Front /back pad wear etc

[Larry C Leung]

That mass must be able to move backwards when the car is stopping,
forwards during acceleration, and ideally, towards the inside of turns
when, uh, turning.

LL - NY

On Thu, 12 Jul 2001 09:19:56 +1200 "Dave Eaton" <Dave.Eaton at clear.net.nz>
writes:
>you could also have a movable ballast which travels while the car is 
>in
>motion to counter-act the weight shift.  it was an idea which the 
>german
>class 1 dtm cars used a few years back and is now being picked up and 
>used
>by a few of the current crop of wrc rally cars...
>
>dave
>'95 rs2
>'90 ur-q
>-----Original Message-----
>
>>    My understanding is that static weight distribution is 
>irrelevant
>>to the work required to be done front and rear by the brakes. This is 
> due
>>to 'weight transfer'. I.e. under braking the mass of the vehicle 
>combined
>>with the centre of gravity of the vehicle causes a torque effect 
>around the
>>front wheel axis which results in a 'shift' in 'weight' away from the 
>rear
>>wheels and over the front.
>>
>>This is also the reason you went over the front handlebars on your
>>bicycle when as a kid you tried riding into kerbs to see what would 
>happen.
>> As a result the harder you brake, the less grip the rears have and 
>the
>>more the front have, which may lead to rear lock up unless you have 
>ABS or
>>in the case of  Non ABS systems the lovely heath-robinson spring 
>actuated
>>rear compensator which uses changes in the rear ride height to reduce 
>the
>>pressure to the rear brakes.
>>
>>    For this reason brake systems are designed from scratch in terms
>>of relative piston area so that the fronts do most of the work. This
>>greater work done is *usually* compensated for by the use of large 
>pad area
>at
>>the front and smaller at the rear, but not to the extent that both 
>wear
>>out at the same time. Usually rear pads are relatively 'bigger' than 
>they
>>need to be and hence last longer.
>>
>