Road discs, do we wait a while?

Viewing 40 posts - 41 through 80 (of 110 total)
  • Road discs, do we wait a while?
  • Premier Icon aracer
    Member

    For those calling us road disc sceptics luddites, maybe you can explain to me exactly what the big advantage is? I get the advantage of discs on MTB and CX bikes (I’d not get a CX bike with cantis if buying now), but the reasons they’re a good idea for them don’t really apply in the same way for road race bikes.

    Premier Icon Del
    Subscriber

    no one’s going to release products that aren’t tested into the litigious US market.

    you don’t really have any familiarity with US manufacturing, do you?
    they’re not scared of being sued. they just work on the basis that they ‘might’ be, but if they’re not, it’s a win. in other words, ‘we reckon this is probably ok, until someone kills themselves, and their family sue us, it is’. it’s the ultimate extension of ‘the market decides’.

    Premier Icon cynic-al
    Subscriber

    Ah, that’s why there are so many lethal product failures akin to bike wheels collapsing at high speeds?

    Premier Icon Northwind
    Subscriber

    cynic-al – Member

    Ah, that’s why there are so many lethal product failures akin to bike wheels collapsing at high speeds?

    Ford Pinto… Ford famously did the cost-benefit analysis and decided it was cheaper to have the cars burst into flames and pay out on lawsuits, than it was to fix the car ($11 per car!)

    Premier Icon cynic-al
    Subscriber

    40 years ago?

    mboy
    Member

    The big benefit of discs on a road bike is little to do with braking performance but it’s benefits in wheel and rim design if the rims don’t have the constraint of needing a braking surface.

    I’d agree with this and extend it further… Packaged correctly, a disc brake setup could significantly aid in making a road bike more aero. Wheels without braking surfaces would be more aero, stronger and lighter for a given rim width/depth. OK, so you can’t build em radially, but 24 lightweight aero spokes crossed 2x on both sides of each wheel would still suffice. Disc brakes would also get rid of the brake caliper from the air flow, and could also be better designed to sit out of the way of any airflow behind the fork leg up front and integrated into the stays on the rear of the bike.

    As has also been mentioned, rim brakes currently aren’t a limiting factor on the performance front braking wise. Well that may be the case, but where’s all that heat build up going? Into the rim, with the potential to cause a blow out through excessive heat build up. Disc brakes will be inherently safer because of their ability to deal with the heat better. Given that the average 23c tyre isn’t going to grip as well as a 2.5″ Super Tacky Minion either, road disc brakes would have to be made small enough so that they weren’t grabby or excessively powerful anyway, so in fact you might find a suitable road disc brake was actually less powerful in back to back tests than a top of the line caliper brake currently available. But the other benefits could potentially outweigh the drawbacks of less power.

    All the above said, if disc brakes were going to catch on properly on road bikes, they’ve had plenty of time to do so! The XC racing world took its sweet time to fully embrace discs, CX bikes were available with discs a long time ago (I remember seeing them in the shops with discs circa 2001), but we’re where we are with disc brakes on road bikes today because maybe there isn’t really enough benefit to bother? Perhaps what you gain in one hand, you’d lose in the other so to speak, by fitting a disc…

    That Canyon doesn’t half look cool though! And that for me would be reason enough to buy one with discs…

    I was more vehemently against disc on road bikes until I bought some new Shimano SLX for my MTB, and most of my anti disc brake arguments evaporated.

