what size tire to use?
 

What is the biggest rear wheel I put on my 89 sportster ? It has a 130 on it now and want to put a wider one on it. It still has the chain drive.

I am really not sure about an 89. I have a 140 on my 97. It is a tight fit but it works. A 140, i think, is about a 1/2" wider than a 130. Check and see how much clearance you have. Also if you have spoke wheels make sure that they are true or the run out my cause you trouble when you go bigger.

Guy, you can run a 150 tire on it with the help of an offset sprocket kit. Basically it is a front sprocket that is offset 3/16" away from the transmission and a 3/16" spacer that goes between the wheel and rear sprocket. V-TWIN sells them and I believe J&P sells them also. The wrinkle comes in as to whether the fender is wide enough to accept the tire. Also, 150 is as wide a tire as you can safely run on a stock width rim. Hope this helps.

Thanks for the help, so your not sure if the fender is wide enough for the 150 ? Do these offset sprockets put a strain on the shaft or bearing sence there sticking out further ? Just wondering...................

As far as strain on the sprocket shaft and or bearing, no. You're only talking 3/16" or .1875" which is about the diameter of a wheel spoke. I measured inside a fender I have lying around about your year model and it measures 170mm which leaves you 10mm on each side. All your bolts will have to be installed from the inside of the fender and use acorns on the outside. Plus you're going to have to consider clearance for the wires.

Cool man , Thanks again for all the help, I'll let you know what I decide. I was thinking of going with a fat bob fender, does this chande anything, or are we still about the same ? Thanks .........................

It won't make any difference. You'll have the same amount of space between the fender supports either way.