Tech reading for all big brake freaks :)

[dan_b]

If increasing grip at the front means the front end breaks away later than the rear, you get understeer surely? I agree that more grip is more grip regardless, but isn't it a relative shift in the balance of the car toward more understeer if you increase overall traction at the front only?

[Jamo]

If the back breaks away before the front the corning angle is increased during the turn. If it breaks too much you get oversteer.

Nope if it was balance in weight then yes.

Take it you didnt race radio controlled cars then mate

The downside is the increased drag and tramline tendencies.

[dan_b]

My car tramlines pretty badly these days anyway - worse since putting the uprated ARBs on for sure. Hmm. Still think a 235/40 might be a good progression for braking though. Have to think about that a bit more, I'm needing 1 new tyre in a few months (front right seems to be heavily worn on the shoulder, can't think why!)...

[S2central.net]

Upside of wider tyres is increased grip of course. The downside is increased drag produced by the fatter footprint. Another consideration is the extra rotational mass from a heavier tyre. Every kg of rotational mass has a direct effect on the cars ability to accelerate. And thirdly the increased weight is unsprung - this generally has a detrimental effect on suspension system, where lighter is more responsive and therefore better.

Assuming perfect corner balance then wider front tyres (compared to rear) will REDUCE understeer as the rears will break traction first.


Paul

[HPmuirt]

Be interesting to see if you have the RS2 disc splash plates on yours Si, Mines got em from the factory, and so does my bro's and one other 95 S2 that I know of, I can't however fit those RS2 airducts as I have the pressed wishbones as opposed to the other S2/RS2 cast type and they won't fit

Jas

Hey Jas,

How do I tell the diff between S2 and RS2 splash plates M80 ?

Hoping to get the Monoblocks on in the next day or 2 (so many delays ) so I'll have a look see.

Cheers n

Si

[Sir Buff]

http://www.mtm-online.de/de/highlights_audi_s2_clubsport.html

[Keeper of The Kitten]

A small increase in tyre width will only result in a small increase in weight - equivalent to the width increase of the tread area x circumference of tread area, as the sidewalls will be largely unaffected within a small amount. If you have a net decrease in sidewall (dropping 5% without going up in width by about 40mm) the tyre weight may remain very stable. Any weight increase is bad, unsprung is worse, and the inertia of a rotating object is worse still as they really hate changing direction.

As for drag, that's mainly due to the projected area - and the vast majority of it is hidden when viewed from the front. There can be some planing on a cushion of air for very wide tyres at very high speeds. Rotating wheels are bad but most of the wheel is shrouded so (unlike an open wheel car) the effects will be negligible, especially at relatively low speeds.

If all else is equal, a stickier tyre will be an improvement. Given the weight of the S2 front end, wider tyres will be beneficial. On lighter cars, the ground pressure generated will reduce with a tyre width increase, and if that isn't counteracted by use of negative lift it can actually present a problem - but this is unlikely on a road car as you're unlikely to be able to fit tyres that are too wide.

__MDC__

[S2central.net]

Nice analysis there... more sporting experience than mine for sure ! Always knew I was in the wrong firkin industry...

Paul

[Jas11n]

Hey Jas,

How do I tell the diff between S2 and RS2 splash plates M80 ?

Hoping to get the Monoblocks on in the next day or 2 (so many delays ) so I'll have a look see.

Cheers n

Si

Erm, not got a pic of the normal S2 splash plates, but they look nothing like the one in the pic below, which is the RS2 one.
The normal S2 ones are big round plates, just say smaller than the original sized discs.

]

Sorry to intrude on your thread Sau