1981 KZ 440

First time posting here. I've searched the site trying to determine the widest tire fitment front and back on stock wheels for this bike with no luck. Any help would be greatly appreciated. thanks guys

Welcome aboard! No one will be able to positively answer your question unless you state exactly which 1981 KZ440 model you have. Different models use different size wheels and tires. Your best bet is to simply add the exact year and model of your bike to your signature line. That way it will always be there and you don't need to add it to your text. Ed

If it's a 440-Ltd, then the rear tire is probably a 130/90-16. 130 is the width. 130mm = 5.1 inches. I guess measure the gap between the tire & swing arm to see if a wider tire will fit. be sure to make allowances for the drive chain & chain guard. A 140 tire is about 5.5" wide, so you'd need more than a 1/4" gap on each side. Keep in mind that the actual tire width can vary, so a 140 could be a tad narrower or wider than 5.5". Also, you'd need to consider whether or not wider tires are appropriate for the wheels.

Thanks Martin. The bike is a 440-LTD. The rear tire size you stated is what came off the bike. Unfortunately the tires are flat and dry rotted so measuring the gap may be a challenge. I'm doing a restoration so the bike is down to the frame. I will have the wheels stripped down soon for paint as well. My hope was to have tires ordered and on soon in order to help with making the assembly go smoother. If I don't get a response from someone soon that has went with a wider tire, I may just play it safe and order the original size. Thanks guys.

Thanks for clarifying the model. I cannot say what will work on your bike, but on my KZ650-C1 I used rear tires one size wider (130-18 vs 120-18) than stock for years. They were difficult to mount on the rim. However, as I became more observant about my tires I found that the 130 tire did not actually provide better traction (even in the exact same model tire) than did the stock 120 size tire. The reason is that the profile of the 130 tire is changed by squeezing the tire onto the rim meant for a narrower tire. As a result, the actual contact patch was no larger than the stock size plus the contorted profile reduced the amount of tread on the street when the bike was leaned over. I went back to using the stock size rear tire and am happy with it. I suggest you may want to stick with the stock size which I believe is a 130-16 on your bike. I definitely would not go wider on the front tire.

When shopping for tires, compare the widths of the tires that have the same size marked on them. Different tire brands and even different tire models withing the same brand tend to be different widths even within the same stated tire sizes. Below is an example of two front tires for my bike. Both tires are Michelin, and both are size 100/90-19. One is a Michelin Macadam 50E; the other is a Michelin A48. You can see that the widths are quite different, and that difference is still there when the tires are mounted on rims. Ed