    BUT (and maybe Ribena can answer this after his Alpine descents) can anyone else honestly say they never end up with rubbing discs and or slightly warped rotors? I’m pretty sure, actual ‘dings’ to the rotor aside, that they seem to warp with general use. I’ve gotten over it on my MTB, but the constant scuffing and ting ting ting of a warped or misaligned disc would do my head in on a road bike, I’d prefer the ‘disadvantages’ of a calliper brake, at least wheels can be more accurately trued that rotors…

    I guess at the end of the day though, it would be much easier for road bike manufacturers to retain the calliper brake mountings? Not like MTBs where they stick out and ‘ruin the lines’ in magazine speak. 🙄

    jota180
    Member

    I have no problem at all with road discs and would love to [ad probably will] have them.
    But ….. given that Colnago have said that their disc braked C59’s stopping distance is 52% less than the rim braked model, I’d be a bit worried in group rides with that sort of disparity – if indeed it is an accurate figure.

    Onzadog
    Member

    But if you can stop 52% quicker than the guy in front during a race, why would you if you’re racing?

    As for the guy behind, you’d have pulled away approaching the corner because he’d have started braking sooner.

    When I first got discs, non of my v-Brake equipped mates rear ended me.

    drofluf
    Member

    jota180 – Member
    I have no problem at all with road discs and would love to [ad probably will] have them.
    But ….. given that Colnago have said that their disc braked C59’s stopping distance is 52% less than the rim braked model, I’d be a bit worried in group rides with that sort of disparity – if indeed it is an accurate figure.

    Accepting that 52% for the moment (and I’m not sure that I believe it) I’d expect a similar variance between well set up and poorly adjusted rim brakes

    jota180
    Member

    Accepting that 52% for the moment (and I’m not sure that I believe it) I’d expect a similar variance between well set up and poorly adjusted rim brakes

    So if you were now in a mixed disc/rim brake group, the difference between the best disc and worst rim will be huge? – again, accepting the 52% figure

    oldgit
    Member

    given that Colnago have said that their disc braked C59’s stopping distance is 52% less than the rim braked model, I’d be a bit worried in group rides with that sort of disparity – if indeed it is an accurate figure.

    Say what!

    Going back to the bit up there, is heat build up an issue on 700c rims which are effectively huge discs? Whilst we know heat build up on road discs are.
    And TT bikes, do they even need them. Surely not for stopping. I’d have thought fully intergrated was the way forward there. And surely a full disc wheel would be less aero with a disc added?

    jota180
    Member

    As for the guy behind, you’d have pulled away approaching the corner because he’d have started braking sooner.

    When I first got discs, non of my v-Brake equipped mates rear ended me.

    It’s not the corners though, it’s those little incidents where people brake on instinct, when you’re within a couple of feet of each other it could get interesting.
    I don’t think I regularly sit that close to a group of mates at speed on a MTB

    mrmo
    Member

    until shimano/sram/campag release disc compatible brake levers it is a pointless waste of time discussing discs and whether they will take off. The simple answer is they won’t.

    Premier Icon cynic-al
    Subscriber

    Why are mtb rims relatively unchanged? (Bar the aero aspect)

    Why aren’t track rims radically different?

    Premier Icon kilo
    Subscriber

    Packaged correctly, a disc brake setup could significantly aid in making a road bike more aero. Wheels without braking surfaces would be lemore aero, stronger and lighter for a given rim width/depth.

    The change from rim to braking surface on my deep section carbon race wheels is practically unnoticeable I don’t see how a wheel with a disc on it will be more aero

    oldgit
    Member

    couple of feet

    more like six inches in some cases.

    I also can’t help notice that the Colnago is fully rim brake compatable.

    This whole road disc thing seems a great idea, especially on my all year round training bikes…I can think of at least one time a year I need more braking? But would I wan’t it slapped right now onto a top end Cervelo or SuperSix Evo.

    oldgit
    Member

    I don’t see how a wheel with a disc on it will be more aero

    Let alone the larger weightier hubs and extra hoses.

    Surely a rim needs added integrity around it’s outer area, to hold the tyre and take shock from the road. In a way a braking surface is taking advantage of this need?

    JRTG
    Member

    No mention yet of the new SRAM red hydraulic discs yet? They are due to be released anytime time soon and a few big companies are waiting for them before releasing their road disc models. They will be here soon!

