Brake Pads

[Prince]

What's the difference between carbon rim specific brake pads and standard aluminium surface brake pads?

[AndreZA]

One is specifically for carbon rims and the other is for aluminium rims.

 

 

 

Sorry, I'll get my coat.

[CAAD4]

If you use Alu pads on carbon rims, you will end up with real deep section wheels... Wait Mampara I'm right behind you.

[Bike Mob]

 

Carbon ones are funny coloured...mine are yellow... and normal ones are black

 

 

Hold the door!

Tarmac-GSTR2010-01-13 01:34:46

[Prince]

One is specifically for carbon rims and the other is for aluminium rims.

 

 

 

Sorry' date=' I'll get my coat.[/quote']

 

 

 

Well that was helpful

[Thug]

Most brake blocks for Carbon rims are made from a cork which are not recommended for Aluminium rims due to the inferior braking power between the two materials.

 

 

 

SwissStop make pads that can be used on both Aluminium and Carbon wheels (yellow ones). BUT, I'd be very careful and check the pads for metal contamination prior to putting on the carbon rims, otherwise you are likely to score the carbon.

[mtbN00b]

 

Most brake blocks for Carbon rims are made from a cork which are not recommended for Aluminium rims due to the inferior braking power between the two materials.

 

 

 

SwissStop make pads that can be used on both Aluminium and Carbon wheels (yellow ones). BUT' date=' I'd be very careful and check the pads for metal contamination prior to putting on the carbon rims, otherwise you are likely to score the carbon.[/quote']

 

guess you do not need to get your coat

 

[Bike Mob]

It's all about abrasion, and heat dissipation.

[Minion]

http://www.zipp.com/support/askjosh/carbonwheels.php contains some more info on carbon-specific brake pads.

[Prince]

So in a nutshell better to have specific brake pads for each type of rim. I was hoping to get around changing brake pads every time i change wheels!

[AndreZA]

I was hoping to get around changing brake pads every time i change wheels!

 

 

 

and that is why I sold my carbon wheels. The other option is that to have carbon rims with alu brake surfaces.

[Prince]

I was hoping to get around changing brake pads every time i change wheels!

 

 

 

and that is why I sold my carbon wheels. The other option is that to have carbon rims with alu brake surfaces.

 

 

 

Wise man, this changing pads is driving me nuts, it's a major shclep.

[Minion]

Zipp make brake pads that you can use on both their carbon rims and normal aluminium rims.

The Zipp rims have some kind of coating on their braking surface, so I'm not sure if the Zipp pads will work on a pure carbon braking surface.

 

[Johan Bornman]

When  you apply brakes, the heat is generated in the softest of the two materials, which is the pad. The heat is created as the molecular bonds in the rubber is stretched and broken. This heat is generated at the interface of the two adjacent surfaces. Since rubber is a reasonable insulator, the heat cannot move backwards into the pad but it readily gets transferred tot he aluminium braking surface, since alu is an excellent conductor of heat.

From here the heat goes a little distance in the spokes but most of it gets dissipated by airflow.

 

Carbon as used in wheels is an excellent insulator and it cannot transfer the heat from the pad. The result is that all the heat stays in the pad and it starts to melt. The moment it melts, you have no braking whatsoever since a melted pad is like an ice skate and just glides.

 

What they then had to do was to find a pad that effectively sublimates i.e skips the liquid phase and goes directly into a gas. Cork (and similar synthetic materials) is ideal for that. It accepts reasonable heat and instead of melting, simply starts to smoke. The smoking cork doesn't create an ice skate effect and keeps on braking even though it gets very hot.

 

This effect is very easily demonstrated on long steep hills. Take a carbon wheel with standard rubber and brake hard. It decellerates normally until that moment when  it starts to melt and then gives you the sensation of a cut brake cable. Your only option out is to release, count to ten and pray, and then re-apply the brakes once the rim has cooled. This takes a cool head.

 

The evidence that the pad melted is tiny crumbs of solidified rubber on your inner thighs and washers in your chamois.

 

In Gauteng, the only place I know of where you can do this is in the Suikerbosrand reserve.  

 

The real danger is lack of braking, not damage to the rim itself.

 

 

Johan Bornman2010-01-13 17:09:13

[Woofie]

Wow.

Dont know if I really like the idea of my brake pads "burning" up on a long decent.

Carbon looks nice but there is just too many niglies in my mind.

I think I will stick to normal rims.