Yeah, I spun the wheels and watched the tread and sidewalls and everything looks really smooth. I am not sure how to properly check for runout with this hand/eye inspection. My old tires had the wobble, and the first set of new tires did not fix it and now this is a brand new set and it still wobbles. So with three sets of tires causing the same wobble, does it seem feasible that something is loose or worn in the front end that does not stand out with hand and eye observation? The dealer swears the tires are perfectly balanced and aligned. Including the laser alignment of front and back wheels. There is no play in the steering. Maybe I should just take it to another dealer for a diagnosis and see what they come up with? Thank you so much for the feedback and helping me figure this out.
Perfect balance & alignment means
absofreakinlutely diddly squat if you're talking about something that's not round &/or running true to start with!! It's only beneficial if those things aren't causing wobbles or vibrations regardless of how well it's balanced or aligned to start with!!

And then there's the question of '
who's version of perfect?' - that of the dealer, who's tech might occasionally get to do a balance using a machine that may or may not be well calibrated, &/or who's never done anything but use an outdated & proven inadequate version of a factory alignment, with all the scope for errors that lot brings; or the 'perfect' of a mob who do these balances & alignments all day every day using highly trained & skilled techs working with state of the art & frequently checked/calibrated machinery?? There's 'perfectly balanced & aligned' iaw the lowest common denominator, there's everything in between, and then there's 'truly perfectly balanced & aligned' iaw those highly trained & skilled techs using proven & benchmarked 'World's best' machinery & practices' - which of those three do you reckon is the best reflection of
your dealer's 'perfect'??
If you can get a wheel in the air & you are still agile enough to then get a reasonably useful eye down close to it, you can relatively easily do a rudimentary 'roundness & run-out' check with a jack & anything heavy with a solid straight edge that you can sit up close to the tread surface &/or the sidewall of the tire as it spins!! (A brick comes to mind, altho a dial gauge stand, gauge, & probe would be a lot better - just not essential!

) You just need to lift the wheel enough to let it spin, then slide that something solid with its straight edge in/under & up
reeeaaallll close to the tread - as close as you can get it without impeding the spin - then spin the tire and closely watch the gap between tread face & straight edge... does it change any? If not, then the tire is reasonably round, but if you think the gap varies
AT ALL, then there's likely a 'roundness' problem worth checking! If your 'not moving' solid straight edge actually
HITS the spinning tire then you've
REALLY got an 'out of round' problem!! And regardless either of those results, close variable gap or actual hit/stop, will mean you'll have a wobble/vibration as you ride that you just can't get rid of, no matter
how well you balance the wheels or align the steering! :bdh:
You can due the same for 'run-out' or 'true' simply by sliding your straight edge up
reeeeaaalll close to the sidewall (you should probably even do it on each sidewall to be sure!

) and then closely watch the gap - any variation on either side means the tire isn't going to be running the tread straight down the road as it rotates while you ride; but if you started with a gap, no matter how imperceptible, then just as with the 'out of round' test, any actual touching/stopping means it's
REALLY bad!! Regardless, in either case to some degree it'll likely be causing wobbling at low riding speeds and vibrations at higher speeds, with an increasing wobble/vibration under brakes that gets worse as you stop harder!! Normally, these wobbles/vibrations are quite noticeable, altho they might
juuust be detectable as something you think
could possibly be coming from the belt at a given speed, which is why so many get caught up in that being the problem when it's really the tires; but as others have mentioned, the belts/belt tension &/or worn cush-bushes in the drive cog can definitely produce that 'belt vibration' on their lonesome too!
Still n'all, it is possible that, especially on an older Spyder &/or especially on something that's towed a lot, it could well be something like a worn swing arm, worn swing arm bushes, or worn rear wheel bushes too. But those rudimentary Run-out & roundness checks are fairly easy to do, so I'd do them
BEFORE starting searching elsewhere!! And I'd
NEVER take just
ONE Dealer's diagnosis as being infallible, especially if there's some relatively simple tests you can do yourself to confirm/deny that diagnosis!!
Good Luck! :cheers: