tdcalhoun89

May be a silly question, but it's something I thought of the other day. Since putting on larger wheels and tires on my Mustang, wouldn't the optimal tire pressure change with the width of the tires/wheels?

I'm sure it wouldn't change that much, maybe one or two PSI. Anyone have any ideas about this?

I have 17'' x 9'' wheels and 275/40 tires.

cliffyk

It does, however modern radial tires are much more insensitive to inflation pressure than were older radial and bias ply tires--this has been in part engineered into them as very few people actually monitor their tire pressures with any regular frequency. So you need to find your own "sweet point" where treadwear and performance cross.

Right now I have 275/40-17s on the back at 28 psi and 245/45-17s on the front at 32, after 6k miles or so on these tires the traction in he back-end, handling up front. and treadwear¹ is what I would expect so that's where I keep 'em...

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¹ - I run at the high end of the recommended camber up front, -1.3°, which causes accelerated wear on the inner edge of the tires. It also greatly reduces understeer and plowing in turns. The GoodYear store where I get my alignments and tires mounted never fails to mentions this, I have to tell them at each visit that "If tread life were my major concern I would drive a Corolla."

69MustangCoupe393cid

275/35/18, 38 up front 36 out back. Less than that I was seeing wear on the outside of my tread. Winter tires 225/50/17 I run 30 up front and 28 out back, might even lower the rear more because I was getting center wear still. It depends on the tire too, some tires have a very stiff center block and can take more pressure and not wear bad. It's more trial and error, every car is different.

TRUEBLUE3934

I was running 36psi front 35psi rear when I had the 275-40-17 on all four corners.
I guess I am one of the rare guys who checks tire pressure every week or so.

uberstang1

I run my current tires 10 psi out back.

tdcalhoun89

Thanks for the information cliffy. I'm not concerned about tire wear or gas mileage. I'm running -1.5° up front. I've been keeping them inflated around 33° psi. Seems to working well, so far. My new tires haven't seen too much mileage yet though.

Trueblue, you're not the only one who does. I check mine every time I get gas or weekly, which ever comes 1st.

Uber, for some reason I feel like you have a slightly different set-up than me... You're probably getting ready for that IRS swap, right?

uberstang1

Were are no longer friends, but since were talking about getting stuff ready.......