Community Forums

dhenning · 05-05-2011, 08:58 AM

My tires only have a maximum psi (65)cold. I'm trying to find the best operating psi?

Randy the sly old fox · 05-05-2011, 09:36 AM

Unless you can find the mfgs load/inflation data, or your TT mfg has a reccommended inflation - you should use the information on the sidewall of the tire - ie the max pressure.

dhenning · 05-05-2011, 10:12 AM

Thanks Randy

Techie · 05-05-2011, 11:38 AM

You'll also need to know the weight placed on each tire position & axle in order to adjust the PSI.

Automobilist · 05-05-2011, 11:59 AM

Here's the quick and simple method to check for proper operating pressure:

Get an infrared (IR) temp gauge at Sears, HD, etc. When the tires are warmed up from driving, take a tempurature reading at each tire tread outer edge, and in the center of the tread. (3 shots per tire) If the outer temps are hotter than the center, the tire pressure is too low. If the center temp is higher, the pressure is too high. General numbers are about 1-2 psi difference for every 5 F temp difference.

This procedure should take all of three minutes to accomplish. The IR gauge is extremely handy to have around as well.
For those interested in having their RV handle as well as it can, these numbers are very useful for correcting toe-in, camber, etc.

Ray,IN · 05-06-2011, 07:26 PM

If you have ST-Special Trailer tires they must be inflated to sidewall maximum. http://www.carlisletire.com/product_...are_safety.pdf Carlisle Tire(top page 2) thinks this is so important they void the warranty if operated otherwise.
Nearly all OEM trailer tires are operating withing 10% of their maximum weight rating, thus the sidewall maximum inflation recommendations.

RVNeophytes2 · 05-06-2011, 07:46 PM

Quote:

Originally Posted by Automobilist

Here's the quick and simple method to check for proper operating pressure:

Get an infrared (IR) temp gauge at Sears, HD, etc...

The result should be around 120F. According to another thread, damage may occur when the temp is above 180F.

I don't like inflating the tires to maximum: it is hard on the suspension, harsher riding, probably a greater chance of loosening your nuts. On the wheel, of course.

My hourly safety check is with an IR gage that cost me $15. I was 4 PSI low in a dolly tire, the temp registered 147F, compared to 120 +/- 10 on all the others.

wingnut60 · 05-06-2011, 07:53 PM

RVNeo--
Do I read you correctly that you stop hourly for a safety check?
Joe

FastEagle · 05-06-2011, 10:56 PM

Quote:

Originally Posted by dhenning

My tires only have a maximum psi (65)cold. I'm trying to find the best operating psi?

It's on your tire placard. It's also in your owner's manual.

FastEagle

Ray,IN · 05-08-2011, 12:25 PM

Quote:

Originally Posted by RVNeophytes2

My hourly safety check is with an IR gage that cost me $15. I was 4 PSI low in a dolly tire, the temp registered 147F, compared to 120 +/- 10 on all the others.

That alone is an excellent reason to keep ST tires inflated to sidewall maximum. Then there is the warranty issue.

Kurmudgeon · 05-09-2011, 01:10 AM

Quote:

Originally Posted by Ray,IN

That alone is an excellent reason to keep ST tires inflated to sidewall maximum. Then there is the warranty issue.

It's an even better reason to change to LT tires on your trailer. Even 120 degrees is and indicator that your tires may be overloaded. When I travel I periodically stop and check my tires. They are never more than warm to the touch. At 120 degrees, it would not be possible to keep your hand on them for more than about a second.

It had never occurred to me to use a laser thermometer to check my tires. Thank you for the suggestion. I'll throw mine in the truck next time I hit the road.

JP