So I'm running 44/16 w a GI of 74.3

Two friends are running 46/17 w a GI of 73.1

Why is skidding more difficult w my bike. The frame geometry seems identical to theirs. Could the crank arm length be an issue?

Was thinking of swapping out the rear cog for a 19t. Is this ok? Lowering my GI to 62.5.

(FYI I've been a singlespeed commuter since I was in college. I now ride for fun and have started using the fixed side of my flipflop hub.)