Had tires rotated in December and they were inflated at the time. Checked today for the first time, and they're at 40psi.... Too high?

 

Whats size, maker, model tire and Driving preference?

 

Maybe not. It's probably below the max pressure for the tire so it is safe. You'll get better tire wear but you may feel like the ride is too stiff. If so, drop the pressure a few and try again. I wouldn't go below 33 or so. I run my Conti ExtremeContact DWS at 35.

 

Stock size, BF Goodrich A/S super sport. Feels fine - Max is 55psi.

 

Then leave them at 40 psi. They certainly are not over-inflated.

 

Thx for the advice!

 

Manufacturer recommended max psi is 50.

If your tires are wearing on the outside add PSI

If your tires are wearing on the Inside leave at 40.

If you care about MPG add PSI.

If your have too much body roll add PSI.

If the ride feels bumpy, leave at 40.

 

Check you tire label on pressures, last time I checked ir was 32 psi.

Also there are tutorials on how and when to measure tire pressure.

Normally you need to measure the pressure when the car has been at rest for a couple of hours. The tires pick up as much as 4~6 psi while on the road and depending on outside temperature.

You can read 38~40 psi on the tires if it has just been minutes after you have ran your car on the highway and/or heavy stop and go traffic..

I normally measure mine 1st thing in the morning. That's the true reading and it should be 32 psi.

Cars with regular air will lose 1~2 psi every 2~3 weeks. Cars with Nitrogen will not lose air pressure.

Hence I check air pressure every 2 weeks. And true enough I add air, 1~2 psi to keep it @ 32.

 

Any vehicles tire pressure labels from the vehicles manufacturer are really valid only for the original fitment tires. And, they represent a compromise between tire wear and ride quality/handling. Stay below the Max psi on the sidewall (and the load - est. by vehicle loaded weight distributed over the 4 tires) and you'll be fine. Most tire places send you out the door at 40 psi because you are less likely to come back complaining about cupped tires, etc.

40 psi is fine as long as you don't mind the stiffer ride. Plus, you are less likely to overheat the tires compared to the lower psi's that manufacturers like. They like the lower psi's because they ride better and can sell more cars. On big touring bikes I've stayed close to sidewall max psi for years, just to get the best tire wear.