I took off the deraillers and inner chain ring on my 1960s Olmo racing bike. It has a little 5 speed regina freewheel. I wanted to run 48-18, but the chain kept slipping, so I went with 48-16.

This climbs surprisingly well. I'm not sure if its the efficiency of a tight chain and 700g weight savings, or if its just not fiddling with downtube shifters, or having a running start up several hills. I would normally go up in 40-18 or 40-22. I seem to go up a bit faster, and feel much fresher at the top of hills. I made it up everything today except for giving up on a steeper section of a 10% hill (went in too slow). Made it up other 10% hills though. (All the hills around here are pretty short). 45kph top speed is pretty cool too.

Next step is taking my geared bike up everything in about the same gear inches, to see if I've just been a weenie about downshifting, or whether it is that much more efficient.