xtx, I just installed a 16t front sprocket because I felt the same, I commute everyday on about 75 k's of freeway, felt like I was killing it.....

It now cruises about 120 k.p.h. on about 4,000 rpm (GPS), it feels so much more comfortable and the speedo now reads a 2 k.p.h. difference.

I haven't ridden it off road as yet so I can't comment on that.

regards

Chris