Do road bikes need through axles .

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  • Do road bikes need through axles .
  • dragon
    Member

    My MTB brakes harder on the front than a road bike ever could

    Are you sure about that? You can regularly on a road bike do dead stops from 35mph+ on highly grippy tarmac, I don’t do that on my mtb.

    Trail-rat haven’t cotic dropped that fork now and gone with a through axle fork? (Admittedly only 9/10mm but still through)

    A guy i ride with has that fork. Its a nice idea, as in it takes any normal front hub. But is a ball ache completly undoing the qr axle into two bits (not including springs) and bending the fork to get the wheel out.

    whatnobeer
    Member

    Lets all be honest. Road bikes only ‘need’ through axles because ‘people’ want disc brakes on them. ‘People’ only want disc brakes because they’ve all taken up road cycling after years of mountain biking and want the same technology, not because it’s better, but because of 3 things:

    1) They’re fat and heavy from all the cake stops at the top of mountains that they push their bikes up so they ‘need’ better brakes to slow the extra mass down.

    2) They don’t know how to set up road brakes to work properly.

    3) They’re convinced disc brakes are the future because they’re new, and like 650b mountains and 29ers before that, must be better.

    4) On top of all that they have no idea how far a road bike can be leaned over into a corner and still grip, but they’re all scared of the speed because most will never get more than 20mph on their 160mm carbon ego steed.

    On top of all that people are idiots and cant work QR levers properly.

    Premier Icon Rusty Mac
    Subscriber

    How long before you get 9mm and 10mm maxle style axles for road bikes as the mountain bike standard ones are just too heavy.

    I’m sure someone will come up with a quarter or half turn maxle style skewer with a QR lever that is 37.8008135 quicker to change than a QR or current through axle. With the addition that in the smaller form factor you could have a smaller and therefore lighter hub shell (same as a current QR shell) and overall lighter wheel. Or some such marketing twaffle.

    mrmonkfinger
    Member

    Everything whatnobeer said.

    How long before you get 9mm and 10mm maxle style axles for road bikes

    Given that marketing dipshits combined with clueless buyers have already decided on continuing to try and make 140mm discs work (cause they’re lighter, so must be better for a road bike, right? WRONG), I think that’s almost a given.

    2) They don’t know how to set up road brakes to work properly.

    Well, they could pay the nice man in the bike shop a tenner to fit and set up their brakes with some decent pads.

    But I bet most riders don’t do that, either.

    Premier Icon ransos
    Subscriber

    Lets all be honest. Road bikes only ‘need’ through axles because ‘people’ want disc brakes on them. ‘People’ only want disc brakes because they’ve all taken up road cycling after years of mountain biking and want the same technology, not because it’s better, but because of 3 things:

    I take it you’re running friction down-tube shifters, Weinmann single pivot calipers and clips & straps?

    Premier Icon jameso
    Subscriber

    aracer – Member

    Except that it’s not lighter, and unlike a suspension fork there’s no need at all for any increased stiffness or strength at the hub of a rigid road fork (and before you suggest it, increasing the stiffness there wouldn’t allow you to remove material anywhere else to any noticeable extent).

    Course it would – the axle becomes part of the structure. Through axle forks can be a totally different structure to a regular one as a result – doubly so with discs versus rim brakes

    I’m with aracer on this – and if you want better stiffness to weight ratios in a rigid frame, fork and wheel structure (particularly a carbon f+f) thru-axles aren’t a great way to do it compared to changing the stays or fork design(or the rest has to be damn stiff before a thru-axle is needed to keep up). An XT QR clamping hard to a std size end-cap will transmit forces pretty effectively to the frame/fork. Thru axles make a big difference to sus f+f (or over some lame ‘ti stix’ QR) but that isn’t carried across to rigid bikes anywhere near as much.

    My MTB brakes harder on the front than a road bike ever could

    Are you sure about that?
    Dead sure : ) you’re right that off-road the speed is lower and grip may not be as good, but to clarify that comment my steel Jones with a truss fork, 180mm rotor, on big rims and 2.0 Big Apples, loaded with 15lb of touring gear plus water, on dry tarmac on a steep descent sees some pretty high brake forces. ie on a ~30-mile overseas descent, very steep in places where I’ve hit well over 50mph for significant sections and had to brake hard along the way. And it still brakes harder off-road in the right place than my disc-road bike with big-ish tyres can on-road, in terms of deceleration and force put through the front end. Geo and fork stiffness as much as anything. Never had the QR / axle shift once.
    So I don’t see any major reason for thru-axles on rigid frames / forks beyond liability and sales features, compatibility etc. At the same time they are a functional and sensible design solution and I’m not against them – I wouldn’t pretend that they’re ‘needed’ though.

    mrmonkfinger
    Member

    Never had the QR / axle shift once.

