Tire Pressure 2010 32BA

[Topcat95]

32BA owner that can give me some help with recommended psi for Michelin XRV? Red Bay says 105-110 (rated at 110) tire shop ay 95? F53 chassis

[allegro1x]

I usually try to keep my tires at 100 and haven't had any problems. Max on side walls is 110. Always check pressure before you head out, especially if you haven't driven MH for several weeks. Dave

[luvlabs]

I would say that both of you have your tires over inflated for the load you are carrying. The result is that your ride will be hard and somewhat unsafe because your actual contact surface with the road is reduced. Tire pressures are determmined by the weight the tire carries - not what the tire shop guy says, not what the sidewall says, and not what Tiffin says. Weight determines everything.

You need to get to a scale and get your coaches weighed before you determine what your correct tire pressures are. Check your local truck stops for CAT scales, leave your toad unhooked, and spend the 10 minutes and $10 to get your axle weights.

Once you have those in hand, add 5% to each axle weight to allow for side to side differences (you can get 4 corner weights later) and then look that weight up in the Michelin tire charts (available online). Use those tire pressures + 5 psi (safety factor). I think you will find that your front pressures will be 90-95 psi and your rears around 85 psi and your coach will ride and handle much better.

[Calliedo02]

what luvlabs said. Weigh the coach at a gas station CAT scale when fully loaded for a trip.

[Tireman9]

What Chuck in Houston says


Based on data I suggest you use 47/53 to 45/55 weight split if you only get the total for an axle. Few RVs have any axle at 50/50 side to side load split.

Use the heavier end load figure when you consult the Load/inflation tables to learn the MINIMUM CIP for the tires on that axle.

I suggest you add 5% to 10% to that minimum CIP as long as you don't exceed the max for the wheel. This will save you the hassle when the morning temperature changes which will affect the CIP by 2% for each 10F change in temp. But if you have the extra margin you don't need to worry. If you choose to set your CIP right at the minimum needed then whenever the temperature drops you will need to add air. Your choice.

All tires on an axle should have the same inflation +/- 2 psi or less variation if you have a good digital gauge.

[allegro1x]

Concerning my post about tire pressure - I have also up graded my suspension - bigger front sway bar and additional sway bar behind rear axle with a trackbar. My tire pressure info wasn't from tire guys, I had my frontend aligned at a big truck shop (dump trucks and 18 wheelers). We usually don't go out for more than 2 weeks at a time, so we aren't really loaded down to much. Probably as many opinions about rving as they are rv's out there. Dave

[Mr_D]

Originally Posted by allegro1x

I usually try to keep my tires at 100 and haven't had any problems. Max on side walls is 110. Always check pressure before you head out, especially if you haven't driven MH for several weeks. Dave

The pressure shown on the side of truck size tires is NOT the maximum the tire should have when cold.
It is the MINIMUM pressure when cold to support the MAXIMUM rating of the tire.

[TimLoon]

On my 2004 Workhorse 32BA, I weighed front and rear of coach. Then called tire manufacturer, Hankook and they emailed me the chart for my tire size. I ended up with 90 on the fronts and 85 on the rears. For the two years these tires have been on, the pressure has never changed. Took it in for a servicing this spring and on way home I thought my teeth would fall out. Technician set the pressure at 110. Wow, that was harsh.

[skypilot_1]

Originally Posted by Mr_D

The pressure shown on the side of truck size tires is NOT the maximum the tire should have when cold.
It is the MINIMUM pressure when cold to support the MAXIMUM rating of the tire.

Wow, I've seen some miss information on the internet, but is the grossest and most dangerous by far.
http://www.tirerack.com/tires/tirete...jsp?techid=196

[skypilot_1]

Originally Posted by skypilot_1

http://www.tirerack.com/tires/tirete...jsp?techid=196

Technically that is correct...but misleading. As tire's maximum inflation pressure is the highest "cold" inflation pressure that the tire is designed to contain. So by calling it "minimum" implies in could be exceed.
My concern would be that someone would think they could increase the tire stated pressure when told its a minimum.

[Tireman9]

I also covered this specific question on July 3 this year on my blog on RV tires.

See the link in my signature

[lanerd]

Tire pressure has nothing to do with make/model/upgrades of/to the rv. It has everything to do with the size of the tires and the weight applied to them.

Therefore the only true way you can determine the tire pressure required is first to find out the actual weight on the tire and then look up the tire mfg'ers weight/pressure table and find the correct pressure for your size of tire.

Ron

[Mr_D]

Originally Posted by skypilot_1

Wow, I've seen some miss information on the internet, but is the grossest and most dangerous by far.
http://www.tirerack.com/tires/tirete...jsp?techid=196

Sorry but I'm going by the PUBLISHED DATA from the actual tire manufacturer!

The pressure on the sidewall of a Michelin RV tire and many others is not the "Maximum" the tire should ever have (unlike car tires) it is the minimum to support the maximum rated carrying capacity of the tire.

From page 2 of the 06/07 Michelin RV Tire Guide:

"If you look at the tire's sidewall, you'll see the maximum load capacity allowed for the size tire and load rating, and the minimum cold air inflation needed to carry the maximum load."

From page 6 of the GoodYear RV Tire and Care Guide:

"How much air is enough?
The proper air inflation for your tires depends on how much your fully loaded RV or trailer weighs. Look at the sidewall of your RV tire and you’ll see the maximum load capacity for the tire size and load rating, as well as the minimum cold air inflation, needed to carry that maximum load."

From TOYO:

Q: What are the consequences of inflating the tires to accommodate the actual loads?
A: If the inflation pressure corresponds to the actual tire load according to the tire manufacturer’s load and pressure table, the tire will be running at 100% of its rated load at that pressure. This practice may not provide sufficient safety margin. Any air pressure loss below the minimum required to carry the load can result in eventual tire failure.

But then they go ahead and publish a weight/pressure chart allowing lower pressure for RV's!!

From the August 2010 Motorhome Magazine "Tread Carefully" tire article:

The maximum load capacity allowed for the size tire and load rating and the minimum cold air inflation needed to carry that maximum load are located on the tire’s sidewall.

So, when you can get the tire manufacturers themselves to change their statements then I'll listen to you, otherwise I'm sticking by what they publish in their literature and magazine articles.