Tricks for a Trek

Recreation Vehicles

April 1, 2009

377

April 1, 2009

The Safari Trek motorhome is one of the most common coaches we see in our shop. Its combination of Class A livability and relatively small size make it a favorite among RVers, and the P32 chassis is a reliable platform when used within its capacity (16,000-18,000 lbs.) It’s not the greatest handling coach, but the good news is, it responds well to some positive changes.

Trek owners are a passionate bunch that love their coaches very much. Quite often, we get a Trek owner in our shop that wants to get the best handling possible out of his coach, and this month that customer was Barry Schmidt and his wife, Kinau. That’s me on the far left.

trekownerslowres The P32 chassis the Trek is built on really has troubles at both ends. At the back, you’ve got 2.5-inch wide leaf springs (the same width used on contemporary pick-ups) which do little to control lateral (side-to-side motion) motion of the rear axle. This contributes to that “tail wagging the dog” sensation, where excessive motion at the back of the coach tends to steer the front, and causes a very uneasy feeling when the wheel is turned back and forth quickly. This problem is easily remedied with our SuperSteer Trac Bar, which attaches at one end to the rear differential housing and the other to the frame.

The other problem at the back is sway. Remember, a motorhome is the opposite of a car in that most of the weight is carried in the back, so the handling has got to be determined by what your rear suspension is doing. As such, we normally add a larger anti-sway bar to the rear than on the front. On the Trek, the stock rear anti-sway bar is 1-3/4 inches in diameter, which is fairly large, but not large enough to adequately control sway. Unfortunately, there isn’t a larger bar available, so we replaced the rubber bushings with urethane bushings which help a bit by reducing deflection.

One of the things you have to be careful about when trying to improve the rear suspension is ride quality. You can’t remedy handling issues simply by adding more leaf springs-it does help somewhat, but not enough to really control sway. So, we turned to the E-Z Cruise product from the E-Z Ride Corporation (e-zridecorp.com). This product installs between the frame and the leaf spring, and works using a compression and shear action. It’s made up of steel mounting brackets and rubber springs with steel plates inside, and comes in different rubber densities depending on the application. I think this product makes an unbelievable difference in the Trek chassis. Here’s a photo installed:

ezcruiselowres To improve handling up front, we replaced the stock coil springs with 7/8-inch wire diameter with our SuperSteer coil springs, which have a full one-inch wire diameter. This addition cuts down on sway by increasing the spring rate. We then replaced the 1-1/4-inch front sway bar with a much thicker 1-5/8-inch unit from Roadmaster. As a rule of thumb, every 1/8-inch increase in thickness is supposed to increase roll stability by 30%–and you could really feel the difference in this coach.

Next, we’ll be installing a Safe-T-Plus steering control (safe-t-plus.com). The stock 710 Saginaw steering box is heavy duty, but it does have some trouble returning to center. I like a nice, crisp return to center feel, because it cuts down on rut tracking (where the coach feels like it follows every crack in the road), wind drift and wandering. Safe-T-Plus has a variety of models to suite different applications; I like the silver model, which has 140 lbs. of centering force.

The next thing we’d like to see Gary do is add Koni FSD shock absorbers, which put the finishing touch on ride quality and handling. But as it stands, Barry’s Trek is one sweet-riding coach.

Barry tells me that the former owner sold the coach because he didn’t like the handling and wanted to downsize to a Class B. I’m betting that if this Trek handled then the way it does now, he wouldn’t have ever sold it.

Now, a couple of announcements: We’ll be in Albuquerque, New Mexico for The Rally on April 17-21, and Sedalia, Missouri for the Escapees Escapade on May 24-29. Whether you have a Trek or not, come by and say hello!