Bonneville America Forums Forums Technical Forums General Tech Front end wobble

I have read a few posts about some of you that have had this same issue, i never felt it until after i changed the front spring to the progressives and then lowered the forks through the tripple tree about 3/4 " (back down 1") not sure what to make of it, i only really feel it a bit in the corners and when off throttle slowing down, if i let go the bars it will pull right and there is defidnatly a shake (you can see both ends of the bars wobble) at hyway speeds 120 klm per hour its good. Could this be that the oil is not even in the forks? The new spacers i cut i am sure they are the same length but if one were mm longer etc would that do it?

You didn't mention what tyre you are wearing.

I had a similar problem with the Lasertech tyre, changed to ME880 problem solved.

Are both forks the same height?. There is a procedure to make sure the forks are parallel, in the shop manual....by lowering the fork you changed the tail..so any minor alignment could show up...

Tiny measurements that make a preload longer or one fork a tad shorter are unlikely to be noticed unless you are racing...I'd guess that maybe the rear wheel might be a skosh out of square before I'd buy into the forks causing it to pull right. Sounds a whole lot more like a cupped tire wobble combined with a tiny bit of alignment distress.
So how much sag did you end up with using the new spacers? By lowering the fork the suspension has a little less travel (by virtue of the fender hitting the triple tree) so you might need to recalculate. About 30% of the total travel or 25% if you ride more racer style (to make the forks quicker in the turns, the fork dive changes the angle faster).
So have you loosened the axle, bounced the front end and retorqued? Always a possibility of a minor alignment prob there when loosening the tubes in the tree.

The classic causes for this are tires and steering head bearings. If you've been wearing the same tire and it's not especially old, check the bearings. Support the bike so the front wheel is off the ground and swing the bars side to side, you can feel if there's a notch in the bearings.

I had a similar symptom. It was the steering head bearings.

It could be the head bearings, it probably is the worn Lazywrec, & it might be both.

I wound up going through a few front tire due to cupping before I swapped out my head berings for a set of All Balls tapered rollers. No issues since then.

well got home put her up on the lift, spun the front and it definitely wobbles from side to side, not sure if the tire or rim, looks more like the tire though. Rotated the steering and moved her up and down and nothing, steering is pretty smooth, might be i am dealing with a cupped tire , who knows how long, when the rear was lowered and not the front it took a bit of weight off the front and less contact space i think, maybe when i dropped the front and put more weight on the front etc it became more noticeable, just a thought not certain, so i will bring it in and have it looked at maybe swap her out for me880 front touring tire with the same tread as the rear.

That front end shake is all too common with our bikes. Each time I throw a new tire on the front, the wobble goes away yet slowly returns as the tire wears. I need to replace the bearings like Z did and be done with it. It's annoying AND it's hard on tires.

The All Balls stuff is really good, I have it in my vintage bikes and they are smooth as glass. One day when I have the front end apart I'll be putting those bearings in my America, too. At 12K km you are right in the zone for wobble due to tire cupping, happened to me with the stock tire right at that mark. A new tire will be a revelation to you. I swapped for new last fall because the wear bars were showing.
Hey Keith: what brands have you had the cupping reoccur? It never returned for me when I went over to Avon.

well i am really hoping its just the tire and not the rim, cause i am not likely going to be able to find a rim in this area any time soon, i have to be ready for Nelson. Hopefuly i can get her in and have them check it for me. Is it better to replace both tires or just the front? Rear looks fine and lots of tread left.

My bike never had that issue and wore my Lazertec almost bald. Right at the very end maybe just a slight shake. Wendy's bike has not had that shake return since the new tire but only time will tell there.

Both at the same time is a wonderful luxury but you'll be fine just replacing the front if the rear is in fair shape.

27000km. on front lazertech tire before noticed any cupping,lucky I think.

Well could not wait to find out so went down bought a ME880 front tire 110/90 18 and its a full fit but a nice looking tire, took her for a spin and wobble all gone.... i wish life were that simple.

Glad and sad to read this thread. I have what I guess is the same wobble. I thought caused by under inflated front tire, which lead to cupping, which lead to wobble. Or, poorly balanced front tire, assuming dealer or factory balances front tire.

So do the bearings cause the wobble, and hence the cupping, or maybe the cupping cause the bearings to need replacement?

I still have the original equipment front tire, and I think I ran it for some time at 22 psi. I am at 8,200 miles now.

Wonder if when change front tire, should change bearings as well as brake pads.

WHOA! 22 psi is low. Aren't they specs to be at 31 front 32 rear.

A bounce test can be helpful
http://www.youtube.com/watch?v=OW-CmACI5xQ

The difference between All Balls steering head bearings
http://www.allballsracing.com/22-1020.html
(22-1020 is the appropriate kit for an '07 Speedmaster)

and the stock very low quality bearing set is like comparing a Blue Ray DVD to an 8 mm home movie.

DIY on this job would fall somewhere around medium difficulty, and if you ask me, there's no reasonably easy way to do it without access to a hydraulic press.

Most machine shops and garages that do full line engine work should have an appropriate press. The press part is only a 5 minute job.

Yeah, I felt like a jack ass for not checking my pressure.... Knucklehead.

FWIW, changing my original equipment tire, which was due, eliminated my front end wobble.