[Closed] Hydraulic discs on road bikes - interesting FAIL!

Yep, read that ages ago.

What an idiot some bike journos are.

You'd better get used to this.
When Mtb'ers who can boil 180mm hydraulic brakes at Llandegla get road discs...

Its all good having the stopping power but you still only have two square inches of rubber on the road.

he just sounds like a tool to me.

So he dragged his brakes, cooked them and crashed - hey that's a surprise

What a ****ing idiot. I find it amazing some road users are oblivious of the improvments made to the sport in MTBing. Yet most (NOT ALL) MTBers i know atleast have a grasp of whats going on with road bikes.

I explain to people how to use disc brakes with short and hard braking and they just don't listen. After the fourth or fifth time I give up telling them.

[i]If you eliminate the brake surface on a road bike and reduce material, I think you’re going to make it too fragile. It would be unable to maintain its stability.[/i]

huh? He's saying road wheels need to be stronger than MTB wheels?

blimey, I'm not reading all that, is there a tl;dr version

globalti - Member
Scroll down and have a look at the picture of his disc!

Out of interest, any engineers know what temperature that corresponds to?

I found a key [url= http://www.smex.net.au/reference/steelcolours.htm ]here[/url] but it's for generic steel (rather than stainless) so not sure if it applies. If it does, the temp must have been 250-300 😯

[img] [/img]

From the article

"The brake fade that led to my accident is something I’ve experienced on my mountain bike on several occasions with multiple brands of brakes"

Sounds like operator error to me...

Some (a lot) of road riders like to drag their brakes. Do that on a long alpine descent with discs and thats what happens. Journos fault or a sign that disc brakes on road bikes aren't as awesome as everyone on here thinks?

So basically actua;ly use road suitbale brakes on the road and not some lightweght thingy
Secondlyt dont brake constantly with them or they will stop working

Thirdly

Plus, most trails (other than World Cup DH courses, perhaps) are designed to break up massively fast descents with small rollers or short climbs to keep the rider’s speed in check. Lastly, you’re rarely going 30+ mph on the trail.

Never let a [man made] trail rider loose on the road

Unless I'm very much mistaken, a bicycle generally has 2 brakes. I can think of a pretty straight forward solution to his dragging brake problem, unless of course his hands are linked up Honda style.

I have a rotor around the garage that looks like that. Will see if i can find it before admitting to the bufoonery that caused it as without pics it could not have happened.

Some (a lot) of road riders like to drag their brakes. Do that on a long alpine descent with discs and thats what happens. Journos fault or a sign that disc brakes on road bikes aren't as awesome as everyone on here thinks?

Do that with rim brakes and you'll run into problems too.

The biggest reason for discs on a road/commuting bike is the low maintenance and longer wheel life. I can't see why you'd need more power than it takes to skid out for any other reason.

he biggest reason for discs on a road/commuting bike is the low maintenance and longer wheel life. I can't see why you'd need more power than it takes to skid out for any other reason.

This is why I don't really see the point in discs on high end road bikes. They make far more sense on commuters/winter bikes.

stupid rotor design fail.

Do that with rim brakes and you'll run into problems too.

Like? I know plenty of not exactly lightweight men and women who've dragged their brakes down big alpine passes. No problems reported other than tired hands?

The biggest reason for discs on a road/commuting bike is the low maintenance and longer wheel life. I can't see why you'd need more power than it takes to skid out for any other reason.

yep and yep

weight is the only reason i can see to change current road brake setups, though i doubt hydraulics is the way to go for that?

I've had a tyre blow-out from overheating the rims before. Not a pleasant experience!

I feel very vulnerable on the road bike with calipers, compared to my DH bike with 225/205 rotors and 6-pot calipers!!

Old article. Got laughed at the first time around.

