Here is my HO longtrack set up. Stock ramps, stock spring, 17.5 gram pins, 50 degree helix, beige spring set at 18lbs. 22/43 gearing and I use the ski-doo gold belt. This for flatland riding, for 10,000 feet I remove 5 grams from the pins and use a 200/350 spring. I am running a 136 X 1.5 track.