Originally Posted by RayGreen
............ As with some of you, my butt does get sore but I'm getting toughened up. My present bike is a 15 speed cheapie (Wal-Mart) that I inherited from my youngest son. On my best days, in the hills of Central Ky. I'm barely averaging 15 mph.................
You do realize that the little speedometer computer only uses one magnet on the spoke and not two?
Heck, if you're averaging 15 mph in hilly country you can't be hurting too bad.