Ok. Did a search and didn't find anything
God knows what you typed then, this subject has been done to death…
Anyway,
I ran 33/13 on 24” wheels for a long time and I got on fine with it.
it’s sort of “mid-size gearing” I guess, got rid of that bike about 6 months ago, I recently got an off the peg BMX which came with exactly the same 33/13 gearing for 20” wheels, so maybe my old Dirt jumper was geared a bit high, I’ve also run 38/16 on 24” which again felt fine, a slightly lower gearing ratio, so it spun out a bit sooner but made accelerating easier…
They (whoever “they” are) reckon around “55 Gear inches” is optimal (Chain ring divided by Sprocket, Times wheel diameter in inches)…
I assume your running 24” wheels so:
Example 24” SS gearing:
“Mid size”
38/16 X 24 = 57
36/16 X 24 = 54
33/13 X 24 = 60.92
32/14 X 24 = 54.85
“Micro gearing”
27/12 X 24 = 54
27/10 X 24 = 64.8
25/11 X 24 = 54.54
25/10 X 24 = 60
25/9 X 24 = 66.66
The advantages are always being debated, and it’s not worth getting into yet again, basically pick a gearing ratio you like the feel of. Using your Bulb you could go for a 27/12 ratio but I would recommend sticking with a 32 or 33 Tooth chainring and trying out 13/14/15 T sprockets (again assuming your running MTB cranks, it’s low profile gearing and you can get some useful ratios, the fact that you’ll struggle to go bellow 12T on a normal MTB cassette hub does dictate your options a bit.
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on a bmx though there are advantages, mainly lower profile sprocket so less likely to wreck it grinding
