Hi, I've been chasing a speed wobble for 4 yrs. Every time I go above 85 mph (140km/h) and hit a bump or tar line I get a wobble and have to slow down. Here's what I've done so far:


2011 FXDB 7500 miles, bought with 2500 miles


1. fall away check
2. checked tire pressure
3. replaced tires/balanced wheels
4. checked rear wheel alignment
5. checked rear shock setup
6. checked spokes
7. brought bike to dealer, explained the issue and they couldn't find anything wrong.


What's next? Steering damper? Chassis stabilizer?

 

Mine was never as bad as what you've described, but there was a trace of it... This seems to have fixed it: https://www.hdforums.com/forum/dyna-...tor-mount.html

 

I'd start looking at rider input, vehicle/engine alignment, and your front fork suspension. Ride heavy on the bars at those speeds and you'll set up all sorts of fun oscillations as the bike tries to stabilize itself and you fight it. And the stock front fork setup is pathetic; have you done any work on the front or are you still running those short soft springs and too light of viscosity fork oil? And vehicle/engine alignment; a Dyna will live an die by that alignment.

I can run some not to be openly mentioned speeds, the bike is stable but I've made certain the alignment is correct, the forks are upgraded, and most importantly, the rider knows not to give the bike too much input through the bars...

 

I never had a really bad wobble until recently. Turns out my axle pinch bolt on the lower fork was a tad loose. Tightened it up and wobble disappeared. As far as tar patches my fork brace fixed that (got it for the grooved roads in Northern Colorado). I've also noticed that swapping out my front springs with progressives greatly improved the feel of the front end, feels like its on rails now.

 

If everything checks out, put a steering stabilizer on it. I have run my street bike to 135 mph (closed course) with one and bike is laser straight.
The stabilizer also gives you piece of mind and is a must at very high speeds.

 

Hmmm I checked the pinch bolts when I replaced the front tire.
As for riding style affecting the bike, I've messed around with that too, I've ridden other hds and haven't had a problem.
My front and rear suspension is stock and I don't get wobbles on good highways.
I'm now considering the predator front mount.

 

I had a bad wobble at around 75 mph. Then it would go away once I hit 80 mph. At that speed, it can be interesting trying to decide whether to ride through it or slow down.

I tried most of what you listed. Eventually, added the Tru Track which cured it. Can also do Sputhe and change the front which is a lot easier than the rear. I would think the predator would do the same.

 

Get a vibra-technics motor mount and be done with it, and check your spokes.

I had the same wobble at higher speeds, and in hard cornering, got the motor mount and all went away... then a few thousand miles later... it came back and I noticed while cleaning my spokes one day that I had a few loose ones in my rear wheel.. got rid of the spoked wheels and now with alloy wheels I've taken my bike up to 120mph and have had zero wobbles, as well as many 90+ mph runs.

I also added a steering damper before all that and the improvement was negligible, but its peace of mind now.

 

Came here to say the same thing.

 

Thanks