Different Brake Pad Wear - front to rear?

[NSX2play]

I believe it is normal for brake bads to wear faster at the fronts than the rear since the fronts do more of the braking but on my NSX not only do my fronts wear faster but under heavy braking my fronts also lock up first. I have StopTech AeroRotors on the front and Powerstop slotted rotors on the rear. I use a high performance street/track pad made by TechnoFreno of Italy.

This leads to a few questions:

Under these circumstances is it possible that my brake bias is now biased too much to the front?

If so, would I get better braking by installing a proportioning valve and biasing the brakes more to the rear?

If I do that, is it better for the fronts or the rears to lock up first?

 

[nsxtasy]

Originally posted by NSX Maven
I believe it is normal for brake bads to wear faster at the fronts than the rear since the fronts do more of the braking but on my NSX not only do my fronts wear faster but under heavy braking my fronts also lock up first.

The front of the car does more of the braking, due to weight transfer. This is true on any car.

However, that does not necessarily mean that the front brake pads will wear out faster than the rear brake pads, for two reasons: (1) on most cars, including the NSX, the front brake pads are larger (greater surface area) than the rear pads; and (2) similarly, the front brake pads are thicker than the rear pads when new.

I generally replace front pads twice as often as rear pads on my mostly-tracked NSX. However, I suspect that those with more street use do not necessarily do so.

 

[DanO]

...but under heavy braking my fronts also lock up first. I have StopTech AeroRotors on the front and Powerstop slotted rotors on the rear...

Under these circumstances is it possible that my brake bias is now biased too much to the front?

If so, would I get better braking by installing a proportioning valve and biasing the brakes more to the rear?

If I do that, is it better for the fronts or the rears to lock up first?

If their going to lock up, it is almost always better for car control if the front tires lock up before the rear tires so a front bias is designed into cars from the start. A car that has too much rear brake bias will be considerably more difficult to control under lockup conditions as the rear of the vehicle will loose traction and any steering input or turning momentum or traction difference will set the car in a spinning motion that is difficult to control.

The only time I’d use a brake biasing device is to control a too-strong rear brake bias (like big brakes on all 4 corners) or under racing conditions to control the bias in changing grip conditions: more grip (race tires) = more front bias, less grip (race tires in the rain) = more rear bias. If that last parts seems backwards then one has to remember that as car stops faster, more weight is transferred to the front giving the front more traction and the rear less, since a tire’s grip and stopping ability is dependant on weight for traction, that means that the front can take on more of the braking responsibilities without locking up and conversely, the rear will have to do less of the work because it has less grip (weight) to work with. Under poor grip conditions where the car cannot stop as fast, there will be less weight transfer to the front tires and therefore there will be more weight (grip) available to the rear tires.

One note: some (most?) biasing devices keep a 1:1 ratio up to a certain adjustable brake pressure threshold and then starts biasing, this allows for maximum braking (more relative rear bias) under low weight transfer (light pedal effort) conditions.

.015

DanO

 

[MvM]

NSX Maven
I recently switched from OEM to Axxis pads on the front. They definitely feel a lot grabbier. I have a pair of Aerorotors ready to install but haven't had the time yet.
Concerning wear: I believe more agressive pads will usually wear quicker. I don't think however the amount of wear says much about your brake bias or about your braking ability but more about the pads make-up.
As far as lock up is concerned, it's normal for your front wheels to lock up first. With the Axxis pads I do seem to be able to brake close to that point more easily then with the OEM pads though.
I hope that this will be even better with the Aerorotors installed.