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-   -   Best tire PSI for street radial tires? (http://www.hotrodders.com/forum/best-tire-psi-street-radial-tires-181223.html)

elano 07-17-2010 06:49 PM

Best tire PSI for street radial tires?
 
I just mounted some pretty wide bfg 295/50/16s on a pair of 16x8 wheels. What's the method for figuring out the corect psi? For even tread wear more than traction I suppose. A friend told me to pull through some water and look at the patch but I'm not really sure what to look for. Had 30psi in them, now 27 and not really sure if I should go lower. MAX psi on them is 35.

72highboy390 07-17-2010 07:07 PM

32 psi will be good

Ford Junkie 07-17-2010 07:59 PM

tread wear is not going to be good with 11 1/2"s of tire on an 8 in wheel if my conversion of 295 width to 11 1/2 in. is correct. Looks good but wear suffers greatly, I have worn several sets out this way and they refuse to wear even as the sidewall wants to straighten at highway speeds which makes the center of the tire carry the load.

tire psi will have to be determined by how heavy the vehicle is. No real way to figure this other than the contact patch on the pavement. Run it through some water as stated to make sure all of the tread pattern is evenly hitting the road.

HTH,
Tony

elano 07-17-2010 11:54 PM

Dang. Well what would be the best PSI for traction then? lower or higher?

Also when I roll through the water, do I want to look at the wetness of the tire tread or the print it leaves? Also how far to the edge of the tread do I want? The tread seems to kind of taper off on the edges.

Ford Junkie 07-18-2010 05:24 AM

Same test for traction. Unlessss your doing a burnout before hand if so then you'll have to drop the pressure some as it will increase with heat from the burn out.

You don't want hte rolled edge sitting on the pavement very much maybe 1/4" or so.

sqzbox 07-18-2010 08:30 AM

On low pro tires, look at the max pressure rating and start at 5-6 lbs less that the max rating. You have to consider tire temp as pressure will rise when hot and decrease when cold. Ride quality will also be effected by pressure. Some have even gone to nitrogen gas to keep pressure even at all temps. Nitrogen also works on air shocks and air ride suspension.
When you do the wet tire test, do it cold and hot and check for any difference.
This will show you the best over all pressure to run or if you got it right. :D

cucumber1949 07-18-2010 08:59 AM

The way that seems to work best for me is that when I have the car up on the 4-post lift, I raise the lift to bring the tires up to my eye level, get behind the rears and look for the full width of the tread to contact the lift ramp. I deflate the tires a little, and then slowly inflate them a step at a time until the sides want to lift off the ramp, take out a pound and call it done. Remember, as you start to drive the vehicle, the pressure will rise slightly due to the tire warming up. This works out to be 14-15 lbs on the rear of my T, 26 lbs for the fronts. When I had the super wides on the back, it was 9 lbs. My tires wear evenly and the car handles well. Of course you don't need a lift to do this, but I'm getting older and stiffer LOL, and my car has yet to be driven through any water, intentionally or otherwise :-)


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