Tire size to Rim ?

I'm sure this question has been asked before. My 19" front tire ( 100/90x19 - recommended by the Forum ) on my 77" KZ1000A is mounted on the stock rim which is a 1.85. Seems to work just fine and not having any problems that I know of.

I'm converting over to an 18" front having purchased another New rim Takasago of 1.85 x 18". Want to mount a 100/90x18 tire ( Avon AM 26 like before ). Any problems with this size tire ?

That tire should be fine. Obviously, the front end will be lower than before which will steepen the head angle and quicken steering unless you also drop the back.

suggested rim size for that tire off Avon's website is 2.15-2.75 but that likely will be fine as 100/90/19 recommended size is also 2.15-2.75.

OUr bikes were designed for a different tire design, a 3.25x19 tire being the OEM size. they have a different sidewall structure allowing a smaller rim. Avon still sells the old sizes. I have them on my kz750G

www.avon-tyres.co.uk/motorcycle/roadrider

Avon recommends these sizes for the KZ1000. Changing to an 18" front just changes the diameter, not the width.

Front: 100/90-19
Rear: 120/90-18

Nessism, I'm actually running a 120/80 series x 18 on the rear of my KZ. I'm wondering if I should go with a 100/80 series x 18 in the front instead of a 90 series ? Looking at the Avon Roadrider AM26's, they don't have an 80 series tire in that size for the front and that is the brand of tire I'm running on the back. There are other Manufactures like Bridgestone BT-45's that do carry the 100/80x18 but "Good or Not Good" to mix Brands ?

Being short in height, my bike has a 12" shock in the rear and I went with the 80 series rear tire to help me with a little better foot placement.

Roadrider (Universal - Front/Rear)

Material # Model Tire Size Service Index Rec Rim Rim Min-Max OW mm OW In. OD mm OD In. Depth mm Revs / km Revs / Mile Shop Now!
90000000680 AM26 100/90-18 56V MT2.50 2.15 - 2.75 108 4.3 642 25.3 5.6 516 825.2 Shop Now
90000000683 AM26 100/90-19 57V MT2.50 2.15 - 2.75 109 4.3 671 26.4 5.6 493 789.6 Shop Now
90000000684 AM26 110/80V18 58V MT2.50 2.15 - 3.00 111 4.4 640 25.2 5.6 517 827.8 Shop Now
90000000681 AM26 110/90V18 61V MT2.50 2.15 - 3.00 116 4.6 663 26.1 5.6 499 799.1 Shop Now
90000000664 AM26 120/80-17 61V MT2.75 2.50 - 3.00 120 4.7 629 24.8 7.5 526 842.3 Shop Now
90000000682 AM26 120/80V16 (60V) MT2.75 2.50 - 3.00 126 5 601 23.7 5.6 551 881.5 Shop Now
90000000674 AM26 120/90-17 64V MT2.75 2.50 - 3.00 128 5 649 25.6 7.5 510 816.3 Shop Now
90000000675 AM26 140/80V17 69V MT3.50 2.75 - 3.75 143 5.6 665 26.2 7.5 498 796.7 Shop Now
90000000656 AM26 3.25-19 54V MT2.15 1.85 - 2.50 98 3.9 664 26.1 5 499 797.9 Shop Now
90000000661 AM26 90/90-18 51V MT2.15 1.85 - 2.50 97 3.8 619 24.4 5 535 855.9 Shop Now

I wonder if I should go with a 90/90x18 since this size tire seems to be for the 1.85 rim that is going on the bike ? I do know that the 100/90x19 that is currently on the stock 1.85 rim appears to be a little too wide for the rim. At least that's my opinion.

But then again maybe the 90/90 will look too small on the bike. Any input is alway appreciated !

90/90 not only will look too small; it will BE too small.

100/90 is the correct metric width for the 1.85 rim. Ed

Ed, Should I look for a 80 series tire in the front of that size, since I have an 80-series ( 120/80x18 ) tire in the back ? Or is it a big deal ?

Unfortunately Avon doesn't offer the 100 in an 80, just 90 ?

Why 80 series? 90 is the recommended profile.

To match the front. Again, I have an 80 series tire in back. Probably not a big deal ?

Nessism wrote: Why 80 series? 90 is the recommended profile.

Excellent question! A 100/90-18 tire has a diameter of 25.09". A100/80-18 tire has a diameter of 24.30". The difference in total diameters is .79". The difference in the height of the axle above the ground is half the total diameter difference which is a mere .395". That's slightly more than 1/3 of an inch. When you consider the location of the seat between the front and rear axle lowering the front forks by 1/3" will hardly lower the seat height at all; certainly not by a noticeable amount. I would stay with the recommended profile. Ed

A Very Appreciated " Analytical ' Evaluation Ed, and I " Thank You " for good solid advice !