What ratio should I run on my BMX bike?

Going to be riding street and ramps. Does 25x10 sound about right?

the ‘standard’ ratio on bmx was 44x16 so everything is broken down to whatever gets you the closest to that. 36x13, 33x12, 30x11, 28x10, 25x9, 22x8.

25x10 would kill you for riding around on the street because it’s really low. you’d get nowhere. 28x10 is the way to go since 25x9 is the closer smaller ratio and, also with anything smaller, you’d potentially have problems with the bearings in the driver exploding because of how small things get.

Yea. Im running smallxsmaller

Its rockin.

small gearing is important for bmx but it gets to the point where it’s overkill and looks ridiculous. 25x9 and 22x8 look horrible. i don’t think i could aesthetically do smaller than 28x10.

Im 25x9 stock. Suprised at how it feels although I guess smaller wheels make for fun times… BMX people use weird terms. 9 tooth driver?

i don’t know where driver came from but they’re still called ‘cassette’ hubs despite only having one gear.

Is there a nonasthetic reason for those micro drivetrains? I wouldn’t want my only gear to be 9 teeth. I can (& did) maul a 14t accidentally.

it stays out of the way when grinding and other tricks and trying to keep your drive train from getting messed up.

if you think about the bottom bracket height and then the height of the axles to the ground you could easily bash larger diameter sprockets a lot. it’s the evolution of bmx products and solving problems of design. bikes used to have bashguards that bolted on to the downtube/bottom backet (or were built into the frame), but those died out around 91-92. then they started using really thick sprockets (10mm or so) in the mid to later 90s and heavy, thick chains like you’d find in garage door openers. that turned into bashguards that bolted onto the sprocket as sprockets got smaller since the thick chains would grind the frames as the drivetrain shrunk. then people realized they didn’t need all this bulk and weight and drivetrains got even smaller, the smaller sprockets could be a little stronger while being thinner.

this is probably a more well written history and explanation.

I guess I just dont understand having never ridden a bmx bike. My thought it why run 9t when you can run 14. that’s 5 extra teeth to wear down

how long will that 39x14 setup last when you’re bashing the sprocket into ledges/ramps/walls/etc? depending on how you ride, chances are you’re going to bend or break the teeth off the sprocket before you wear down the teeth.

i made a thread on bike forums about this recently


the bmx forum on bikesforums is stupid.

bikeguide is sadly the only bmx forum to go to for tech advice.

i get that now, it’s just the kind of thing I would never think of because I have no experience in bmx. When my bike friends talk bmx I just zone out because it’s all greek to me.

32X11 fuck the world !
have you checked out bmx board?


So, I went 25x9.

good choice

[quote=“Getfucked”]32X11 fuck the world !
have you checked out bmx board?[/quote]

bmxboard is the best bmx forum but someone stole my account and i can’t post anymore. i don’t know how i can prove it was my account in the first place to get it back.