What's causing this front end wobble?
 

So recently I noticed a front end wobble on my 15 street glide at highway speeds. My only recent change to the bike is a set of Monroe air shocks. The steering head bearing was adjusted last summer, so it's probably not that.

The stock shocks on the street glide are 12" from eye to eye. The Monroe shocks are 14" long fully extended. Could the belt tension caused increased shock height cause the wobble in the front end? Could it be the different riding angle the bike is at due to the longer shocks?

Im going to lower Monroes to 12" and take another ride. Then I'm going to increase the shocks to 15" and re-tension the belt. Any other ideas?

Very possible the front tire is cupped. That's where i would start.

Well I couldn't sleep so I went out to the garage and checked belt tension. Belt tension is within spec, regardless of weather the shocks are at 12" or 14". So that's out.

Tires look good, no signs of cupping, and pressure is correct.

neck bearing tightness check fall away per manual or wing it

Basic geometry at work here. Taller rear suspension effectively decreases rake angle and that decreases trail. Less trail means the bike turns quicker & is less stable going straight.

Certainly possible. The rain is just letting up here, gonna drop it down to stock height and take another ride.

I have recently noticed a little more play in the tracking of my 2015 RG. I changed out wheels and tires in the rear, from a 16" to a 18" rear, front was the same size (19"). (Bought HD Agitator wheels). The height difference on the wheel tire combo, from axle hole, is literally 1/2". That's how much it changed the rake angle on the front and I can feel it in the bikes stance. I think it is crazy that this little bit of height can make that much difference.

I have ordered a set of 3/4" suspension lowering kit from Covington Customs to put on my Progressive 944 shocks. I want to see if that will bring it back down to stock riding stability.

Have the fall away checked again
That will do it everytime

I was having a similar issue. I had just put new tires on and the steering head bearings cleaned and lubed. Double check the steering head bearings I found mine were set to loose.

I had a wobble at about 35 mph only when I let go of the handlebars, it didn't wobble at highway speed or if I had hands on the bars. I tightened my neck barring a little and no wobble now. This is the second bike I have had to do this too.