when i was at the shop were i bought my bike there was a guy there with a speedmaster.he has 18 on his .he said he rides mostly highway.when he tookoff it sounded like he had to slip the clutch alot to get rolling.that's what i ment with killing low end.17 is nice i'd like to try 18 some day.cruising 85 & 90 sounds pretty sweet to me.ride safe there englishyankee.