Brake balance

[chris.richard]

The Alfa 164 has brake bias of front 69%,rear 31%
I checked the ones for a Porsche 911 turbo, and they're 66% front, 34% rear.
I thought there would be more of a rearwards change on the porsche. Maybe weight transfer is still the major factor, rather than static weight balance.

[rutthenut]

What about brake limiting valves? Does the 164 use one of those, I can't remember?
If so, the bias would be a static figure, but rear bias would decrease [by a lot] when actually using the brakes. Just a thought.

J.R.

[chris.richard]

Yes, it does.

[Martin K]

Just some thoughts on this....

Not only is the weight in a Porsche more rearward, it is also lower. As a result weight transfer to the front wheels under braking will likely be less in a Porsche than in a Strat with a higher mounted V6.

That being said, Porsches will still be set up relatively 'safe' to drive - i.e. with forward bias so that (without ABS) the fronts will lock before the rears under even the most difficult conditions (wet, snow, ice, loose gravel etc) so that the drivers don't end up sueing Porsche because the cars are 'dangerous to drive'.

On all the rear and mid-engined cars I have driven I have always found that much more braking can be added to the rear wheels than would seem imaginable. Generally around a 60/40% split front/rear and in perfect dry conditions even more on the back - particularly if there is more grip available on the back as is the case with larger rear tyres.

But without adjustable bias to balance things, I would also go for a safe static setup with the front brakes having around twice the effect of the rears, i.e. around 2/3rds front, 1/3rd rear.

The other way to achieve brake balance is to build the car with equal braking front and rear (i.e. same size master cylinders, caliper pistons, discs, swept area, pad size and same pad material all round) and then use a brake pressure proportioning valve to limit pressure to the rear brakes.

[kens]

Just some thoughts on this....
On all the rear and mid-engined cars I have driven I have always found that much more braking can be added to the rear wheels than would seem imaginable. Generally around a 60/40% split front/rear and in perfect dry conditions even more on the back - particularly if there is more grip available on the back as is the case with larger rear tyres.


I have noticed that modern mid-engined Ferraris have four pot Brembo calipers on each corner. This reinforces your statement about being able to utilize rear brakes more that one would expect. Also, observed in the Ferrari showroom, the e-brake was a seperate Brembo unit. I found that unfortunately the Brembo e-brake sets sell for about $1,000. No joy in that price.

[Swamprat33]

Hi Kens. I assume by "e brake", you mean emergency brake, or Hand brake as we call it in the UK.

If that is the case, then i have a set of the Brembo Handbrake calipers on the rear of my CAE Corse.

I obtained them through AP in the UK, and they cost me around £250 including mounts. Strangely enough, i could not find any info about these items from brembo in UK.

Cheers

Tim