My Valkyrie has always had a minimal shimmy in the front end on deceleration. Nothing terrible, but it was there.
Most sidecar rigs exhibit this problem, which is why many have steering stabilizers.
When I pulled off the Dnepr and installed an almost identical Ural car, the shimmy got much worse, not only at low speeds but at any speed decelerating. Anytime I let off the throttle it would start. I check head bearings, tire pressure, alignment, load balance, and everything else that has been known to cause this all to no avail.
Yesterday, unrelated to the shimmy, I changed front tires, from a Dunlop D206 Radial to a D404 Bias Ply. My shimmy is gone! 100% gone. Today I was able to decelerate from 70mph to stand still with very light pressure on the handlebar and NO SHIMMY AT ANY SPEED.
Before you say the tire was the problem, I should point out that the tire I removed was installed after the shimmy started and wore out at about the same rate as every other tire has since I bought the bike. Unless the last two tires were both bad, I installed each the same, cleaned, inspected, packed, torqued, and preloaded the bearings, etc. etc.
I guess what I'm saying is, Don't give up! There's a solution to every problem if you just keep plugging away.
Huh... I only get a tiny bit of shimmy when excelerating. If I install your tire with the rotation backwards, do you think it would cure MY problem?
Maybe! But you might have to do it on the First Monday after the first Saturday of last month for it to work. :0)
One never knows, do one?
I changed front tires, from a Dunlop D206 Radial to a D404 Bias Ply. My shimmy is gone! 100% gone.
Was the previous tire balanced? I've noticed a slight increase in my shimmy since the tape one tire weights disapeared.
No, I do not yet have a steering damper, I just keep both hands on the bars between 15 and 25 mph. No problem after that.
Radial tires seem to have more sidewall flex then bias ply tires.
I suppose it is because the tread area is bound by the belts so it won't flex. That may be part of the cause.
Notice how the radial tires on a four wheeled vehicle bulge above the tire footprint. Some have a tendency to squirm. My brides new Honda Accord radials will squirm on some deeply grooved pavement.
Lonnie
Originally written by Mark in Idaho on 8/13/2006 10:29 AM
I changed front tires, from a Dunlop D206 Radial to a D404 Bias Ply. My shimmy is gone! 100% gone.
Was the previous tire balanced? I've noticed a slight increase in my shimmy since the tape one tire weights disapeared.
No, I do not yet have a steering damper, I just keep both hands on the bars between 15 and 25 mph. No problem after that.
Yes, All three tires, both 206's and the 404 were balanced on the same balancer.
Hi Mike..methinks ye war infested with the dreaded "mystery shake" syndrome best cured by a visit from ghostbusters. Actually, even my rig with the UNITFORK setup w/damper shakes slightly upon deceleration. Really only noticeable with empty sidecar...go figure
