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Death of the rim brake looming?

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    #92
    Macy0161
    Registered Users Posts: 9,290 ✭✭✭Macy0161


    harringtonp wrote: »
    Realize road is different but reckon I'll be one of the last to make the switch. Many roadies are so paranoid about weight, I cannot imagine them going for discs as they are now. You're adding several hundred grams and asking yourself why...
    As far as I'm aware most of the professional bikes need weight added to make UCI minimum weight. The debate with the pro's has been dominated by safety and how aero they are. I haven't really heard weight raised as an issue.
    Inquitus wrote: »
    They still haven't sorted the time it takes to change a Disc brake wheel, there were a good few demonstrations in the Tour of how long it takes compared to a Rim Brake wheel, before the whole Peloton starts using them I think they will need to resolve that issue. If you get a puncture within 10km of the finish, and before the 3km rule kicks in, the extra time it takes to change a Disc wheel is enough to leave you unable to chase back on in time, you are talking at least 30 seconds extra or so, and we saw a lot of faffing trying to get them on from time to time as well.
    Rim brakes didn't seem to help Nario too much this year with his wheel changes...

    Unless they have filed off the "lawyer tabs", would a bolt through really be that much longer? They faff so long with quick release I'm not sure it'll make that much difference tbh. The biggest issue will be a uniform standard, which must also be an issue with rear wheel changes even with quick release.


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    #93
    GreeBo
    Registered Users Posts: 27,088 ✭✭✭✭GreeBo


    Inquitus wrote: »
    They still haven't sorted the time it takes to change a Disc brake wheel, there were a good few demonstrations in the Tour of how long it takes compared to a Rim Brake wheel, before the whole Peloton starts using them I think they will need to resolve that issue. If you get a puncture within 10km of the finish, and before the 3km rule kicks in, the extra time it takes to change a Disc wheel is enough to leave you unable to chase back on in time, you are talking at least 30 seconds extra or so, and we saw a lot of faffing trying to get them on from time to time as well.

    How is changing a disc brake wheel any longer?

    I frequently pop the front wheel of my bike to stick it in boot or just to lock it to the back and its disc brakes....havent noticed it being any slower tbh?


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    #94
    Eamonnator
    Registered Users Posts: 6,561 ✭✭✭Eamonnator


    GreeBo wrote: »
    How is changing a disc brake wheel any longer?

    I frequently pop the front wheel of my bike to stick it in boot or just to lock it to the back and its disc brakes....havent noticed it being any slower tbh?

    Are your wheels quick release?

    Most of the disc wheels used by the Pro teams are bolt through axle. They allegedly take a little longer to instal.


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    #95
    Inquitus
    Registered Users Posts: 13,734 ✭✭✭✭Inquitus


    Eamonnator wrote: »
    Are your wheels quick release?

    Most of the disc wheels used by the Pro teams are bolt through axle. They allegedly take a little longer to instal.

    Yep firstly there is no common standard yet so Neutral Service can't really help you, so you need a teammate on Discs, or the Team Car to make it to you, which can take a good while in the case of a group pile up on the run in. Secondly they all use bolt thru axels and there was plenty of footage of riders and mechanics struggling to get wheels off and on during the Tour.


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    #96
    Lemming
    Registered Users Posts: 14,148 ✭✭✭✭Lemming


    Eamonnator wrote: »
    Are your wheels quick release?

    Most of the disc wheels used by the Pro teams are bolt through axle. They allegedly take a little longer to instal.

    * A little slower to remove, but not much slower, all considered. Bolt-thru axles only need to be loosened enough that the threading can be undone by hand, then the rest of it just slides out.

    I find bolt-thru/disc wheels a lot less hassle to re-mount however as there's no faffing around readjusting brakes or readjusting the tension of a Q/R lever; the axle will only allow the wheel to sit in one position.



    Disclaimer: speaking from an MTB perspective - and I'll assume that the roadie bolt-thru follows the same notions.


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    #97
    jon1981
    Registered Users Posts: 4,359 ✭✭✭jon1981


    Why, out of interest, would they use bolts instead of quick release?


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    #98
    cython
    Registered Users Posts: 4,758 ✭✭✭cython


    jon1981 wrote: »
    Why, out of interest, would they use bolts instead of quick release?
    One suggestion I've heard in favour of thru-axle (not bolts in the traditional sense, for what that's worth!) is that under sufficient braking force (specifically the torque/torsion generated) with discs there was thought to be a chance of the wheel popping out of the dropouts, where the thru-axles mean this can't happen due to the enclosed loop with the thru-axle passing through it.

    This may be all nonsense/overkill, but it is one of the arguments I've heard against mixing discs and traditional QRs.


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    #99
    ford2600
    Closed Accounts Posts: 4,457 ✭✭✭ford2600


    cython wrote: »
    One suggestion I've heard in favour of thru-axle (not bolts in the traditional sense, for what that's worth!) is that under sufficient braking force (specifically the torque/torsion generated) with discs there was thought to be a chance of the wheel popping out of the dropouts, where the thru-axles mean this can't happen due to the enclosed loop with the thru-axle passing through it.

