When I bougth my '07 america it had a 17/42 set-up,but I went to a 18/42 to lower the hwy rpms.I just changed again to a 41/18.(found the 41 on clearance!)This set-up is great for one up riding,but I find myself having to down shift alot when riding two up.So, I'll be changing back to the 18/42 !Hope this helps.
