I come from many years of motorcycle riding, and found my problem was simply a matter of overcontrol. Try too hard, and the thing darts all over. My suspicion is that when you feel the bumps from the suspension through the handlebars, you automatically tend to react, and steer the Spyder slightly.-Scotty
I think a problem for us experienced two-wheelers is leaning. When the Spyder hits a bump, or you ride on a road with a pronounced crown, the machine tilts. This takes a bit of getting used to. I often ride on poorly maintained county roads with many ruts, bumps and steep crowns; Spydie rolls left and right like a brand new pilot trying to keep the wings level on a gusty day!
On a motorcycle, when the bike tilts with the road (or a wind gust), the rider immediately hauls it back upright. Try that on the Spyder and you're ride's gonna get real interesting! Ask me how I know...
I've also noticed the Spyder does "wander" a bit on the straight stretches -- like a four-wheeler. It's not an "out of control" wander, rather it just moves a little with variations in the road. The problem for us experienced two-wheelers is the rider moves opposite the Spyder; when the Spyder moves left the rider's body doesn't move immediately (a body at rest tends to stay at rest). This is VERY disconcerting for the motorcycle rider who NEVER leans opposite the bike except at slow speeds making tight turns. It also might may make the inexperienced Spyder rider feel like the Spyder is trying to scoot out from underneath him or her.
Interestingly, I don't notice this tendency during a turn. I believe it's because the suspension and steering are "loaded up," so-to-speak, with the forces of the turn, and the rider is already leaning away from the centripedal force.
Like a four-wheeler, if the rider tries to force the Spyder NOT to wander on the straights, the result is almost always overcontrol. The secret is to give Spydie her head just a bit in the straights and go with the flow.
Lastly, I find at highway speeds (70+ mph) it's best to lean forward a bit and put a little bend in my arms. That way when my upper body sticking out in the slipstream takes a wind gust there's enough give so my body movement isn't transmitted to the handlebars.
The best advice I can give a new ryder is to take a few moments in a parking lot getting used to the "feel" of Spydie. Start slowly and work slowly into the faster stuff. Try to avoid the distraction of traffic until you feel more comfortable. Use the dealer's demo Spyder if possible, because the lack of adequate cooling air while learning to ride (lot's of slow riding, stopping and sitting) isn't good for the engine during break in.
The bottom line is Spyder ryding involves a learning curve -- but it's a very shallow one for the committed!
Life is a highway...
Mark