Motorcycle tire size question?

Question

I just bought a 1978 kawasaki KZ-1000 (dont laugh). It came with a 120/90/18 rear. There is 3/4" on either side of the tire for clearance. If i get a lower profile (80 series) how big a tire can i cram in there?

Answer 1

it is best to stay with the size the manufacturer originally put on the bike .

Americanmototire.com is about the cheapest place I have found online for tires and you can have them within 3 or 4 days of ordering

Answer 2

Don't laugh, they're a good bike.  I got over 100,000 miles  out of my 79 shaft drive before the cam chain guides and idlers hardened and conked out from age and heat.  You might be able to go with a 130 IF you can find them in a 18 inch.  You could also try finding a 16" wheel from an LTD with a 130 or 140, but yould probably have to swap sprockets to keep your rpms down unless you would actually want it reving faster.

Sometimes you can find Continental K112 retro tires advertised.  They come in 18" sizes and are in inch widths with 100% aspect ratios.  I ran them for years before they quit making the 17" sizes.

Answer 3

Your tire size on older bikes will be limited by the availability of the market (often only the stock tire sizes are available) and

MOST IMPORTANTLY, the rim size.  The older bikes rims are often not as engineered as the newer bikes, so only the original tire will allow for a proper fit and a great seal.  

The good news is the new rubber compositions in what used to be horrible second rate sizes now grip like glue and really awaken these old steeds.

I highly recommend ronayers.com for tires, shipping is reasonable, and in my years of buying from them, the one return I needed to do, they covered it 100%.

Answer 4

if you're trying to "pimp out" this bike, its kinda useless. Its like 20" rims on your Ford tempo.  Maybe just cruise the hog and live the dream.