Why are the front disks on the LT1 cars smaller than the rear disks?

 

I would guess because the rotational speed nearer the center of the disc would be less than that of the outer part of the disc...therefore giving the front brakes more braking power by grabbing a disc with less rotational speed than the rear brakes. If that made no sense, I apologize.

 

Just like Bowtie said. But basically...in laymans terms.....the weight of the car when slowing and stopping is thrown to the front which bears the majority of the braking load.

 

 

Because GM doesn't develop new parts for each car... they go to the "parts bin" and try to use whatever parts they already have in the manufacturing process..... they kept the front discs the same as they had been using on the 3rd Gens with drum rear brakes, then pulled some old Corvette parts out of the parts bin when they added the rear discs to the 4th Gen.

 

I see what you are saying but that does not make sense. A brake applies torque to stop the car. Torque is force * distance (ie lb-ft, in-lb etc.). Say the caliper can exert a force of 100 lbs. If the force is applied 1" from the center of the disk then you have 100 in*lbs of torque. If it is applied 2" from the center of the disk you have 200 in*lbs of torque or twice as much. If all else is equal then bigger disks will always be better. I'm sure the just did it this way to save money somehow.

Dustin

 

As was stated, parts were available. Additional stock performance potential of LS1 drove the upgraded brakes.

LT1 fronts are smaller diameter, but wider than rears. Total mass of fronts is probably more than rears. Mass counts more than size....in brakes anyway.

Brakes turn kinetic energy into heat to slow/stop a vehicle. That heat needs to be absorbed by the rotors and disipated or transferred to the air. Here is where more mass helps.

The heavier, vented fronts have to do about 80% of the work in a max stop so on LT1s they are stressed very heavily. Front pads are larger and caliper force is greater than rears, but smaller average diameter of braking surface requires more caliper force. That's not good.

LS1 front brakes are larger diameter, which helps. C5 front upgrade helps more. Fronts need upgrade, but rears are probably good enough for C5 or maybe even larger fronts.

LT1s should wear out front pads much faster than rears.

My $.02

 

And there lies the mystery .... the rear pads on a 4th Gen will typically need to be replaced two or three times before the front ones need replacement. My 94 still has the original fronts.

 

It's all those water burnouts!

 

Yeah, but the front pad wear should even out when I pull it down from 130mph trap speeds

 

The rear pads have a very small area. With ABS standard on all the 4th gens, GM was able to increase the rear breaking pressure, in order and reduce the tendancy to nosedive, without the risk of locking up the rear. As a result, the rear pads wear fast.

My fronts lasted to 75K, my rears lasted till 150k

 

that doesn't make any sense to me Your rears wear fast but outlasted your fronts?

I don't have abs and my rears don't lock up preamturely. Removing an abs senor and disableing abs doens't affect the proportioning valve. I would think that the vehicle would be designed to handle safely/well even if the ABS malfunctioned/was disabled. Stopping power won't automatically be tied directly to pad wear anyways.

EDIT* I just looked in my log, it was the rears on my car which is consistent with others, we did the fronts on my friends mustang at about the same time. I still don't know if they were all put on at the same time by the previous owner though so its irrelevent*


Fred, GM replacements? I haven't been through a full set myself since they were good when i got the car, just curious.

-brent

 

I bought my car new. It needed rear pads replaced at 50K miles. I replaced them with the Perf. Friction Z-rated pads. My OEM front pads are still at least 50% of original thickness, and have never been replaced. They now have about 70K miles on them.

Over the course of maybe 5 years on the boards, I've seen the question of "why do my rear pads wear out first?" pop up with surprising regularity.

 

I've replaced my breaks once and it was the rears one, the front ones were fine. Maybe the back ones are thinner to begin with or that fact that it has something to do with the e-brake?

 

This should be obvious. Due to the brake bias on the Camaro's the rear breaks are under size for the job they do. I fact I think most will agree that the entire system is under size for the job it does.