Originally Posted by ramblinboy
thanks all! Tire pressure at 110 all round Workhorse says 95. Im reluctant to soften a tire that feels like its giving way. Part of the problem maybe how its loaded going into the curve and not accelerating coming out - shifting weight to the rear of coach. This thing steers like a rabid squirrel with my previous whining Toyos and now this. Time for an alignment as you suggest.
You really haven't told us much about your Chassis. I will assume it is a standard W22 and will have front GAWR of 8000# and rear GAWR of 14500# and has Michelin 235/80R22.5 tires. If we assume that you have not overloaded your motorhome then your front axle weighs 8000# or less
and your rear axle weighs 14500# or less
Using Michelin load inflation chart for a 235/80R22.5 tire with a load of 4000# (half of front axle GAWR) I get inflation pressure of 90 PSI for the front tires
. Using the same chart with a load of 7250# (1/2 of rear axle GAWR) I get 85 PSI for the rear tires
. If you have changed tires size the proper inflation for the GWAR's of your chassis will be about the same.
I think your tires are severely overinflated for the load. Overinflation can cause a multitude of issues, all of them bad. One of the bad things that overinflation can do is cause steering problems. Overinflation tends to make the tread of the tire bulge out in the center. This places less pressure on the outside of the tread making it easier to roll under.
As others have mentioned, you should get your front alignment checked. Workhorse did not include adjustments for Camber and Caster and therefore does not have a specification for either. From the factory Workhorse W series chassis have a caster of ≈+3°. Through experience MANY of us who own W series chassis have determined that the chassis steers much better if the caster is ≈+5.5°. Caster can be changed by adding wedges between the front axle and the leaf spring. Generally adding a 3° wedges under each front spring does the job. Changing the Camber would have to be done by bending the front axle. Not recommended and probably not necessary. Whatever it is is probably fine.
I would start by lowering your tire pressure to 90 PSI for the front and 85 PSI for the rear. You might find that with lower air pressure the symptom you describe will go away.
If you are still not satisfied with the steering find a shop that can add alignment wedges to your front axle and set the caster to ≈+5.5°.