# different ways to bed in brakes



## sethwas (Apr 30, 2002)

This may sound odd, but can you just jack your car up on jack stands and take the rims off the hub and just accelerate the car so the rotors spin real fast on the jack stands and then hit the brakes. You can get the brakes to spin alot faster, although the rotors have less momentum than the rims and tires.This way stop-n-go doesn't have to be done on public streets.

Seth


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## lshadoff (Nov 26, 2002)

Here is the definitive dscussion about brake fade and what to do about it, by Mike Kojima.

Lew


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## sethwas (Apr 30, 2002)

I read that years ago when it first came out.
It's how I bed in brakes now, more or less.
However I don't recall it mentioning anything about bedding in brakes with the car not on the ground.

Seth


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## lshadoff (Nov 26, 2002)

sethwas said:


> I read that years ago when it first came out.
> It's how I bed in brakes now, more or less.
> However I don't recall it mentioning anything about bedding in brakes with the car not on the ground.
> 
> Seth


You can't do it wth the wheels off the ground because it takes the inertia of the moving car to generate the heat necessary. You want to apply brake pressure for a long enough time to heat up the pads until they outgas. Just slamming on the brakes after the wheels are spun real fast lasts less than a second.

Also, it's a lot safer since there is a finite possibility that the car will fall off the jack stands with all the revving and braking.

I bed in pads on the expressway. You never have to stop, just drag the brakes until the pads heat up and let them cool, and do it several times until the pattern suggested in the article is completed.

Lew


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## sethwas (Apr 30, 2002)

Interesting.

Then what's a brake dyno?

Seth


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## lshadoff (Nov 26, 2002)

sethwas said:


> Interesting.
> 
> Then what's a brake dyno?
> 
> Seth


A brake dyno measures horsepower by applying a counter force to the engine and measurng the power and torque it takes to hold it at a fixed rpm. The rpm is varied and the horsepower and torque measured for each rpm to produce a dyno curve.

I have heard of using an electric motor and measuring the current needed to oppose the engine or a water brake and measuring the pump motor current draw The calculation of horsepower from current is straightforward.

This is the kind of device auto manufacturers use to determine Brake HorsePower (BHP). The engine is usually bolted directly to the device.

Lew


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## sethwas (Apr 30, 2002)

Thanks,
That's what I thought, which is why i found it funny to be reading it in a brake article in this months SCC.

Seth


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## ReVerm (Jan 13, 2003)

lshadoff said:


> I bed in pads on the expressway. You never have to stop, just drag the brakes until the pads heat up and let them cool, and do it several times until the pattern suggested in the article is completed.


Before I say anything else, let me state that I'm not arguing with you, but am rather adding what you've said.

Another reason that the in-air bedding process might not work that great is that a number of brake pads specify in their break-in instructions not to drag the brakes during the bedding process. Hawk now say this, as do Porterfield. So if you have any of those pads, it will be impossible to break them in properly with your drive wheels off the ground.

Oh, and the other big issue is that you can't bed the brakes on your non-drive wheels that way. So yeah, no wheel-dyno brake bedding either.


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