Tire pressure ? for aftermarket 330ci rims

WilliamsGPE · Jun 11, 2004

Hello -- I just replaced my 01 330ci's badly worn (by the prev. owner) OEM rims with some Mille Miliga's and Goodyear F1 DS3's and would love some advice on the "proper" tire pressure.

I know there is room for play depending on preference, but what would be a good avg. cold psi for :

Front 225-40-YR18
Rear 245-35-YR18

I've been running them at 40 cold (how they were filled from TireRack) but would love some thoughts on where they ought to be. The OEM sticker says 36 front, 42 rear, but obviously those were thicker profile 17's...

Thanks!!!

MrElussive · Jun 11, 2004

40psi all around seems fine...perhaps a bit too high if you deal with a lot of crappy roads (i.e. potholes, poorly maintained roads, etc.). Based on the roads I deal with, I would run at around 36psi...40psi is more for track events.
Somebody please chime in if they have a different view.

HornyHornet · Jun 11, 2004

With 18s, going ~36psi is good to maintain the road comfort. Since a larger wheel can make a ride stiffer, rlaxing on the psi will help. Now, for spirited driving, 40psi seems right.

theBMWenthusiast · Jun 11, 2004

i run at 36psi on my 2004 325i, its a good drive

mscoins · Jun 11, 2004

WilliamsGPE said:

I have the Style 71s with Michelin Pilot Sports (225/40R18 front, 255/35R18 rear). Pressures I use are 33 front, 39 rear - recommended by my service advisor. Those pressures provide a quality, firm ride on everything but rough or segmented pavement and deliver good grip during spirited moments.

MrElussive · Jun 12, 2004

33 in the front is kinda low. I don't understand why BMW and Mercedes recommend more pressure in the rear and more in the front. I know their reason is that most of their cars are RWD and the rear tires should be nice and tight for better traction. But don't you want even psi all around, for the same amount of traction to all four tires during a turn, for example? And howcome my RWD car with 18" wheels is rated for 35psi all around (I run at 36psi, though) ?

mscoins · Jun 12, 2004

MrElussive said:

I figure they (BMW and Michelin) know more about it than I do, so those are the figures I use - and with excellent results I might add.

rjp325i · Jun 12, 2004

The door jam sticker that is on my 2004 330i that has 18s states 32 frt 38 rr for light load and 38 frt 46 rr for max load. I use 36 lbs front with my 225-40-18 Pilot Sports and 39.5 lbs rear with the 255-35-18s on the car. It is a matter of personal preference after you try a few different settings.

WilliamsGPE · Jun 13, 2004

Thanks for the replys. 40 is a tad harsh esp. on the s#itty LA streets I drive on. Maybe I'll just up the pressure when making a canyon or PCH run!

BTW I had wanted Mich pilot sports (huge F1 fan) but am happy the tirerack guy talked me into these eagle f1's. When warm they seem to claw into the pavement -- even with all traction systems off I have to get really angry with the throttle to squirm the back end.

MrElussive · Jun 13, 2004

Michelin Pilot Sport's are great tires, but the Eagle F1's are probably better. I wouldn't be surprised if the Bridgestone S-03 Pole Position's are better as well. Pilot Sport's are very over-rated, I think. They have great dry road traction, but they create a lot of road noise and they are only decent in the rain.

mscoins · Jun 13, 2004

MrElussive said:

I am curious what your basis is for this statement. The reason I ask is the 330s at the Performance Center driving school use them and they were excellent in the wet, especially on the skid pad.

MrElussive · Jun 13, 2004

mscoins said:

My basis is that they came with my car and I still have them after 10,000 miles on my car. When it's wet out, I can't do full throttle in 1st or 2nd gear, otherwise they slip and the traction control destroys my power (but keeps me on track as sometimes the rear end wants to swing out). Also when driving on the highways during the rain, my car hydroplanes if I'm going too fast (60+mph). The Pilot Sport's are also pretty noisy tires. I used to question why my car comes with expensive Pilot Sport tires (as opposed to cheaper S-03's for example), especially since all Nissan wants to do with my car (and the rest of their cars) is cut costs...I'm guessing Michelin just gives auto manufacturers a mad good deal to use their tires on their cars for reputation purposes or something along those lines.
Don't get me wrong, Pilot Sport's are GREAT tires, their dry road handling is great. They are stiff for nice handling and they provide really great traction under hard acceleration and braking. But they are responsible for a lot of road noise and they're only decent in the rain.
As soon as my Pilot Sport's wear down, I'm replacing them for Bridgestone Potenza S-03 Pole Position's. If you ask anyone else on the board who knows their tires (such as Akakubi, but I haven't seen him on in a while), the S-03's provide less road noise, better heat resistance, better dry-road performance, and killer wet road traction!

mscoins · Jun 14, 2004

I know this is getting off-topic, but I am curious to know how the Bridgestone Potenza S-03 compare to PS as far as longevity is concerned. My Pilot Sports seem to be wearing well at almost 6K miles. Anyone?

MrElussive · Jun 14, 2004

That's a great question. As for the Pilot Sports based on what I've heard/read, some people say they wear ridiculously fast and some people say they wear ridiculously slow so I honestly have no idea. I can tell you that I have almost 10K miles on my Pilot Sports (and my car) and they are still biting just fine...no signs of wear so far but as soon as I finish this post, I'm going to perform the penny test on the treads.

EDIT: Just did the penny test and the tires still have a good amount of tread left on the front and rear tires, and wear seems to be very even with the fronts and rears, which is really good. The car has 9,959 miles. Pretty good for max performance summer tires.

Tire pressure ? for aftermarket 330ci rims

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