Disc brakes on road bike

I have an On-One Pompetamine with Avid BB7 Road mechanical discs and Versa 11sp levers (for the hub gears). It lives in the shed but I did use it for one winter.

The brakes are very powerful once bedded in.

The main issue is free float on the levers - the lever moves almost to the bar when braking. It's difficult to dial this out without getting brake rub, possibly because the BB7 caliper is single-actuated - only one pad moves.

I am using shockingly expensive cable outers so that's not the problem.

I am likely buying a fully hydraulic/electronic bike this winter, probably a Focus Cayo Disc.

Shimano hydro levers have free float adjustment but apparently it doesn't do much, and there are reports that the levers rattle due to the lack of tension provided by a cable system.

I don't trust SRAM to get all this right either, and their hoods are ridiculously big so I'm sticking with Shimano regardless.

There are also reportedly some issues with chainline on 135mm disc setups, which Trek have addressed with a specific hub design.

This is an article on 135mm spacing and chainline which I haven't read yet:

http://www.bikerumor.com/2012/11/28/tech-breakdown-how-135mm-rear-hub-spacing-affects-road-bike-chainline-shifting/

My prediction is that for the foreseeable future mechanical setups will be crap and hydro ones will be expensive, and both will be heavy. The Bianchi CV disc is well over a kg heavier than its rim-braked counterpart, mostly in the wheels I'd guess.

After decades of banging on about the virtues of light wheels the cycling press has apparently forgotten about this issue when reviewing road disc bikes.

Here is a quote about chainline w.r.t the Spesh Tarmac Disc.

"The Tarmac Disc is one of the few race-ready bikes designed with disc brakes. It has the same short chainstays as the regular Tarmac and uses a specially designed hub that places the freehub further inboard to resolve the chainline issues that can occur with a wider axle and short chainstays - which is why most disc road bikes feature longer chainstays".

I think it came from here:

http://road.cc/content/feature/126901-20-hottest-disc-road-bikes

The new 105 groupset (5800, 11sp) offers hydraulic brakes AFAIK.

Or have the manufacturers found a way to combine full hydraulic with cable operated STI shifters?

This is the one I have - TRP HY/RD works this way. The cable on the front is very short and I'm using compressionless housing (expensive!), so it has good feeling to it. With normal housing it used to feel like squeezing a sponge, especially on the back (long cable).

Lumen wrote: »

Yes.



There are two hydraulic-compatible Shimano levers:

785: Di2
685: 11sp mechanical shifting

Confusingly the 785 was out first.

I would prefer hydro-Di2 because that means I never have to change cables.

Hydraulic levers are expensive - think the Shimano 685s are around €300 and the SRAM red ones are €500. Wouldn't want to break them that's for sure.

Lumen wrote: »

I don't understand what the "or 22" means.

22 gears maybe?

Raam wrote: »

22 gears maybe?

An obvious solution to the chainline problem is to use a 9 or 10 speed block with 11sp sprockets and spacing.

It feels like several different sorts of stupid are overlapping here.

Anyway the cheapest Tarmac Disc (with hydro brakes and mechanical shifting) is almost €6k which is a bit spendy for a commuter bike.

http://www.specializedconceptstore.co.uk/tarmac-pro-disc-race/33250/15tarmac

Lumen wrote: »

I don't understand what the "or 22" means.

In that context it sort of looks like they're verbing "22"... I guess it's synonymous with "crosschain" but doesn't yet have the stigma of being what idiots do.

BUYER’S GUIDE: 16 OF THE BEST DISC ROAD BIKES FOR 2015
http://www.bikesoup.com/magazine/buyers-guide-best-disc-road-bikes-2015/

dfdream wrote: »

Anyone seen selections of disc wheelsets for road bikes...

Askium One Disc, €200 RRP
http://www.mavic.com/wheels-road-triathlon-aksium-one-disc#.VF2y1Yvkf4o

KSYRIUM PRO DISC €1000 RRP
http://www.mavic.com/wheels-road-triathlon-ksyrium-pro-disc

Four from Reynolds
http://www.reynoldscycling.com/wheels/road-disc-brake

Three from Zipp
http://www.zipp.com/wheels/303-firecrest---carbon-clincher-disc-brake/
http://zipp.com/wheels/303-firecrest---tubular-disc-brake/
http://zipp.com/wheels/202-firecrest---carbon-clincher-disc-brake/

