Lets talk Tire Pressure.... Yet Again

[TLeenhouts]

Okay, I'm probably talking oranges and potatoes here because I have a Class A on a Workhorse chassis. Tires are 245/R 19.5.
Had new tires on it when I bought it. With 36K miles on them, the tread was still about 90% there. Could not balance them. After checking, they were out of round by about 1.5 inches. Sticker by the drivers seat calls out 95psi. Manual calls out 85psi.
Started checking and found that the tire dealer was trying to sell me a tire that had a SPEED rating of 31 mph (B). Load range G.
I ended up with Kellys on the front, Load range G, speed rating (L) 75 mph and Falkens on the back, Load range H, speed rating (M) 81 mph only because they didn't have 4 more Kellys.
You have to check the speed rating as well as the load. A (B) rating is only sufficient for a delivery truck running around town, not highway speed all day.

[IDguy]

Been working on getting my TPMS to work right. It constantly alarms so I turn it off.

I seek 82 psi cold. I see it rises about 10 psi driving. I reset high alarm so remain puzzled why it complains.

[jadatis]

I am able to calculate a highest pressure, at wich comfort and gripp is still acceptable.
Because you had a blowout, and that is mostly courced by to low pressure for the speed and load, I think my answer will come above 80 psi at least for one axle.

And above 80 psi cold is not allowed anymore on an E-load tire ( or do you have F-load)

But then it would indicate that you better go for tires with higher maxload.

Need from vehicle next.
GAWR's , GVWR, configuration ( 2 axles I think, but rear Dual or Single load) , better those weighed axleloads, even better axle-end.

Then from tires next
Maxload or loadindex
Loadrange to determine pressure behind AT is called reference-pressure.
Speedcode or max allowed speed of tire.

I know, you did that routine, but I pigheadedly think I can do it better.

After that I can yudge better if you can go higher.

[jgwmjw2]

[QUOTE=Long & Winding road;297322]Lets talk tire presure .... Yet Again.

Let's NOT talk tire pressure again, OK? Everything there is to know has already been written on tire manufacturer's websites.
1) The pressure on the decal is a close approximation.
2) The number on the tire is the maximum rating for the TIRE, not the recommended pressure for the coach.
3) Weigh the coach and use the tire companies pressure tables to be exact. Companies are legally liable for incorrect information.
4) Ignore the opinions and folklore of the internet "experts."

[Pete'sMH]

[QUOTE=jgwmjw2;298375]

Originally Posted by Long & Winding road

Lets talk tire presure .... Yet Again.



Let's NOT talk tire pressure again, OK? Everything there is to know has already been written on tire manufacturer's websites.

1) The pressure on the decal is a close approximation.

2) The number on the tire is the maximum rating for the TIRE, not the recommended pressure for the coach.

3) Weigh the coach and use the tire companies pressure tables to be exact. Companies are legally liable for incorrect information.

4) Ignore the opinions and folklore of the internet "experts."

X2!!

[Bill Johnson]

Originally Posted by HMCSW

So you have the about the same psi as my 30,000 pound Diesel Pusher. I stick with the manufacturers charts.

My manufacture chart shows that my motorhome max weight GVWR is 20,500 pounds. Using the sticker on the wall 83 pounds Goodyear says these tires will carry 21,280 and at 110 lb they will carry 26,720 why would I second guess the manufacture? If I'm over that I'm possibly over weight for axles and everything else

[HMCSW]

Originally Posted by Bill Johnson

My manufacture chart shows that my motorhome max weight GVWR is 20,500 pounds. Using the sticker on the wall 83 pounds Goodyear says these tires will carry 21,280 and at 110 lb they will carry 26,720 why would I second guess the manufacture? If I'm over that I'm possibly over weight for axles and everything else

I am in agreement: go by tire manufacturer chart for pressure. They actually know what they are doing. The tires can carry the weight but the RV chassis in not designed to go over 20,500.

[Bill Johnson]

Originally Posted by HMCSW

I am in agreement: go by tire manufacturer chart for pressure. They actually know what they are doing. The tires can carry the weight but the RV chassis in not designed to go 20,500.

