Tire pressure on motorhome

[sanrus]

tire pressure on tires are at 90 psi and should be at 105, it is 22 degrees outside here in Michigan. We are ready to start out for Texas Monday the 27th.
should i add the extra air or will they increase as they warmup. They are 221/2 in. on a 40ft. 36,000lbs CC affinity. Any help? Coach has been sitting for a few months on roadgravel?

[Dirtbuster]

Always check your air before starting any trip. Add air if needed. You will gain a couple of PSI once hot, but not much more.

[DriVer]

Originally Posted by sanrus

tire pressure on tires are at 90 psi and should be at 105, it is 22 degrees outside here in Michigan. We are ready to start out for Texas Monday the 27th.

Are all the tires the same pressure on the same axle? 90 PSI in or itself is not devastating and you should be OK to run with what ya got. Do you have a TPMS? That will help you keep an eye on the pressures as you are going down the road.

The correct process would be to inflate to 105 before you leave since you'll probably be running in cooler weather for a couple of days. In Texas it was reported to have been in the mid-seventies. Once you get down there for a few days you might wind up with more air than you need.

[Pairajays]

You will get a lot of conflicting information on this subject. I used to adjust my tire pressure compensating for ambient temperature. There are several charts that gives guidance for this method. After discussing this subject on several forums and getting different opinions, I contacted several tire manufactures and asked what the correct procedure was. Without exception, they all said keep the pressure as recommended for the load on the tire, irregardless of temperature. For example, if your tires require 105 psi then that is what they should be if the ambient temperature is 60 degrees or 80 degrees.

Jim

[B Bob]

If it were me I would add some air to the tires to bring up pressure to what it is supposed to be. Then check after and hour or two and if you go way above your target pressure let some out. My guess is that since you will be in the cold for a while you will need extra air till ambiant temps go up.

[bdpreece]

Add air now and as you get to warmer climates check the tires when cold and adjust accordingly.

[sanrus]

thanks, i guess i'll be adding air to the tires before i leave. thanks again

[bdaball]

I assume 105 is what your charts say for front and rear axle both,(?)

Based on our last departure in below freezing weather and heading to warmer climates I would not add air. I think you will be surprisd how much they "warm up".

Having said that. I can't overstate the importance of a TPMS to monitor same. I use a TST system but you can search all day long on which brand is for you.

Happy Motoring!

[Bay37QSB]

Originally Posted by Dirtbuster

Always check your air before starting any trip. Add air if needed. You will gain a couple of PSI once hot, but not much more.

Last summer we were seeing 15-18 psi increase in the tires from cool morning temperatures to 8 - 10 hours on the road when it was 85+ degrees out.

[offthewall]

Originally Posted by sanrus

tire pressure on tires are at 90 psi and should be at 105, it is 22 degrees outside here in Michigan. We are ready to start out for Texas Monday the 27th.
should i add the extra air or will they increase as they warmup. They are 221/2 in. on a 40ft. 36,000lbs CC affinity. Any help? Coach has been sitting for a few months on roadgravel?

I would bring the pressures up to 105 when the tires are cold regardless of the ambient temp. The next morning, when the tires are cold, check again and adjust to 105 if required. NEVER let air out of a warm tire.

[Elkhartjim]

Originally Posted by offthewall

I would bring the pressures up to 105 when the tires are cold regardless of the ambient temp. The next morning, when the tires are cold, check again and adjust to 105 if required. NEVER let air out of a warm tire.

...never, never, never, let air out of a warm/hot tire. Only check and adjust pressures on cold tires.

[a k]

Ok, how about this. My rims are only good to 130lbs. I set my tires at 120 and ten miles down the road they are reading 140. Now what? Plus the tires say do not exceed 130 lbs. what to do what to do. 'm going crazy. Does that mean I can carry a heavier load when hot?

[offthewall]

Originally Posted by a k

Ok, how about this. My rims are only good to 130lbs. I set my tires at 120 and ten miles down the road they are reading 140. Now what? Plus the tires say do not exceed 130 lbs. what to do what to do. 'm going crazy. Does that mean I can carry a heavier load when hot?

The tire max pressure is the COLD max pressure. If they are spec'd at 130 COLD, they are designed to hold higher pressures when warmed up. NO, you can't cary more weight when hot.

[a k]

What about the rims?