Sidecar Passenger Position

I have a Vetter Terraplane [lead 9"] and a Motorvation FII[Lead 5"]
both have the passenger sitting slightly in front of the axle.
I guess it doesnt matter, as long as the passenger is not sitting behind the axle. that would kind of offset the weight distribution.

Well now you got me going. First, why are you asking this? Are you having handling problems? If your passenger is sitting forward of your present axle and someone said he should be sitting above or behind, what would you do? Move the passenger, move the axle, move the sidecar, move the bike, or junk the present rig and get another?

I rode with 4 other rigs on Saturday from the SKUNKs. I'm always curious as to what will make my rig handle better. I noticed that they were either slightly forward, on, or slightly behind the sidecar axle. Mine is more than slightly forward of the sidecar axle. My Bingham MK III is bolted to a CAL I frame so I could unbolt, redrill holes in body, and re-attach. My thought is that there would be less weight then on the front of the bike for better stearing. There is nothing major wrong with my rig. I just like the adventure/curiousity of the sidecar.

Weight towards the Rear is usually best for weight distribution witin reason. Think in extremes..what it the passenger was sitting on the nose of the sidecar? What if he was way out back? Where do we see the racers passengers sit? Some of the HPS rig designs are now putting the passenger right behind the rear wheel. When the question comes up on where to add ballast is it in the front? NO, it is towards the rear and out as far as possible. Yes, rear is best for overall stability, especially in left handers. If you have to ability to experiment go for it, a few extra holes in th efloor of the sidecar body aren't gunna hurt.
As I stated at SCT you may reach a point where the rig wants to understeer in left handers. So much here depends upon riding style and th erig you actuallu have. Let us know what you find if you play with this on your rig.

I answered the call. Since no one provided any suggestions on how
far to move the sidecar body back and I have more guts then brains, I
made radical change. The measurements are from where the back of the
sidecar seat meets with the bottom of the seat. To center of axle of
sidecar - 2.5" ahead (moved body from 5" ahead) To center of where
swing arm is attached to frame - 1.5" behind.

With empty sidecar noticed some change, lighter on front end of bike
and easier to steer. Was thinking I needed to move back more. Put
100 lb bag of corn and two large marine batteries in sidecar seat (no
son to try out until 10/29). WOW, what a difference on the front end
of the bike. There's a real twisty road north from my place, tried
out with caution. IT HANDLED GREAT. Now need to get son with all
his body parts and give another test.

I still think the guy that set the rig up for me did a great job and
would recommend him to everyone. I realize he could only get it
close. How often you drive, where you drive, and how you drive may
be cause for finer adjustments.

Wayne

Way to go, Wayne,
When in doubt, find out!
I always say "If you're afraid of a little blood, you make a poor Soldier".

Problem is, now all of us are going to be drilling holes in our sidecar floors. (Did you use fender washers?)

Leave the old holes open. They'll come in handy during next spring thaw.

Lonnie

Yes, I used fender washers. I would like to see how the ones with a moulded fender will work around that.

Wayne

Molded in fender?
Swing-arms can be moved too!

Lonnie

Got to test drive the rig with my "big" son with the new sidecar body position. It handled better. Now I wonder how it will handled with additional 2.5" more moved back. That would put him over the axle. If it's nice tomorrow, I think Ill find out.

Better 🙂

less pressure on front end of bike so less stress on my shoulders and arms. Easier to steer.

Wayne, my reply at SCT said:
>Wayne,
Keep going and I think it wil continue to seem better and better
up to the point that steering begins to be compromised on left
handers and possibly whem going up steep hills under power. In other
words th efront end will possibly want to break traction under these
conditions. Proceed but do so with care and awareness. You ARE going
in th eright direction!
Please keep us posted.
Claude<

I think this bears witness to what you are describing. Steering seems easier at this point but as you go back more and more you will ,sooner or later, begin to feel the front wheel break traction when you take off from a stop into a left hand turn under power (no biggie).Eventually you will probably find that you have gone tto far as you will induce understeer (pushing the front end) quite easily on left hand turns and maybe on steep slopes.
So, as you go farther be sure to test the rig each time you do an adjustment. Yopu can actually do this pretty easily in a sharper left hander by steering quicly and more than you need to to see if th efront tire breaks traction. It may do that even now. Do this after you are into a turn at a safe speed so you will be totally in control. As you continue to move th ebody back do this each time and you will soon see that the tire breaks traction a little easier.
THERE WILL BE A POINT WHERE THIS CAN BECOME DANGEROUS SO PROCEED WITH CAUTION.

I've done my final movement of the sidecar body backwards so now where the back of the seat meets the bottom of the sidecar seat is centered over the axle of the sidecar, a total of 5". I don't have any traction problems with the front of the bike in corners. It sure is better on my arms and shoulders. Less pull at high speeds to right. I'm satisfied. Now I'm going to work on the sidecar suspension. To do the Dauntless upgrade is expensive plus even more with the freight to and from, wish I was closer to them. Going to try using a Mountain Bike Coil over Spring rated for 750 lbs. 6" from eye to eye and 1.5" dia.

I would have though the designer would have figured this out and that there would be a reason why it would be located where it was from the factory. When you play with with a manufacturers design and attachment recommendations, any recourse for failure of the components would go out the window I would presume.