I purchased a set of RC wheels with Avon 21" front tires and have recently noticed that it is rubbing the back of the fender. I discovered it about 4 months after I had it installed when it began bubbling my paint on the back of the fender. I since have heard that the avons are known for growin. I now have extended the fender tabs to provide additional clearance. I now have about 3/8" clearance. Is this enough? Should I change to the Metzler I have been told they dont grow as much. Second question if I do change the front to the Metzler will I notice any ride difference if I leave the 200 Avon in the rear.

 

You can fix that by going back to a 16.

 

have the 21'' Avon on mine I have right at a 1/4'' of clearance after just drilling out the rear fender mount holes and lifting it up or tape a rubber hose to tire rotating till tight against fender and tightening fender bolts after drilling out rear holes .3/8'' should be more than enough if that is what you have on the fender at about the 2:00 position looking from the left side running front Avon and rear metzler seems fine to me when I need front tire will change to a metzler just because

 

If it did noit rub before, check the tire pressure.

 

I enlarge the rear fender bolt holes by two drill bit sizes. I than rotate the fender forward to its max. I have yet to have a tire rub the fender doing this.

 

I ran 5,000 miles or so on the stock fender in the stock location with a PM 21" and a Metzeler with no clearance issues. Metzeler's design keeps them from growing in circumference at speed. I have now gone to the Klock Werks Benchmark fender made for the 21", and like it for having no rivets and no "dovetail" flare at the bottom, and keeping the stock look which I liked.

 

Amen here with the Metzler tire up front, drilled rear hole with a 3/8 and tilted it up placed a 3/8 nut on the tire a spun it no touching but it sure did with a 3/4 in nut.