QuestionI have a '01 Sportster and am wondering how large a rear tire I can have installed without compromising overall handling, safety and clearance. The fenders are stock and have not been altered in any way.
Thanks
AnswerHi J.D.,
Thanks for the question, and Happy New Yesr.
The basic answer to your question is "however large a tire will fit between the swingarm rails". But there is more to it than that.
I understand that "fat rear tires" are all the rage and style now for cruisers, and you are smart to ask about handling problems. When you fit a larger-than-specified tire to your bike, handling will be affected. Sometimes it's a subtle difference, sometimes not. It depends on what size the tire is, what the tire profile is like, the tread pattern and so on.
The most noticeable handling trait you will see with a larger-that-stock tire is how the bike behaves while cornering. With a wider tire, as the bike leans over, the rear end of your Harley "rides up" on the wider edge of the tire, tipping the bike into the corner at a slightly steeper angle. This will make the bike tend to "fall" into corners, requiring more pressure on the inside handlebar to make the bike stay on line. Basically, you will lose the even, nuetral steering characteristics of the Sportster.
If you want to talk about wide rear tires while not thinking of style, there is a reason for them. On high-powered bikes, and especially on high-powered sportbikes, the combination of the power transfer demands from the big motor, plus traction demands of high cornering loads result in the need for wide, flat tire profiles. Fat tires have always been a style item on cruisers, but in truth they are not needed to the same desgree as on sportbikes. None the less, they have become popular due to the resurgence of the chooper look, with sizes moving into the ridiculous, if not dangerous.
No disrepect to your Sportster (it's one of the best looking bikes out there in my opinion), but you have no NEED for a fat rear tire. But if you WANT one, I strongly suggest you do not go up more than ONE size in width from stock. I think anything bigger than that and you will see a real decrease in ride quality, especially in cornering. Also, I'm not sure anything bigger will fit the space available without major swingarm modification.
If you value good cornering ability, I'd stick with the stock tire size and invest in a higher quality tire instead. If anyone gives you grief for having a girlie-sized rear tire, just make your point by passing them in the corners.
Have a great year, and enjoy the ride.
Bill Roberson
