were do you start on brake ballance, on your cox,as it first time for me with a rear engined car, ive always run with my back brakes hardly working on my mini,,,,,

I've been thinking about this myself lately, but from the lack of discussion on here i'd say 50/50 was acceptable, that's what i'm going for anyway.

BTW In the past i've made adjustable biasing valve out of a load valve from an escort van - cut down the arm and replace with a thread, then wind up and down to suit - they work pretty well.

50/50 is to much pressure to the rear wheels, for RD going I would say more like 75/25 maybe 70/30 otherwise with the weight at the rear all you will do is lock up the rear brakes all the time. You do however need slightly more pressure than you would with a mini as you have the engine to slow also. Obviously its a perference thing and if you have an adjustable bias valve then I would suggest finding a quite rd and trying different setting out till you find what suits. Remember to try the setting in the wet also, you may find what is OK in the DRY is terrible in the WET. When we use to set up the minis for racing we would make sure that at full brake pressure i.e. jumping on the brake pedal that the rear wheel would be just able to turn by heaving on the wheel. This meant no matter what that the rears wouldn't lock under heavy braking and would allow the rear of the car to pivot easier round the front (creating oversteer).

I don't run any sort of balancing device at all. They all just come on when I press, mind you I only have drums at the back.

There has been some discussion about this in the past, try:
viewtopic.php?f=5&t=8

The general feeling seems to be that with a basically 'Mini' setup you need to have more rear bias than on a Mini, because of the weight distribution as mentioned.
My GTM build manual suggests front brake lock up is a common problem.

Surely the reverse is true; if you want oversteer you need more rear bias, hence at it's most extreme, the handbrake turn (or left foot braking on a Mini).
The most oversteer on braking is caused by having locked up rear wheels !

Agreed you may not have adjustable balancing, but there is still an intrinsic balance in any system.
It would be interesting to know what calipers and master/slave cylinder sizes you're running?

Brake balance is effected by master cylinder size, front and rear if you run seprate cylinders, where you put the balance bar if you have one, what size calipers or slave cylinders you have, also what size disc/drums, and to ad further to the mix what pads/shoes material. also the weight distribution of the car and weight transfer adds further variables.

it gets quite complicated quick and obviously drivers preferance.

Currently i run about 50/50 on the balance bar, same size master cylinders front rear, 10 inch disc front, 9 inch disc rear, 4pots front with simular piston area as a mini caliper, Sierra cosworth rear which give a simular clamping force but ever so slightly less, green stuff pads front. std pads rear and its suits me quite nicely.

so many variables

this sort of thing is best done by saying what you have actually got on the car, or wishing to run, then asking for what experiance people have of that setup and options, rather than just saying what balance should i run? More info is needed or if you donot know what setup to start off with im sure we can give tips and pointers, pros and cons

WEST

Something else worth bearing in mind, the more camber you run the less tyre in contact with the road resulting in locking up sooner

I've got a single brake circuit with the standard Mini master cylinder. It's one of the later plastic reservoir versions but I think the bore size is the standard 0.70".

The rear brakes are Super Minifin drums with standard linings and 0.75" slave cylinders.

The front brakes are now solid 8.4" discs with Metro 4 pot calipers and EBC Green Stuff pads.

I'm still not impressed with the braking for such a light car. They lack 'bite' and need a lot of pedal pressure to stop hard even when warmed up. I suppose I've got used to the massive servo assistance that you get with modern small cars now.

When you put your foot on the brake it causes a sudden transfer of weight to the front, you can adjust this transfer by adjusting the brake pressure front/rear therefore eliminating/reducing brake lockup. If you find that you are locking up the front wheel under heavy braking then apply more pressure to the back. (this is also done if you're on the track and its starts raining you will always adjust the bias more to the rear to even out the loadings) The reason why we limited the pressure to the back of the mini when racing was because with a locked up rear end it will tend to steer itself and that becomes uncontrollable, where as if you apply more pressure to the front the rear becomes lighter therefore sliding around the corner which is best for a front wheel drive car as you can use the oversteer to counter act the understeer common in front wheel drive cars. As I said earlier its up to personal preference, I much prefer a car to oversteer than understeer as its a quicker and more controllable way of cornering. I have always used a bias valve on my previous cars however I'm now racing a single seater and I'm getting use to the balance bar system which opperates slightly differently to the bias valve. I haven't had my Coupe on the road yet so I'm still unable to comment on what brake pressures I'm running however I believe I will be still running a front over rear bias on mine.

Thanks John that's useful to know.



I'm not a fan of EBC, we tried their Black Stuff pads, which are the softer compound, on our Cooper S, I wasn't impressed with those either, lack of bite and generally felt dead.
Swopped them for a set of std. oe spec pads and they were much better, more initial bite and haven't made them fade so I'm much happier.
Given the lighter weight and more rearward weight balance of the coupe I wonder if your pads are just too hard and never getting up to temperature?

Certainly wouldn't disagree with any of that


Assuming you're talking about the std Mini valve, then you would notice a difference compared to a balance bar, because the mini valve is a pressure limiting valve not a 'bias adjuster'.
Even if you have an adjustable one it does nothing at low brake pressures (so not affecting the brake balance), then when it operates it just stops the rear pressure rising any further.

So you effectively have: a single fixed brake balance setup for light pedal pressures, and a second balance setup for heavy pressures (once the valve has operated) that varies with pedal pressure - the more you press the pedal, the more the balance goes towards the front.
The balance bar on the other hand truly changes the balance between front and rear, by a fixed amount, at all brake pressures.

Fair comment, but I did start off with standard pads and I was even less impressed with them. The Green Stuff pads are a definite improvement over standard but still not what I was hoping for. When I raced my Mini Marcos and also still used it on the road I used Mintex M171 pads (that's showng my age) and they felt much better than my current set up.

Just for information all the braking system is new and nothing is siezed, sticky or binding.

We use to use Carbon Metallic pads on the front of our race mini (Cooper S Calipers)and they were unbelievable, I had them for 4 seasons and they were still good when I replaced them. They were so good that I could brake from 180 kph and lift the back wheels completly off the ground with no brake fade what so ever. Not sure who sells them over this side of the world though. EBC pads are good but they seem to suit heavier saloon cars/race cars rather than light ones like ours. You need to remember that our cars are only around 600kg where most std saloons are 900 - 1500kgs quite a significant amount more. Unless you are doing a lot of circuit racing or speed events STD road pads should be good enough especially those who have discs all round. I would be surprised if you can create enough heat on the road to cook a set of std pads. And on the flip side of that I would say that the EBC ones wouldn't get enough heat into them to work properly on the road either. Like most things it comes down to preference, if it were me I would have a STD set of pads for day to day driving and a set of mild competition ones for circuit days etc.