JustinTL

Hello everyone, Please help me to consider this.
I just put the 4 new Michelin Primacy MXV4 99H 235/55/17 on my car. and I don't know what proper air pressure that I should set for them.
the recommendation is 32psi. but because of the width and the aspect ratio is changed so I am a bit confuse.
I set them right now is 34psi. But I just feel a bit of losing performance (but ride quietly and comfortable)
Any recommendations guys?

Pete2010

It's probably just in your head - but if the tires weigh more, you'll lose performance. That PSI sounds right (make sure that is cold). Only when you go to low profile XL tires do you need to put them at 42PSI cold. That's what I do with mine.

I have to ask - why the change? Are those your winter tires?

Edward'TLS

Of course you're losing performance. You are losing lots of performance.

1st, MXV4 is a "grand touring A/S" tire, meaning crappy performance. Go for "high performance A/S" or "ultra-high performance A/S" tires for better performance.

2nd, the OEM tires for the FWD TL are "V" speed rated. The tire shop shouldn't have sold you the "H" speed rated tires due to safety reasons. V-rated tires have stiffer sidewall for higher speed, than the H-rated tires. Thus a drop in performance for your new H-rated tires.

3rd, going from 245/50/17 to 235/55/17 meaning that the new tires have a smaller contact patch and a thicker sidewall. This equates to degraded performance.

So your feeling of losing performance is absolutely valid.

JustinTL

thanks guy. I was force to replace it during heavy winter time. so there is no winter tires around. and I found a good deal with this michelin.so far the tires run smoothly and quietly on freeway so I feel quite ok. but I will plan to put on the set of Falken Ze 512 this summer. how is that?
i will go with the size 255/45 with wider tire and lower side wall, so also speed rate is W. and total is 500 bucks. so tempted to go with it,hihi

JustinTL

diameter is still 17