Chevy Chassis is out of control

[ericsmith32]

Frankly it doesn't seem any different than my grandparents E450 31ft but I'm getting tired of being pulled over! Pulled over outside of Jackson MS because the road suddenly started tossing the RV around and couldn't slow down quick enough (although the step was starting to come down so it was good timing). My wife got pulled over for the same but was the wind in KS. Starting to think it could be our age, grandpa never pulled over except speeding and he's worse than we are!

Planning on this in the following order.. Alignment.. Changing out the rear D Load Range with E's and pumping them up to 80lbs (front are already changed out)... Steering stabilizer up front .. and shocks last.

It does track straight and ride good for the most part but is easily influenced by wind and road conditions. And it does excessively bounce over the dips in the road. Typical RV's that I'm used to but has to be better. Thinking about a rear sway bar to but those are pricey for my budget. Anything I should look into?

[ron_dittmer]

ericsmith32 wrote:
Still want to do at least the stabilizer someday but not on the list right now.

Eric, I am sorry to say that "No Rear Stabilizer = No Good". If you have nothing in back right now, a heavy duty rear stabilizer will be your single biggest (and noticeable) improvement in cross winds or other turbulence, and in any kind of curve or turn.

[ericsmith32]

Final verdict.. Drove from Nevada MO to Fort Smith AR today. Took old 71 for about 30 miles. A lot of wind and crazy weather. Totally different RV, steering is tighter and doesn't bounce like a bucking bronco over crazy terrain. The bad is it seems harder to keep it in line around town.. Slow speeds. Pumping up the rear tires to match the load was a negative. One must have a bad belt. Still want to do at least the stabilizer someday but not on the list right now.

[Ohio_Engineer]

I see comments on people using different tire inflation levels but no reference to actual tire loads.

When selecting the Cold Tire Inflation, there is a minimum which is the inflation needed to support the measured load on the heavier end of that axle.

Tire Placard or door jam sticker is simply an estimate based on what someone thinks you have loaded into your RV. Its not unreasonable to start out using that inflation but if you really want to ensure the best tire life then you need to confirm actual tire loading for your individual unit as not everyone carries the same number of bowling balls.;)

[ron_dittmer]

ericsmith32 wrote:

ron.dittmer wrote:
The subject of tire pressure is interesting.

I wonder who else has observed the same as me. That is....When I put in the proper tire pressure, my tires appear severely under-inflated.

Anyone else feel the same?

Took the fronts down to 55 and yes they do look low.

Yep! It just never looked right to me. To feel better about it, I add 5 more psi per tire than spec. If anyone wonders, I have used multiple gauges to make sure the reading is right. The tires still look a little low, but not as bad. With 30,000 miles, they have been wearing fairly evenly. The outer edges are not wearing faster which would otherwise be the case with under-inflated tires. The same goes for over-inflation, the inside is not wearing faster.

A little odd tire wear I do get is related to strong cross winds when driving the open plains for days at a time. The steering correction for so long a time "checks" the front tires on one side. If I get lucky, I get the reverse later to even out the tire wear. Nothing can be done about that except not to travel on those days.

With our first motor home (1983 Toyota/Mirage), cross winds were so bad on one trip across the Great Plains, we actually ruined the front tires during that trip. Upon returning home, I flipped one of the two tires on it's rim so the bad-wear was balanced, placed on the inside for better handling. That bought a few extra years.

[ericsmith32]

From what I've read both chassis benefit.. The Fords require more work as the Chevys have the adjusters on the arms from the factory.

[Harvard]

Thanks for showing us the report.

What is remarkable is, like the Ford E Series, the Chevy has a broad normal range of +caster (LH 3.6 to 5.6 and RH 4.0 to 6.0).

BUT, it begs me to wonder if the Chevy would also benefit by going to the upper edge of the caster range. In This case there was only about 1 degree of +caster gained. Even at mid range LH would be 4.6 and RH would be 5.0 which is a lot better then where it was set.

[ericsmith32]

I'm not exactly happy with the business end but the alignment results there's no doubt it's much improved! Didn't have the pressure gauge to take the tires down to 55 so most likely it improve beyond what the alignment brought. Had alot of heavy wind on the way home and it did push it some but I'd say only a 1/8 of what it did before. Going on a trip next weekend so will be able to judge more.

[ericsmith32]

ron.dittmer wrote:
The subject of tire pressure is interesting.

I wonder who else has observed the same as me. That is....When I put in the proper tire pressure, my tires appear severely under-inflated.

Anyone else feel the same?

Took the fronts down to 55 and yes they do look low.

[j-d]

Ours do not, but the 65-F and 75-R that we run at is bumping the max 80-PSI for a Load Range E tire. And 65 IS max for Load Range D. With a lighter coach, the related lower pressure could give the tire a soft look. Remember when radials came out, we were warned they could "Look Low" when they were not. And worse, they didn't look much "Lower" when nearly flat. We had a passenger van that ran 16.5" wheels and Load Range D tires on it, running 35-PSI. They looked low, but wore properly.

[ron_dittmer]

The subject of tire pressure is interesting.

I wonder who else has observed the same as me. That is....When I put in the proper tire pressure, my tires appear severely under-inflated.

Anyone else feel the same?

[IAMICHABOD]

Thanks j-d!

[j-d]

IAMICHABOD wrote:
If I have the numbers right and according to the Michelin chart with my 225/75r 16 my pressure should be 50psi with the front axle wt of 3880 or 1940 per tire. and the rear pressure at 60 psi with the weight of 7930 or 3965 per set of duals.

Is that correct?

YES, It IS!

Eric, If you still have the coach in the driveway, go ahead and adjust pressures in all six. Just be sure to observe Single/Dual. Pressure may be the end of the trail.

[ericsmith32]

I'll drop it to 50 when it gets back from alignment. That is if it get alignment.. starting to wonder if I'm getting yanked around. The first shop couldn't do it due to the long wheel base. They took it to another but it'll cost 160 with them.. better be perfect at that price. Not having the RV in the driveway makes me nervous!

[IAMICHABOD]

I'm interested in this air pressure discussion.

If I have the numbers right and according to the Michelin chart with my 225/75r 16 my pressure should be 50psi with the front axle wt of 3880 or 1940 per tire. and the rear pressure at 60 psi with the weight of 7930 or 3965 per set of duals.

Is that correct?