I have been seeing this question pop up more and more in the forums, and it seems like every day someone is asking me when I’m going to put a larger tire on the back of my Ninjette…

Short Answer: 140/70-17

Long Answer:

Anything larger than a 140 will most likely rub against the chain guard. You could possibly remove the chain guard and cram something larger in there, but removing safety features is always a bad idea. Also, anything larger on a 3.5″ rim is not a good idea. So, before start going nuts with tires, there are a few things you should consider:

By going with a tire larger than the stock 130, you’ll loose some of the nimbleness of the Ninja. Granted it won’t be much, but enough to notice it. You’re also going to be adding some additional weight to the the rotating mass of the bike, all while increasing the final drive ratio a tad with a taller tire (Which will be exaggerated even more if you have gone to a 15 tooth sprocket). This means more power needed to turn the tire, and possibly a minor loss in performance.

Overall: So, unless you know what you’re doing — Stay with the 130. Larger tires are most likely better suited for people who track their bike vs. around town bashers.

Note: When buying new tires — The 130,140/70-17 is a popular front tire on some sport bikes. So, make sure you’re buying a rear tire, and not a front, compounds and sidewalls may differ.