Fascinating article on the subject here: How not to do it.

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

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 **** 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.

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.

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 here 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 😯

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.

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

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 = 4396J

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!