    Was a good article on road.cc (can find it though) about them and the thought was they would help in a crowded peloton especially as wet carbon rims have pretty poor breaking performance even with the most advanced pads.

    Premier Icon the wanderer
    Subscriber

    I don’t see how a wheel with a disc on it will be more aero
    Let alone the larger weightier hubs and extra hoses.
    Surely a rim needs added integrity around it’s outer area, to hold the tyre and take shock from the road. In a way a braking surface is taking advantage of this need?

    That’s not what we’ve seen on mtbs. Compare old mtb rims to a set of Stans.

    I would have thought there would be some advantage to be had in reducing rotational weight.

    Premier Icon scaredypants
    Subscriber

    I don’t imagine it’ll be an instant, total switch for road pros. Wet days in big mountains will be where they appear first, surely – where potential gains are biggest ?

    Salsa are on it this winter with the collosal, a mile munching road bike.

    140mm bb7s

    I can see discs being an advantage on long wet alpine descents. One benefit is the additional confidence you will have, knowing the brakes will respond instantly… Even if the tyres may still break away 🙂

    I am happy with the looks too. One of these is already in my imaginary dream bike shed.

    mrblobby
    Member

    Was a good article on road.cc (can find it though)

    Hmm interesting.

    when you’re within a couple of feet of each other it could get interesting.

    I’ve ridden in a few chaingangs with our race team, with gaps of no more than a few inches, and this was never an issue. If you can use a dual-pivot brake in this situation, you’ll be fine with discs.

    mrmo
    Member

    I’ve ridden in a few chaingangs with our race team, with gaps of no more than a few inches, and this was never an issue. If you can use a dual-pivot brake in this situation, you’ll be fine with discs.

    To be honest i would be more concerned with hot steel discs in a crash situation, chainrings make enough mess as it is if you happen to be in the way.

    Premier Icon aracer
    Member

    Colnago have said that their disc braked C59’s stopping distance is 52% less than the rim braked model,

    Complete BS. Current stopping distances of road bikes are limited by geometry, not the performance of the brakes. Any decent rim brake is powerful enough to send you over the bars if you use it hard enough.

    A lot of you are simply guessing what the differences are (between discs and rim brakes) based on mtb riding etc.

    I have two roadies. One runs hydro discs, one runs calipers (Ultegra).

    It’s not even close. The disc bike is faster (downhill) – more controlled, more consistent. One-finger braking with loads of modulation, wet or dry.

    Who cares if people can’t see the point in road discs! All that matters is that I have a choice, and currently that is, unfortunately, limited.

    JonEdwards
    Member

    Watching this concept with interest. Less to do with braking performance, more to do with how the wheel can be modified.

    All of a sudden carbon clinchers would make sense – currently the ones with ally braking surfaces are heavy and the full carbon ones have iffy stopping (I’m told) and you don’t want to score them in the wet…
    Potentially you stand to lose a load of weight at the rim, for the addition of a few g at the hub (crossed spokes, disc mount).

    Internal hose routing could clean up the aerodynamics a bit (straight down through the fork, exit by the caliper – similar for the back end).

    Disc clearance issues can be solved with a bit of ingenuity in lever design. Shimnano Servowave/Avid taperbore thingy is the concept – variable leverage, so the pad can sit a long way from the rotor, move in quickly for the initial part of the lever pull, then have the leverage ratio ramp up once the pad is in contact with the rotor.

    Heat dissipation is potentially an issue for brake draggers, but that’s the same issue as for MTBs, although the end result of getting it wrong is potentially more dangerous (higher speeds, traffic, etc)

    Largely it’s about the manufacturers actually deciding they want to do it, and create the appropriate standards. Hopefully they’ll have got their sh*t together in 2 years time, when it’s my 40th…

    Luminous
    Member

    Whilst they wont need a braking surface they’ll still need to be reinforced or they’d be too weak

    Wheels appear to be on the limit already, while having to contend with rim braking requirements.
    http://www.youtube.com/watch?v=c0dzMp61G5w

    Its slightly frustrating as there is great scope for integrating a caliper into the frame. Heat can disipate through the disc and into a specially designed hub, but also into the frame, which in turn can be deisgned to manage air flow to cool a caliper, etc.

