[Riderjeff]

Are there any fitment issues when putting an 800 supersport 3-spoke on the rear of a GT? Can I use the stock caliper, disc, and sprocket?

And, BTW, I'm in the market for a 4-pot/4-pad Brembo caliper for the front, don't care if it's left or right. If you know of one available, please PM.

 

[ps1k]

rear axle on the supersports are 17mm.
you can fit new sleeve and bearings to convert it or knock them out of the stocker.
everything else on the rear is good to go.
front you'll need to either space the rotors 5mm or find a 4 pot caliper.
you'll also need a ss/monster axle and spacer.

 

[MajorSoftie]

I don't believe that is correct. I believe the 17mm axle went away long before the 800SS.

Older SS wheels take the 17mm axle, but later ones take our axle. I believe the change was around 2000 or 2001.

 

[Muschi]

all supersports share that 17mm rear axle, even the SS1000DS with
the banana swingarm has it.