Road hydraulic discs

I can see disc mount positioning on hubs to be one of the first things that get standardised, either that or quick and reliable caliper re-alignment.

Is mount does this ( and post mount to a certain extent) – its only that its become accepted for post mount to use slotted mountings to allow for low manufacturing tolerances. Tighten up the manufacturing tolerances and everything just slots together – rear cassettes remain aligned properly when you swap wheels right now

Cable disks is the obvious solution in terms of braking performance and reliability, but this doesn’t have the same desirability as hydraulics.
This is probably the reason why this has taken so long to come to market in any real sense. I’m sure they’ll find a way to market it though.

I pretty much have to agree, the reason road bikes have mostly stuck to rim acting calipers up to now has very little to do with power or ultimate braking performance, in those respects they are mostly adequate for the application until of course you’re twatting down an alp boiling the glue off of your tubs, there a disc brake may help (assuming it doesn’t fade as previously the linked article described)…

Do cable disc fade in the same way? a lack of fluid for them to boil would suggest that isn’t an issue simply making all of the mechanical components sufficiently resistant to sustained heating, and of course light enough to build a bike to the weight limit…

The use of a disc brake opens up a few new design options for other areas of the bike wheel profiles/rims, frames and fork crown areas but using a hydraulic disc means the hoods are now going to have to accommodate a master cyclinder obviously wit Di2 less of an issue as the “shifter” is now just a couple of micro switches, but very few non pro’s will be riding with leccy shifting, of course if you were to take a current Ultegra STI unit and use it to actuate a cable disc caliper, I can’t really see the problem for the average MAMIL, most of the benefits of Disc brakes, without the problems and cost of implementing hydraulics…

Internal routing would be a touch simpler to achieve with mechanical discs than hydraulics so again wheres the benefit to hydraulics on a road machine?

TandemJeremy – Member
Tighten up the manufacturing tolerances and everything just slots together – rear cassettes remain aligned properly when you swap wheels right now

Cassette(chainline) adjustment is a lot less critical though. A proper ISO standard for hub width would be great for swapping wheels.

rear cassettes remain aligned properly when you swap wheels right now

Not really, mine needs a little tweak when I swap wheels, and you’re not talking about the very small tolerances of discs.

Can’t see you’ll get a totally ‘universal’ set up for a long time, if ever.

Can’t see you’ll get a totally ‘universal’ set up for a long time, if ever.

The one saving grace with road discs is that they are completely new. None of the issues that MTBs had where they were introduced gradually and a lot of people subsequently upgraded disc ready frames. At the moment road discs do not exist in the market, you can’t upgrade an old frame to discs so aftermarket manufacturers aren’t going to be on the scene for a few years yet – it’ll be restricted to Shimano and SRAM (Avid) and Magura initially.

I hope and pray that everyone sits down and comes up with ONE standard so we don’t end up in yet another standards quagmire:
centrelock vs 6-bolt
IS vs post mount

The pros simply won’t use it otherwise as it’ll make wheel changes too slow and neutral service will be even more of a pain in the arse than it is now.

Internal routing would be a touch simpler to achieve with mechanical discs than hydraulics so again wheres the benefit to hydraulics on a road machine?

No it wouldn’t. You can route a hydraulic hose any way you want whereas cables have to have internal guides and stop points to maintain the tension.

Universal standard? Well for pro teams why don’t neutral service (or the organisers really I suppose) hand out a jig for setting the brake calliper and a facing tool that makes the hubs fit a caliper fitted with the jig. Teams (and indeed neutral service) then get to face and if necessary shim their hubs until the work in calipers fitted with the jig. Would take long before hubs / wheels were supplied already properly faced.

Just a thought.

crazy-legs – Member
No it wouldn’t. You can route a hydraulic hose any way you want whereas cables have to have internal guides and stop points to maintain the tension.

Not with full-length outers.

Sorry but all this waffle about needing some new standards…
Utter cobblers the applicable standards exist already and are established, so why reinvent the wheel (pun intended)…
100/135mm axles, IS mounts on frames/forks, with PM calipers and adapters so users can run whatever size rotors they like, and 6 bolt hubs, or centre-lock if you like, (both align with the same calipers so ultimately it makes bugger all difference).

What a load of bollocks this thread has become, you lot have talked yourselves into the need for hydraulics with miniature quick connecters just so some tarts can have more aesthetically pleasing routing, and the needless bling and car park posing factor that come with transferring the input force from the lever to the caliper using fluid as opposed to cables…
Shimano, SRAM, Campagnolo, Formula, Hope, etc must be rubbing their hands with glee…

cookeaa – the problem is that hub widths vary, so as you replace a wheel with a different hub, you have to re-align the caliper. Therefore, there needs to be a tighter standard in this area to allow for fast wheel changes from “neutral” cars.

