I have heard of the wobble a lot with the 21/18" combo. I always hear it with the 200 tire and not so much with the 180 though

 

Haha, yeah man. Sometimes I really roll, but yesterday was insane. This patched member could ride. My bike is just a tad wider than a Dyna, LOL.

 

Ok, so I've got a 2010 flhx with a 21/17 combo 200 mm tire. I experienced this same high speed wobble, it about scared the $hit out of me. It doesn't do it all the time. I've had the bike over 100 with no issues, but this particular time I too was catching up to the pack and hit about 90 when all hell broke loose. Ive spent the last few weeks researching this issue. I've checked neck bearings, tire pressures and countless other things. Bumped the front tire pressure up to 42psi and that seemed to help a little. But, I think I'm convinced that its the loss of "trail" that effects the ability to stabilize this wobble. I'm also thinking there's something going on with the size of the rear tire in relationship to the front tire ( as described by a previous poster)??? This whole thing has freaked me out so bad that I'm also considering going down to a 19/17 combo like the CVO. Confused

 

I had mine in the shop for motor build last November and while it was in I had them adjust/tightened up while they had it all apart. I'm somewhat convinced it has to do with the 21" front wheel adding additional rake. I played with air pressure in tires and rear shocks some slight improvement. New springs from Race Tech with gold emulators and 1" lowering kit is on the way. Hope this does the trick. If not then I will continue with the process of elimination. Possibly rear shocks next.

 

I lowered mine 1" and added intiminators when I went with the 21/17 200 rear. I have never had a wobble.

 

I thought we are talking 18 / 21 combo. Not 17/21 anyways that what my setup ends up. 17s is more sidewall steel ,anyway here in California. Highways if youdon't 80 mph+ , keep your *** away from the car pull lanes or else you might get run over , or use the side streets

 

Chi Town Eric, is your bike lowered in the front?

 

Ok, so how does going from an 18" to a 17" help? The difference in tire size is going to make the diameter of both the same.

If you put a 21" wheel up front you making the overall diameter larger, effectively raising the front of the bike and also changing rake and trail. Common sense would dictate to correct this you lower the front end.

 

Bike is lowered 1" in the front, head bearing checked, in spec.
Will be taking it out tomorrow for some high speed test runs. If this fails, going back to stock sizes.

 

Please keep posted. I am getting ready to purchase some wheels in the near future.