Hi folks..
I have a Ural sidecar mounted on 1974 R90. Not the ideal combo as the frame is a bit anemic for sidecar use.
With some suggestions from members over on the Yahoo groups site, I have added several strengthening struts to lock the frame halves together to stop the flexing.
I run the Avon sidecar tire on the front, the Metzler block K on the rear, and a Duro is on the sidecar. The sidecar is lower mounted with a square tubing subframe, using the Ural ball and collet?(sp) mounts with Velorex clamps on the top struts. All is very solid.
I have Steerite modified trees, making steering very nice.
One thing I would like to improve..The rig seems very sensitve to the contours of the road..little changes in the road surface seem to make the rig wander in the lane. I am pretty sure the R90 frame is no longer flexing as it was doing before the strengthening struts were added, that really showed up when going into a curve. That is all very stable now. This happens just going straight down a blacktop, slightly wandering left and right as the contours of the road change.
I have very little toe-in set on the rig, sometime hard to really get a good accurate measurement, but I try to set it 1/2 inch, or perhaps a little less.
If it were my only sidecar experiance, I might think it normal, as it is really not that bad, but my Kawasaki W650/Cozy rig and my Ural Tourist rig do not do this (they both have issues in other ways 🙂
I try to keep the toe-in small, trying to improve tire life, but do you think more toe-in would stop some of this walk-about on the R90 rig?
Would welcome any insight from others.
Thanks,
David
Hi David, It is hard to tell with out seeing the rig, if you get to our area ever (Enumclaw WA) we do free saftey inspections. I ran a Ural for many years on an R100/7 and found that it worked very well. At the same time my wife ran an R100S with a Sputnik sidecar that also worked very well. I did have full sub frames on the bikes so that the BMW frame was not an issue.
Jay G
DMC sidecars
www.dmcsidecars.com
866-638-1793
Discovered a big part of the problem..after working with toe-in, shock settings, air pressure, etc., I could not detect any significant change. I finally jacked up the Ural sidecar, and spun the tire. viewed from the back, it did some side to side movement, as in the wheel not being trued-up with spoke adjustment. I changed it out with the spare wheel from my Ural, spun it, and it was noticeably straighter. Went for a test ride. Holy smokes...a very noticeable difference!
I am going to get the original wheel trued-up, balanced, and a new duro tire put on. Hopefully the Ural wheel can be trued-up. Anyone have any experiance along these same lines?
David
Make a small setup wit a fixed shaft and a dial indicator, a small wrench and start tweeking cross wise. (I number the spokes with whiteboard marker)
At the end the rim should run true and all spokes should have nearly the same sound. pling.
What you really need is patience and possibly a few new spokes, they like to rip off the head or thread.
have patience and luck.
Sven
Also check the wheel rim for concentricity. Many earlier wheels weren't round and the welded ends weren't well lined up.
Lonnie