    Sample size of one…

    It doesn’t alter the fact that, with current ‘slot dropout QR + disc’, braking will cause gradual loosening of the QR.

    How long that loosening takes, and whether it ever affects you is another question entirely.

    cynic-al
    Member

    Its not a fact Monkfinger.

    Premier Icon molgrips
    Subscriber

    They don’t know how to set up road brakes to work properly.

    Please tell us how – I didn’t know there was any adjustment to be made.

    trail_rat
    Member

    “Please tell us how – I didn’t know there was any adjustment to be made.”

    have you checked that your looking at the brakes and not a VCR, a betamax or something like that ? there are alot of adjustments immediately obvious.

    the key thing is to use the mechanical leverage…. ie dont set the pads a mm away from the rim , you need the lever to travel a good distance and youll find your power improves and becomes much less wooden – common mistake most amateur MTB mechanics make winding them right up so the brake contacts the rim in the first few degrees of pulling the brake lever.

    Premier Icon Lifer
    Subscriber

    I really don’t understand the opposition to choice.

    Premier Icon ransos
    Subscriber

    I really don’t understand the opposition to choice.

    Choice = incompatibility.

    Premier Icon molgrips
    Subscriber

    there are alot of adjustments immediately obvious.

    On road brakes? Distance from rim is one – what else?

    Premier Icon Lifer
    Subscriber

    ransos – Member

    Choice = incompatibility.

    😐

    mrmonkfinger
    Member

    Its not a fact Monkfinger.

    Erm, yes, it is, cynical.

    It’s the same fact which means every car manufactured today has conical nuts holding the wheels on – so reversal of forces (obviously on a car that happens with every wheel revolution) do not loosen the nuts.

    More generally, it’s the same reason why any threaded fastening can vibrate undone.

    Denying it doesn’t make it not true.

    On road brakes? Distance from rim is one – what else?

    Pad position (maybe alignment too). Pad material/compound.

    and

    Cleanliness of cable & outer go toward removing friction. Nicely cut (i.e. square ends not a half-assed effort) outers mean you don’t have to “squash” the end of the cable as you brake.

    Both of which go toward less braking effort at the hand for same braking effect.

    cynic-al
    Member

    Well I have had qrs with discs on non lipped forks that have not loosened.

    Saying its true does not make it true either!

    trail_rat
    Member

    height of the pad on the rim , angle of the pad – fore and aft as well as vertically , centralisation of the caliper , ensuring the caliper is free to move , ensuring the lever is in the correct place for your hand to operate it propperly – plus what mrmonkfinger saids

    pdw
    Member

    Its not a fact Monkfinger.

    Indeed, but it is the case that the forces that can be created by a disc brake are uncomfortably close to the clamping force required by the ISO standard for QRs, so you’re relying on the QRs exceeding the standard, and on people operating them correctly.

    Well, turns out that people are fallible, and given the potential consequences of wheel ejection, it seems sensible to use a mechanism that is less reliant on the user getting the tension on a QR just right.

    The higher braking forces possible from rubber-on-tarmac, coupled with the smaller discs that seem to be fashionable on road bikes means the force on the axle is potentially higher than on an MTB.

    As for the whatnobeer’s generalisations, I have disc brakes on my commuting road bike because a) they wear down a sacrificial metal disc rather than a structural part of my wheels and b) they behave predictably in the wet. I’m in no great rush to have them on my summer road bike as the rate of rim wear is pretty much negligible, but I’d be happy enough to have them in the future.

    trail_rat
    Member

    “It doesn’t alter the fact that, with current ‘slot dropout QR + disc’, braking will cause gradual loosening of the QR.”

    of shit QRs …..

    I generally ride from the door or throw my bike fully built in the van , the only time i take tires off is when i get a flat – so its not like they get checked every ride – or even every 10 rides…..

    when ive had skewers that come loose gradually(usually cheap ones or Hope) – i bin them and fit propper skewers from a good manufacturer. – such as shimano with propper internal cam QRs.

    dragon
    Member

    “It doesn’t alter the fact that, with current ‘slot dropout QR + disc’, braking will cause gradual loosening of the QR.”

    of shit QRs …..

