Wobble Question

[Gear1]

A question for the Triumph brain trust: my 2018 Bonneville T100 will wobble when i aggressively straighten up the bike when exiting a turn. Below 60 mph the wobble damps out after 3-4 cycles. At higher speeds it takes 5 -6 cycles to damp out. I can also cause a wobble by a small but sharp push on either hand grip. Obviously I can damp the wobble by firmly grasping both handgrips. I’ve been reluctant to test this above 80 mph, as it appears that the wobble might go unstable and actually get worse rather than damping out. Is there anything that can be done about this or is it the nature of the frame and suspension design?
Craig

 

[Vector]

What tires are you running, what condition are they in?

 

[Gear1]

Sorry, I omitted this, Vector. Avon Storm 3D, front 110/80-ZR18 (10mm wider than the stock Pirelli front, same diameter), rear 150/70-ZR17 (stock size). Tires are new this spring, approx 1000 miles, wearing very evenly, and well balanced.
Craig

 

[Vector]

Did you make any other changes?

 

[Gear1]

No other changes. However I have been riding a bit more aggressively as the Avon tires inspire a great deal more confidence than the OEM Pirellis. The Avon front tire is a bit heavier due to the slightly larger size and radial construction; because of this it requires a bit more counter steer push on the handlebar to get the bike to turn into a corner. Perhaps this is the cause along with a bit of frame flex?
Craig

 

[Vector]

I have no idea what it may be, I assume the fix would be a steering damper,

Norman Hyde steering damper Triumph Bonneville, Thruxton and Scrambler | NewBonneville

Norman Hyde steering damper Triumph Bonneville, Thruxton and Scrambler

newbonneville.com

 

[dacvulcan]

A question for the Triumph brain trust: my 2018 Bonneville T100 will wobble when i aggressively straighten up the bike when exiting a turn. Below 60 mph the wobble damps out after 3-4 cycles. At higher speeds it takes 5 -6 cycles to damp out. I can also cause a wobble by a small but sharp push on either hand grip. Obviously I can damp the wobble by firmly grasping both handgrips. I’ve been reluctant to test this above 80 mph, as it appears that the wobble might go unstable and actually get worse rather than damping out. Is there anything that can be done about this or is it the nature of the frame and suspension design?
Craig

I have a new T100 Gold Line and when I take my left hand off the bar to wave I feel slight shaking and also wonder if it is the chassis design or the stock Pirelli Phantoms. I have the feeling that is I took both hands off it would tank slap.

 

[OldRider48]

I have a new T100 Gold Line and when I take my left hand off the bar to wave I feel slight shaking and also wonder if it is the chassis design or the stock Pirelli Phantoms. I have the feeling that is I took both hands off it would tank slap.

Did the bike exhibit this behavior before you changed the tires??

 

[dacvulcan]

A question for the Triumph brain trust: my 2018 Bonneville T100 will wobble when i aggressively straighten up the bike when exiting a turn. Below 60 mph the wobble damps out after 3-4 cycles. At higher speeds it takes 5 -6 cycles to damp out. I can also cause a wobble by a small but sharp push on either hand grip. Obviously I can damp the wobble by firmly grasping both handgrips. I’ve been reluctant to test this above 80 mph, as it appears that the wobble might go unstable and actually get worse rather than damping out. Is there anything that can be done about this or is it the nature of the frame and suspension design?
Craig

My '22 T100 Goldline has had the slight wobble since I bought it in June. I finally took it back to the dealer who found the front wheel to be out of balance. The second I pulled out of their lot I could feel the change. For the first time the bike felt smooth and I could take both hands off the bar without fear.

 

[Gear1]

As a data point, the tires were balanced when installed, and have remained very smooth from a vibration standpoint. Still looking for ideas!
Craig

 

[JeffsGarage]

Steering dampener is a good idea.( as Vector says) especially if you really are pushing the bike. But you only want a dampener on a well tuned bike, otherwise it may just hide the underlying problem.
My two cents: You might want to repack your triple tree bearings or maybe just tighten the nut. It just an idea, but if that is loose at all, then that is most likely the source of the issue.
other possible reason for a wobble leaving a turn is that your forks are not balanced.? are they both adjusted the exact same.? Do they both have the EXCAT same amount of fork oil? Does one of them leak at all? This is all just my opinion, but from experience. I had a wobble and it turned out it was the triple tree bearings. about 10 bucks if you do it yourself, maybe 150 at a shop. put the bike on a center stand or on a wood block or whatever, just get the front wheel of the ground...and then grab the forks and shake the front end. .If there is any play at all, even a small bit, where the front end meets the frame, i'd bet thats you problem..

....all this assumes it's not tire issue, which is sounds like you've already taken a pretty good look at.

 

[shanered6]

Front tyre to wide go back to original width ... you'll find it will upset the balance of the bike at half lean angles and transitioning from corner to corner .

 

[Name Etc.]

Agree on triple tree head bearings and head shake. Every time I’ve had this problem. Three bikes three makes it’s always been the bearings. Bad or just a little loose

 

[Gear1]

Jeff and Name,
Great suggestions; I had checked the fork bearings, but not the fork oil level. I had changed to BikeTecParts progressive front springs and Ricor Intiminator valves, but have not rechecked the oil levels since the installation. I'll do that next. (The transformation in ride quality and control with the Tec springs and Intiminator damping valves was dramatic: no more jarring to the hands and arms in the very poor roads around Pagosa Springs CO.)
Interesting thought by Shanered6: I actually found the bike to have better turn entry (lean in) and has much better stability and grip in the corners with the Avon Storm 3D tires (10mm wider in front). Left to right transitions in the twisties are much better than on the original Pirelli (OEM) tires. The only issue here is that countersteer force required is a bit higher, but not objectionable, than with the Pirelli Phantom front. The wobble is only induced if I very quickly press on the handelbar on turn exit. Thanks for everyone's thoughts!
Craig

 

[Rolandrat]

I dropped forks 12mm no wallowing in corners or shake at 95 mph. Wish I’d done it years ago