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Are BMX Stem Bolts Universal?

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Generally, stem bolts come in different shapes and sizes. However, in some cases, they are universal. So, asking if BMX stem bolts are universal is not a crazy question.

Are BMX stem bolts universal? BMX stem bolts are universal. However, their universality applies only to BMX bikes. In other words, one can only use a BMX stem bolt on another bicycle if the receiving bike has the appropriate dimensions.

In the subsequent paragraphs, we discuss more on BMX stem bolts. We talk about the many sizes, how to measure them, and much more.

close-up view of bmx bicycle frame isolated on black background

What Is a Stem Bolt?

A stem bolt is a small device used to hold down a bike’s stem to the handlebars. It keeps your stem from self-adjusting while you ride your bike.

What Size Are Stem Bolts on BMX?

As we mentioned earlier, stem bolts come in different shapes and sizes. The varied sizes have standard measurements and different thread pitches. The diameter for each bolt head is also different for every stem bolt.

So, what size are stem bolts on BMX? BMX stem bolts come in different sizes including, M8, M6, M5, 5/16″, etc. 

The M on the M8 BMX stem bolt stands for the metric designation of the bolt. The 8 refers to the diameter of the bolt, and it is measured in millimeters. 

  • The standard thread pitch of the M8 bolt is either 1.0mm or 1.25mm, with 1.25mm being the standard measurement. The length of the threaded section is about 24mm, while the overall length is 33mm. The bolt head has a diameter of 11mm. 
  • The M6 stem bolt has a diameter of 6mm, while the standard thread pitch is 1.0mm.
  • The M5 stem bolt has a diameter of 5mm with a standard thread pitch of 0.8mm. 
 Bolts on a gray background.

How Do You Measure a BMX Stem Bolt?

There are various kinds of stem bolts, but not every stem bolt will fit into every bike. Before you decide to purchase a stem bolt, ensure you take an accurate measurement of your bike’s stem bolts. 

The best device for measuring a BMX stem bolt is a thread checker and caliper. You can also try to measure it with a metric ruler.

  • To get the length of a BMX stem bolt, measure the dimension from the thread to the underside of the bolt head. Going by this, the length of a stem bolt is the length of the shaft without the bolt head. 
  • To determine the thread pitch, measure the distance between each thread. Doing this can be a bit complicated if you do not have a thread checker tool.

Getting the actual measurements of your stem bolt ensures you get the perfect stem bolt for your bike. You also avoid a situation where the stem bolt is not properly secured, causing the steerer to twist. 

Close-up of several stainless steel bolts

Best Metals for BMX Stem Bolts

Two of the best metals used for making BMX stem bolts are titanium and stainless steel

  • Titanium is an excellent material for a BMX stem bolt because it offers durability and lightness. However, titanium stem bolts are expensive, and in some cases, the quality of the titanium can be poor. 
  • Getting a stainless-steel stem bolt is not complicated. You can always find one strong enough for your bike’s stem. Quality stainless steel BMX stem bolts do not rust, and they can handle more torque than recommended.

Final Thoughts

BMX stem bolts are universal for BMX bikes. However, stem bolts come in varied sizes, and to get the ideal stem set up, you need to measure the diameter of your stem bolt. In trying to get the size of your stem bolt, having a thread checker is essential for accuracy.

Get the correct measurements and you are good to go.