Shaft rear tire sizes?

I have a 79 KZ1000 shaft Kawasaki. I currently have a 130/90/17 tire. Can I goto a 140/80/17 without rubbing?

What tire sizes do you guys run?

I'd be careful about going too wide on a stock rim. According to Kawasaki.com the stock rear tire on the 1979 KZ1000-Shaft was 450V-17 (see diagram below) which is the rough equivalent of a 120 series tire (see table from Bridgestone site below). According to that table, your 130 series tire is already 1/2 inch wider than stock. A 140 series tire would be a full inch wider than stock on a stock rim.

For many years I ran a 130 rear tire on my KZ650 on the stock rim. On my bike, that is a full inch wider than stock, so the rim is considerably narrower than what is actually required for the 1" wider tire. As a result, squeezing the 1" wider tire on the rim deformed the cross-section of the tread and changed the profile of the tire. A few years ago I switched to a 120 series tire, which is about 1/2" wider than stock, and I found the bike handles as well, or maybe even better, than with the 130 series tire because the 120 tire's profile is not deformed much at all. I'll never go back to the 130 (even though it looked cool). It was a royal pain in the butt to mount and it didn't help handling.

So squeezing that 140 series tire on your stock rim will most likely change the tire's profile and could negatively effect handling. As far as rubbing goes, the 1" wider tire on my KZ650 rubbed the chain guard, so I replaced the chain guard with a narrower one. I don't know if the wide tire would rub other stuff on your bike. Ed

I run a 130 rear and a 100 vs. a 110 front. No need to go larger even with the torque my 1105 puts out
while doing my best Eddie Lawson impersonation . A 140 will fit but it will be tight. Be careful on which
tire you choose.

.

Good Fortune!

You guys give the best advise! I think I will stick with my 130 tire, but I will drop down a series 130/80/17, down from 130/90/17.

Now, wondering about my from tire. Currently its a 110/90/19… Any thoughts?

Don't go any wider than what is recommended for your size rims, you will worsen the handling due to excessive tyre wall flex.
The wider the tyre the less accurate and slower the steering will be (Especially regarding the front tyre).

According to Kawasaki.com (see diagram below) the stock front tire for the KZ1000-E1 is 350V-19. I would go with the stock metric equivalent 100/90-19 (see Bridgestone table below). One thing you may want to do, if possible, is eyeball the various tires in person before buying. Different tire makers, and even different tire models within the same tire maker, build tires of different widths even though the carry the same tire size on the sidewall. If you look at the pic at the bottom you'll see 2 Michelin front tires, both 100/90-19, that are very different in width. When they are mounted the difference is still noticeable. Ed

Your front size is fine but I would stay with 90 aspect on the rear. Hard to get specs on the old 450-17 size, but as far as I can find it was relatively close to a 400-18 in overall diameter at about 26"-26.5", a 130/90-17 would be the same basically, where a 80 series would cut near 1" off the diameter and would look pretty lame to me, and actually cut your gearing ratio considerably so the engine would be running quite a bit more revs vs the 90 series.
The old 400-18 was a 100% aspect ratio meaning same sidewall height as width, not sure the 450-17 followed the same rule, but if it did to any extent, a 80 aspect would not work very well.

Ok, so after reading all this great information from you guys, I have decided on staying with the sizes I have currently on my bike now. 110/90/19 (front), 130/90/17 (rear). Later on, down the road if I keep this bike (would only trade it for a single cab, double cab, or thing VW) I will have custom wheels made with different sized tires. For now, I'll stick with the size that I have.
I have approx. 4 more pieces to polish, replace the handle bars, swap my carbs, fix my turn signals, tune the carbs, and replace my tires, and she is on the road for this spring coming! This site, and you guys have been a very valuable resource for my, and my KZ! Thanks again!

How wide are the wheels?

For a 1.85 front, a 100/90 tire works well. I wouldn't go to 110 unless the wheel is 2.15.

For a 2.15 rear, I'd use a 110 or 120/90 (max) tire

2.5 rear can go to 130/90

Nessism wrote: How wide are the wheels?

For a 1.85 front, a 100/90 tire works well. I wouldn't go to 110 unless the wheel is 2.15.

For a 2.15 rear, I'd use a 110 or 120/90 (max) tire

2.5 rear can go to 130/90

It is a stock wheel. I don't ride my bike hard, or fast. I work 9.5 miles from home, and only would ride the bike on nice days, and an occasional Friday. I also have a '79 Bus that I take out every now and then. I never go out on the Highway and the bike rarely goes over 55 mph. I primarily am doing this for looks. My future plans for the bike if I keep it is to have a stretched custom shaft with a hidden mono-shock, custom wire rims with a wider rear tire (not too wide though, I don't like the super wide look either). I want to create a stretched, but with a slightly cafe look, but old-school. I'm gonna merge the three looks together tastefully! But for now, with clip-ons, lowered, black, and polished, I'm happy with it's current look!

The ST was completely different from other KZ1000s. It didn't use a 1.85x19 front wheel and a 2.15x18 rear. I don't know what width rims they were, but the front tire on the ST was a 3.50-19 instead of the more normal 3.25-19 for the time, so I would assume a 110/90-19 would be a fine fit, and as to the rear, again, a whole different bike. Not a 2.15" wheel and for sure you don't want less than a 130/90-17 rear. I really suspect a 130/90-17 is still going to be a smaller tire than original in circumference, but suspect a 140/90 too large. This again is the age old problem of obsolete parts. a 4.50-17 is fit, anything else a compromise one way or the other.
Low profile was not even dreamed of in those days. Gay looks in tires came in later times. :laugh: