Maybe it’ll improve them as they (should) be less likely to do what they do now and just lock up as calipers are more on/off compared to discs.

Why don’t you ask that chap whose wheel fell off the other day?

“Maybe it’ll improve them as they (should) be less likely to do what they do now and just lock up as calipers are more on/off compared to discs.”

thats down to the nut holding the bars to the seat though.

Probably true for mtbs, but on the road, you hardly every need to brake.

Careful now, Paul Sherwen will suddenly pop up and tell you that if you touch your brakes in a corner you’ll suddenly be 20 places back in the peleton with no chance of winning the stage… 😛

The only thing my road bike needs is a better rider.

I’m thinking I should buy one whilst I can still get calipers and QR. But then my road bike is also now UCI illegal (well apart from being too light) as I filed off the lawyers lips.

Will this allow the frames and forks to be more laterally stiff yet vertically compliant, if so, I’m in.

But is there no standard for the distance from the axle/nut/flange face that sits against the dropout, and the face the disc/rotor sits against, either 6 bolt or centrelock? If that’s identical on all wheels, and a standard disc/rotor thickness and diameter is decided on, shouldn’t wheel swapping be simple?

Trying to soldier on with the existing QR system on the basis of backward compatibility that won’t be possible anyway seems, well, silly.

I’ve never had any problems with QRs on my disc-braked mtb – what’s different about road bikes?

As an aside, and oft mentioned, but it’s perfectly possible to make a better, lighter, stronger, more aero rim once you no longer need to factor in the strength and shape needed for a braking surface.

Not that possible actually. Turns out that most rims are roughly the right dimensions for the structural job they need to do regardless of braking. There is some potential for weight saving but not as much as people seem to think. As has been posted above though, it does make carbon rims much more practical given how crap they can be in the wet with calipers and how expensive wearing them out is.

CaptainFlashheart – Member
As an aside, and oft mentioned, but it’s perfectly possible to make a better, lighter, stronger, more aero rim once you no longer need to factor in the strength and shape needed for a braking surface

mtb disc rims didn’t suddenly get lighter once they lost braking surfaces…the profile might be a little different but the basic shape is pretty similar – even moreso with a decent rim depth a la aero rim.

thats down to the nut holding the bars to the seat though.

That’s a constant though 🙂 Make it easier to brake without locking up and fewer people will. There will always be some the just grab handfuls regardless of course 🙂

I can’t help but feel that some development in tyre technology is needed. It baffles me that punctures are accepted as part of the game in pro racing. They happen very regularly and often play a part in the outcome of races. The same situation would not be tolerated for any other component on a bike.

So, if they sort out tyre technology to make punctures a thing of the past then there would be much less need for quick wheel changes and compatibility issues would be less significant.

They happen very regularly

Not as much as you might think. Teams have got through Grand Tours without a single puncture. Besides, it’s a choice to some extent – you can make puncture-proof (or just more resistant) tyres but they’re heavier and roll less well. Given that the vast majority of punctures are fixed with no fuss or issue and you never hear about them, you just have a skewed view of it. No doubt a fumbled change or puncture with no support nearby can have a big effect but it’s pretty uncommon in reality.

I’ve never had any problems with QRs on my disc-braked mtb – what’s different about road bikes?

I haven’t had problems with Shimano QRs, but the Specialized ones that came with a (long gone) FSR were awful – they would progressively loosen as the ride went on, you had to remember to stop every now and then to tighten them up 😯

you can make puncture-proof (or just more resistant) tyres but they’re heavier and roll less well. Given that the vast majority of punctures are fixed with no fuss or issue and you never hear about them, you just have a skewed view of it.

My point is that at the moment we have a choice between puncture proof but heavier and less good at rolling or running the risk of punctures. I’m arguing that development should be able to reduce the gulf between the two options.

With regards their frequency, pro teams must know that a puncture in the final 30 km virtutally rules a rider out of contention. I find it amazing that they are prepared to tolerate this as a risk. There is no other component on a bike that is treated in the same way.

I haven’t had problems with Shimano QRs, but the Specialized ones that came with a (long gone) FSR were awful – they would progressively loosen as the ride went on, you had to remember to stop every now and then to tighten them up

Sure, but that’s a poor quality product rather than the design itself.

Do road bikes need them? No.

just put the caliper in a better location

Or just make sure the dropout slots face forward, that plus rider weight under braking and a decent QR (ie not some daft weenie ti job) does a perfectly good job. My MTB brakes harder on the front than a road bike ever could and the XT QR works fine.