Asima Airotors, what are they actually good for, other than saving a few grams?
They bend if you fit them wrongly (following the rotation arrows :roll:)
They cook if you use them too much.

clamping on Ashima’s new and ridiculously light Ai2 rotors

Did anyone else read that and think "well what do you bloody expect then?"

I still don't understand disc brakes on a road bike. Fit a disc brake and you need to beef up areas of the frame that wouldn't need to be with rim brakes. You then need to change the dish on the wheel. You then need to build the wheel to withstand the braking forces out from the hub to the tyre.

There are advantages:

1. Rain performance
2. carbon rims don't like heat

I bet I could tackle both 1 and 2 with a bit of materials science and come up with a better rim brake surface. I was actually going to look into last year but everyone started saying disc brakes were coming so there didn't seem much point.

Like? I know plenty of not exactly lightweight men and women who've dragged their brakes down big alpine passes. No problems reported other than tired hands?

Melted tub glue, melted patch glue, blow out, brake fade from glazed pads.

Dragging brakes is just poor technique.

a road wheel is essentially a massive disc. this road bike disc brake thing is just fashion.

I think there are valid general points made here, but as usual its straight out with the knives.

note from hayes:
Another thing people don’t think about is, even though they’re skinny, a grippy road bike tire on hot pavement can create a tremendous amount of torque at the rotor and caliper. It’s much easier to lock up a mountain bike tire on a loose surface than it is to lock up a road tire in good conditions.

People are quick to call the guy a fool, not every rider will be riding in the relative flatlands we have here.

The point is surely roadies will want super light weight brakes and although we might have no problems in the Uk, in the Alps and other countries with huge descents they will boil them.

On some long alpine descents even the best rider will have to drag a brake, traffic, road conditions, you cant let gravity take over some time, and not every one has big Kahunnas

I'm nobodys fool and had one of the old early crappy Hope XC brakes fail on an Alpine descent, The front boiled after repeated hairpin late braking and lost all use. You dont get far either on just a rear brake, that went the other way and locked the rear solid, hell of a skid and a luckily just a long walk home.

I can lock the wheels out on my road bike in both dry and wet without any trouble.

Only reason I can see to move to discs on a road bike are aesthetics.

I can lock the wheels out on my road bike in both dry and wet without any trouble.

The same arguments were advanced for mtbing though - I can lock my wheels using v-brakes. I know which I'd rather use.

Use cable discs.

Problem solved.

To be fair to the guy, if I was hammering down a mountain pass (E.g. in the rain) I probably wouldn't want to pump the brakes either. Road tyres break traction pretty easily, and slides are harder to catch. Grabbing a handful of front brake at 40mph doesn't end well, I can understand why you might want to drag your brakes.

Dragging brakes is just poor technique.

[img] [/img]

Modern tandems now are moving to disk brakes without issue.

It's not about 'being able to lock the wheel' with rim v disk brakes it's about modulation.

Modulation with disk brakes is far easier for the average rider to get right and is easier because disks offer a more consistent braking surface than a rim.

I'm amazed with my cantibraked cross bike how much crud gets on the rim - it realy affects the braking - even just riding on the road you get that grey gunk as the rim/pads wear.

Being able to lock your wheel by hauling on the lever isn't really a measure of success for a brakign system.

You haven't ridden a tandem. My Super Galaxy has a boat anchor of a drag brake, originally sourced from mopeds.

Yes, a brake designed specifically for dragging. And you're wrong - I have ridden a tandem.

Thing is on a road bike the energy you have to disapate could be much greater due to the higher speed. 1/2mv^2 n all that.

I cant help but think they are a solution to a problem that does not exist.

The current crop of road brakes from 105 up really are very good, ok you can remove a bit of weight from the rim and lighten the wheels but it really makes bugger all difference. As you have to add additional weight and strengthining to other areas.

Thing is on a road bike the energy you have to disapate could be much greater due to the higher speed. 1/2mv^2 n all that.

In other words, more braking force is required. Isn't that an argument for better brakes?