[lwmcguire]

I would be considerably more concerned about overloaded or under inflation of my tires than a slight encroachment on GVWR

Tire charts are a great tool and a solid reference

As the driver you determine your situation

For example , you are traveling across the Midwest on a 100 degree day traveling on 150 degree asphalt with a 30 mph crosswind

Anyone routinely traveling the Midwest has done this more than once

This is the time to be monitoring the tire temperatures closely or you might contribute another gator to the intestate

It isn't the time to be marginally inflated either

[Bill Johnson]

Originally Posted by lwmcguire

I would be considerably more concerned about overloaded or under inflation of my tires than a slight encroachment on GVWR

Tire charts are a great tool and a solid reference

As the driver you determine your situation

For example , you are traveling across the Midwest on a 100 degree day traveling on 150 degree asphalt with a 30 mph crosswind

Anyone routinely traveling the Midwest has done this more than once

This is the time to be monitoring the tire temperatures closely or you might contribute another gator to the intestate

It isn't the time to be marginally inflated either

That's why everyone should have tpms, they can monitor tire pressure and temperatures. I was traveling through Iowa at 75mph at times on a 95 degree day without any problems. Without tpms we never know what is going on

[gte534j]

Originally Posted by Bill Johnson

That's why everyone should have tpms, they can monitor tire pressure and temperatures. I was traveling through Iowa at 75mph at times on a 95 degree day without any problems. Without tpms we never know what is going on

Totally agree on the tpms especially if you have a trailer. You can also test the blow out function on the tpms by unscrewing the monitor on the valve to simulate sudden loss of air pressure.

[Scubawise]

Hi front set 75 psi rear 80 psi cold..with tpms start some read lower? Driving hours they read a little higher?

[Bill Johnson]

Originally Posted by Scubawise

Hi front set 75 psi rear 80 psi cold..with tpms start some read lower? Driving hours they read a little higher?

Yes very much so, I watch the pressure and temperature and nothing is anything near abnormal, my old motorhome on the 450 chassis would increase temperature and pressure much quicker. If everything stays within manufacturer specifications I'm keeping my tire pressure at the recommended settings, I'm not going to increase pressure because someone on a forum thinks it's better

[Hooligan2]

Originally Posted by Long & Winding road

THat has to be Wrong.....Most Class C's show around 75 psi. If they said 70 I might try it but 60 has to be wrong IMO.

Waynetaylor55 has a class C on 225/75R16 tires.. Chart shows pressure range from 50 to 90 psi depending on the load. 16 inch tires on my Sprinter based RV , placard calls for 61psi which agrees with chart for my Fully loaded RV I am within 300 lbs of max.

For OP -- You varying tire pressure by so few pounds will not usually show any change in ride or wear.

[Scubawise]

I keep it based on driver tag 75 from 80 rear 16 inch

[airforceret]

I've always run max psi imprinted on the tire. Over 250,000 miles traveled in various rigs (most with those dreaded China bombs) and my flats have consisted of a cut valve stem, 2 nails, the metal bracket from the POS mud flap, and a curb.

[16ACE27]

Originally Posted by airforceret

I've always run max psi imprinted on the tire. Over 250,000 miles traveled in various rigs (most with those dreaded China bombs) and my flats have consisted of a cut valve stem, 2 nails, the metal bracket from the POS mud flap, and a curb.

And compressed spine vertebrae.

Max tire PS{ is great for travel trailers; not so much for motorhomes.

[Bill Johnson]

Originally Posted by 16ACE27

And compressed spine vertebrae.

Max tire PS{ is great for travel trailers; not so much for motorhomes.

Right, I couldn't imagine putting 110 pounds in each tire. That would be way over the axle capacity and everything on the motorhome, why would I want to be beat to death by my tires for no reason. Raising the air pressure isn't going to make a e450 chassis into a f53 chassis or f53 into a freightliner. Overloading the chassis and raising air pressure in the tires doesn't make sense to me

[Pete'sMH]

Agree. My sidewalls say 110 max. My yellow sticker says 92 all around and my pressure/weight tables say 85. I run 90 or a bit less.

[airforceret]

Originally Posted by 16ACE27

And compressed spine vertebrae.

Max tire PS{ is great for travel trailers; not so much for motorhomes.

I run max PSI on my motorhome last 5 years and nearly 40,000 miles and no issue. If it rides rough it's because your suspension needs work, not the PSI in your tires. I had spring work done on mine by a professional company and it rides fine. For a premium ride you need to go air ride. It's a big truck with a box on it so you have to treat it like one.