BMX bottom bracket types

There are four different types of bottom bracket shell in BMX frame that you have to consider before buying it, before we start ask yourself why are you buying it? What for and the purpose?

The answer you can find yourself below, by reading my layman terms of words.

American (Old school/skool)

example of 1pc crank in american bottom bracket

Example of 1pc crank in American bottom bracket

Yet people are still using it and considered first type of original BMX bottom bracket, but now this size is inconvenient for a BMX rider to use as it’s heavy and bigger bearings and cups to slot into the frame bracket, the pedaling not smoother as the current trending version named Mid Bottom Bracket, as this type of bottom bracket is using sealed bearing instead of old school type of bottom bracket (American type) using ball bearing, hence there are solution for this type by using sealed bearing for this type (Image) as shown in this image.

You can now buy it online simply and install it by yourself or preferably go to the bike shop if you don’t have tools at home or experience to uninstall.

For the moment, I’m not gonna share more information about the size and length. Once I get it right i will update it here.

Euro (BMX/MTB)

example of euro bottom bracket

This is example of Euro bottom bracket shell threaded comes in Mountain bike frame

This is the most tedious part to explain about, but I have good information as for this BMX frame that using Euro BB is typically used in racing BMX and MTB frames.

The type of bottom bracket is hard to find for it right now on freestyle BMX, as most BMX frames are using American and Mid BB types.

Difference between this type and others are, Euro BB is the only one that have its own special by using thread like Mountain bike bottom bracket, is just that the length of the frame bottom bracket could not always be the same, so buy a bottom bracket according to the shell length, we don’t want to buy just to make it redundant it wasted.

Compare to other type of bottom bracket, this type is weaker than the other types of bearings, as the bearings are small than the other types, Plus the cups may unsure about durability of the thread inside the bottom bracket shell may loosen at the time that we don’t know, for the reason this type off bottom bracket is now no more fused in freestyle BMX frames and only for race BMX frames.

This type its not common and rarely use in freestyle BMX frame, as nowadays called street or dirt bike instead and more to extreme and durable material they put it into the BMX frame.

But now the technology has change from time to time, most of the BMX frames is fused in with press-fit type of bottom bracket shell and no more threaded shell needed.


spanish bottom bracket

Example of Spanish bottom bracket

So far I have never touch or buy it this type of bottom brackets before. But still I’m going to share some information gathered from my observation, cause I’ve got one friend of mine still using it till now, as the frame suits for him.

Seems I have interested with this type of bottom bracket long ago. As the bearing is small than the Mid BB bearings, but larger then the Euro bearings, weaker than American brearings but yet weaker I have found the review which have said that this type of bottom bracket has not given them any sort of problem on fly out, ramps or dirt at all over the whole 7 years, which i may believe depending on your weights that pressure on the crank spindle.

Advantange of this type of bottom bracket is that the weight is lighter than the Mid BB, as our goal is to create a custom build BMX bike with a lighter material.

But the most famous of all times by now is Mid BB as always.

Mid (Famous/Trending)

example of mid bottom bracket

Shadow Conspiracy mid bottom bracket

Lastly, most interesting topic that I love to share about as this type of bottom bracket is using American BB without the cup, which means that the bearings from the cup itself taken out, and press-fit inside Mid BB, the bearings for this type is super durable than other types of bottom bracket,

Q: Why this bearings are called Mid instead of calling it no cup american bearings?

A: Based on my knowledge that they are using reverse engineering, as this bearings size is in the middle form the others types of bottom bracket, maybe they don’t bother or unsure to name it as whatsoever, cause the technology of BMX changed drastically after 2001, since it was called freestyle BMX bikes came with American bottom brackets, followed by Euro.

most of the brands are now selling this type of bottom bracket, as it is super durable but heavier than the Spanish BB, you can find it anywhere in the world.


All of this type stated above are press fit except euro BB, it is threaded bottom bracket shell and the bearing cups as well.

The differences that makes people confused are the size and length of the bottom bracket shell

Decision Making

Make sure that you need to know your budget before buying frame separately, or else if you don’t want to make yourself in trouble buy complete bikes before making decision on buying all parts isolated but even worse, cause you end up may buying wrong things that can make it redundant, we don’t that either me too.

So for the reason i post this topic in my blog is to share experience on what I had done before, I bought a complete bike using American and Mid BB shell.

It’s feel completely different, based on material and top tube to be considered as well which this topic I’m not going to explain about it here.

But I will create the ideas soon and leave the link here.

So as beginner you can get a bike completely free but requires effort to get it, maybe ask your neighbour or friend for any redundant BMX, before that ask them did they quit BMX and reason? You need to know it as for your own reference, cause everybody have their own perspective.

I love and respect you guys, please comment below if you have something to share and advice.

Appreciate it thanks!


  1. My son is wanting to get into BMX and we found this article very informative and gives us more to consider before our purchase especially when considering the size and length of the bottom bracket shell. Good stuff!

    Thank You!

  2. Hi there! Thanks for the comment! Well thank you! you have to read this information before getting it for your son. It’s crucial to know about it before buying.

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