Retard.......

[Tim Davey]

So , first track day  today chez Castle Combe. I could not , so it seemed, get anywhere near locking the wheels no matter what pressure I applied to the brake pedal. And yet it felt there was more there to be had. ( there was I sensitively modulating half the sole of my foot heel and toeing, rather than stamping 10/10 for style but only 5/10 for effective braking and lap time( not measured) ) So any suggestions for better retardation per unit force applied ? Pad compounds ?

[Jonathan Kay]

Pedal travel felt OK? Not spongy? No squealing?

What's the car's history?

Jonathan

[Tim Davey]

Pedal hard as a rock, minimal travel. Racing history but I was pressing VERY hard and admittedly making gains but just expected a lock up to come as some point. That it didn't implies insufficient pedal force or pad/disc sub-optimal retardation . ( standard brakes , only a 140 supersport not a rocket ship) and it did slow mighty fast but locking being the braking equivalent of spinning when cornering ; friction circle and all that I'm just a touch disappointed that I couldn't lock the brakes) 

[garybee]

What tyres are you on?  I have no trouble locking the fronts on ours but it's wearing Yoko' A539s and I'm guessing you're on something stickier.

[martyn]

You should be able to lock the wheels.

How hard were you trying really? How does the pedal feel when driving normally? Have you ever managed locked the wheels? By the sounds of it you have very good breaking performance which suggests that nothing is wrong.

With certain combinations of master cylinder and brake pedal pivot ratios, it is possible to create a pedal that is incredibly firm with minimal travel, but also requires a large amount of force to generate the same stopping power.  That may feel completely alien if you're used to an overly servo-assisted "normal" road car.

As for solutions.. different pads, different pedal ratio, different master cylinder.

Its certainly a nice problem to have, and is the opposite to my car where I feel that the wheels lock earlier than they should.

[john milner]

Glazed pads/discs?

[OliverSedlacek]

If it's an ex racecar then there is a fair chance a previous owner has 'upgraded' to a big bore master cylinder. This gives a much firmer pedal but you have to push harder on the pedal.

[Tim Davey]

Thanks to all for the responses. My poorly expressed point was I suppose:

• Astonishing braking performance
• Lots of pedal pressure required to achieve the above
• What more performance was to be had given that 'lock-up' was never achieved ?
• Do I need to do more cycling in order to do justice to the brakes i.e. more brake pedal force ?
• Is there a disc/pad combo that would give a larger retard/force ratio? 

Standard rotor and disk materials as far as I know . ( but be aware my learning curve is far from shallow)

 

 

[Roger Ford]

 Pedal hard as a rock, minimal travel

Sounds like a "race" master cylinder to me. I hate them. Have to push so hard you lose any sensitivity. Though other people like them. Look at downgrading to a standard master cylinder. You'll gain extra travel, but be able to lock up easily and hopefully be able to feel when that lockup point is coming.

If you don't know what pads are in there, might be worth getting some fresh Mintex 11/44s first to see if that makes any difference. May as well change the front discs as well given that they're only £26 a pair.

 

 

 

[john milner]

Mintex 1144 are generally accepted as being only suitable for the front so unless you know otherwise it is probably best not to fit them at the back.

[Tim Davey]

Thanks to all .