Chassis Ramblin’s
By Brad Sears
Well it is Sunday here in rural New Hampshire, 23 degrees outside and an ice storm rolling in tonight. This coming Wednesday we were supposed to be pointing the old Fortravel’s nose south, but plans have changed. The old guy, me, got slammed with bronchial pneumonia, so we will not be heading south, nor will I be going anywhere soon.
So what to do on a Sunday afternoon? Watch the Daytona 500 on TV, thats what. Ya, so what you ask? Well it has to do with what I have been writing in my blogs the past several weeks, chassis handling.
In looking over what is on the market to try to eliminate some of the lousy handling that we have in motor homes, it is amazing at the number of products that are sold for the front end of the vehicle as opposed treating the rear of the rig.
However it is a known fact that the rear overhang as compared to the total length of the rig has a lot to do with tail wag and handling. It is a fact that NASCAR mechanics appear to think that when solving a drivers handling complaints that making adjustments to the rear of the car is where it is at.
After last weeks blog several folks indicated that adding supplemental air bags to the rig was the the best investment that they had made for their coach. When I thought about this for a minute, I had to agree.
Being a gear head and a teacher, I could not just put air in the new air bags on the back of my 33 foot Southwind on a P-30 chassis, I had to play and keep notes. I played with air pressures and measured chassis height for each pressure. I played with this chassis for over a year trying to make it behave. It was built during the national 55 mile per hour speed limit and at 55 it did not handle too bad. But over that? Another story.
I soon came to the conclusion that all weight distribution was not created equal and that I had to run more air pressure in the right rear bag than the left side. The reason is simple when you think of it. All roads are engineered with a crown to allow for water to run off to the side. With a lot of overhang and a bunch of weight in the overhang as the coach tips to the right the effect is like a bunch of weight hanging on a rope and will try to pull the tail off to the right and down.
This action will tend to lift the weight off the left front wheel and upset the camber and caster.
the 500 is over and as usual the television pundants were all wet. They had worked for weeks setting up this wonderful match up between the Hendrick’s team and the Gibb’s crew matching Chevrolet and Toyota. When it was all over the Captain, Roger Penske and his merry band, driving Dodges snuck in to steal the apple pie off the window sill. One two finish with Newman and Bush as top dogs.
Stay tuned for more stuff next week.
Brad Sears