Discussion
Anyone? Hopefully the photo shows what I believe to be the pad being polished.
The front brakes were ok at Silverstone GP circuit except the rear drums are wearing very quickly. At Oulton, 20 min practice and 20 min race they gradually got less and less effective, unable to lock the fronts. It didn’t feel as if they were overheating though.
The front brakes were ok at Silverstone GP circuit except the rear drums are wearing very quickly. At Oulton, 20 min practice and 20 min race they gradually got less and less effective, unable to lock the fronts. It didn’t feel as if they were overheating though.
With a drum brake set up on the rear your front brakes are obviously doing most of the work, but given the relatively low weight of your car and your front brake set up you shouldn't be lacking bite . I would suggest a pad along the lines of Performance Friction 01, or Carbotech 08 both of which I have used to great effect with a 1300 kg car.
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I used to use 1144s, they seemed very sensitive indeed to how they were bedded in. After losing a test day or two trying to get them to work properly (they were overheating and stinking within one lap at Rockingham) I ditched them and fitted racier pads- 1155 or 1166, can't remember which, but they solved the problem. This is on a 100bhp 610kg Caterham with rear drums. 1144s are a fast road pad really. I use them on the rear of my current Supersport.
Thanks
One other issue I have had is the rear drums seem to be doing the lions share of the work, a new set of OE pads are lasting a race meeting (20min practice 20 min race oulton)
I tried a balance valve at the rear which was interesting, when braking heavily at 90% it was ok - at 95% despite increased effort no more retardation.
I don't think its the pads fading as they were pretty crap early on! The brakes are much bigger (and vented) that the std MG Midget ones ive used in the past!
One other issue I have had is the rear drums seem to be doing the lions share of the work, a new set of OE pads are lasting a race meeting (20min practice 20 min race oulton)
I tried a balance valve at the rear which was interesting, when braking heavily at 90% it was ok - at 95% despite increased effort no more retardation.
I don't think its the pads fading as they were pretty crap early on! The brakes are much bigger (and vented) that the std MG Midget ones ive used in the past!
My Caterham had standard 9” triumph spitfire discs on the front with IIRC type 14 calipers (probably exactly the same as standard Midget disc brakes?) and the rear axle was Morris Ital with 7” drums. I never found 1144s wanting for bite at low temp nor operating temp. All this makes me wonder if your problem is on the hydraulic side i.e. is your master cylinder matched correctly to both your front calipers and rear wheel cylinders?
Now that I think about it (and this is going back a bit..) I might’ve changed my rear wheel cylinders from 9/16” to ¾” to reduce pedal travel and tone down the rear braking effort.
Now that I think about it (and this is going back a bit..) I might’ve changed my rear wheel cylinders from 9/16” to ¾” to reduce pedal travel and tone down the rear braking effort.
Thanks Russell
Midget discs are smaller than spitfire discs, it's an old upgrade to fit MGB (or Princess) callipers and spitfire discs I agree there may be an unbalancing of pressure, which is why for the last race at Oulton I fitted a pressure limiting valve to the rear I think a change of pad material and smaller(?) rear cylinders is next. The caliper uses the same size pada as Elise fronts. performance pads seem very expensive any recommendation? 1155?
Midget discs are smaller than spitfire discs, it's an old upgrade to fit MGB (or Princess) callipers and spitfire discs I agree there may be an unbalancing of pressure, which is why for the last race at Oulton I fitted a pressure limiting valve to the rear I think a change of pad material and smaller(?) rear cylinders is next. The caliper uses the same size pada as Elise fronts. performance pads seem very expensive any recommendation? 1155?
IMO 1155s probably aren't inappropriate for your car and should work well. I've never come across pads glazing before but if they aren't getting too hot and the performance is decreasing over a session then maybe that's what you have?
One observation I will make is that I have experienced braking problems this season caused by brake pads overrunning the disc friction surface and running in the disc bell as yours are, IMO it must cause at the very least additional heat and possibly uneven pad pressure on the disc, as well as preventing the pad from 'floating' in the caliper.
In your situation, clean up the discs and pads with emery paper, knock the lips off the inside edge of the pad, possibly file the pad down to prevent the pad from running in the disc bell?
I alleviated the problem by fitting different shaped pads which didn't overrun the disc surface.
One observation I will make is that I have experienced braking problems this season caused by brake pads overrunning the disc friction surface and running in the disc bell as yours are, IMO it must cause at the very least additional heat and possibly uneven pad pressure on the disc, as well as preventing the pad from 'floating' in the caliper.
In your situation, clean up the discs and pads with emery paper, knock the lips off the inside edge of the pad, possibly file the pad down to prevent the pad from running in the disc bell?
I alleviated the problem by fitting different shaped pads which didn't overrun the disc surface.
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