KZ400 Tire sizes.

New to this site just joined yesterday. Hello Everyone.
I own a 1978 KZ400. Looking to replace worn out tires. The tire size on there now is a 3.25-18 front and 3.5-18 rear. I've been looking and trying to find a updated tire size. The rim is a 3.5-18 inch stock rim, wire spokes style with an intertube. So a bias ply tire. Is there something you recommend for this bike. I've been seeing on forums people going with a 110-90-18 in the rear and a 100-90-18 in the front. I want a wider tire than factory in the rear. Maybe just a tad bigger up front. Will a 120-90-18 fit on this size rim out back, Or any bigger size tire i could go with. what do you recommend? I know I can only go so big because of the frame size. And going big effect's handling. I basically want a wider than stock tire, with a cool tread pattern. Examples would be the pirelli sport demon, michelin macadam, or a shinko 712, great price on the shinko's a pair for under $100. I've been looking at other tires also. I'm building a cafe racer style bike here. I want to know if these tires can be run with a tube. or are they a radial. Will these old style rims mount and hold a radial? Any issues. Just unsure of how to go on this route. Any info on sizes and type of tire would be nice. Could you also recommend what will work on this. And send me info. Thanks Mike Wilson.

I am dead sure a 110-90 won't fit on the front. I put one of those on the front of my KZ750 and it rubbed the fender.

I believe 110-90-18 is the closest metric equivalent to 4.00-18, which is what my 750 runs on the rear. So, I believe it is a bit bigger than 3.50-18. I am not sure if 120-90 will fit the back of yours, maybe. I think it does on my 750, I have run 4.75-18 on the back before.

As far as tire type, the Bridgestone Battlax have a good buzz. Check out Dennis Kirk, they have a huge selection and good prices.

Mustangmikewil wrote:

I want to know if these tires can be run with a tube. or are they a radial. Will these old style rims mount and hold a radial?

I believe all bike tires are radial design. Any tire can have a tube installed, even if it is "tubeless" type. The old rims should be able to handle any tire you want if it is the right size.

I like those Bridgestone Battleax tires Sweet. What i'm looking for. Thanks. Just need to find the size thats right for what i'm going for. Just a new style tire will change the bike a bunch.

1.85 x 18 is the stock rim size front and rear for a KZ400

a 110 tire is about at the limit