Discs Or Drums?

[Davey]

Originally Posted by AdrianH

OK I did miss understand the drum brakes bit, I remember our old Triumph Herald That was drums all around.


For a bit of fun Energy is Kinetic energy KE = (M*V*V)/2 (can't figure how to get squared!).

So a Sierra at 1000 Kg doing 50 mph, must change to metres per sec. errr. 22.35 mps

KE is 249761.25 Joules

A 500 Kg car at 100 mph is 499522.5 Joules

So our little car at 100 compared to a Sierra at 50 has twice the energy because of the square, but half the energy of the Sierra at 100 mph.

Adrian

Errr yeah, I think . I threw the question out to see what would come back but I have a sneaky suspicion that your sums are better than mine. I shall be erring on the side of caution and using discs all round, probably with a servo .

D.

[AshG]

trust me you really really really really really really DONT need a servo.

i was dubious until yesterday when i drove the car properly for the first time with sorted brakes.

due to the increased pedal ratio the breaks were very very effective with very little foot pressure. it took absolutely nothing to lock the car up

the ideal setup for the roadster to get through iva without any problems is

sierra 22.2mm master cylinder
240x24mm vented front sierra discs
standard sierra 53.9mm front callipers
203x46mm sierra drums with 20.6mm slave cylinders.

as far as i know this is the only break set-up for a roadster that has passed iva first time without any tweaking of the rear pressure.

[Bonzo]

Duly noted & written in my book Ash

[Davey]

Thanks for the input Ash but mine isn't exactly as per the book, for one thing it will be significantly heavier, despite my aims for a 650KG kerb weight its looking like I'll be lucky if its under 750KGs. I'll hold fire on the servo till I've tested it all (I have a private road available adjacent to the build location ).

D.

[flyerncle]

Drums it is then, 1 Snare and a Kettle

[spud69]

Originally Posted by AshG

as far as i know this is the only break set-up for a roadster that has passed iva first time without any tweaking of the rear pressure.

I had the standard sierra setup, rear drums, and mine passed fine. Stops on a sixpence and no brake fade at all on a tight and twisty track, and that's rally booting it.....

There is no need to be concerned about upgrading brake setup the Sierra disc and drum works perfectly adequate on the 500kg roadster. You can always uprate them after IVA if you feel them to be insufficient.

Just Have Fun....AndyH

[james3004]

Thanks for the advice Ash

Looks like drums is the easier/better option for the roadster