    My Specalized Tricross unwinds the front QR under heavy breaking regardless of the make. I even used the tried and tested Shimano QRs, yet they still undo. I’ve never worked the problem out, but I think it must be a fork design issue, on top of the forces acting from the disc.

    Premier Icon nemesis
    Subscriber

    It doesn’t alter the fact that, with current ‘slot dropout QR + disc’, braking will cause gradual loosening of the QR.

    If you’d said

    It doesn’t alter the fact that, with current ‘slot dropout QR + disc’, braking will cause forces that can result in gradual loosening of the QR if insufficiently tight.

    Then you’d be correct. Just because the force is there doesn’t mean it’s an issue in itself.

    mrmonkfinger
    Member

    Well I have had qrs with discs on non lipped forks that have not loosened

    I’ve got QR forks with discs. The QRs have never loosened. So what?

    Sample size of 1 (again).

    shit QRs

    fit propper skewers from a good manufacturer. – such as shimano with propper internal cam QRs.

    this is kind of the point – a decent QR will (a) clamp harder in the first place and (b) stay tight much much longer, maybe even so long that you’d never notice the problem… wheras a tossy lightweight (coughroadiecough) skewer with plastic cam has all the clamping force of a wet flannel and will come loose much muh easier with a painful result

    also, smaller brake disc = more force applied to axle & hence more likely to loosen the QR

    Premier Icon ransos
    Subscriber

    I’ve got QR forks with discs. The QRs have never loosened. So what?

    It disproves your assertion. If you’d said “may” instead of “will” you’d be correct.

    Premier Icon nemesis
    Subscriber

    An analogy is pushing against a wall. If it’s flimsy then I might push it over. If it’s not or I don’t push hard enough it will never fall over no matter how long I push. The decent QR done up properly will never move. You seem to think it will just move very very slowly. It won’t.

    TiRed
    Member

    Surprised nobody’s mentioned them already, but my Giant wheels came with DT RWS skewers that you screw rather than lever. On the back, i’ll be honest, they are a pain. On the front, they are fantastic, just unwind until you can drop the wheel out over the lawyer lips – much faster than normal QRs.

    And of course you can instantly see whether they are unwinding. I’ve not tried them on disk wheels, but after my new Hopes loosened on the last ride, I’ll give them a try. They really are very good (on the front).

    mrmonkfinger
    Member

    The decent QR done up properly will never move. You seem to think it will just move very very slowly. It won’t.

    If the vertical(ish) force from braking is greater than the opposite vertical force from rider weight, then you get mechanical precession. The tightness of QR doesn’t come into it, braking force does.

    The tightness of QR does affect how quickly that precession will result in the QR coming loose. An extremely tight QR would mean very little effect from the precession, but not ‘no effect’.

    It disproves your assertion. If you’d said “may” instead of “will” you’d be correct.

    you’re right, I should have said “never noticably loosened”.

    Premier Icon nemesis
    Subscriber

    Except that (good) QRs actually bite into the dropouts (see the marks left) which stops that actually happening. One reason why Hope’s original QR design with concentric ridges on the dropout facing surface was so crap.

    mrmonkfinger
    Member

    Fair point – although dragon’s experience would imply that they’re not enough to prevent it happening.

    Premier Icon nemesis
    Subscriber

    I’m going to suggest that the dropout on those forks are particularly hard maybe so that the QRs don’t bite in – steel fork maybe?

    cynic-al
    Member

    So Monk, you seem reluctant to fully concede your point.

    Seems plenty of folk have ridden qr forks with discs without loosening (even only noticably 🙄 ).

    Is this a sort of “infinite monkey” point?

    dragon
    Member

    They are aluminium. Maybe over the weekend I’ll have a look at how marked they are.

    pdw
    Member

    If the vertical(ish) force from braking is greater than the opposite vertical force from rider weight, then you get mechanical precession.

    Mechanical precession occurs where you have a rotating radial force, not just an alternating one, and the resulting force is dependent on the direction of that rotation. This is why it only affects pedals or bottom brackets on one side of a bike, and why switching to left handed threads fixes it.

    If the issue of QRs undoing was down to precession, then surely switching to left handed threads would fix the problem?

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