Frequently asked questions and information about building BMX wheels.
What is Effective Rim Diameter (ERD) and how is it measured?
Effective Rim Diameter (ERD) is the diameter measured at the nipple seats of the spoke holes in the rim. This distance is used to calculate the correct spoke length. If the rim you are using isn’t listed in our calculator, you can measure the ERD yourself and submit it to us. There are easy guides on how to do this here or here.
What is Pitch Circle Diameter (PCD) and how is it measured?
Sometimes mistakenly called “Flange Diameter”, Pitch Circle Diameter (PCD) is the diameter of the circle created by the spoke holes on a flange, not the outer diameter of the flange. This is the distance measured between the centers of opposite spoke holes of the same hub flange. Some rear hubs have different size flanges, thus two different PCDs. These hubs may require two different spoke lengths when lacing the wheel.
What is Flange Offset and how is it measured?
The Flange Offset is measured from the true center of the hub to the center of the hub flanges. Since some rear hubs have different offset flanges, the flange spacing cannot be simply measured and divided by 2.
What does 3-cross mean?
Essentially it means how many times one spoke crosses over another on a given side of the wheel. When a wheel is fully laced, and it intersects with another spoke 3 times, it is considered 3-cross. When it intersects with another spoke 4 times, it is considered 4-cross. Most modern BMX wheels using 36 spokes are 3-cross. In a 3-cross spoke lacing pattern, just remember the phrase “over, over, under”. This is an easy way to check the lacing pattern is done correctly, when following the path of an outer spoke it should cross “over” two spokes and “under” one spoke.
What gauge spokes do I need?
Most modern BMX bikes use 14-gauge (14g) spokes. This refers to the thickness of the spoke.
What length nipples should I use?
We recommend using 5/8″ (16mm) long nipples.
How do I lace and true a wheel?
This is a lot harder to put into words, but it’s not that hard once you try it. There are some great videos online, like this one here!
Help! I still don’t get it!
The best and easiest way to lace up your new wheel is taking it to your local bike shop and having it built by a professional. They can ensure you have the correct spoke length and lace up your wheel perfectly.