disc brakes for rd [what are they like?]

hi,i was looking at the cable operated disc brake system for a rd bike.
i recently spoke to a mechanic and he said with thin tyres they are too good
too easy to lock up the wheels and skid.
auh i thought is abs coming ? or is it just a case of a learning curve ?
your experiences please.

Your mechanic is talking mince.

Yes, disc brakes make it easier to get to the point of being able to lock up wheels and to skid. However, they are also designed to allow a reasonable amount of control over the braking effort applied and so skidding is easily avoided. The learning curve is neither that steep or that long.

Mainstream bicycle companies, like many businesses that are based around the leisure industry are fairly risk averse. They simply aren't going to mass produce something that inherently puts it user at risk and face a litany of lawsuits from the litigous.

Disc road bikes are seeing a lot of uptake, just from their intended cyclocross market but also from other sectors such as tourers, bike-packers and people with a penchant for riding around hilly terrain. The main reason for this uptake isn't any perceived fashion or adherence to a new fad but because the brake work and work well.

Moving on from that, the geometry of a bike is more likely to affect it's likelihood of skidding than the actual disc brake itself. I have a recumbent bike and the position of myself as the main load is directly in front of the rear wheel and there is virtually no load going on top of the wheel. Despite putting nice skinny slick tyres on the bike and riding it around the Peak District at up to fairly high speeds, I'm happy to report that the amount of skidage has been negligible.

With the current state of the cycling and the bicycle market, there are likely to be a lot of changes and innovations coming out of the next 5-10 years. Some of this will be driven by advances in various various competitive and racing disciplines and a fair few will prove to be viable and sustainable in the commercial market. If your mechanic is spouting nonsense about already proven technology and design changes then it may be worth looking about for one that is more willing to embrace the new things that you are likely to be purchasing in the future.

Took my disc (hy:rd) equipped bike for its first test on some proper hills last weekend. They were FANTASTIC. 70kmph descents and I've never felt safer going in to the hairpins.
As per TSK post above, your mechanic is talking crap. The modulation on discs is far and away thir biggest selling point and advantage over rim brakes. Imagine the difference in the wet!
I admit I had nagging fear about them overheating and boiling the fluid but during a 6km descent with some heavy braking I didn't event have a hint of fade, my fingers weren't tired and I descended a good 2 mins faster than my 2 mates and there was zero discolouration on the rotors on inspection afterwards.

I recommend.

Been using a disc mtb with skinny slicks on road for years.
Your "mechanic" is talking out of his arse.

In the dry negligible, in the wet and especially muddy big difference. Perfect for winter bikes.

My mechanic at work says the same, but he's a MTB'r, so he's biased anyway. I told him to shut up.

i guess,the shop does not sell road bikes with disc brakes and it may have been sales orientated.
i was looking for an option for a bespoke road build.
whilst listening to the commentary watching the tdf they said that riders getting skolds in the event of an accident was the reason for
the uci not ok'ing them.well.i thought, if thats the only reason may be they are worth looking at.

Suggestion for a road disc fork? - the more the merrier and axel to crown around the 370mm mark

whilst listening to the commentary watching the tdf they said that riders getting skolds in the event of an accident was the reason for
the uci not ok'ing them.well.i thought, if thats the only reason may be they are worth looking at.

If that's the case, then Mark Cavendish shouldn't have been using the hydraulic rims brakes.

Nothing nicer than coming to a full stop* on the Col Du Tourmalet on a loaded touring bike at 70km/h 20 metres from a apex by using just one finger (HY/RD).

*driver in opposing direction decided to get on my lane.

A skinny 23mm front tyre is very difficult to skid on smooth dry asphalt on a typical road bike, the bike will overturn first. Like others have said, discs actually have better modulation so you're really less likely to skid.

Having said that I think the current crop of road discs are a little undersized, a lot of them have 140mm rotors even. The amount of heat generated down a hair-pinned 20km alpine descent is not something a typical disc braked MTB rider would encounter, yet they normally sport 200mm rotors on downhill MTB's.

But yes, I'm running TRP Spyres on my Genesis Croix, and absolutely love them. Reliable, controlled braking in all weather. Ideally I'd run hydraulics however circumstances didn't allow it.

Road discs can get away with being smaller as they cool via faster airflow.

The reservation I have is the impact on fork design. Headtubes have got plenty stiff enough, but fork blades are going to change. Are stiff forks going to ride well? Or are we going to have put up with bikes stepping out to the right under heavy braking?

I've had cable discs (BB7 on 105 brifters) for 4 or 5 years now and even what is probably slightly dated technology is great.

Commuting in the wet is fine and descents are far less wearying on the hands. I also find them far easier to adjust, dial them in until they're touching and then step them off until they're not and that's it.

The only time I've skidded is coming round a blind corner on a descent far too fast and discovering a land rover blocking the road.

thank you all, good point from 'miro'. on fork and headtube rigidity being important things to consider and the impact on feel of the bike. may be now i will check out the genesis croix!

The fork rigidly is usually because the left side need to be beefen to prevent flex when under power, this is why thru-axle are slowly being introduced into road bike, such as the Saracen Avro (with shit brakes oddly enough).

I hear electricity is quite useful

I have some bb5's... They are shit... But still better than most road brakes. Go for bb7 or better.

My ridgeback flat bar bike had hydraulic discs which were utterly fabulous. My lynskey has cable discs and they are very good but not as fabulous, mainly because they require much more maintenance.. Considering an upgrade, but then I also have to decide whether to go di2... Ho hum

If you wait a little I imagine you'll be able to test ride both as the 2015 MY bikes come into the shops.

You can always get 105 hydraulic instead.

It's not the extra power that's an issue, but where those braking forces are directed. i.e. at the end of the fork rather than the stiff fork crown.

I think the benefits are not clear cut for racing bikes with progress being made in direct mount and hydro rim brakes.

Someone needs to build a disc around the centre of the hub, out of the air flow and distributing forces through both fork blades.

© lfgss 2014

:)

Pretty much why I emphasised on thru-axle for road bicycles, it handle the asymmetrical torque of the disc brakes well without resorting to over engineering the left fork arm.

Someone needs to build a disc around the centre of the hub, out of the air flow and distributing forces through both fork blades.

Great, next thing you'll be telling us bigger tyres is just as fast.

I think you've got that one covered.

Someone needs to build a disc around the centre of the hub, out of the air flow and distributing forces through both fork blades.

That's an interesting idea. Can someone who knows stuff explain how that won't work? I expect mounting and cable routing could be a problem.

Cos the spokes are in the way?

...cable routing could be a problem.

Through the axle hollow?