Listening to Car Talk this morning a question about octane @ altitude was dicussed. This person lived in Denver. She wanted to know, because of the thinner air, if she could use a lower octane in her car without the a problem and Click & Clack thought she could. I live @ sea level and found that I can run mid-grade just fine. Since I don't ride a mile up I was wondering how high you would need to be to drop down to an 87 octane? I don't remember this octane question being discussed before. If it has, sorry for bring it up again but in this economy a buck saved means I can ride more.