Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Question for Weeksy.

[RickyX]

Originally posted by Shazaam!

No. Physics 101. F=uN. Surprisingly, area doesn't enter into it.

But............the stress on the contact patch would be lower for the larger area...thus wear would not be so severe..........

[Steve M]

Interesting point about tyres. I still think (but I may well be wrong) the CoF is important. After all the fastest corner speeds at Gp's come from the 125's, which have the smallest tyres. Although wheelbase etc comes into it.

[baylissboy]

Shazaam is correct,it's a physics thing!! The only other thing that would improve the braking is the radius of the disc!! The larger the radius the greater the braking effect,the surface area of the pad makes no difference!!

[DJ Tera]

But isnt force also related to area??


Force = pressure/area

Therefore pressure = force X area

or something

Its been too many party night since my A-levels 7 years ago

[Edited on 9-6-2004 by DJ Tera]

[Steve M]

DJ - The force you mention is the force pushing the pads together, determined by how hard the lever is squeezed - the harder you squeeze the quicker you slow down ( as Shazaam states ) The rate at which you slow would still be the same for a given lever pressure no matter what the size of pad/disc area. A small pad/disc area would just get very hot quickly and the brakes would fade.

My head hurts now!

[RickyX]

Originally posted by DJ Tera
But isnt force also related to area??


Force = pressure/area

Therefore pressure = force X area

or something

Its been too many party night since my A-levels 7 years ago

[Edited on 9-6-2004 by DJ Tera]

DJ,
From the above, I assume you got a "D" in A Level physics
You are 100%......wrong!

Pressure (stress) = force/area
Do not get confused with the pressure on the brake pad backing plate and the area of the friction material.
Take the following:
1. Brake Pad "A": Backing plate area = "1", friction material area = "1"
2. Brake Pad "A": Backing plate area = "1", friction material area = "0.5"

Force applied due to hydraulic pressure will be the same for "1" and "2".
Friction force generated between 1 and 2 will therefore be the same.
However, STRESS on friction material "2" will be 2 x stress on friction material "1"...therefore the heat generated wqill be more and the wear rate will be worse.........
Enough.

[RickyX]

Originally posted by DJ Tera
But isnt force also related to area??


Force = pressure/area

Therefore pressure = force X area

or something

Its been too many party night since my A-levels 7 years ago

[Edited on 9-6-2004 by DJ Tera]

DJ,
From the above, I assume you got a "D" in A Level physics
You are 100%......wrong!

Pressure (stress) = force/area
Do not get confused with the pressure on the brake pad backing plate and the area of the friction material.
Take the following:
1. Brake Pad "A": Backing plate area = "1", friction material area = "1"
2. Brake Pad "A": Backing plate area = "1", friction material area = "0.5"

Force applied due to hydraulic pressure will be the same for "1" and "2".
Friction force generated between 1 and 2 will therefore be the same.
However, STRESS on friction material "2" will be 2 x stress on friction material "1"...therefore the heat generated will be more and the wear rate will be worse.........
Enough.