Posted 8/4/2017 4:12 PM (#94441 - in reply to #94412) Subject: Re: Results from the Rally weight in
One thing I think might need to be taken into account when looking at the weights is the distance between the center line of the bike and the center of the sidecar tire.
My thinking is that a wider track outfit would be able to handle good with a somewhat lighter sidecar.
Not sure if my terms are right but I'm thinking along these lines.
If you picture the center line of the bike as a pivot point and the weight on the sidecar tire as the force being applied to the bike, similar to the torque on a wrench acting on a bolt. Then a sidecar with a weight measured at the tire of 200 lbs and a track width of 4 feet is putting 800 lb/ft on the center of the bike when the sidecar wheel lifts off the ground. Now if this same sidecar is moved one foot closer to the bike it would now only have an effective torque of 600 lb/ft.
Not really know where this all leads to but just idle thoughts I had while looking at the results. In part this was brought to mind as when I was asked if I had a problem with my sidecar lifting easily when riding with no passenger as I only have slightly under 20% of the total weight of the outfit on the sidecar wheel with no passenger.
I also think the height off the ground of the weights of the bike and sidecar have a major effect on the lifting/handling, I do carry a fairly heavy tool bag and jack down low in the sidecar and near the back.
Again not wanting to disagree with others just thinking out loud so to speak.
Posted 8/4/2017 6:48 PM (#94442 - in reply to #94441) Subject: Re: Results from the Rally weight in
Location: Minneapolis, Minnesota
Your thinking is perfectly solid. The distance from the center line of the bike to the center line on the sidecar is in effect the moment arm and the longer the moment arm the more force is transmitted for the same input.
The thing that works for you in keeping the sidecar down also works against you on acceleration and deceleration. The inertial force of the sidecar is greater, for a fixed weight, the further it is from the bike. I guess all of sidecaring is a compromise.
Posted 8/6/2017 7:16 AM (#94460 - in reply to #94412) Subject: Re: Results from the Rally weight in
Al, my thanks as well to you for doing this. My rig was weighed second; I only wish now that I had thought (as other people did) to have you check the weights (and consequent percentages) when I was on the rig, and when I was on the rig with the 50 lbs of gear I normally have in the sidecar trunk. But even without that, this info is great.