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front or rear
oadamo - 12/2/10 at 06:05 PM

whats the advantage or disadvantage of having the brake caliper on the front or back of the disc. most raod cars have them on the front but cars like the lotus elise have them on the back ?
adam

r1_pete - 12/2/10 at 06:11 PM

I thought it was for cooling, but if the sporty little number has them at the back it rather defeats that argument.

Maybe its to be opposite to the steering rack??

speedyxjs - 12/2/10 at 06:14 PM

quote:
Originally posted by r1_pete
Maybe its to be opposite to the steering rack??


No, mine are on the same side as the rack.

Mine are all to the rear (not sure about the Astra though).

r1_pete - 12/2/10 at 06:24 PM

Now you got me wondering, THIS seems like a plausable explanation...

Alan B - 12/2/10 at 06:40 PM

I though fronts behind and rears in front was best to put them closer to COG and hence reduce the PMOI.

oadamo - 12/2/10 at 06:41 PM

quote:
Originally posted by r1_pete
Now you got me wondering, THIS seems like a plausable explanation...


good find has anyone got a book or somthing about brakes they could have a look in to see what it says about the position.
adam

JekRankin - 12/2/10 at 06:50 PM

It can have an affect on wheel bearing loads under braking.

An explanation, (pinched from Racecar Engineering) is on the fourth post of this thread.

link

I find it quite hard to follow! :-)

Jek

Angel Acevedo - 12/2/10 at 06:55 PM

It is desirable to have then as close to the CoG to reduce PMoI.
This within packaging constraints.
AA

DOH Too late

meany - 12/2/10 at 08:56 PM

quote:
Originally posted by JekRankin
It can have an affect on wheel bearing loads under braking.

An explanation, (pinched from Racecar Engineering) is on the fourth post of this thread.

link

I find it quite hard to follow! :-)

Jek


an extract from the above link, which i find hard to believe...sounds like a load of tosh to me.

We can think of it like this: Gravity acts downward on the car, with additions and subtractions due to inertia effects and aerodynamic effects. The road surface holds the car up. Or, we may say the road holds the tire up; the tire holds the wheel up; the wheel holds the hub up; the hub holds the bearings up; the bearings hold the spindle up; the spindle holds the upright up; the upright holds the suspension up; the suspension holds the sprung mass up. If the caliper exerts an upward force on the upright and a downward force on the disc, that just means the brake is helping the bearings and spindle hold the upright up. It doesn't change the total support force, only the load path within some of the unsprung components.

britishtrident - 12/2/10 at 10:47 PM

The angular position of the front calipers on production cars is a lot more to do with steering rack location than reaction forces at the wheel bearing.

With the rear calipers the main consideration is available physical space and the design of hanbrake linkage/cable.