[JPThruxton900]

What to get?

 

[TomJ]

Tried a few of them and all made it hard to handle in a parking lot (low speed fighting back and forth), as the race bikes tended to do (but were un-rideable at speed w/o them). If you're getting death wobble, work with the geometry, I'd personally check triple tree bearings, different tires, pressures, etc. (if you haven't already), before trying a damper.

 

[AandJCycles]

Norman Hyde is the way to go

 

[CHRIS211083]

I had a Norman Hyde style one before was good but I found getting correct chain alignment, torquing up the rear axle correctly and tire pressures fixed it.

 

[stoanee]

Dime City cycles has them.

 

[Scrammy]

I get wanting one. They look the business, and I love Norman Hyde's. But if you mean it literally when you say "need", I'd agree with those who suggest you solve whatever the problem is first. I don't personally believe there is anything inherently unstable about these bikes... mine is actually more nose down than stock, and still tracks like a train. Something might be wrong that you'll be glad you sorted out.

 

[Cleveland Rider]

You can't lose with an Ohlins damper. They really are the benchmark of suspension bits. I installed one recently on my Thruxton RS and am very pleased with the results. Exiting tighter technical turns are a breeze now. While the bike does give good feedback while pushing the envelope...there is a level of comfort only a steering damper can give you. My only regret is hiding mine under the triple trees out of view.

 

[JPThruxton900]

The problem I’m having is a side to side handlebar shake between 50 mph and 60 mph. This is what I’ve done so far but it’s still there:

• new tires (Pirelli sport demons)
• tried different tire pressures
• checked spokes and wheel alignment
• bearings are good
• steering bearing adjustment is good
• everything torqued down to spec
• chain and rear wheel aligned properly
• wheels are balanced

running out of things to check. The bike has progressive front springs and Hagon rear shocks. Not sure if that’s the problem. Any suggestions are appreciated.

 

[RichBinAZ]

Check the side to side runout of the front wheel rim, also the side to side runout of the front disc.
How are the wheels balanced?
weights on spokes = good,
stick on weights not equally distributed either side of the centerplane could cause a dynamic instability even though the wheel is statically balanced.

 

[JPThruxton900]

The wheels were first balanced with weights. Then I removed the weights and added Ride On tire sealant and balancing fluid. The wheel runout is good, I’ll check the front disc.

 

[Scrammy]

The problem I’m having is a side to side handlebar shake between 50 mph and 60 mph. This is what I’ve done so far but it’s still there:

• new tires (Pirelli sport demons)
• tried different tire pressures
• checked spokes and wheel alignment
• bearings are good
• steering bearing adjustment is good
• everything torqued down to spec
• chain and rear wheel aligned properly
• wheels are balanced

running out of things to check. The bike has progressive front springs and Hagon rear shocks. Not sure if that’s the problem. Any suggestions are appreciated.

If after you've tried all these good suggestions you still have a problem, I would look at your suspension. Speed wobbles are most often triggered by the front wheel being unweighted. That can be caused by excessive rebound damping in the fork... a bump compresses the fork, and the springs don't get the wheel back on the ground fast enough. That moment of insufficient contact can be enough to initiate oscillations. In these forks, rebound damping is handled by oil viscosity. My personal opinion is that this is made more challenging by progressive wound springs (which I have used on my bike and then removed). They compress so easily through the first bit of their travel that whoever is setting the fork up tries to compensate with heavier oil, creating new problems. (My experience was that they were an especially bad match to Hagons, which seem to have quite a bit of static friction... the fork compresses easily, while the shocks momentarily resist compression).

I feel like I'm repeating myself from other threads - sorry - so I'll quit there, other than to say that when a suspension shop sorted my bike out, it came back with constant rate springs up front.

EDIT... I've just figured out it was actually you I gave this speech to on another thread. Sorry about the rerun. Good luck with your issue.

