Tire Pressures?

[OrangeRevolution]

I have an '09 Fit Sport. What kind of tire pressures are you running? Earlier years responses would still be useful.

Honda specifies 33 psi all around on my car. This seems ludicrous considering the VERY heavy front weight bias. I think Honda is doing this to keep things simple/stupid and for the (ridiculous) TPMS. I've found the factory-recommended tire pressures to be way off for every Honda I've owned, so yes, I'm saying I don't trust Honda for optimum performance/tire wear.

For example, some quick checks of the rear tires show tire temps much hotter in the center. I've already dropped the rears 2 psi (the centers are still high) and will probably go 4 psi lower.

What are you track junkies running out there (and under what conditions/with what tires)? TIA!

[MINI-Fit]

Depends on what you want.

For street use-

34 to 36 psi front and rear is fine. If you have higher temperatures in the middle tread then let out some air.

38+ psi if you do commuting and want a little better mpg but harsher ride and more wear on the center tread.

For performance driving you can try slightly higher psi in the fronts just so that the tire doesn't roll over as much but the actual performance and psi will vary with which tire you have (stock vs other performance tire) and your driving style and event surface/layout.

Also, your suspension settings and alignment allow you to use more or less of the tires. Stock suspension and alignment is lacking. Upgraded and lowered suspension with camber kit in front will help make better use of the tires.

Don't run the psi too low- more rolling resistance and you'll wear out the shoulder tread faster which is already the tendency with any front wheel drive car.

[OrangeRevolution]

Thanks a bunch, MINI-Fit. (er... mahalo!) Sort of confirms what I had thought. I have some lower-profile "max performance" tires on order (which also have a higher load rating), so it looks like I'll be playing around a bit. The tires should have considerably less roll over than the factory all seasons. I was more wondering if the pressures would be too low to start hitting the blasted TPMS. Good to know mid-30's +/- is what you're running. I do plan suspension mods since the stock is kinda sloppy with a lot of body roll. The car is for street use (other family users), but I will drive it too, and I drive rather hard. I don't care about maximizing gas mileage -- mostly traction, safety, and reasonably even wear is what I'm after.

P.S. Looks like you're having some fun in your BOM Fit in your signature pics!

[dank24]

A lower profile tire will hold more lbs of pressure. I am running currently 45psi front and 40psi rear. No problems yet, just feel the road a bit more.

[Jodele]

When I bought my 07 Fit, I got the 16” accessory wheels with it. I demanded to get the recommended tire pressures for the 16” wheels. I did not get a response from the Honda dealer that made any sense... so, I reported this to the DOT and a response from the Honda Engineers came within 2 days!!!!!!!!!

33-psi front
30-psi rear

Right from the horse’s mouth…

The sticker on the B pillar says 33-psi front and rear…for the stupid people.

[SHG_Mike]

What are you looking to use your car for, or more importantly what are you trying to achieve with the pressures?

For performance goals you want the lowest PSI in the front that will still hold the sidewalls stiff (ie. if your folding over the side walls and rubbing the lettering off you need more pressure) and then in the front you will want 3-4 psi in the rear higher.

last i was out i ran 29F 37R tires were Kumho V710

[Jodele]

You are almost correct…

To get the best performance (stick), you want the most consistent contact patch, i.e. contact pressure. A tire that is consistently under inflated will ware out the outside edges of the tire tread (under the side walls) because the sidewalls are supporting the car. A tire that is consistently over inflated will ware out the center of the tire tread just like a balloon. Neither one of these conditions will give you optimum performance because one portion of the tire tread is loaded higher (and therefore over heating) than another and therefore that portion of the tire will lose traction before the other…I think that you can figure out that that is not optimum. The only way you can test to see if your tire is correctly inflated, is with a pyrometer (tire temperature gauge). Watch Formula 1 sometimes and you will see the suspension and tire engineers carrying one all the time. It is that important. The old ones used to use a needle to stick a probe down to the cord of the tire (through the tread of the tire). The new ones use infra red light to read the temperature. The light ones are also give you instantaneous readings.

If you have handling problems (over steer or under steer) and you need to fine tune your handling characteristics because you can not adjust your suspension properly (read this as a last resort), you can adjust your tire pressures to get the desired characteristics at the cost of tire ware and traction due to localized over heating of the tread.

If you don’t own a pyrometer, you’re not qualified to make haphazard tire inflation pressures like you did…

[SHG_Mike]

i wouldnt say you cant mess with tire pressure if you dont have a pyrometer, the method i described was the easy free way of finding a better pressure, i dont think hes looking to spend 100 bucks to get the perfect temp tires on the way home from work, I think he was looking for a general rule of thumb

[Type 100]

Went to a trackday the past Saturday. 37F/32R on Toyo Proxes 4s. At my size (205/45R16), the Toyos are reinforced so they need 5 psi more air.

[Sugarphreak]

Rule of thumb is usually add 10 psi for the track; then make adjustments on each run as necessary. The tires will heat up significantly after your first run so you will have to bleed them back.

If you are talking about driving on the street, I usually run around 35psi gives a nice all around responsiveness depending on what kind of tire you use.