Originally Posted by
Cyclesafe
Well, at 90rpm, 32mm tires, and a 175mm crankarm a 44/11 gets you 28.9 mph, a 46/11 gets you 30.2 mph, and a 48/11 gets you 31.5 mph. All speeds reached only while descending. Any benefit of the taller combination would be fleeting at best.
You beat me to it. Was just going to say that if your wife can spin out @ 30 mph while loaded with 25 lbs or more of gear attached and she's not descending, and can do it for a sustained effort, she should turn pro.