Bias ply tires in "on road" appications

[KarlVP]

So, I got a set of maxxis creepy crawlers.

This is my first set of bias tires. I am wondering, for on road use, what PSI should I run them at. I started at 30, and have since gone down to 20.

I still can't get the full width of the tread to contact. About 1.5 inches on the outer lugs still isn't making contact with the pavement. Should I go down to 15 and keep trying to get the full contact area?

Hip said that on a TSL or similar you want only the middle of the tread to contact the pavement on road.


Just wondering.

 

[Toyotanut]

When I had my LTB's I aired them down to where I had a full contact pattern(bout 15psi) till I got to the trail then aired down from there. Of course without air I just drove back home on single didget pressure and then just aired back up.

 

[lethe]

i used to run my sx's at 14 psi on the street and still couldnt get full contact with the tread. with them aired down that low corners were really mushy and i was getting worse gas milage then usual. i just run them at 30psi now, it rides a whole lot better and i dont get flat spots sitting at a stop light

 

[Brian H]

The lower that you take down the pressure in the tire the hotter it will get.Bias ply tires can handle it but the bad part about lowering the pressure is when you go to drive it in the morning there will be one heel of a flat spot in the tire and it will shake the **** out of you until the tire warms up. The reason the tire crowns in the middle of the tire is just the way its made not much you can do to get away from that.

 

[skrause]

The bigger the tire, the lower the pressure it needs. It's all about the amount of surface area the air is pressing against. Flat spotting is a fact of life with bias tires.

 

[Berne]

Karl....

one other thing you might notice, is that the 'right' air pressure may change over time, especially w/ the creepy crawlers, as the tire breaks in...

I can tell you for sure (you saw them work on the comp jeep) that they are a pretty tough tire, and, especially when new, are stiff as hell....

 

[79chevy39.5's]

i drive my bias ply 39.5 tls's around town a little and to and from wheelin i usualy run them at what ever psi the sidewall has a smooth transition

 

[tomsbrokeagain]

with how much you street drive run um low enough to get full contact after all you'll be grenading that front diff the next time out and will be a pavement princess again.:fawkdancesmiley:

 

[03 CON]

Karl, I normally run my bias plys right around 15 on the road. More gets less flat spots, but only lasts about 2-3 miles anyway, seem to get the best wear at 15...

 

[wayne_fj40]

This is how I go with my swampers

Do you really need maximum load pressure?

Consider that standing flat and level (static), loaded the way you normally run is one thing. Now further consider you lose full tread width contact as the 4X cruises at higher and higher speeds. Centrifugal force tries to increase the diameter of the tread. You only have to look at dragster tires when they light 'em up to convince yourself of this tire reality. The sidewalls tend to hold the outer edges closer to their static diameter than the center of the tread and hence the center of the tread spins into an ever increasing diameter with increased speed. In other words, while moving at highway speeds, the tire is trying to run more on the center of the tread than the edge. That

 

[Long&Low]

One thing to check is to see how hot your tire gets when running that low on pavement.

With my rim size, tire width and height, if I run 15 or less on on paved surfaces for a while the tires get noticeably hotter.

Also check to seein gif your tires are bulging while driving right before the contact patch. That can add up to significant heat build up.