I need a new rear tire and I am wanting go fatter than the stock 160/70 B 17 that is currently on the bike. I am wondering what would be the best size to go with without having to modify anything else on the bike or if that is even possible. If you know anything please let me know.

 

You can go 180/60 easy enough with the stock wheel, all you need to do is make sure the turn signal wires are tucked up out of the way cleanly.

 

How about 180/55 B17 seems to be more options for that size.

 

Hmmm, let's see you want a fatter tire. I shared that the 180/60 will fit just fine, I have the Pirelli Night Dragon mounted on my 09 FXD.
And now you want to know if a tire smaller then the 180/60 like a 180/55 will fit too?
Uhmm, I'll have to get back to you on that after I do some "tire size" research,, Ok?

 

If you find a tire you like, find out what size rim is recommended for it. Not just the diameter, the width.
You probably have a 4.5" rim/wheel. That might be too narrow for some of those wider tires.
I put a 180/55 17 on a 4-1/2" rim and it narrowed the width of the tire too much. Now I'm putting that tire on a 6" rim.

 

Yes, not all 180s are recommended for a 4.5" rim, but the Pirelli Night Dragon is one that is

 

I have been running the D407, 170/60-17 on the back of mine for several years now. Get about 14-15k out of the tire.

I'm currently in the process of lacing up a 16x5 profile rim on my stock hub, which will allow me to use the 180/65-16 tires that a lot of the touring bikes use.

 

Most of the "180/55's" are for 600cc sport bikes. HD's weigh roughly twice what a 600 CBR/R6/636/GSXR600 weigh. Check the load limit before you buy.

Might want to refrain from wheelies too....

 

I have a 180/55R17 Pirelli MT60 RS. It has a maximum load of 805 pounds. That seems pretty high for a motorcycle tire.

 

Not really, considering it's nearly a 700# bike. My Night Dragon is rated at 853.
Folks need to look at load and speed ratings, the factory rear tire for my bike is 73V the NG went 75V and there's an option for a reinforced 81H