Are bolt-thrus a better design solution though? Yes. And they are more fool-proof, that keeps liability concerns down too.

Sure, but that’s a poor quality product rather than the design itself.

Of course, I’m just pointing out that some people may have experienced this kind of thing and come to the conclusion that all QRs are the same.

IMHO through axles are an short sighted option. Dragging an axle through the bearings isn’t all that good. Muck etc. It may be an interim option but there has to be better. Its is off course more of an issue with MTBs as the wheels get dirtier and the axles are changed in worse conditions.
Of course this is not really a big deal, but then neither is the theoretical issue of QRs being a problem. I haven’t ever even heard of a wheel releasing when it shouldn’t have when the thing has been installed properly. I do feel that many modern QRs are pretty poor compared with decent internal cam ones.
Funnily enough I can’t say that I have ever even needed to think if two disc wheels will interchange whereas rim brakes set up properly have no more than the odd mm between rim and brake block. Much more likely to have a variety of rim widths and its easy to knock a caliper out of line with a rush e wheel change.
The whole thing does smack of the being manufacture led rather than what is needed doesn’t it?

Of course, I’m just pointing out that some people may have experienced this kind of thing and come to the conclusion that all QRs are the same.

Possibly, but I would think most people have used Shimano QRs at some point, and they seem to be the best made of the lot.

FWIW I agree that bolt-through is a better design, but I’m not convinced there’s that much wrong with QR.

15mm Front? 12×142 rear? yet more borrowed MTB “Standards”, Trek probably get a small cost saving by ordering the same Wheels for half their road range as their 29er MTBs

Is there an issue with Road frame/fork torsional stiffness or “Steering accuracy”? Or for that matter Disc braked road bikes ejecting their QR attached wheels?

I wasn’t aware of any, QRs and discs played together quite nicey on MTBs for a while, and still do in some cases…

I wasn’t aware of either being a burning issue for roadies…

TBH serious riders will be looking at disc braked road bikes more as winter training machines than for their “Best” bikes, primarily because they can drag a heavier but lower maintenance disc braked bike up and down the hills between seasons and neglect cleaning it a bit more…

Disc braked “Road bikes” primarily appeal to commuters and maybe tourers and half of those are buiyng CX bikes rather than disc specific road bikes, there are merits, I just don’t think they are there for the flat backed Whippet on a Dura Ace equipped composite machine…

They’ll still be as nonplussed as the UCI are over the idea of using discs in competition.
And I certainly don’t think the UCI would ever do a full U-turn and attempt to compel the use of discs at any level of road racing, they might repeal their competition ban on them, but I expect any decision to use them would be on a stage by stage basis for most pro teams/riders and only if they can see some significant merit over and above callipers…

Obviously manufacturers are keen to introduce a new bunch of standards to a market that’s been pretty static for a few decades, Sales suffer when there’s no great need for consumers to buy a new bike.
I’d say well done to the UCI for resisting pressure from likes of SBC, Trek and Co, but they’ll no doubt fold soon enough…

Obviously manufacturers are keen to introduce a new bunch of standards to a market that’s been pretty static for a few decades,

A chunk of that yes, and that ‘run on the banks’ analogy .. one moves and the rest follow / are dragged along.

The current sample size is rather small. As much as I dislike lawyers lips on my caliper equipped road bikes they are also one “fix” for the problem and should prevent it in the vast majority of cases.

I have also experienced a wheel ejection on a disc equipped MTB with a properly done up QR (no lawyers lips, smooth, hard, brand new dropouts) 😥 I’d certainly have bought through axle MTB XC forks had they been available when I last had enough spare cash to spend on a new pair of forks, though a better solution for that problem on road bikes is caliper brakes.

I haven’t ever even heard of a wheel releasing when it shouldn’t have when the thing has been installed properly

Chance of improper installation is a consideration in any design.

I can change a wheel with a through axle quicker than tightening a QR

mtb disc rims didn’t suddenly get lighter once they lost braking surfaces…the profile might be a little different but the basic shape is pretty similar – even moreso with a decent rim depth a la aero rim.

Off the top of my head, Xc717 disc rim is about 6% lighter in disc version than it is rim brake. I expect some roadies would really care if you could take off 25g rotating weight from an open pro. Well, that would be more like 30g once you scaled that weight saving up to 700c. But given the size and weight of aero rims you might be getting into diminishing returns of weight saving engineering out the braking surface on something that massive in the first place.