Enve SES 3.4
http://enve.com/products/wheels/ses-3-4-disc-clincher-ses34d/

Or just browse bike24:
http://www.bike24.com/1.php?pgc=18:8717::17:76::5236:5237;content=7;navigation=1;menu=1000,4,123,30;mid=0;orderby=2

These DT Swiss ones are sweet, 1430g claimed for €1250:

DT Swiss RC 28 SPLINE C DB Carbon Wheelset Clincher 2014
http://www.bike24.com/1.php?content=8;navigation=1;product=79797;page=1;menu=1000,4,123,30;mid=0;pgc=18:8717::17:76::5236:5237::13516:13517;orderby=3
edit: DT Swiss actually claim that they're 1325g
http://www.dtswiss.com/Wheels/Road-Wheels/RC-28-Spline-C-db-en

outfox wrote: »

What advantages do thru-axles offer? I've never seen one.

Unarguably better rotor alignment. Possibly less rotor rub under load due to stiffer fork.

What a mess.

I'm adding 'caliper brakes' to my list of things they can take from my cold, dead hands. They'll go right after '68mm BSA bottom-brackets' and before 'actual seatposts'.

I have hydraulic discs on my MTB and they are great when they work which is almost all the time. There are two drawbacks which spring to mind though. First is that there must be a hundred different kinds of pads which are not compatible with each other, basically I can't just go in to a shop and buy pads, I need to order them online. Second is that the one time the line sprang a leak it was a nightmare to fix, a snapped break cable is far far easier to fix. Luckily the hydraulic lines seem to last longer than cables.

Are either or both of those issues still a problem for the new road disc break systems? The MTB ones I have a pretty old so maybe things have improved since then.

My new supercommuter arrived last night, haven't ridden it yet except round the estate.

It's a Cannondale Synapse Ultegra Disc 2015 with an Ultegra Di2 transplant. There is a factory Di2 version but it doesn't match my club kit so I had this one built up by Epic Cycles in the UK who got stock in December and I trusted not to screw it up.

It weighs 8.5kg before pedals and cages which is OK for its intended purpose.

Reasoning for this specific purchase...

I wanted through-axles but there isn't enough choice in the market yet when accounting for other preferences. Most of the road disc bikes have endurance geometry, and typically have very short top tubes and ridiculously tall head tubes, and/or slack angles. This one isn't too bad in that respect, it's clearly not a race bike but seems to fit me OK.

One advantages of QR skewers is that I can fit my existing dynohub wheel.

I chose Di2 for less frequent maintenance and hydraulic discs for consistent braking in all conditions. The discs should make wet cycling in heavy traffic safer-for-a-given-amount-of-stupidity with shorter reaction times possible (don't need to clear water from the rims).

Internal cable routing makes sense with Di2 and hydraulics as the wires and hoses don't need to be changed routinely, and the lack of internal routing put me off bikes like the Genesis Equilibrium Disc Ti that have cables hanging off the frame.

The brakes are clearly much better than cable discs, though there's still much more lever travel than rim brakes the free stroke isn't too bad. I'd still take rim brakes every time in the dry.

It doesn't have any fittings for mudguards - neither the fork crown nor seatstay bridge are drilled, so I might get an ass saver. My winter boots have made a front guard unnecessary.

I'm not fussed about carbon fibre but in this build it keeps the weight down a bit - titanium would be another half kilo or so.

IMO disc brakes on road bikes are still hard to justify. On a recreational bike e.g. weekend/sportive bike there shouldn't be any need to brake hard and fast in the wet. For the same money you could get a rim braked bike that's easier to maintain and at least a kilo lighter.

But this isn't a recreational bike, it's fast urban transport. Ultimate MAMIL commuter, if you prefer.

Anyway here it is. The steerer needs a chop when I've ridden it a bit and the cages will change. I might get some fancier wheels when my credit card has cooled down.



Other bikes I considered:

- Focus Cayo (boring paint job, not available yet)
- Cannondale CAAD10 (SRAM only)
- Stoemper Darrell (availability? price? weight?)
- Specialized Tarmac Pro Disc Race (too expensive)
- Bianchi INFINITO CV Disc (too expensive)
- BMC Granfondo GF01 (even uglier than the Synapse)
- Giant Defy (too compact-looking)
- KTM Revelator Sky (odd geometry)
- Storck Aernario Disc (wasn't confident about sizing, 399mm chainstays a bit of an unknown, lack of availability of Ui2 version)
- Rose Xeon (C)DX (too endurancy, bit ugly)
- Simplon INISSIO GRANFONDO (geometry too CXey)