Pads Rubbing Against Discs

[stewie911]

Funny enough, that thought already crossed my mind, I kindly denied it though.

 

So just to be clear, they get very hot on long rides?

 

Not on long rides, but on long descents where you brake alot.

 

I once had to stop halfway down a mountain 'cause the brakes overheated. Was raining, so I just threw water from a puddle over the discs, instantly turned it to steam.

 

Rotors must have been well over a 100 degrees.

[Grebel]

Funny enough, that thought already crossed my mind, I kindly denied it though.

 

So just to be clear, they get very hot on long rides?

 

They get very hot on technical downhills that are short as well!!! I trashed a new pair of gloves removing a stick from my brakes...

[Mojoman]

Not on long rides, but on long descents where you brake alot.

 

I once had to stop halfway down a mountain 'cause the brakes overheated. Was raining, so I just threw water from a puddle over the discs, instantly turned it to steam.

 

Rotors must have been well over a 100 degrees.

Wouldn't this cause them to warp?

[stewie911]

Well I was full of adrenalin and wanted to get going as fast as possible. Probably wasn't the best idea, but what the hell.

[Wedge]

Thank you again Drongo, I loosened the caliper, pulled the brakes and re-tightened them. Hey presto, no more rubbing and squeaking.

 

Drongo for president!

[Johan Bornman]

AVIDS

 

If a bleed (all the best!) doesn't work then the piston seals are probably finished.

Caliper will need an overhaul.

 

I've never managed to sort Avids on outrides where they have failed. Always had to remove caliper and get the rider to tie his/her fingers together to remind themselves that they have no brake that side.

 

If you don't have the bleed kit and some patience, then you need your LBS.

 

SHIMANO ROCKS

 

You didn't quite say it, yet I agree. Avid sucks.

 

Marius' frozen brake is very, very common.

 

Toss them and get Shimano or Hope or anything else.

[Johan Bornman]

Wouldn't this cause them to warp?

 

Yes the heat does cause them to warp, especially if you hit a little bit of water whilst they're hot. Incidentally, the discs probably reach 400 degrees on steep descents. The boiling point of absolute fresh brake fluid is in the region of 240 degrees and it it is slightly older, half of that. Mineral oil boils at about 150 degrees, maybe slightly less. Therefore, the effective boiling point of both brake systems is essentially the same.

 

Discs can get hot enough to glow dull red in the dark. They are so thin, that warping is inevitable. If you use your brakes, they will warp and touch. Irritating.

[The Drongo]

Funny enough, that thought already crossed my mind, I kindly denied it though.

 

So just to be clear, they get very hot on long rides?

 

Wedge!

 

To be clear, they only get very hot through long BRAKING.

 

It all 'boils' down to braking technique. It is a lengthly subject, but a few basics that help are:

 

Your front brake is your most effective brake. It can bring you to a complete stop in about half the distance that your rear brake alone will.

 

To avoid overheating try avoid prolonged braking, or dragging your brakes. On steep descents try pumping the brakes (not grabbing) alternating the load between front and rear.

If you need to bleed speed off rapidly start by applying the front brake first followed by the rear, shift your body weight back over the saddle, and even down towards the back wheel.

To help slow yourself without using braking, 'flare' your body by sitting upright and spreading your shoulders, this bleeds off speed.

 

Anticipate! Bleed off speed before a sudden stop is needed.

 

Try using your front brake only on a dry level surface, and see how much quicker it stops you than using the rear brake alone. Avoid 'grabbing' the lever, squeeze it to the point of full lock. (modulation)

 

Use your arms to brace against a front brake stop, shift your body weight back to balance the momentum of your body. As your bike slows, your body continues moving forward and this lack of control is what causes the 'over the bars' effect.

 

Matal pads run hotter than resin, and scintered give a good inbetween, but all have various pros and cons, probably suitable for another thread.