Need help from a speedometer gear size expert!
4 at 74 is 5.4%
on 29 teeth that is 1.57 teeth. You are borderline as to making it worth-while. Changing the gear, you will still be off. Since it is off in the right direction, personally, I would make a mental note of the 5.4 %, and just leave it. It's pretty hard to get a speeding ticket, when traveling 5.4% slower than the limit.
5.4% at 37mph is just 2mph, at 55.5 it is 3 mph. And no matter what, that speed-O is still gonna be out .43 tooth or ~1.1 mph@74mph, you can't get closer than that.
The thing of it is; you gotta take the current one out to determine what you have, put it back in. Then find what you need, get it shipped to you, then swap it in;
meh, too much work for me, when 5% is so easy to calculate mentally.
jus saying.....
Oh crap I got it backwards
You said;
I'm actually traveling four mph faster than what my speedometer is showing.
In that case ok, ya got me, I would speed it up
