Truck vs RV Tires

Lovin Life · 10-20-2015, 09:21 PM

I am a newbie to the RV world, so please forgive me if I sound rather stupid! LOL

I don't like the way the RV "sways" or "wanders" around on the road. Have read many threads on doing the alignment, check correct tire pressure, add sway bars, rear trac bar, shocks, etc.

I just had the RV aligned at a local truck shop. He informed me that the alignment is fine, but the tires are feathering and squishy. Yes, he said squishy! He suggested that I purchase "Semi" truck tires not "RV" tires.

Not sure which way to go. This is a Ford E450 chassis. There are "adequate" shocks, bushings, sway bars, etc. on rig.

Not sure if you can help, suggest, or if anyone needs more information.

Thank you in advance.

**fhenn** · 10-20-2015, 09:27 PM

what does it say on the side walls P or LT Or ????

Lovin Life · 10-20-2015, 09:34 PM

On the pic i have, the tires are michelin load range E. the RV is still at the truck shop. Specs are useless.

**fhenn** · 10-20-2015, 10:43 PM

They should have a letter in front of the numbers, that is what I need. The second part of the question is what tire pressure are you running to low will give you that feeling

**EA37TS** · 10-20-2015, 10:54 PM

Since you have an E450 Chassis I am going to make a couple of points based on my experience with my Class C which was also on a 450 chassis.

I am going to guess your tires are Michelin LT 225/75R16. Those are the same tires on my Class C and I drove many miles on those tires with no problems what so ever. If the tires are LTX M/S LT 225/75R16 Michelin issued a recall for tires manufactured between 2010 and 2013. You need to check the date stamped on the tires to determine if they are subject to the recall.

On my Class C I did nothing to the suspension. Yes I did have some wind push but I did not have any tail wag or sway. One thing my Class C did have that Thor does not install are Ride Rite air bags on the rear suspension. It was nice being able to adjust the ride comfort with a couple of PSI up or down of air

Lovin Life · 10-23-2015, 11:25 AM

After speaking with Michelin, he suggested that i bring the rig to Discount Tires to see if the tires were on the recall list. I picked up rig from Truck shop and brought it to Discount tires. So happy that I did. All numbers corresponded to the recall list EXCEPT the DOT stamp. The truck guy said that the tire stamps were on the inside of the dual tires so he could not read it! Funny thing, the info was on the outside! The Discount Tire guy said that i had the best possible tire for this RV. He said that they were not really "feathering". The RV drove straight, Tires had proper air psi. After 6000 miles the tires needed rotating! that's all it needed! I learned more about tires, load, etc than i ever wanted to know! lol

Thank you all for your help!

On to the next project...which one shall that be? air bags? solar system? GPS system? too many to name! lol

blw2 · 10-23-2015, 07:23 PM

Did you base the "proper" tire pressure on actual weights?

I wasn't able to get the 4 corner weights on mine
but once I set my pressures based on the axle weights, according to Michelin's pressure/load chart.... I notice a marked improvement over the 80PSI original setting.

Lovin Life · 10-26-2015, 05:04 PM

blw2,
The RV is now in storage for awhile. I need to do research on where I can have it weighed near the house. Once I weigh it, i will try your recommendations.

I am also going to look into Ride Rite air bags for the back suspension, but i think there are a few different kinds.

blw2 · 10-26-2015, 05:52 PM

for what its worth....
based on my research, & talking with folks at Josams truck alignment shop
the problem with these E-series chassis won't likely be "solved" with air bags

the two issues that seem to be most prevalent are, in no particular order or ranking:

1) alignment - insufficient + caster angle - which is the angle that causes the steering to re-center.... lack of this is the dead zone or wander, and bump steering

There's a guy over on another forum that posts about using some aftermarket alignment bushings to push the +caster up.... I think his number was +5 degrees or more
Apparently the caster adjustment also affects camber, so according to the folks at JKosams it's a trade off I couldn't get that much caster out of mine as it is. Perhaps with the aftermarket bushings ( I think they are ingliss)

2) leaf spring system on the rear. The leaf springs allow side to side movement of the axle relative to to the frame - the wagging of the dog....
A panhard rod is apparently the fix here.

the steering stabilizers, particularly the safe t steer and similar, offer a benefit to counter blowout forces and bump steering, which i would assume would mask the caster issue but it really doesn't address the problem directly. regardless, I'm thinking these would be good to have for blowouts and lots of folks have posted improvement in handling from them...

The stiffer aftermarket sway bars, some folks have posted a perception that they have helped, but from what I can tell they are really better intended to resist leaning in turns.... which isn't really a problem I seem to have.... But I suppose they must serve to stiffen the suspension which must offer some folks help...

If I had the budget, I would like to install a safe t steer and a panhard rod

But my MH handles ok as it is.... not perfect, but ok. I just don't think i have a big problem with mine.

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