[E90 335xi]

What tire pressures do you recommend for an E90 335i xDrive with Michelin Pilot Super Sports stock staggered sizes (225/40-18 front / 255/35-18 rear)?

And since I'm asking... what pressures are recommend on the street with those same tires?

The factory 36F/41R (cold) pressures seem way too high. Last track day my rear pressures shot up to 48 after just a few laps. I then dropped them to 36F/36R (hot).

Thanks!

[davidwarren]

You could drop the rears to 38 cold and see how that treats you. Try a bit lower on the front but watch for sidewall roll. I find 34ish cold to be about the lower limit for the street for the fronts. 36/38 hot on the track sounds about right to me. I run PSS street and track too. Same sizes.

[chris82]

From my experience and some others at road courses, we'd normally run them at 36-37 hot

[ApexWheels]

You certainly want to drop pressures once arriving to the track. How low (your baseline) will be determined by the temperature of the track (conditions) and your driving style. On a hot day, your temps will rise a bit higher/quicker. On a cooler day, temps will not rise quite as fast. Keep a log, and this way you will have historical data for the future. This should help with determining your baseline when you first arrive to the track.

Furthermore, I would think about purchasing some extreme summer tires (depending on how often you take the car to the track). Although the MPSS are fantastic street tires in respect to wet and dry performance, they do not hold up under track conditions and repetitive lapping. The heat will start to deteriorate the tires, and you will find yourself spending more money in the long run managing these street tires for double duty use.

I recommend going to an extreme summer tire like the Hankook RS-3, Dunlop Direzza ZII Star Spec, BFG Rival, or Yokohama AD08-R. All of these can be daily driven in reasonable climates, and certainly driven to and from the track. Most of these perform best anywhere between 36 - 38 hot, but it is difficult to make a blanket statement as everyone has their own personal preferences.

- Ryan

[E90 335xi]

Thank you all for the replies!

[chris82]

Originally Posted by E90Mack

the guys at On Edge Motorsports had me running at about 25 psi, as measured right after coming off the track, on a very hot day at Thunder Hill. I now just stick with that (working my way down to 25 by letting air out after each morning session to get down to 25psi, then usually just leaving them in the afternoon, then getting a nitrogen refill at the end of the day), and they feel great. I do wear through some tires.

What was the reason for that? That's ridiculously low for a track or street setting, and maybe why you're going through tires?

[just_dirty]

25 psi hot is very low!

[davidwarren]

Originally Posted by E90Mack

the guys at On Edge Motorsports had me running at about 25 psi, as measured right after coming off the track, on a very hot day at Thunder Hill. I now just stick with that (working my way down to 25 by letting air out after each morning session to get down to 25psi, then usually just leaving them in the afternoon, then getting a nitrogen refill at the end of the day), and they feel great. I do wear through some tires.

25 hot off the track is ridiculously low. If you are 25 hot right off the track, those are dangerously low once they cool down. I'd say you need at least 10 more psi measured hot.

[3002 tii]

Originally Posted by ApexRaceParts

You certainly want to drop pressures once arriving to the track. How low (your baseline) will be determined by the temperature of the track (conditions) and your driving style. On a hot day, your temps will rise a bit higher/quicker. On a cooler day, temps will not rise quite as fast. Keep a log, and this way you will have historical data for the future. This should help with determining your baseline when you first arrive to the track.

Furthermore, I would think about purchasing some extreme summer tires (depending on how often you take the car to the track). Although the MPSS are fantastic street tires in respect to wet and dry performance, they do not hold up under track conditions and repetitive lapping. The heat will start to deteriorate the tires, and you will find yourself spending more money in the long run managing these street tires for double duty use.

I recommend going to an extreme summer tire like the Hankook RS-3, Dunlop Direzza ZII Star Spec, BFG Rival, or Yokohama AD08-R. All of these can be daily driven in reasonable climates, and certainly driven to and from the track. Most of these perform best anywhere between 36 - 38 hot, but it is difficult to make a blanket statement as everyone has their own personal preferences.

- Ryan

+1

It's going to royally suck when you come back to the pits only to find your PSS all shredded up. I use PSS on cold / wet track days and even then I find Star Specs can handle damp conditions quite well.

[E90Mack]

Originally Posted by E90Mack

the guys at On Edge Motorsports had me running at about 25 psi, as measured right after coming off the track, on a very hot day at Thunder Hill. I now just stick with that (working my way down to 25 by letting air out after each morning session to get down to 25psi, then usually just leaving them in the afternoon, then getting a nitrogen refill at the end of the day), and they feel great. I do wear through some tires.

So, the above quote by me. For whatever reason, I had thought when I was at ThunderHill (this June), that I had been at 25 previously (Oct of 2015). So I ran at 25 the last time there (June)--it was super hot and the car actually felt pretty good.

After reading through some of your comments, I thought, wow, I'm really an outlier here. So I read through my earlier notes from last fall, and found that I had been at 35 last fall, not 25. Going from memory on this may not have been a good idea...

Today I did a track day at Sonoam and the On Edge guys had me at 39 fr and 42 rear after a few rounds of adjustment (on a fairly cold day). Car never felt great all day, though I'm not sure that was the tires.