Tire Advice Please!

[Diesel_d66]

got the Michelin pilot sport AS3 mounted Monday and they feel great! very little road noise, excellent grip, less tramlining, and less bone shaking when hitting those speed bumps or pot holes.

whats the proper PSI for these michelins? IIRC, the manual says 33 front and 38 rear but I think those are run flat numbers.

[Lucky1]

I think the Michelin Pilot Super Sports are probably a lot more comfortable than you'd think because they are softer than some of the ultra high performance tire alternatives. I can attest that they have both loads of grip and long tread life! Worth considering IMO. Be forewarned though, when going from RFT to non-RFT you may find the chassis and suspension overall feel softer because they were designed for a rigid tire.

I'm debating MSS on my Z4 M but I'm actually worried it might soften the ride too much and since its my summer sports car I don't necessarily want to soften it up.

[Lucky1]

Originally Posted by Diesel_d66

got the Michelin pilot sport AS3 mounted Monday and they feel great! very little road noise, excellent grip, less tramlining, and less bone shaking when hitting those speed bumps or pot holes.

whats the proper PSI for these michelins? IIRC, the manual says 33 front and 38 rear but I think those are run flat numbers.

You should use the PSI recommendations listed on the sticker on the bottom of the driver side door frame. I usually add an extra 2psi on top of that personally. The number should be the same for any tire make as long as you bought the same size tires

[Hawkeye]

Originally Posted by Lucky1

You should use the PSI recommendations listed on the sticker on the bottom of the driver side door frame. I usually add an extra 2psi on top of that personally. The number should be the same for any tire make as long as you bought the same size tires

This is definitely not true. Each type of tire takes different pressures. I would look up the recommendations from the tire manufacturer itself. It will give you the PSI recommendation based on the tire, size and load.

For reference my truck recommends 32psi (factory tires) but the slightly larger LT rated tires I put on recommend 45psi. Quite the difference and because of the type of tire (LT vs 4 ply). I would expect the Run Flats to be different as well since they are a different construction than a traditional tire.

[Diesel_d66]

The tire rack sales rep I just talked to said try 36 for front, 42 for rear.

[Diesel_d66]

Along with the tire mounting I also got a full roter and pad replacement. So now my brake pedal is a little mushy. I felt what I can best describe as bubbles or pops in the breaks on the 2 day of driving. Any advice on what this could be? I had new break fluid less than a year ago so the fluid was replaced with the breaks.

[Steeler]

Originally Posted by Diesel_d66

Along with the tire mounting I also got a full roter and pad replacement. So now my brake pedal is a little mushy. I felt what I can best describe as bubbles or pops in the breaks on the 2 day of driving. Any advice on what this could be? I had new break fluid less than a year ago so the fluid was replaced with the breaks.

Needs bleeding more.

[Hawkeye]

Originally Posted by dbarton62

Needs bleeding more.

Yup - I'd say they didn't bleed the line enough. Take it back to whoever changed your brakes.

[Huz-Z]

Now this is weird. Yesterday, I used the chat feature to talk to a rep at Tire Rack about my Michelin Pilot Super Sports that I bought from them last summer. The rep that I chatted with advised me to inflate per the sticker on the door frame.

[Lucky1]

Originally Posted by Huz-Z

Now this is weird. Yesterday, I used the chat feature to talk to a rep at Tire Rack about my Michelin Pilot Super Sports that I bought from them last summer. The rep that I chatted with advised me to inflate per the sticker on the door frame.

Yes and here's why I believe that is correct as a guideline. Tires have a maximum amount of pressure they can hold and it is different for each tire. But your car's chassis and suspension are designed for a certain tire size at a certain psi. If you changed tire sizes or tire classes I could see this guideline being less meaningful but if you keep the same tire class and size you shouldn't deviate significantly from BMW's guideline if driving on the street most of the time. +2 PSI over recommendation seems to be the most common approach I've seen on forums and works well for me also. I followed this model even when I switched from RFT to non RFT because the chassis was meant for a harder tire but by putting on a softer tire the chassis got a bit sloppy and so did the steering. 2+ PSI helped compensate for that.

[Huz-Z]

Originally Posted by Lucky1

Yes and here's why I believe that is correct as a guideline. Tires have a maximum amount of pressure they can hold and it is different for each tire. But your car's chassis and suspension are designed for a certain tire size at a certain psi. If you changed tire sizes or tire classes I could see this guideline being less meaningful but if you keep the same tire class and size you shouldn't deviate significantly from BMW's guideline if driving on the street most of the time. +2 PSI over recommendation seems to be the most common approach I've seen on forums and works well for me also. I followed this model even when I switched from RFT to non RFT because the chassis was meant for a harder tire but by putting on a softer tire the chassis got a bit sloppy and so did the steering. 2+ PSI helped compensate for that.

Thanks, that makes sense. I'll give it a try. I may elect to go back to the psi recommendations on the door frame sticker. If I do, it won't be because your idea isn't a good one - its a great one. It will be because the streets here in St. John's Canada are simply THE WORST in all of North America, and I'd worry about rim/tire/suspension damage if the pressure is too high. Even driving around in my X5, its a constant symphony of bump bump bang, sudden slalom around a huge pothole, car weaving side to side over the uneven road surface, bump bang etc. All this while I serenade with words that can only be represented by pressing the caps lock key and using the top row of the keyboard. I imagine you get the idea!