Kz900 Stock Rims - Largest Tire Size?

I really like the look of the stock rims so I don't want to go with a more moden (mag) look, but if I change out the swingarm with one that allows more width, what's the largest tire that will fit on the rims? I'm about maxed on the stock swing arm with a 120/80-18 tire.

And then as a followup - what's the largest size I can run without having to monkey with the chain for clearance issues? Is the 120 about as far as I can go without having to offest the front sprocket/etc?

Swingarm changes are new to me...just looking for some insight from the exprienced out there.

Stock wheel is 2.15" wide. 120/90-18 is as big as practical on that width wheel. Guys have run wider I'm sure, but it's not functionally correct.

Thanks - that makes my swingarm decision pretty easy.

you can always get a rim a spoke kit from bucanans and they come in a few different sizes i have 2 3.5 inch rims and a 4.25 inch rim from them and i have a line on a 5.25 incher that i would love to use with something.

Good to know - maybe next winter. :laugh: