I want to upgrade to a larger wheel/tire for my 1997 Roadking. What is the largest size I can go and still use the stock fender?

 

Largest wheel you can upgrade to and still use the stock fender would be a 21 x 3.5 with a 120/70-21 tire. Some guys raise their fenders a tad bit in fear of rubbing but most bikes get away with just swapping the wheel out and calling it a day. We always do recommend checking for clearance, but we have sold hundreds of this exact setup with absolutely NO issues! Feel free to check out our gallery and wheel selection and let us know if we can help you with your future purchase! Custom Harley Wheels

 

You need 5/16" of clearance between the fender and tire all teh way around. Tape a 5/16" nut to the center of teh tire and spin. If it hits raise the fender. i always advise to raise the fender as I did have some customers with issues. Accurate information and honesty are our policy.

 

I have the 21" on the front of my 04 RK Custom and taped a 1/4" nut to the tire and it did rub so I simply redrilled the aft fender mounting hole a little bigger and lifted the rear of the fender up as I tightened the fender bolts. Be sure to use locktite on the bolt if it comes loose you can burn the paint on the fender also use tape over the hole before drilling so you don't chip the paint. I love the look of the 21 in the original fender.

 

Good points! That is how it is done. Thanks for that.