Who has worn out their brake discs ?

[Winmoz]

I’ve popped BBKs on the front of many of my track toys. Never on the back. Atom included.

It’s all about weight transfer. Doesn’t matter where the mass is in a car , when you decelerate, the mass will want to keep on trucking forward. Thus the forward most friction point becomes the most critical.

In the biking world, this is demonstrated by stoppies. The bike wants to pivot on the front wheel. The weight transfer is to the front and the back goes light, so big brakes there would have less effect.


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[cvjoint]

I have the same pad/caliper/disc front and back and the front pads wear out a tad quicker and the front rotors gave out first. My car is also heavily staggered with far wider rears. I deduce from this that the front brakes do more work than the rears. Weight transfer is on the balance a more important factor than weight balance, even on the Atom.

Many folks believe the rotors are warped when in fact it's uneven pad deposit that causes similar symptoms. A quick resurface of a rotor can be done with a tough track pad or with a bit of sandpaper.

I don't have a hand brake on the Atom so I don't know how it works on this platform. But if you park the car after driving it hard and pull the handbrake you can warp rotors on other cars. It's a common trick for track day cars to leave it in gear and never use handbrake in the paddock for this reason.

[reg]

A bike is a very different applicatuon because weight transfer is the rider himself as he is almost on the front wheel.

It makes no sense to me putting bigger brakes on the front when all the weight is at the back. If this were an issue we would see the same thing as on bikes, but we don't, disks are often the same size with same.

I don't like arguing on an internet chat forum so lets agree to disagree!

The more weight is at the back the greater the potential transfer. The front axle is the pivot point. In cars the average is 10% transfer, under braking, it why we have brake bias adjusters etc. Iv'e run smaller calipers and less aggressive pads on the rears on pretty much everything, so do many manufacturers.

Stability and control under heavy braking is at least as important as ultimate stopping
capability. All cars, from pickups to Formula One, are designed with the majority of the braking torque on the front wheels. There are two reasons for this - first, if we ignore the effects of aerodynamic down force, the total of the forces on each of the vehicle's four tires must remain the same under all conditions. When the vehicle decelerates, mass or load is transferred from the rear tires to the fronts. The amount of load transfer is determined by the height of the vehicle's center of gravity, the length of the wheelbase and the rate of deceleration. Anti-dive geometry does not materially effect the amount of load transferred - only the geometric results of the transfer. Second, when a tire locks under braking, braking capacity is greatly reduced but lateral capacity virtually disappears. Therefore, when the front tires lock before the rears, steering control is lost and the car continues straight ahead - but this "under steer" is a stable condition and steering control can be regained by reducing the pedal pressure. If, however, the rear tires lock first, the result is instantaneous "over steer" - the car wants to spin. This is an unstable condition from which it is more difficult to recover, especially when entering a corner.

Most mid-engine pure racing cars are designed with 55-60% of the total static load and 45-50% of the total braking torque on the rear tires. These cars feature literally tons of rear aerodynamic down force and the footprints of the rear tires are always significantly larger than those of the front. Most passenger cars are front engined; none of them have any appreciable download and almost all of them have the same size front and rear tires. In extreme cases (front wheel drive) they may have 70 % of the total static load on the front tires. They are therefore designed with a preponderance of front brake torque. Most current production cars feature anti-lock brake systems (all cars should). Sophisticated ABS systems ensure that, under heavy braking conditions - even braking with tires on different surfaces - each tire is braking at something very closely approaching its maximum capacity while the ABS system prevents lock up.

http://stoptech.com/technical-support/t ... -selection

Generic, but good info.