Phil Harrison

Is there a consensus out there as to the "best" (i.e least road imperfection-sensitive) tyre pressures for STiUK in OEM configuration for everyday enthusiastic road driving?? Is there a cheap (i.e. less-than 4 new Toyos or new set of 18") way of improving the twitchiness??

TIA

Phil

Dave T-S

Phil
On OEM tyres, I found our STi's too soft at the rear and am running them at 32 to 33 psi front and rear.

Re the twitchiness, I think it is almost certainly a combination of the front Suretrac diff and the tyres. The RE040 has a wide flat radial tread block pattern and these tread patterns always appear to exacerbate tramlining/twitchiness/torque steer type problems.

You may also want to have the geometry checked.

Got my 18" Prodrive PFF-7's sitting in the garage, and Toyos being fitted next week, so will report further....

russell hayward

My OEM tyres have now done 11k, and look like they will reach 20k easily. However, they have "gone off" noticeably over the last couple of thousand, tramlining much more and generally feeling less grippy than before.

Had the PPP installed today, and with the extra power, this has become a real problem.

Time for a new set I think. Pirelli of course.

JohnS

iTrader: (1)

I found that 34 front and 32 rear suited my driving style and roads the best. Any more and the car gets even twitchier over bumpy roads!

John

russell hayward

Bumpy B roads are a problem.

Hopefully the springs due to be released will cure this.

STI MAN

How are lowered / stiffer springs going to cure B road bouncing

Should make it worse, shouldn't it?

I had the Prodrive springs fitted to a my01 after I moved to the Isle of Man, most UK roads were generally much better after the upgrade, but when the car was running on the IOM roads (Mainly B road quality, except for the TT circuit) it was much more difficult to keep direction.

If the upgrade will lower the car, but not stiffen ride any firther I'll take them!

russell hayward

Cue Mike with a technical explanation of why I am right.

Dave T-S

Russell
Due to the fact that the tread blocks are tapered, there is more of the tread exposed and the gaps between the blocks are smaller as the RE040 wears. This will probably give more grip in the dry, less in the wet, make the ride harder (and thus increase the "jigglyness" the STi suffers from on certain surfaces where the spring and damper rates are in conflict with each other) and also increase the tramlining effect. This will all make the tyre feel like it is going off, but it probably isn't.

Mr Wood assures me the forthcoming Prodrive springs take the jigglyness out of the ride

russell hayward

Thanks Dave, is there anything you haven't an answer too ??

Springs I believe are £130 ? + fitting. Don't take this as gospel.

Driveability is much much improved with the PPP. You can drive the car in 6th at 40mph, and it will pull away.

Dave T-S

Russell
Loads I'm mainly full of useless information

The price of the STi springs has not been released yet. The WRX ones are £195 inc vat, plus fitting, and I would expect them to be very similar.

Also worth doing a proper alignment check while the springs are being fitted.

russell hayward

I was told £129.95 by the Dealer, but there again wouldn't be surprised if that was rubbish.

Hoppy

Just a comment, but the best 'upgrade' I ever fitted to my car was a set of good tyres. Better than the PPP, better than STi suspension, better than the fabled bump-steer mod. Car transformed with pukka rubber.

Cheers,

Richard.

Andy W

Just on the subject, I had a 215,40,17s on the STI for a couple of days and tramling was noticeably reduced and the steering was lighter, will get the 225's back on in the morning.

Andy

Phil Harrison

Thanks Guys - some erudite advice, as always from Dave. Thing is, I'm expecting my PPP any day (next friday??? ) and there ain't no other spare cash . Though the comment that PPP makes matters worse, while not unexpected, is definitiely in the category!! However, I'm as much looking for the PPP to increase the 'driveability' as I am to give the car the ultimate edge which can rarely be used on public roads, so it may not matter too much. It's the checking back for some minor hazard and then finding I'm two gears too high that irritates me!!

Cheers,

Phil

[Edit] PS, what are these PPP springs? Cost?

[Edited by Phil Harrison - 10/12/2002 4:23:34 PM]