what is the biggest tire i can put on my 11 road king with 18 x 5 rear

 

I'd say 200 from personal experience. Anything wider than that's probably gonna rub

 

I have a 200/50 on my 18" rear. No problems.

 

We don't mount 200 tires on 18x5.5 rims as some customers with that size combo experienced a high speed wobble. I only mount 180/55/18 tires on that size rim. If you want a wider tire get a 17x6.25 rim and get a 200/50/17 tire on it.

This is our experience.

 

I have an 18 200/50R on my RK. No issues...

 

 

Yea I've was told there was a wobble issue with a 200 on the stock Harley rim but never experienced any issues with it. I did however go to a 17 inch and 200 when I had the Extreme Machine wheels mounted on my 13 RK. They didn't want to do the 200 on the 18

 

A 200/55 is going to need a 6.0/6.5" wide rim, in either 17" or 18", according to my favourite brand Avon. Low profile tyres such as these sizes are much more dependent on correct rim width than our earlier higher profile tyres were.

 

Most of the drag guys run 180 or 170 to give a wider contact patch because on the narrow wheel it pooches up and really is no gain for traction