KZ1000 rear wheel on KZ550

From what I've read.. some KZ750 rear rims can be interchanged with KZ1000 rear rims.
Also, KZ750 rims can be interchanged with KZ550 rims.
So it stands to reason(if the previous statements are true) that some KZ1000 rims will interchange with KZ550 rims?

The rim I'm looking at is an 18"2.50Mag(with disc brakes) off a 1989 KZ1000 which I am proposing to install in a 1981 KZ550, which currently has an 18"2.15Mag(with drum brakes) same style 7spoke.

Is this possible without much modification?
I'm thinking that installing KZ1000 brakes on a KZ550 might be tricky? Would it be better to find a KZ1000 rim with drum brakes? so far the only KZ1000 I've seen with drum brakes has a 16" rear rim. do 18" with drums exist?
Other concerns are the axle size, chain length,
and whether the chain sprocket lines up.

Has anyone tried this?:silly:

The 1980 KZ650-F1 and 1980-83 KZ550-A have an 18" cast alloy rear wheel with drum.
For a disk brake the KZ750E rear wheel is probably the closest match, but the conversion is probably going to take some work.

As for swappability between modles, it depends upon what 750 & 1000 you're talking about. A 750-Twin is completely different from a 750-4, and the early 1000s can be quite a bit different from the later models.

I'm thinking swing arm clearance.
Steve

Same here. as well as the swing arm, fitting or adapting the brake pedal & rear master cylinder are probably going to take some doing. The only model I know of that's easy is the KZ650CSR: the disk brake conversion for it is just a simple matter of swapping parts.

Thanks for all the replies!
I guess my question could have been simpler.
My current rim is a 2.15 18”, Is there a wider KZ rear 18” wheel that would easily swap its place?(or, which one would require least modification). I do weld and can move some things around but would like to avoid modifying the swing arm.
Like a 2.50 or 3.00?

It usually helps to mention the specifics beforehand, especially what motorcycle it is. I was assuming you had a KZ550LTD.
For a disk brake conversion you are going to have to modify the swing arm if it currently has a drum brake.
The KZ1000P police has an 18 x 2.50 cast alloy rear wheel.
All of the 18" cast alloy wheels of the smaller models that I know of are 2.15 or less.
If you want a fat rear tire with drum brake, then you're probably going to have to go with a 16" LTD wheel.

JMKZHI wrote: It usually helps to mention the specifics beforehand, especially what motorcycle it is. I was assuming you had a KZ550LTD.
For a disk brake conversion you are going to have to modify the swing arm if it currently has a drum brake.
The KZ1000P police has an 18 x 2.50 cast alloy rear wheel.
All of the 18" cast alloy wheels of the smaller models that I know of are 2.15 or less.
If you want a fat rear tire with drum brake, then you're probably going to have to go with a 16" LTD wheel.

Sounds like it's not worth the work for now. If I were to replace the swing arm I would probably find one with a monoshock.
For now I'm hoping that a 120/90-18 tire will provide enough grip. I'm guessing that a 130/90-18 might be on the border of too much for the 2.15 rim?

I've had several rear 130/80-18 tires over the years. (Note it is an 80 series, not 90. The 130/90 might be too tall.) It worked fine as far as chain clearance etc, but I don't have a chain guard.

The wider tire seemed to give decent straight line grip, but was less stable at high speed and did not corner as nicely as a 120/90-18.

loudhvx wrote: I've had several rear 130/80-18 tires over the years. (Note it is an 80 series, not 90. The 130/90 might be too tall.) It worked fine as far as chain clearance etc, but I don't have a chain guard.

