Like Roger, I never knew there were lots of different gear ratios available other than the standard 3:70, 4:11, 4:30, etc. But when we ordered the rear ends for my 27 and Dans rpu the guy offered stuff I had never seen, like 4:00, etc.

But as far as your original question, you won't notice a bit of difference between the 3:73 and 3:75.

Don