This isn’t a “what bike” to get question, rather how to figure out how BMX bike parts are sized and assembled. However, if this needs to go in the weekly beginner thread, I’ll go there.
My son has a Redline BMX bike. Currently he has a one piece crank set on the bike. This week one of the bearings came apart, so we disassembled everything and got a new bearing. However, he said he wants a three-piece crank set for Christmas. If we do that, what do I need to get?
– Would the new crank use the same bearings and bolts in the current bottom bracket, or does everything in the bottom bracket get replaced? Most of the options I see only have the two arms and the center piece that connects them.
– Does he need a new chain ring? The one he has is pretty small and has 25 teeth. It looks like some of the options include a new chain ring.
We don’t have a good bike store around, so I’m on my own. I’m confident that if I get the right parts I’ll be able to get it put together.
**Edit:** This is what we have https://imgur.com/a/WcyJmg1
Thank you.
by Zocalo_Photo
4 Comments
It looks like an American BB so you would hammer out those cups and buy bearings, spindle, and crank arms. You will also need to replace pedals. 3pc uses 9/16 pedals not 1/2”
you’ll need something like [this](https://www.empirebmx.com/products/empire-bmx-usa-american-bottom-bracket).
[this](https://www.empirebmx.com/products/sunday-saker-v2-cranks?variant=40213500067927)
And some pedals. I like [these ](https://www.empirebmx.com/products/odyssey-twisted-pro-pc-pedals?variant=40213461467223)
I’d probably get a new sprocket too.
If you see an option that includes a chainring, it’s probably meant for racing, and if the bike currently has a 25t sprocket, it’s for sure NOT meant for racing.
you can also get Mid BB (more common these days) or crankset with mid BB included and mid/usa bb convertion cups
also have in mind if you’re going to buy bb and cranks separately the spindle diameter 19 or 22mm