Topic: Rear Wheel Fishtail At High Speed

[Anonypotomous]

I've noticed my rear tire feels like it's fishtailing a bit when im riding anything over 60+ mph (freeway/highway)  I did just get new Kenda K761 Dual Sports put on about a month ago (5/19) by my mechanic.  I have ridden probably 150-200 miles since that date.   I didnt find any answers/clues when using the forum search.  Any ideas/tips on troubleshooting this?

[Davez134]

Does the freeway have grooves/lines on it? Or smooth asphalt?

[alacrity]

occams razor first:
Check to be sure you have proper inflation in rear tire,
Check spoke tension... is the rim "wiggly?"
check that your rear wheel is mounted correctly and properly snugged up per spec.
IF it is and you get wiggles at the hub, you need to get some new wheel bearings.
check to see that your shocks are bolted down fully,
check to see if you have any play in your swingarm (do this by jacking up the bike, unbolting the shocks and removing the rear wheel. If you can wiggle the swingarm, you need new bushings there -- get the bronze ones from various suppliers).
You're sloppy butt feeling is gonna be from one of the variables above, most likely.

[DH]

+1 on all of the above. The rear spokes on my 750 caused this once. It felt like the rear tire was "squirming"
under accelleration at high speed. Had spokes tensioned/wheel trued and symptom disappeared. But do check
the other areas, including the steering neck bearings for wear/play.

[snowfighter2]

Dont forget to check the bearings in steering.  I can't remember where I read this; front end wobble=swing arm bushings, rear end wobble=steering bearings. +1 on the rain grooves on concrete highways, I've always hated those.