Better front brakes

[stuthemong]

Hi all,

I've recently returned to the tuscan fold, and I am absofrikkinlutely loving it.

I find the car has too much rear brake bias, and when stopping firmly, allied with engine braking, the rears actually lock up sometimes whereas the fronts never do, this is the opposite behaviour to my preference (!) and I'd like to fix this.

I can think of a few main options:

1. Pad change to something more aggressive uofront

2. 322 rotors and spacers from TVR power and new pads up front
http://www.powersperformance.co.uk/store/slug/brak...

3. 330mm carbon Lorraine discs and pads
http://www.carbonelorrainebraking.co.uk/tvrbrakes....

Has anyone any experience/advice as to what would be best to do? What are preferred pads now for tuscans? Historically I've got on well with EBC yellowstuff on my cerb, but what's the fashion these days?!!

Thanks in advance for any ideas/suggestions!

Best

Stu

[m4tti]

Get the larger discs and spacers from power, and use the ferrodo pads.

EBC are pretty much budget gear. I wouldn’t use them.

[stuthemong]

Do you know if the ferrodo pads are dusty at all? Do the larger discs actually make much difference, or is it the pads that are the main effect? And finally, would you put the same lads front and rear?

Thanks

[magpies]

Rear bias is dangerous - would not pass a VOSA test

Shouldn't there be a brake limiting device in the feed to the rear?

Do you 'track day' your car? if yes then you 'may' need different pads for that and daily driving

[magpies]

Rear bias is dangerous - would not pass a VOSA test

Shouldn't there be a brake limiting device in the feed to the rear?

Do you 'track day' your car? if yes then you 'may' need different pads for that and daily driving

[Basil Brush]

magpies said:

Rear bias is dangerous - would not pass a VOSA test

Shouldn't there be a brake limiting device in the feed to the rear?

Do you 'track day' your car? if yes then you 'may' need different pads for that and daily driving

There is a limiting valve on the rear circuit but from past discussion, rears locking first seems to be an issue on a few people's T cars, mine included. There was a thread a few years back about trying to resolve it by a guy who'd gone on a track driving course with a T350 and had a bit of a shock.

I originally had the 291 front discs as mine is an early car, but changed them to 322 S spec ones along with DS2500 pads all round. This improved the bite and feel massively and stopped the rears locking first.

[s6boy]

stuthe said:

Hi all,

I've recently returned to the tuscan fold, and I am absofrikkinlutely loving it.

I find the car has too much rear brake bias, and when stopping firmly, allied with engine braking, the rears actually lock up sometimes whereas the fronts never do, this is the opposite behaviour to my preference (!) and I'd like to fix this.

Stu great to hear someone coming back to the fold and glad you're enjoying it.
When you say 'allied to engine braking' are you letting the clutch out in a lower gear whilst braking without rev matching or even coming off the power quickly? If so that is why the back is locking up as the lightly loaded rear is coping with the 'drag' from the engine.
If this isn't the case and you want to upgrade then the ds2500 as mentioned is a really good progressive pad. I also upgraded to 322mm at the front simply because visually I think they fill the wheel a lot better. I didn't actually notice any difference in the stopping power though, and my understanding is that if there is any it would be negligible, the main benefit being a greater surface area to dissipate heat and not as I had expected additional bite/leverage from the larger diameter.
However nothing is going to stop the rears locking under heavy braking given what I've said above, although something else that could help would be stiffening the front suspension to limit dive and balance out weight transfer.

[spitfire4v8]

The change in leverage effect is only something like 5 percent from the bigger discs so that's not really going to help much as said. However the braking effect is governed by many factors, including the mean radius of the friction area, the leverage effort of the mean radius over the tyre contact patch, the friction generated between the pad and the discs, or rather the pad and the burnished-in pad material on the disc surface .. so ..

thinking laterally you could put some really rubbish tyres on the front, and excellent ones on the back .. that would help make the fronts lock sooner.

Also, bed the pads in properly .. you need that pad material coated over the disc evenly. Poor bedding in proceedure means poor performance from the pads you already have.Possibly try scouring the disc faces with some abrasive and brake cleaner, and bed the pads in again.

You're unlikely to generate high brake temps on the road, so you want a road pad that works great from cold temps. Soft pads, not hard track/race pads then.

Other than that you're into bigger changes say to a much larger front disc, larger front caliper pistons, adjustable brake limiters to the rear (i've used those to good effect before) or even dual master cylinders. You need to be aware of the differences in braking effort front to rear in changing conditions though .. you don't want to bias the brakes so far forward for dry heavy braking that they lock pretty much instantly in the wet. Adjustable pedal boxes are good for splitting the proportion of bias under a variety of pedal pressures, and adjustable rear pressure valve will only reduce the rear pressure once a threshold has been reached.

Or learn to heel and toe ? I'm assuming that if you knock the car out of gear and just apply the brakes strongly, then the rears still lock first ? otherwise it's your driving technique.

Also worth pointing out that although larger discs maybe have a small effect on the braking effort, the greater diameter means that for any given angular velocity of the disc, the linear velocity of the disc face past the pad increases, this makes the brakes less likely to snatch and lock (if they do indeed lock up after your upgrades), and helps you keep the disc on the point of locking when modulating your pedal pressures so generating better braking. IE a larger disc helps in terms of overall leverage effect over the tyre, and also controlling that tyre's adhesion... double win.

It must also be said that, although a locked wheel isn't as effective as one on the point of locking (I think something like 15 percent slip is considered close to optimum) .. a locked wheel will still slow you down, but of course gives you no directional control.

Edited by spitfire4v8 on Wednesday 15th May 15:07