How to build a flatland BMX bike

A flatland BMX is a little different from any other type of BMX. The mods that make it great for doing tricks make it essentially useless for any other purpose. Even a polo bike (stay tuned for “How to build a polo bike!”), with it’s silly low gear ratio, can be ridden to and from the court. A flat bike, not so much. Nevertheless, it’s a unique and loveable style and a great way to waste time.

Here are the basics:

  • Low gear ratio, like 2:1
  • Short top tube
  • Short chain stays
  • 4 pegs
  • Slick, sticky tires
  • A freecoaster rear hub
  • A seat that you can grab on to.
  • Of these, the 4 pegs are probably the most important thing. Everything else is negotiable, but it all goes towards helping you lay down sick moves.

Now let’s have a look at my old bike, which is about to undergo some major surgery. A white street style BMX with red and blue accents leaning against a tree

 

My first bike, built myself with considerable help from friends. I loved it very much, especially the paint scheme, but it’s time to upgrade. The main thing with this beast is that it weighs about 9000 pounds, and the 21-inch top tube makes it about as maneuverable as a Lincoln Continental.

I stripped it down to cannibalize some parts:

  • Handlebars (The dip in the middle is nice for your knees)
  • Wheels (Nankai freecoaster rear hub)
  • Seat (grabbable plastic bottom)
  • Cranks (ugh)
  • Chain (red!)
  • And stem (low offset – it is good not to have long levers sticking out from your center of rotation)

Then I got some new bits:

 A fork, sprocket,headset, and bottom bracket

  • Frame – Zion Low-Kee, a flatland specific frame with an 18.1″ top tube, short chainstays and a very un-slack headtube.
  • Fork – KHE Tanaka, with zero offset (again, keep everything close to your center of rotation)
  • Ronin sprocket – 21 teeth, both for the low gear ratio, and to keep the teeth from chewing up the frame.
  • Headset and BB, both from 1664. Nothing special, but satisfactory.

 

With all the parts assembled, and a clean, tidy workspace, start bashing stuff together.

Unfortunately, I forgot to take pictures of the assembly process. But there are lots of resources for that, where much smarter people will explain how to do things properly. Start with the bible.

The only things on a flatland bike that are difficult/non obvious to assemble are the headset and bb. Before you start bashing on the bearings with a hammer, try this:

a makeshift headset press with a big bolt and some washers.

Observe: a big bolt and a bunch of washers. Works like a charm. Or you could spend some money on a proper headset press, but that’s just crazy talk.

Several cuts and bruises later, you should arrive with something like this.

picture of a finished flatland bike.
Kindergarten Style!

Get a rad dude with a nicer camera than yours to photograph it, then go ride it til breaks. Good luck!

 

 

KHE 

Ares

Zion

1664

In Transit

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