    This may be all nonsense/overkill, but it is one of the arguments I've heard against mixing discs and traditional QRs.

    I think in early DH riding that happened with qr.

    Given braking force is applied at 70mm or so from axle rather 311mm or so you need a much bigger force for same braking as your lever is so much smaller..

    It should make front of bike stiffer to I would think


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    #100
    GreeBo
    Registered Users Posts: 27,088 ✭✭✭✭GreeBo


    Eamonnator wrote: »
    Are your wheels quick release?

    Most of the disc wheels used by the Pro teams are bolt through axle. They allegedly take a little longer to instal.

    Yeah I use quick release, but isn't the slowness an issue with the bolt through rather than the disc then?
    The disc just slides between the pads and that's it....unless I'm missing something?


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    #101
    Inquitus
    Registered Users Posts: 13,734 ✭✭✭✭Inquitus


    GreeBo wrote: »
    Yeah I use quick release, but isn't the slowness an issue with the bolt through rather than the disc then?
    The disc just slides between the pads and that's it....unless I'm missing something?

    Yep the issue is with the bolts, but they are part and parcel of all the Disc wheels used in the pro-peloton today, hence the issues making a quick change, that and the lack of standards meaning neutral service is of little use.


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    #102
    GreeBo
    Registered Users Posts: 27,088 ✭✭✭✭GreeBo


    Inquitus wrote: »
    Yep the issue is with the bolts, but they are part and parcel of all the Disc wheels used in the pro-peloton today, hence the issues making a quick change, that and the lack of standards meaning neutral service is of little use.

    So there are no quick release disc sets?
    I don't see how disc brakes and quick release are related...are there no disc forks that support quick release??


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    #103
    Inquitus
    Registered Users Posts: 13,734 ✭✭✭✭Inquitus


    GreeBo wrote: »
    So there are no quick release disc sets?
    I don't see how disc brakes and quick release are related...are there no disc forks that support quick release??

    As far as I understand it its a 2 fold issue, #1 safety, as the additional force from Discs can work a QR Skewer loose, #2 flex. where climbing out of the saddle can cause the rotar to rub against the pads with a QR skewer.

    https://cyclingtips.com/2015/10/road-bikes-are-headed-towards-through-axels-but-why/


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    #104
    benneca1
    Registered Users Posts: 485 ✭✭benneca1


    From my mtb background following a puncture remounting a front disc wheel is a doddle the rear done outside in the rain and cold gives you two problems instead of one. Lining up the disc rotor and lining up the cassette and chain. Invariably to get the bloody rotor into the gap between the pads you end up touching the rotor with oily hands bugger up your braking surface. The whole way home the damn thing squeals like a double decker bus. To sort it you have to clear rotors and pads(if you are lucky). On a mtb the added braking performance is amazing and worth the hassle. On a road bike id only go disc if I went tubeless as well where hopefully risk of having to remove a wheel on the road is reduced. On plus side your runs and wheels will be cleaner in winter.


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    #105
    jon1981
    Registered Users Posts: 4,359 ✭✭✭jon1981


    cython wrote: »
    One suggestion I've heard in favour of thru-axle (not bolts in the traditional sense, for what that's worth!) is that under sufficient braking force (specifically the torque/torsion generated) with discs there was thought to be a chance of the wheel popping out of the dropouts, where the thru-axles mean this can't happen due to the enclosed loop with the thru-axle passing through it.

    This may be all nonsense/overkill, but it is one of the arguments I've heard against mixing discs and traditional QRs.

    Bloody hell I never considered that! Off i go to tighten my QR, I only tightened it as much as i would normally do for rim brake wheels!


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    #106
    magicbastarder
    Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,494 CMod ✭✭✭✭magicbastarder


    i can see on my 'traditionally' mounted wheel - with discs - is that under heavy load, you can see the wheel flex to the left. makes sense, the wheel is being braked on one side but not the other.


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    #107
    GreeBo
    Registered Users Posts: 27,088 ✭✭✭✭GreeBo


    magicbastarder wrote: »
    i can see on my 'traditionally' mounted wheel - with discs - is that under heavy load, you can see the wheel flex to the left. makes sense, the wheel is being braked on one side but not the other.

    I'd be very surprised if that's actually happening, based on the width of a wheel.

    I have seen them flex during aggressive peddling when throwing the bike from side to side, bmx style


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    #108
    Lemming
    Registered Users Posts: 14,148 ✭✭✭✭Lemming


    magicbastarder wrote: »
    i can see on my 'traditionally' mounted wheel - with discs - is that under heavy load, you can see the wheel flex to the left. makes sense, the wheel is being braked on one side but not the other.

    You can mitigate flex somewhat with front suspension forks with beefier stanchions or forks with sturdier wheel arch supports, but nothing like a thru-axle can provide. 15mm is standard diameter for MTB front axles, although 20mm is also common, more so with dirt jump/freeride disciplines.