Svelte roadie + carbon 6kg bike
Fat middle aged mountain biker, freeride Camelbak and 35lbs 'All Mountain' sledge

I'm not sure about the 1/2mv^2 thing...

I cant help but think that the guys braking technique is more than a little ham-fisted..

Ill get my coat.. 😳

Seriously though it does sound like he needs to learn how to brake better..

Svelte roadie + carbon 6kg bike
Fat middle aged mountain biker, freeride Camelbak and 35lbs 'All Mountain' sledge

STWer: 110 kg rider and bike mincing at 20mph (8.94 m/s). = 0.5*110*8.94^2 = [b]4396J[/b]

Roadie: 80kg rider and bike descending at 40mph (17.88 m/s). = 0.5*80*17.88^2 = [b]12787J[/b]

The skinny roadie has nearly 3 times the kinetic energy!

*Edited*

I agree with all the comments relating to the journo's poor braking technique. However, I think he has a valid point as brake / bike manufacturers won't be able to control how users apply their brakes. Some will use them in short hard bursts that allow heat to dissipate while others will drag them. If dragging leads to fluid boil then it could easily result in accidents.

I know that you can over heat a rim brake and blow tyres off the rim etc. but I think the point he is trying to make is that disk should make the risk of an accident lower, i.e. the chances of being able to boil your fluid should be less than the chances of being able to blow a tyre of the rim.

Road disc brakes: a dangerous solution to a problem that doesn't exist.

I like this article... Last time I think we had a bit of a barney about whether it was the parts, or technique, then eventually someone noticed that he chose all the parts himself and they weren't designed for the job. So that's human error, or human error.

But we still had an argument about whether it was human error or human error.

Road disc brakes: a dangerous solution to a problem that doesn't exist.

Surely, the argument over disks on road bikes reflects a move from replaceable alloy rims with worn braking surfaces, to nice carbon rims with (shudder) irreplaceable surfaces and questionable efficacy in the wet. Swapping out a worn rotor has to be easier than replacing the rim on a Hyperon Ultra. It's a solution to a problem that the move to carbon has brought upon us. And lighter rims are always nice 😀 .

a dangerous solution to a problem that doesn't exist.

what's dangerous about them?

Roadie: 80kg rider and bike descending at 40mph (17.88 m/s). = 0.5*80*17.88^2 = 12787J

The skinny roadie has nearly 3 times the kinetic energy!

80kg ain't a skinny roadie ... that's a roadie that would get dropped up most hills )

[s]SCIENCE[/s]
The skinny roadie has nearly 3 times the kinetic energy!

Funny. I've been using disc brakes on a road bike since 2006 and I'm somehow still alive.

Correction...Mountain bikers are fat AND slow.

And lighter rims are always nice

[i]Funny. I've been using disc brakes on a road bike since 2006 and I'm somehow still alive. [/i]

but if you lived in the Alps you'd be dead [b]FACT![/b]

My point was that mountain bikers are fat. Nothing more than that. And I'm aware the physics of it don't add up, but that distracts from my point that mountain bikers are fat.

No, you said:

I'm not sure about the 1/2mv^2 thing...

80kg ain't a skinny roadie ... that's a roadie that would get dropped up most hills )

80 kg includes the bike, bottles, clothing, shoes, tube, pump, tool.

shouldn't that be "and tool" or is it meant as pause... tool ?

80kg ain't a skinny roadie ... that's a roadie that would get dropped up most hills

[url= http://en.wikipedia.org/wiki/Fabian_Cancellara ]Quite handy up some Belgian hills as I recall...[/url]

Only cos they are really short. He gets dropped pretty soon on big alpine climbs.

*facepalm

What's wrong with your face and/or palm?

I thought Indurain was 80kg. Theworry is of course not pros but the lardy have a go brigade like me....

