18" Front Wheel Gain ?

Would there be any advantage going to an 18" front wheel on my 77' KZ1000A over the stock 19" wheel ? I already have upgraded the front with dual disc brakes from an LTD model and well as the single piston calipers.

I doubt the 18" tire will offer an advantage. I say this because Kawasaki used an 18" front tire on the 1978 KZ1000-D1 (Z1R), but they switched back to a 19" front tire when they brought out the 1980 KZ1000-D3 (Z1R). I would have thought if the 18" front tire worked better than the 19" one they would not have switched back. Ed

Ed, Just was tossing around the idea with helping me lower the bike a little for better foot placement.

Already have dropped the front tubes 1" in the front and shorter rear shocks at 12" in the back. Seat is reupholstered and rounded which has helped too.

As far as the height is concerned if you switch from a 100/90-19 tire to a 100/90-18 tire the front fork will drop down 1/2 inch. This is because the diameters of the two tires differ by 1 inch, but from the axle to the ground is half of that diameter. The link below will let you plug in various tire size options and will show you the difference in diameters. Just remember to divide the diameter by 2 in order to calculate how much the axle will drop. Ed

www.tacomaworld.com/tirecalc?tires=100-90r18-100-90r19

You may have fender issues.
Steve

I did this with my 72' H2 but re-drilled the front fender mounting brackets. Worked pretty well.

Maybe more tire options with the 18 versus the 19?

Need a little more input on this question before I make the change over from 19" to 18".

Anyone tried this on their KZ1000 and if so, did you like or dis-like the results ?

Besides purchasing a new 18" front tire, I can do this pretty reasonable in cost, with used good condition parts.

Keep in mind that Kawasaki switched the KZ1000-D model from 18" to 19" front wheel after only one year. I suspect they had a good reason to do so, but I don't know what it was. Ed

All KZ1000-P police bikes had 18" wheels (82-2005). just throwing it out there.

Here's a comment posted by someone elsewhere (this may be more applicable to the rear wheel, though):
Its all related to speed and torque. Big wheel = more speed, less torque, small wheel = less speed, more torque. Taking these in consideration, bigger wheels will have a longer acceleration time, but the motor RPM will be lower once the desired speed is achieved. If you want fast acceleration, use smaller wheels, if you want fuel economy on long travels without frequent stops, use bigger wheels. These are just physics principles, As for the motorcycle, the wheel size was taken into consideration when they engineered the bike according to its horse power, speed required, components sturdiness. Changing wheel size could result in premature components failure. Wheel width will change the contact area, which means, bigger contact area, more friction, more gas. END.

With a 1.85 rim ( wheel ), can you mount a 110/90x18 tire ?

The answer may vary by manufacturer since there are subtle dimensional differences from brand to brand, but Avon does not recommend that combo.

www.avonmoto.com/street-tires/street/roadrider/