We live in north central AZ. Almost all of our trips involve mountain roads and hot dusty Rez riding to go anywhere. I ran 91 or 93 octane when we first got our Spyder After a while I tried 87 octane and could not tell any difference. So I always use 87 if available. Most of our riding is fully loaded 2up multi week trips. Averaging low-mid 30's on most roads, but a little less on freeways. Out west here most freeways are 75 or 80 speed limit.