I can't really see how it can be Ok to sell road bikes where the brakes will fail if dragged. Aluminium rims are a much bigger heat sink

Will the UCI allow discs. Having followed 3 stageaces this year crashes are clal a fact of life. i wouldn't fancy being onone of those multi bike pile ups with hot discs taking the skin off everyone.

If carbon rims are crap for braking then ban carbon rims or add alloy braking surfaces. The bikes wouldn't way more as they are all easily getting to the limit anyway

Crashes? I'm still more worried about the 53 tooth ring doing 120 rpm rather than a disc rotor doing 30 rpm.

I wasn't thinking about the spinning, more the hot enough to remove skin aspect....

I've been using mechanical discs on a road bike since 2003. All weather, all year commuting, winter training and a few months touring, which included several alpine descents with full camping kit. No problems. Very practical for a working bike, especially when the filthy winter rim grinding conditions arrive. Having said that, my 11 year old DA rim brakes still beat the discs for feel and full on stopping power.

Never come across anyone using brake dragging as a braking technique for long hills on the road (tandems excepted). Usual road braking technique would be to pump the brakes progressively to scrub off speed when required, and let the bike run (or pedal) in between. Contrary to what some people appear to believe, cyclists have been successfully descending long hills very fast for many years!

i used to use v brakes on my mtb (road and trail use) never had any problems. switched over to discs a few years ago, and they are better, not because of the power, but because of the consistency.
i used to use caliper brakes on my road bike, never had any problems.
switched over to discs a few months ago, and . . . . . im not convinced they are a lot better, although they do continue to work in the wet.
my set up, tiagra sti levers, tektro lyra calipers, shimano deore 160mm rotors, all fettled to the max to give a fantastic solid lever feel, but honestly not that much power.
as someone who has bought, and used them, im not completely convinced tbh.
(with the mtb i was convinced after 1 tug of the brakes)

[quote=martymac ] tektro lyra calipers,
'nuff said.

Someone suggests that dragging brakes on the road is unusual. Hmm. Maybe on light race bike in a hurry but on a laden touring bike where speed is unwanted you have to. Eg The Devils Staircase road has long drops heading west to the sea. Within a few seconds my loaded touring bike went to near 40 mph freewheeling! I wanted sub 20. Dragging was the only way to achieve this as accelerate/brake didn't keep the speed down. I still think that discs will be the eventual answer but not yet.
As to an answer with no problem, well maybe, just like we said about suspension, discs on MTBs, more than 10 gears, STI/Ergos etc.

Modern tandems now are moving to disk brakes without issue.

[quote=mattsccm ]Someone suggests that dragging brakes on the road is unusual. Hmm. Maybe on light race bike in a hurry but on a laden touring bike where speed is unwanted you have to. Eg The Devils Staircase road has long drops heading west to the sea. Within a few seconds my loaded touring bike went to near 40 mph freewheeling! I wanted sub 20. Dragging was the only way to achieve this as accelerate/brake didn't keep the speed down. I still think that discs will be the eventual answer but not yet.
As to an answer with no problem, well maybe, just like we said about suspension, discs on MTBs, more than 10 gears, STI/Ergos etc.
My tourer has disk brakes. I'd rather drag them and heat up a rotor than heat up a rim and cause a blow-out.

Had Avid Ultimates with 160mm rotors on my Roadrat for 5 years with no problems, perhaps as I've installed, bled and serviced them based on my MTB experience of disc brakes it has been the cause of no issues at all?

I will add that I think that the experience of using disc brakes off road on loose slippy muddy surfaces means small contact tyres on tarmac are a piece of piss to control and not lock up in comparison.

I've been over 70kph and and heaved on them and stopped in plenty of time despite being a fat bugger, so can't wait for road bikes in general to have the kit/mounts to fit them.

Like it are not 2014 will see a load of road bikes with thru axles and hydro discs.

I think the conclusion we can draw from this is that those Aishima rotors are shite.