I have a 200 55 17 on my night train. The handling sucks ... Tires too wide ...
I was thinking of a 180 55 17 .. any comments ????????

 

It will handle better, not sure how it will look. Are you planning on keeping the stock rear rim??

 

Yes ,, I want to keep the stock 6" wide rim. AND you can't see the tire ... I have a custom rear end ... different fender ... saddlebags etc

 

I'd check with the tire manufacturer-whether that 180 will work on a 6" rim.

 

My 07 fxstc did not handle like my 99 dyna until i changed out the stock dunlops for avon cobra/venom tires and changed out the stock shocks to progressive 422s and drop in springs. Now my softail is every bit as good as my dyna in the twisties.

 

What size Avon ft & bk

 

Throw some Metzeler 880 on it and it will handle like a dream.

 

I tell you when I swtiched to Avons from Dunlops it was like having another bike, handles well now. I have a 200 rear and it handles as well as a skinny tire softy

 

what's the fattest (avon) 21" I can put on the stock rim

 

Why wouldn't it?

200mm = 7.87"
180mm = 7.08"

Going wider than 200 on a 6" rim would have problems, going narrower should not.

If anything, when you go to the 180 from the 200 you might want to step up the aspect ratio from 55 to 60 to maintain the same ground clearance and steering/handling geometry; as the 180/55 will be a smaller diameter tire than a 200/55.