discs brakes. I think they have a quick release lever that pulls the pads and they slide the new front wheel complete with discs into the caliper.I'm sure they could devise similar systems for pro cycling.
Bikeradar recently said that a number of the big name manufacturers were working on disc brake road bikes. Could well be for 2014 now.
I'm looking forward to disc brakes on road bikes
I've never found it hard changing a disc bike wheel. Not even a lever to pull, just slot the new wheel in with a modicum of care. Takes a moment. I don't think that's a reason.
I didn't realise they were banned under UCI rules. That'll be the "real" reason then. As soon as they're not, it'll be another bit of shiny bling to shift the new years range with.
I didn't realise they were banned under UCI rules. That'll be the "real" reason then. As soon as they're not, it'll be another bit of shiny bling to shift the new years range with.
Maybe, but why?
I've never had trouble finding enough brake grip to send myself over the handlebars in the dry, or the bike sliding along the floor in the wet.
They're heavy.
They're not in the slightest bit aerodynamic.
They're expensive.
So why would anyone want them? If the major manufacturers start backing them who cares, they'll go the way of 3d tv !
I've never had trouble finding enough brake grip to send myself over the handlebars in the dry, or the bike sliding along the floor in the wet.
They're heavy.
They're not in the slightest bit aerodynamic.
They're expensive.
So why would anyone want them? If the major manufacturers start backing them who cares, they'll go the way of 3d tv !
as has been said its because they are banned by the uci on road bikes for competetion, think big peleton, big crash, lots of sharp disc edges and shins.
They are now starting to come in as the UCI has st rules around the roundness of the edges etc.....they are better as you dont destroy your wheel rim, they stop better and water apparently clears off them faster...expect them to start arriving on good bikes over the next few years but probably not top end as they weigh more (caliper vs disc + braking unit + hydraulic fluid)
They are now starting to come in as the UCI has st rules around the roundness of the edges etc.....they are better as you dont destroy your wheel rim, they stop better and water apparently clears off them faster...expect them to start arriving on good bikes over the next few years but probably not top end as they weigh more (caliper vs disc + braking unit + hydraulic fluid)
WeirdNeville said:
swerni said:
They work far better in the wet.
Is this not a massive benefit?
Not really. Tyres work far worse, so it's nice to have brakes that auto adjust and get a bit worse in the wet soas not to overcome the available grip.Is this not a massive benefit?
Seriously, disc brakes + wet road + 23mm tyre = instant lowside on brake application. You just can't modulate them well enough to not snatch a front wheel IMO.
I ran 1.25 tyres on my mountain bike with 140mm discs and it was okay. Obviously 210s would be a bit grabby. With something like ServoWave tweaked a little bit, the initial bite could be made a lot softer too.
In simple terms, the UCI won't allow it, because they are traditionalists and the people want bike like their racing heroes so it's not easy to market.
Most if not all of the technical problems with mounting discs to road bikes are caused by trying to retro engineer a road bike to use bits from mountain bikes, weights, aero etc is of course a consideration to MTB'ers, but nothing like as much focus is put on it as it is in Road riding and even the most weight obsessed racing whippet XC'ers run discs.
Any of the bike brands could (and are) build ground up road bikes with discs in mind and it would work just as well as one built ground up with rim brakes in mind. Area's would have to be strengthened where other areas could be made lighter to take into account the movement of load, because I don't think there's a need for a tonne more braking power, there's not the grip to exploit it, but disc brakes offer much more control and consistent braking in all conditions.
Maybe they'll revisit carbon disc technology; it didn't really catch on with MTB's but a very small, very light and heat resistant disc sounds perfect for long alpine road descents.
Most if not all of the technical problems with mounting discs to road bikes are caused by trying to retro engineer a road bike to use bits from mountain bikes, weights, aero etc is of course a consideration to MTB'ers, but nothing like as much focus is put on it as it is in Road riding and even the most weight obsessed racing whippet XC'ers run discs.
Any of the bike brands could (and are) build ground up road bikes with discs in mind and it would work just as well as one built ground up with rim brakes in mind. Area's would have to be strengthened where other areas could be made lighter to take into account the movement of load, because I don't think there's a need for a tonne more braking power, there's not the grip to exploit it, but disc brakes offer much more control and consistent braking in all conditions.
Maybe they'll revisit carbon disc technology; it didn't really catch on with MTB's but a very small, very light and heat resistant disc sounds perfect for long alpine road descents.
budgie smuggler said:
Have you actually tried discs on thin tyres though?
I ran 1.25 tyres on my mountain bike with 140mm discs and it was okay. Obviously 210s would be a bit grabby. With something like ServoWave tweaked a little bit, the initial bite could be made a lot softer too.
1.25 inches is a LONG way from 23mm though isn't it. Nearly 1cm wider. A 3rd bigger, when you think about it like that it shows that of course your comparison is not strictly relevant I ran 1.25 tyres on my mountain bike with 140mm discs and it was okay. Obviously 210s would be a bit grabby. With something like ServoWave tweaked a little bit, the initial bite could be made a lot softer too.
okgo said:
budgie smuggler said:
Have you actually tried discs on thin tyres though?
I ran 1.25 tyres on my mountain bike with 140mm discs and it was okay. Obviously 210s would be a bit grabby. With something like ServoWave tweaked a little bit, the initial bite could be made a lot softer too.
1.25 inches is a LONG way from 23mm though isn't it. Nearly 1cm wider. A 3rd bigger, when you think about it like that it shows that of course your comparison is not strictly relevant I ran 1.25 tyres on my mountain bike with 140mm discs and it was okay. Obviously 210s would be a bit grabby. With something like ServoWave tweaked a little bit, the initial bite could be made a lot softer too.
Anyway I just checked the tyres (http://www.chainreactioncycles.com/Models.aspx?ModelID=39338) and they're actually 1.125 not 1.25. So it's actually only a 5 mm difference in width if my maths is right. Guess the contact patch would be bigger due to the 26inch wheels though.
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