Actually thinking again, a single tool that simply faces the 6 bolt holes on the hub an accurate distance from the outer end of the end cap is all you need. Provided manufacturers don’t make this distance too large that is.

Manufactures to work to tight tolerances is all you need

How many road bikes actually get used for racing where “neutral” or team wheel swaps are likely? I mean really, most will just be used by fatties on the odd club ride really won’t they…

And being realistic if you could manage to get all manufacturers to hit +/-0.1mm from the face of the lock nut to the face of the disc mounting on each hub you’d be doing very well, then there’s all the other parts to consider: mountings (even a close fit hole will add another 0.1 diametric clearance to the stack up of tolerances), caliper, pad spacings and the actual disc itself, all have an effect…

“Tight Tolerances” means almost unachievable in this context, hence current systems simply provide adjustments to account for this, a stack up of 0.3~0.4mm either side of the nominal position would not be particularly hard to imagine given all the components in the assembly…

And adding a facing operation to every bike would only serve to increase the potential for an even wider tolerance band problem on each bike, Facing only exists for either A) getting a surface nice and perpendicular to the wheels axle, or B) adding a tenner to the LBS bill for monkeying with a bike…

Having said all of that, Rims vary much more significantly in width and true also, so the issue isn’t exactly a new one is it?

Wider pad spacing and lead in features might help but there will always be a variation in dimensions…

How many road bikes actually get used for racing where “neutral” or team wheel swaps are likely? I mean really, most will just be used by fatties on the odd club ride really won’t they…

Not many, how many bikes have to be approved by the UCI before they can be raced? ALL of them, and i seem to remember the UCI are going to enforce that all bikes must be available to the consumer. So whatever you buy has to be usable in a race situation.

Rims vary much more significantly in width and true also, so the issue isn’t exactly a new one is it?

Do they? have a look at road wheels and there is very little variation. and the QR’s that exist cope with what little that exists.

Oo, Ooooo !.

An Engineering debate !, regarding hydraulic brakes.
Kinda re-inventing the wheel type thing.

Well, you’re all Engineers then by profeesion.
You go to work everyday and earn your living by being an Engineer, right ?.
😉

And for the record.
I have a road format bike.
I have fitted riser bars and hydraulic brakes.
It should be on the road this coming weekend.

You go to work everyday and earn your living by being an Engineer, right ?.

Yep 😀

Although admittedly nothing to do with bicycles…

the point I was failing (and probably still will) to make is that generally the best way to deal with the inevitable problems caused by the stack up of tolerances across different parts and manufacturers, is to design adjustment/accommodation of on-the-piss-ness into any assembly…

And “Tighter Tolerances” means nothing without repeatability, you’d need to be sure that your zero adjustment required, highly accurate and toleranced assembly of brake and hub parts from Shimano/SRAM/Hope/Formula all bought and slotted together flawlessly in say 2013 will all still be directly interchangeable with parts from YM 2014/15/16-etc from every other manufacturer under the sun, far easier said than done…

Also an engineer – at least I was; these days I manage engineers (electrical network types). Though I think what most of the discussion is about is more akin to a fitter’s stock in trade than an engineer’s. Perhaps some of the manufacturing tolerances stuff.

cokeea – why not? – al you need to do is as IS does define the various spacings and manufacture to that.

most of the various combinations of wheel and frame I own and have tried are interchangable with no issues

How many road bikes actually get used for racing where “neutral” or team wheel swaps are likely?

almost every bike that gets raced – in amateur races, if you want service during the race you supply a wheel to go in the support car but the wheel you get during the race is unlikley to be the one that you supplied. Therefore, neutral service issues are probably bigger in the lower ranks than the pro tour where service is provided by Shimano/Enve/Mavic etc.

the best way to deal with the inevitable problems caused by the stack up of tolerances across different parts and manufacturers, is to design adjustment/accommodation of on-the-piss-ness into any assembly…

^ this.

This is the reason caliper brakes have barrel adjusters and QRs, discs (hydro or cable)would need the same quick easy adjustment.

I agree with mustard and can back up what he says from experience. A good wheel change can the difference between getting back onto the bunch or a ride back to HQ…

I hope and pray that everyone sits down and comes up with ONE standard so we don’t end up in yet another standards quagmire:
centrelock vs 6-bolt
IS vs post mount

I can see that meeting happening – Shimano won’t admit 6-bolt are better than centrelock. If SRAM decide to use centrelock is saying Shimano are better. Don’t even get Campagnolo started!