hi all, can anyone tell me the minium distance to the right the sidecar wheel track should be on a 500 to 600lb bike . my brother is trying to build a platform rig fot a 750 yamaha. thx pat
On such a machine from center of bike to center of sidecar tire, I would use about 42 to 44 inches. I would align the sidecar axle about 10 to 12 inches forward of the rear wheel axle. A straight line along center of the bike to a straight line along the sidecar wheel. These lines should be measured at the rear of the bike and at the front of the front wheel. The measure at the front should be ABOUT 3/4 inch narrower than the distance between at the rear. This can vary a bit after the rig is mobile to find the best angle for your particular machine. Start with about one degree lean out away from the sidecar and adjust until you get a geometry that will not pull to either side on flat road at 55 MPH. After about 500 to 1000 miles check tires for wear patterns. Adjust accordingly. Once you have the correct geometry, NEVER CHANGE THE TOE IN. But you can vary the lean out as needed until you get what you want.
Others may prefer different dimensions but these have served me well for ten rigs I have owned, half of which I built.
The track will vary depending upon what sidecar is being mounted on which specific bike. Some are mounted farther from the bike due to panniers and such, or just to be more stable. I usually try to mount at around 12" frame to frame to keep from sharp strut angles and maintaining adequate clearance for controls, foot boards, saddle bags or engine guards. Some clients may desire a wider track for stability, sacrificing some ease of steering.
Wheel lead 15% to 20% of bike wheelbase if practical. Wheel position on different models of sidecars varies from the middle of the car to the extreme rear so optimum wheel lead may need to be a compromise.
For single sidecars toe-in from 3/8" to 3/4" works well for good tire mileage. Doubles may go 1 1/4". Measured from in front of the front bike tire and in back of the rear tire.
I use 2-1"x1" square tubes for straight edges, placed on 4"'x4" blocks, tightly against the rear wheel of the bike and the sidecar wheel.
I always start with a minimum of 1 degree of lean-out with bike and car loaded, driver in the saddle on a level surface.
Unless both lower mounts are at equal height from the ground, any lean-out adjustment will affect the toe-in and it should be rechecked after tweaking.
Lonnie
thx to pheionius and lonnie for your info.pat