    If you think back to the introduction of the triple-clamp front fork concept for DH and Freeride (dual-crown top and bottom of steerer + axle, hence the name), the thru axle trickled down to single-crown forks on the foot of that as besides reducing flex under breaking, the thru-axle stiffened up the 'feel' of the bike in general.


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    #109
    Rechuchote
    Registered Users Posts: 1,171 ✭✭✭Rechuchote


    cython wrote: »
    One suggestion I've heard in favour of thru-axle (not bolts in the traditional sense, for what that's worth!) is that under sufficient braking force (specifically the torque/torsion generated) with discs there was thought to be a chance of the wheel popping out of the dropouts, where the thru-axles mean this can't happen due to the enclosed loop with the thru-axle passing through it.

    This may be all nonsense/overkill, but it is one of the arguments I've heard against mixing discs and traditional QRs.

    Why would this happen more with disc brakes than rim brakes, though?

    (My Bad Bike (22kg 1980s-or-so Dawes) has rim brakes and my Good Bike (9kg Cannondale) has disc brakes, my first experience of these. Both started out with quick-release front wheels, but I replaced the Dawes' one with a screw-in version after some lightfingered person quick-released it and walked away with it in Temple Bar many years back.

    I find the disc brakes so much better in terms of braking control; I'd always choose them now. The only difference otherwise is that I'm not at all sure how to check if the pads need replacement.


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    #110
    Chips Lovell
    Moderators, Politics Moderators, Sports Moderators Posts: 24,268 Mod ✭✭✭✭Chips Lovell


    Inquitus wrote: »
    Yep firstly there is no common standard yet so Neutral Service can't really help you, so you need a teammate on Discs, or the Team Car to make it to you, which can take a good while in the case of a group pile up on the run in. Secondly they all use bolt thru axels and there was plenty of footage of riders and mechanics struggling to get wheels off and on during the Tour.

    Even with the team car, you're going to run into trouble, because most teams they'll just grab the first wheel to hand. If you're the only one on discs, chances are your wheels are near the bottom of the pile.

    It's for that reason I can't see many people going for them in anything from A3 upwards, unless you're being paid to use them.


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    #111
    magicbastarder
    Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,494 CMod ✭✭✭✭magicbastarder


    Rechuchote wrote: »
    Why would this happen more with disc brakes than rim brakes, though?
    rim brakes apply the braking force equally on both sides of the wheel, so there's no sideways force involved.
    with a disc brake, the wheel is being 'grabbed' on one side only, and down near the axle - if there was a disc on each side, you wouldn't have the same sidways torque on it.


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    #112
    Macy0161
    Registered Users Posts: 9,290 ✭✭✭Macy0161


    Inquitus wrote: »
    Yep the issue is with the bolts, but they are part and parcel of all the Disc wheels used in the pro-peloton today, hence the issues making a quick change, that and the lack of standards meaning neutral service is of little use.
    But is there not already issues for neutral service with rim brakes? I know the pro's are shimano dominated, but not all are. And then different cassettes/ indexing issues.

    I'm not saying there won't be issues with disc's, I'm just failing to see everything is rosy in the neutral service garden with rim brakes! Neutral service always seems to be a clusterf*ck.


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    #113
    cdaly_
    Registered Users Posts: 6,440 ✭✭✭cdaly_


    magicbastarder wrote: »
    rim brakes apply the braking force equally on both sides of the wheel, so there's no sideways force involved.
    with a disc brake, the wheel is being 'grabbed' on one side only, and down near the axle - if there was a disc on each side, you wouldn't have the same sidways torque on it.

    OTOH, the disc is mounted to the hub which one would expect to be a fairly rigid piece so I would expect the braking force to be more symetrical and therefore flex to be less.


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    #114
    AllForIt
    Registered Users Posts: 8,302 ✭✭✭AllForIt


    My bike was stolen a couple of months ago and I just got a new one this week. The old one had disk breaks. The new has rim. It's horrible going back to rim. Student at mo and can't afforded the more expensive disk break bike but I'll be getting rid of it as soon as I can. And this is a new bike I'm talking about in perfect con. Can't wait for the rim breaks to become fkd up.


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    #115
    cdaly_
    Registered Users Posts: 6,440 ✭✭✭cdaly_


    nee wrote: »
    I did think they look good on touring bikes, cx/ gravel and adventure bikes though. Seen a gorgeous disced out Thorn yesterday.

    Discs on front as well as back? That's a bit of a departure for them. They used to be adamant that steel disc forks were an abomination...


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    #116
    tomasrojo
    Registered Users Posts: 11,745 ✭✭✭✭tomasrojo


    Given that even drum brakes and coaster brakes still exist and indeed flourish in parts of the world where there are a lot of everyday cyclists, I guess the answer to the OP's question is:

    In professional cycling, maybe
    Generally, probably not.


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    #117
    tomasrojo
    Registered Users Posts: 11,745 ✭✭✭✭tomasrojo


    Probably too late for the spoon brake though.

    800px-Bicycle_spoon_brake_variation.jpg


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    #118
    eeeee
    Moderators, Sports Moderators Posts: 6,831 Mod ✭✭✭✭eeeee


    Wow, that's be a daemon on your solid tyres!


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