    It would be an interesting challenge to work on disc brake integration into a road frame.

    IME, of some concern is the none uniformly distributed, reactionary forces to braking, which act through the frame. Especially on the front, where on my hydraulic equiped commuter, I can epxerience a very unerving reaction in the bike, under certain braking situations. Related to the braking force being on one side of the bike.

    Ultimately, as we know, it is do-able and if there has to be something new delivered to the market to give sales a kick up the back side, then I think we will see it filter into the market.

    What I do not like, is the prospect of having to adopt Di2. Its one thing carrying a multitool with which I can, if necessary, fiddle with a brake or whatever. But stopping because I might get an electrical issue, has potential to be a real PITA, imo.

    I’ll be looking to firstly see what emerges into the market for disc brakes on road bikes, but also for a cable and hydraulic combination.

    Luminous
    Member

    Another thing. With the deletion of braking surfaces on the peripheral part of the wheel, you can reduce the mass at the maximum distance from the hub and so reduce inertia.

    Premier Icon jameso
    Subscriber

    OP, on the comfort issue, I’d expect there’s more to be gained by the removal / redesign of the seatstay ‘brake’ bridge than any additional material or stiffness needed on the stay to cope with disc forces. But also, a lot more comfort comes from the front triangle than people seem to give credit for, it’s not all about the stays.

    Premier Icon mos
    Subscriber

    Has anyone seen the 2013 Roubaix Disc?

    2013 Specialized Road, Cyclocross, Women’s & Commuter Bikes – Roubaix Disc!

    I’de give it another year before they put them on at least one Tarmac model.

    Premier Icon cp
    Subscriber

    That spesh looks great – love the clean outline and lack of rim brake surface 🙂

    jota180
    Member

    Colnago have said that their disc braked C59’s stopping distance is 52% less than the rim braked model,

    Complete BS. Current stopping distances of road bikes are limited by geometry, not the performance of the brakes. Any decent rim brake is powerful enough to send you over the bars if you use it hard enough.

    I suspect it’s not complete BS
    Being able to squeeze the brake till it throws you over the bars doesn’t mean that there isn’t a quicker way to stop, you’d struggle to keep a rim brake just at the point of losing adhesion.
    We all know what the modulation is like with discs compared to rim brakes.

    Premier Icon aracer
    Member

    I have two roadies. One runs hydro discs

    Using what brake levers?

    whatnobeer
    Member

    love the clean outline and lack of rim brake surface

    Back end looks ok. Front looks messy with that cable going down to the calliper. Not a fan of the disc look either. IMO the lack of a braking surface doesnt add much aesthetically.

    Premier Icon aracer
    Member

    Being able to squeeze the brake till it throws you over the bars doesn’t mean that there isn’t a quicker way to stop

    So how do you stop quicker without throwing yourself over the bars then?

    you’d struggle to keep a rim brake just at the point of losing adhesion.
    We all know what the modulation is like with discs compared to rim brakes.

    Do we? No problem with modulating the rim brakes on my road bike so that the rear wheel is just skipping along the road.

    jota180
    Member

    So how do you stop quicker without throwing yourself over the bars then?

    you’d struggle to keep a rim brake just at the point of losing adhesion

    Do we? No problem with modulating the rim brakes on my road bike so that the rear wheel is just skipping along the road.

    How about the front?

    Premier Icon aracer
    Member

    How about the front?

    That is with the front 🙄

Viewing 40 posts - 41 through 80 (of 110 total)

The topic ‘Road discs, do we wait a while?’ is closed to new replies.