Last week’s post on “Tail Wagging the Dog” drew quite a few comments, and I wanted to take the time to clarify a few of the statements that I made with regard to coach handling.
Under normal circumstances, our experiences have found that, if the rear of the coach is not responsive on lane changes, gets pushed by passing trucks or has excessive over hang, the rear track bar makes a big difference. The way we design our rear track bar cuts down a little on the body roll as well.
As some of you noted, if the front axle is moving side to side because of ruts or steering inputs the front track bar will do a lot of good, but it is not the only solution for solving handling issues.
As far as putting air bags or overloads on the rear, we found out some interesting facts years ago. We thought that we would see significant weight shift when we boosted the rear spring pack. What we discovered was, if the coach had a substantial overhang on the rear, we did not shift the weight as much as we thought we would. We merely raised the whole coach up because of the leverage factor of the overhang. One Class C that was low in the rear only came up 100 lbs on the front axle, even though we raised it around several inches in the rear. The more the overhang, the less weight gets transferred. The coach may handle better due to the stiffer spring pack in the rear, however.
Another point that is worth bringing up is that the more we improve the stability of a coach, the less the steering problems seem to bother us. This goes back to the point I like to bring up about the synergistic effect that is achieved when all the components of a steering and suspension systems are doing their proper job.
The Road Performance Assessment we perform allows us to evaluate the system and all the components as a whole and not just hoping we find the “magic bullet” that solves all the problems a coach may have. There are usually a lot of variables we need to consider. Most every coach and every driver have individual characteristics that we want to consider before we make a recommendation.