Tire / tyre pressures

[kasbatts]

Hi all,

Those with 16 or 17 inch wheel set ups, what pressures are you guys running in your tires?

I am running 225/45/17's and just need a start point to work from, I was thinking something like 36psi front 34 psi rear?


Thanks


Steve

 

[decoupe]

Air pressure

Steve,

Resto-mod car with 225/245 x17x8 Michelin Pilot SS and ST lowering springs with 28/23mm sway bars.

I've wondered about modern tires with stiffer side walls, softer compounds and larger diameters combined with 40 year old suspension designs, narrow track and a soft chassis. The last 3000mi I went with the factory recommendations at 30psi (?) but I'm watching for uneven tire wear due to "under inflation". Handling is great and the ride isn't bad unless the road is really rough. Potholes another matter.

I ever get this back on a track I would up it to 34psi minimum but I don't think more air - given the sidewalls and the low cross section is the answer for daily use or even doing the twisties through the mountain hairpins.

 

[kasbatts]

Cool, thanks for that, was out for a little drive yesterday and decided the ride was a bit too jiggly, so will drop pressure down to 34 f and 32 r I think, along with winding down the rebound damping on the shocks to see if this improves thing (I am running Koni shocks with adj rebound damping)

 

[decoupe]

Adjustable dampeners?

Which Koni's? Front and rear? Adjustable coil-overs or springs and strut/shocks?

 

[bmwmadman]

With 16 inch alpinas I run 32 psi all around with no issues. I have mistakenly been down as low as 28-30 psi.

 

[decoupe]

bmwmadman - what tires are you running? Sidewalls relatively stiff?

 

[bmwmadman]

Yokohama S Drives
Standard fitment 205/55 frt and 225 /50 in rears

Gary

 

[kasbatts]

I am running Michelin pilot sport 3

 

[kasbatts]

Which Koni's? Front and rear? Adjustable coil-overs or springs and strut/shocks?

Yes Konis front and rear, I have had them for about 6 years, they are the "sport" model, adjustable by compressing all the way down and then turning the shock shaft.
Unfortunately I have to take them out of the car to do this, the new one's can be done in the car.
Springs are ??? We just found some that worked for us out of the vast stock that Koni NZ carries
We tested and measured the old springs and went up about 30 percent in rate as well as them lowering the car by about 1 1/2 inches.
Sway bars I had custom made here in NZ, they are 26mm front and 24mm rear, and yes the rear is potentially too stiff, this is a work in progress, when I had these bars on without the LSD it wheel spun at any given opportunity, however now with the uprated Diff (about 40 percent lockup) I haven't yet had wheel spin, so the rear bar thickness will end up depending on what the overall balance of what the car feels like, especially in the wet where it will probably be a bit of a monster in its current guise.