Hi all,
Here in the land with no speed limits I thought I'd see if I could hit 100 MPH, and did so with no problem. I inched it to 105 MPH and got a gentle (at first) wobble like when the wind from a truck catches the front fairing. The wobble got progressively worse and as I gently decelerated it continued to get progressively worse to the point that it started to worry me that I may go down on the Autobahn at 100 MPH.
When the bike got down to around 90 MPH the wobble ceased and the bike handled normally. Is this normal behavior for a bike with a batwing fairing? My old Road Glide with the fixed fairing did not do anything like this, but I never got it quite to 105 MPH either. Is there anything I can do to prevent this high speed wobble? Or is the Ultra only capable of 80-90 MPH without becoming a high speed mechanical bull?
Thanks,
Megavolt
Is your wobble accompanied by a shaking of the front end, or is it more of a tail wagging event? The touring chassis, 1979 to 2008 version anyway, has been known for about 30 years now to have a little problem with the rubber mounted rear end not tracking true with the front end. It's a phenomena that can be demonstrated and felt at sub-100 mph speeds in sweeping curves, especially when hitting bumps while leaned over slightly. Reminds me of certain solid axle rear wheel drive cars and what we always referred to as "bump steer", only on two wheels it takes on a much more spooky feel. This little problem is what has spawned all those companies like Ride-Str8 and Tru-Track who make linkage devices to attempt to control the lateral movement of the swingarm/trans in the rear rubber mounts.
The other issue is the front end shake most prevalent on the batwing bikes.
In my opinion this is a combination of a poor fairing design that actually provides lift at high speeds, and a too steep steering head angle which reduces the self centering action of the forks. Most bikes with steep rake angles tend to be sport or racing bikes (steep rake allows easier and quicker turning at the expense of straight line stability), and they come equipped with steering stabilizers to counter the lack of oscillation damping that accompanies those steep angles. You will notice that your Harley doesn't come with such a device. Therefore, correct steering head bearing adjustments are critically important on an e-glide. Too loose
or too tight can interfere with the front ends ability to stabilize itself once something sets off the oscillation. As Ironhorse noted, you need to check all the basics like tires, steering head bearings (make sure they are greased properly and adjusted to spec), etc. If everything checks out good and you still have front end shake, you may want to try a different windshield. I haven't personally tried one yet, but I understand the new screen from Brian Klock is supposed to actually kill the lift of the stock setup and maybe provide a little downforce. Might be worth a try?
Good luck. Once you've checked out the obvious mechanicals to make sure everything is to spec, if you still have the problem then you will probably need to do the same thing many of us have done. Reduce speed to sane levels, especially in those conditions that we know from experience tend to lead to the wobble. There are a few long sweeping curves where I do a lot of my riding, and that's were I first experienced the wobble. Being the curious sort, I didn't change my ways immediately after scaring myself silly, I went back a few more times and ran through the area again at high speeds. Same result, so I eventually figured out that it might be a good idea to slow down through that area in the future (unless I was having a really boring day and needed a shot of adrenaline). BTW, different bikes and people experience the wobble/shake at different speeds. Some claim they need to be doing well over 100 mph, while others like me have had it occur at speeds as low as 80-90 mph.
Jerry
Author
Topic: Wobble When I hit 105MPH - (Is This Normal?) (Read 8587 times)