The wider tire seemed to give decent straight line grip, but was less stable at high speed and did not corner as nicely as a 120/90-18.

thanks for chiming in with specific tire experience, now you’ve got me fired up with more questions! ..although we might be heading a little off this thread’s original topic.
When you say “too tall” do you mean it won’t fit under the fender with enough room for suspension travel or it won’t fit in the swing arm?
i guess by raising the rear it might make the steering marginally more sensitive because of then steeper fork angle?
anyways, i have much more room in the swing arm for height than width.

i also have no chain guard. nor do i have fenders(or much of the rear at all)and i’ve moved the battery to where the air box once was. i’ll try to post pics tomorrow.
the closest thing to the tire by far is the drum brake torque arm, which i plan to modify if need be. i like the idea of a taller tire but should i be concerned about high sidewalls being less able to stay on the rim in extremes? (that might be more of a car thing)

In your opinion(theoretically of course)how would the performance of the 130/90-18 compare to that of the 130/80-18 or 120/90-18?
would 130/90-18 be narrower than the 130/80-18 but wider than the 120/90-18? if so, could that mean potentially a nice compromise between the two?
would the 130/90-18 rear be taller than the 100/90-19 front? would i then need to up the height of the front for balance?

Also, in your experience, how did the 130/80-18 wear over time compared to the 120/90-18?
thanks!!

Back when I first got one of the bikes, the rear shocks were worn out and the rear tire would rub the upper plastic fender occasionally. I think if the tire were slightly taller, it would have hit more. I don't think I recall an issue with tallness and the swingarm. Maybe if the chain was shorter by one link, the tire might move forward too much and hit the arch of the swingarm, but I'd have to take a closer look to estimate that.

I think a 130/80 would theoretically be the same width as a 130/90, but the 130/80 would have to curve more to fit the rim since the sidewalls are shorter, so maybe it would end up a bit narrower. It's really hard to say, though, because you can order two of the same size tires of the same make and model, and they can be very different in width. I have two dunlop front tires that are the exact same nominal size but ones seems like a 1/2 inch wider.

I'm not sure about the wear rate. I haven't really noticed one wearing out sooner than another, but it could have. Having three bikes, the tires get rotten before they get worn out.

The 130/80 ends up pretty close to the same outside diameter as the 120/90. I don't know how much taller the 130/90 would be. I don't think I'd make the front any taller or bigger than 100/90-19. I stick with 130/80 or 120/90 and I think overall I might prefer the 120/90 for its handling. The 130 seemed to get a little wiggly on turns. But that could just be the way I ride or the some difference in the manufacturing. All three of my bikes have different brand of rear tires. At one point I had all Dunlops and that is what I'm basing my thoughts on, but that was years ago.

axel wrote: ...................
In your opinion(theoretically of course)how would the performance of the 130/90-18 compare to that of the 130/80-18 or 120/90-18?
would 130/90-18 be narrower than the 130/80-18 but wider than the 120/90-18? if so, could that mean potentially a nice compromise between the two?
would the 130/90-18 rear be taller than the 100/90-19 front? would i then need to up the height of the front for balance?

Also, in your experience, how did the 130/80-18 wear over time compared to the 120/90-18?
thanks!!

For many years I ran 130/90-18 tires on the rear of my KZ650-C1. I had to change the chain guard to eliminate rubbing. Those tires were difficult to mount on the 2.15 rim, but I managed.

However - eventually I recognized that forcing that size tire on the narrow rim somewhat deformed the shape of the tire and resulted in no more tread on the pavement than would be provided by a 120/90-18 tire. So even though the 130 tire looked wider when mounted it did not provide better grip than the 120 tire, and the center of it it wore at the same rate as the 120. Several years ago I switched back to the 120/90-18 tire and I will stay with that size in the future. Ed

thanks to all for the insights!
i now feel confident that sticking with 120/90-18 is the optimal choice.
below are some pics of exhibit A.
still a work in progress, currently designing a seat and just finished rebuilding fuel tank(had to cut the bottom off and weld a new one because of rust).
also wiring needs to be organized and tucked away.
but completing the workshop build is priority. the bike is my mini vacation when i need a break from sawdust production. kind of funny that they’re in about the same state of completion.

the current rear tire is a 110/99-18