 

[Boy Racer]

In these forks, rebound damping is handled by oil viscosity. My personal opinion is that this is made more challenging by progressive wound springs (which I have used on my bike and then removed). They compress so easily through the first bit of their travel that whoever is setting the fork up tries to compensate with heavier oil, creating new problems. (My experience was that they were an especially bad match to Hagons, which seem to have quite a bit of static friction... the fork compresses easily, while the shocks momentarily resist compression).

I've never understood why Hagons supply and recommend 20W oil with their progressive springs. I run Hyde full length progressive springs, use a 5W oil and played around with the air gap (sorry can't remember what it currently is) which works for me. I also have adjustable fork caps fitted but haven't touched them for a while.

I also have a steering damper really just because I like them

 

[FredBloggs]

I've never understood why Hagons supply and recommend 20W oil with their progressive springs. I run Hyde full length progressive springs, use a 5W oil and played around with the air gap (sorry can't remember what it currently is) which works for me. I also have adjustable fork caps fitted but haven't touched them for a while.

I also have a steering damper really just because I like them

That's only real reason to fit one to a Bonneville. For the bike, they add nothing. Just extra weight. There's something wrong with a Bonneville if it doesn't behave itself in the handling stakes.

 

[twinsisin]

The problem I’m having is a side to side handlebar shake between 50 mph and 60 mph. This is what I’ve done so far but it’s still there:

• new tires (Pirelli sport demons)
• tried different tire pressures
• checked spokes and wheel alignment
• bearings are good
• steering bearing adjustment is good
• everything torqued down to spec
• chain and rear wheel aligned properly
• wheels are balanced

running out of things to check. The bike has progressive front springs and Hagon rear shocks. Not sure if that’s the problem. Any suggestions are appreciated.

Checked wheel alignment... did you check front to rear wheel alignment? This is more important to handling than chain alignment.

Chain and rear wheel aligned properly... before or after aligning front to rear wheel?

When chain is set for a straight shot to the CS sprocket front to rear wheel alignment can be off.

 

[Boy Racer]

That's only real reason to fit one to a Bonneville. For the bike, they add nothing. Just extra weight. There's something wrong with a Bonneville if it doesn't behave itself in the handling stakes.

I wouldn't say that is totally correct as the damper does stop the frontend from unexpectedly wiping round to full lock at very slow speeds or even stationary, which can easily cause a drop of the bike.

 

[ScoutAggie]

Not necessarily ruling out the mechanical, but a couple of quick questions that others might be able to comment on:

a) where is your body weight centered when the shake/wobbles happen, and does changing riding position have any better or worse effect?

2) how much pressure/weight (if any) do you have on the bars when this happens?

 

[Scrammy]

Not necessarily ruling out the mechanical, but a couple of quick questions that others might be able to comment on:

a) where is your body weight centered when the shake/wobbles happen, and does changing riding position have any better or worse effect?

2) how much pressure/weight (if any) do you have on the bars when this happens?

These are the right questions if you're dealing with a bike that's prone to speed wobbling, which usually means a bike with a lot of power... enough to loft the front wheel on acceleration. These bikes don't have that problem, at least not on stock suspensions and not if they aren't loaded with a passenger or a lot of gear. Something mechanical is wrong. My bet continues to be suspension, but I'm biased by experience. The other explanations offered are edge cases, but possible.

 

[DUCKMAN]

This is not the first time I have read a post regarding "weave" at 50mph and above. Including a post from someone experiencing it from new bike.
All the same questions/answers with no positive results.
So I'm going to throw this one in from way out left field.
Years ago Harley touring bikes were afflicted with a front end weave at cruising speeds. Did not affect all bikes and the issue was mostly unresolved for several model years.
It was eventually discovered, if I remember correctly, that the problem was traced to the way some motors were installed during assembly. They were not "true" in the frame.
Don't know if that's possible in this set up but I have read enough of these posts to think someone at Triumph should be paying attention.

 

[Boy Racer]

I have read enough of these posts to think someone at Triumph should be paying attention.

To a 13-year-old model?

 

[Terry Colley]

......I have read enough of these posts to think someone at Triumph should be paying attention....

As if.