Hi, Thanks for the link. I did infact search and read that entire post you linked before I made my OP. That post leaves off waiting "to hear how the setup turns out". My salesman told me at the time of purchase that I should be able to fit a 180 rear, I expressed that was over the top, 170 would be fine. He assured me it would fit. Now his knowledge of expertise is unknown to me, hence why I turned here.
I know for a fact you can get the 120 on the front. The widest we've ever run on the back was a 160 and it just screwed up the handling too much. I don't know about a 170 in there. We were pretty close to rubbing the chain on the 160. I'm not sure about the clearance to the rear shock either.
I'm curious as to why you would want to get that wide in the back.
That big of tire just for looks is not the best idea. A salesman will tell you the sky is green just to sell you a bike, Handling will suffer at the very least. Clearance issues may come up as well. "Plus a 170 would look like a light bulb mounted on that narrow of a rim. Want a bigger tire, get a bigger bike