96' Tourmaster gets squirrelly on the highway

[wfeffer]

I've only had my Class A for a year and have done very little highway driving but every now and then while I'm on the highway things get a little squirrelly.
I don't know how best to describe this issue, but basically I'll be driving along and then it seems to start wandering and when I try to correct it starts to shimmy back the other way which then becomes this very squirrelly back and forth thing.

Does anyone know what causes this and how to correct it? Is this what anti sway bars are for? Any recommendations on good ones if this is the issue?

[Sudsy]

Get it to a service shop. If the tires are inflated properly and you still have the symptoms described there is a suspension problem.



Sudsy

[Sudsy]

Welcome to the world of camping. It sure is fun and the little problems that pop up are a part of it. You will find a lot of help and good info here.


Sudsy

[wfeffer]

Get it to a service shop. If the tires are inflated properly and you still have the symptoms described there is a suspension problem.



Sudsy

The tires are new and inflated properly. One thing I might add that may or may not have anything to do with this, when we bought the RV it actually had the wrong size tires on it, they were a smaller size and I did not notice the issue then. We had the tires replaced with the ones specified on the chassis and that’s when I noticed this issue. It may be that I simply didn’t notice it before or it may not have been there.

What kind of suspension issue do you think it would be? We had the chassis serviced and checked out Around the same time as the tire replacement.

[Sudsy]

I'm not sure of your chassis type. On the Workhorse it could be ball joint ends, king pin bushings or just loose parts.


Sudsy

[wfeffer]

I'm not sure of your chassis type. On the Workhorse it could be ball joint ends, king pin bushings or just loose parts.


Sudsy

It's a Spartan Mountain Master chassis if that helps at all.

[Chuck v]

My 2007 Tour Master had the Freightliner chassis, and I never had any issues like those you describe. Could you describe the sensations you are experiencing a bit more? Is it darting about like the front end is not steering accurately, or is it 'wallowing' around like the rear end is softly suspended?



I would take the motorhome to a scale and weigh each axle and compare it to the factory specification...if it is overweight at all on the rear axle that may be a source of some of the issue. Even if it is significantly underweight, you may need to adjust the tire pressures accordingly. On the rear dual wheels, be sure the inner tires are at proper inflation. Inspect for any broken or loose suspension parts as well. Good luck and let us know what you find.


Chuck

[wfeffer]

It's not a weight thing as we had nothing in the RV when I felt this. It was also right after getting brand new tires so I assume the pressure is good. Though I did not notice the issue with the old tires which were actually the wrong size, they were smaller and looked less like the truck tires that are called for in the manual and on the plaque.

As for what it feels like, it's hard to describe its like a very slow woozy lack of directness. I'll be driving and everything is fine and then feels like it's drifting one way or the other and when you start to correct it seems to overcorrect and this becomes a fight that gets very scary feeling, like the front and back of the rv are going in opposite directions or something. I'm not sure how it goes away or what I do to fix it. It's all really just a feeling and very subtle except for the part where it feels very out of control.

[Chuck v]

Thanks for the additional description. You need to MEASURE the tire pressures and not assume they are nominal/correct/appropriate. Also, you need to MEASURE the axle weights and know for sure that they are both within limits (some coaches are near limits with no added weight and/or are so light they are up on the suspension travel stops, etc.) Let us know when you have real data, or simply go to a reputable suspension specialist. Most of these suspension houses have upgrades to sell, but even if you stay with the stock suspension, you might benefit from considering this advice concerning air pressure and real scale weight:


Once the heavy duty suspension and steering accessories have been professionally installed, finish your motorhome suspension upgrade with a coach weigh-tire pressure setting and alignment. Weighing all corners of the coach allows proper tire pressures per tire manufactures' specs, providing optimum handling and reduced tire wear. Aligning both or all three of the coach's axles allows adjustments of camber, caster, toe, thrust and scrub angles.

Chuck

[Steve Little]

You have two steering dampeners if you have an ifs front end. They likely need replacing. Mine do too.

[Mike1931]

I've only had my Class A for a year and have done very little highway driving but every now and then while I'm on the highway things get a little squirrelly.
I don't know how best to describe this issue, but basically I'll be driving along and then it seems to start wandering and when I try to correct it starts to shimmy back the other way which then becomes this very squirrelly back and forth thing.

Does anyone know what causes this and how to correct it? Is this what anti sway bars are for? Any recommendations on good ones if this is the issue?
Not sure how far behind the curve I am,. But here goes, I found that when I bought replacement tires for my coach, it got really squirrelly! It was my fault, I chose to put a taller/narrower tires on it. That was a big mistake, yup replaced them again. Now it has wider and same height tires. Wow! This really took the squirrelly issues away, also had the front end alignment done at the same time. All in all the coach is more stable when a semi truck passes you.
Mike R
Marysville WA