Is there a point where too much tire pressure (within reason) will have a negative effect on mpg? I remember some people mentioning that going a bit above what the sticker recommends can help, but I figured I'd ask, even though the answer is probably yes.

My mpg had taken a slight drop (nothing huge but enough for me to notice) maybe a month ago even though my driving is generally consistent along. I couldn't really think of what had changed, though I realized that I did adjust the tire pressure, and it may have been on a hot day when it happened. So when I checked it at my next fill-up, it was 38 front and 35 rear, so I lowered it a tad and I've noticed that things are a bit better so far compared to before. So I suppose I have my answer (and I'll be able to verify it over the next tank or two), but I was curious if anyone knew for sure or if they had personal experience with a certain psi being the maximum before things deteriorate.

Just to throw it out there, I have a bone stock Evo IX SE still on the stock BBS wheels but with stock-sized Z1 Star Specs with 14k miles on them (but still a good amount of meat left), if that matters. Thanks ahead of time. And no, this is not an April Fools question.

 

To answer your question, no. More pressure = less rolling resistance = more MPG. However, consider the drawbacks with too much pressure - less traction, firm ride, uneven tire wear, unbalanced handling. Stick with the manufacturer's tire pressure recommendation label on the driver's door jamb (unless autocrossing or drag racing).

 

Hmm... well I guess I'll figure out if I'm just being optimistic or if I'm really noticing better mileage after a couple of tanks.

I know that 32/29 is recommended (if I remember correctly), but even when I had the stock A046s I had always gone with 34-36 front/31-33 rear.

Thanks for the reply.