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leading link front end

I have removed my OEM front end and installed a new Leading link front end manufactured by Wasp cycles in the UK. I attempted to take the rig out this morning and encountered a shimmy problem that became uncontrollable at any speed. There is a quality shimmy dampener installed, from DMC, had it on my OEM setup with NO issues. Perhaps I have done something wrong or missed something on the install, at this point I have no idea where to start or what to look for. Some assistance from riders who have installed leading link front ends on their bikes would be greatly appreciated. I have contacted the manufacturer but have received no reply as yet.

So this is on a BMW K100RS with a Vetter sidecar?

Sounds to me like you have too much trail reduction.  But . . . I'm assuming that after you installed the LL's, you then measured your lean out and toe-in and made all the necessary adjustments?  Because that's Step 1.

And just out of curiosity, what is your measured lean out and toe-in with the LL's?

Do the Wasp forks have a mounting plate on the yoke so that you can choose different amounts of trail?  That would be Step 2. 

Are the LL shocks too soft?  Or not soft enough?  If the shocks can be adjusted, you can play around with those settings and see if anything helps (Step 3).

Are you using the correct size rim and tire?  And by "correct" -- is that what Wasp recommends or somebody else?  Wasp is not necessarily the fount of all knowledge.

The other thing to check, (maybe Step 1-B?) a lot of guys overlook this, is your tire inflation not only up front but at all three corners.   Experiment with some different pressure levels.


Thank you for your reply, The bike is a 1985 K100RS and the sidecar is a Vetter. The lean out is 2 degrees and the toe in is 3/4 of an inch. When the stock front forks were installed I had no issues, the reason I went to a leading link  was to make the steering easier for my 74 year old shoulders. I went with the Wasp unit because of their reputation. My son and I worked on the leading link today for several hours and there is no change, I removed the shimmy dampener, no change. I have notified Wasp but have received no reply as of today. My son informed me that the front wheel looked like it was wobbling, which I felt in the bars. The front end does this as soon as the bike makes forward motion and does not stop. The rim is the standard and the tire has not been replaced. Wasp supposedly manufactured this unit specifically for this bike. The wasp unit has no provision for changing the position of the axle relative to the headstock.

DRONE has reacted to this post.

Lean out and toe-in seem within reason.

But it's weird that the wobble is not speed sensitive.

Have you jacked the front wheel off the ground, then spun it?  Wondering if there is a wobble in the wheel or axle (or tire even!) which of course would mean it's not the LL's.

What about the steering head bearing?  Have you examined it?  Needs tightening?  If it's bad, new ones are available from BMW for about $80 and from aftermarket sources for half that [].  Though now that I'm looking at the fiche I can see there's a similar bearing on the lower fork brace that should also be checked.

If you have a tolerance for Chris Harris videos (I, for one, actually like them) you might take a gander at this one ---->



Thank you for your helpful replies, my son and I worked on the front end last weekend , the front wheel has a lot of spinning resistance when the axle bolts and pinch bolts are tightened. We have ruled out dragging brakes as the problem. It would appear to have something to do with the wheel and axle dynamics. I have received a reply from the manufacturer and he is surprised, wanting to know the headstock angle and some other measurements. The headstock angle is the OEM angle as nothing has been changed there. The rig ran fine after I finally got it dialed in with the OEM front end and the shimmy dampener, running about 3000 miles with no problem. I will be checking the steering head bearings and as many other things as I can this weekend. Thank you again for your input, much appreciated. Craig

DRONE and MGV8 have reacted to this post.

With the front end jacked off the ground and wheel removed, as you slide the axle in does it align perfectly?  And are you running a bike tire or car tire up front?




Craig, Did you ever get your issue resolved??