I've heard different numbers about what PSI I should have in the tires. 32 driving? 40 when cold? Does it matter when I check if it's been sitting or if I drive it to a gas station? And what exactly is affected if I'm off?

Thanks.

 

32 all around will be fine

 

Tire pressure is a trade-off, no matter how you slice it.

Tires not only support the weight of the vehicle, they absorb shock, track through ice, snow, rain, gravel, etc.

Tires handle straight-line forces of acceleration and braking; plus, lateral forces involved with wind and cornering.

If you lower your air pressure - lower, not flat!!:
PRO
- better shock absorbing
- smaller diameter (better torque)
- more shoulder contact for loose surfaces (a beach?)

CON
- tire can be cut easier if you encounter a pot-hole
- tires squeak in cornering as the tread rolls
- tire can possible roll off the wheel in an abrupt maneuver
- tires wear out on the edges faster

If you raise your air pressure - within limits posted on the tire wall:
PRO
- better handling
- better gas mileage due to lower rolling resistance
- better chance of surviving a puncture on a pot-hole
- less chance of rolling off the wheel in an abrupt maneuver

CON
- ride is harsher
- tires wear in the center of the tread as there is less of the edge touching the pavement
- less traction is a low-friction environment (sand, show, gravel, etc.)

Other things to consider
- How do you drive?
- What is your regular driving enviroment like (hills, curves, straight, speed, etc.)

Personal observations
- I hit a pot-hole many years back and blew out both tires on the right side of an Accord that I had.... on a Sunday!
- I drive more agressively than most (I take corners faster.)
- The area where I live has quite a few curves in the road.


I haven't found the "sweet-spot" with my Fit yet. However, on CRX's that I have had, I ran 40 psi front, and 35 psi rear, and tire wear was very even. Honda recomended 28 psi f/r.

I'm planning on running 38/35 in my Fit for a while and see how it does.

 

I think that's where mine are right now, about 36 front and 33ish back. When I checked them before I started out on a road trip they were all at about 40 which surprised me cuz I know that when I first got the car the Honda tech put them at 32. So I dropped them a little before the drive.

I think I'll just try to keep them just below 35 from now on, but thank you for all those words of wisdom. I had no idea.