Oh and in terms of standardisation for racing, if you can machine a hub to precisely accept a cartridge bearing made by another factory with a tight but not too tight fit, then you can machine a standard thickness of disc rotor and a standard distance of outside of disc tabs from centre of the hub to within tiny fractions of a mm surely?
And yes if you have to faff with lawyer tabs and unscrewing locknuts enough to get the open qr to clear them and remove the wheel, then a maxle is a faster way to remove and refit a wheel.

All this talk of calipers being fine in the wet is BS if you ride in real hills/mountains. They don’t work well at all on big descents in foul weather.

They don’t work well at all on big descents in foul weather.

True, but they’re faultless in the Alps and Pyrenees in the pouring rain.

Going back to the bit about disc and rim braked bikes racing together. So the group is heading into a bend in the wet and the disc braked bikes will go faster into the bend? brake later? what could possibly go wrong.
What about handling, optimal speed, position etc? I appreciate that discs are great stoppers, but road bikes at speed are a very different beast to MTBs. If I was flat out down the Tourmalet I’d never think I’ll leave my breaking later as I’ve got discs surely that would just lock you up and throw your weight forward.
Arguements for discs on a TT bike?

QR on a proper road fork without extra tabs? BS.

What is the advantage (which is large enough to outweigh the aero penalty)?

I have to say I am not convinced about thru axles anywhere except 20mm ones on 140mm+ forks. All they seem to do is make life more difficult, and I can’t say I notice the stiffness increase on the rear.

It’s the next logical step in terms of where to go after disc brakes. Meets all the hallowed road bike criteria of stronger, lighter, stiffer.

There are a whole load of factors that need to align though. Firstly, the UCI need to set a date when the manufacturers can ‘sell’ their products to them, then a date when those changes will be implemented. So eg Shimano, SRAM, Campag need to show their working disc brakes on [date] and disc brakes will be allowed as an option in WorldTour races from [date].

That will give the frame, wheel and component manufacturers something to work to and speed the development. At the moment, you can’t race a disc equipped bike so no-one makes a “race-ready” disc road bike; they’re all aimed at Sportive or Endurance riding. Once the UCI get their heads round it, it’ll happen within a year.

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

Disc braked “Road bikes” primarily appeal to commuters and maybe tourers and half of those are buiyng CX bikes rather than disc specific road bikes,

isn’t that due to availability (at commuter price range) ? I’ve seen top end road disc but not c2w prices, admittedly I haven’t been looking very hard (I got a cx but that’s coz I commute offroad)

All they seem to do is make life more difficult,

What you’re missing is that thru axles also do neatly fix the engineering flaw present in a slot dropout QR + disc system.

As already mentioned, there are several easy ways to fix the 9mm QR + disc:
* caliper at front – doesn’t look cool enough apparently
* positively locate the axle in dropout (cotic’s effort) – got to bend the fork apart to get the hub in

Doing either of those two is tantamount to admitting the existing QR + disc setup is a bit liable to cause injury

So instead, the legally preferable route is that we quietly start again with a through axle (QR15) and play up the “stiffness” and “lightness” angles.

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

seems a bit pointless TBH – why try to reinvent the 15mm axle now it is already here and in use?

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).

There are a whole load of factors that need to align though. Firstly, the UCI need to set a date when the manufacturers can ‘sell’ their products to them, then a date when those changes will be implemented. So eg Shimano, SRAM, Campag need to show their working disc brakes on [date] and disc brakes will be allowed as an option in WorldTour races from [date].
That will give the frame, wheel and component manufacturers something to work to and speed the development. At the moment, you can’t race a disc equipped bike so no-one makes a “race-ready” disc road bike; they’re all aimed at Sportive or Endurance riding. Once the UCI get their heads round it, it’ll happen within a year.

So as suggested above you’re expecting the UCI to mandate their use and control their introduction? I wonder who will be liable if things go wrong… 🙄

Only logical on the same basis as 650b is logical (here kitty)

Forward-facing dropouts, simples.

The number of standards in headsets, axles, bbs etc makes my head hurt, and customer’s wallets too.

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

So how does a through axle help with fore-aft stiffness? You have to realise what difference adding stiffness at the hub actually makes, and where the loads are on a rigid fork.

aracer – Member

cynic-al » Forward-facing dropouts, Caliper brakes simples.

Ooe argument, yes, but IMO there is a place for disc brakes on commuters, cross and touring bikes.

Through-axles on rigid forks is pretty pointless IMO (bar standardising to new standards).