so a b-17 would be better on a mtn bike that isnt used for a ton of hard trails, but more distance riding? I did 70 on my mtb and my butt was not happy. sorry for jacking anyones thread, but no point in making two threads with the same title. also, what is the difference with all the different spring models? I am 5'10" 198 lbs, but in decent shape as a lot of my weight is from lifting.