The stem and handlebar of your BMX bike can’t practically hold in position without proper stem bolts. So if your bolts are loose from overly wearing out and you’re looking for replacements, it’s important to get what’s specific to BMX bikes.
Here’s the thing:
Stem bolts come in different shapes and sizes, which means it’s easy to find something suitable for your BMX bike. But are BMX stem bolts universal?
Are BMX Stem Bolts Universal? (Quick Answer)
BMX stem bolts are universal only for BMX bikes. They come in different sizes including 5/16”, M5, M6, and M8. Understand that as much as the stem bolts are universal for BMX, it’s important to measure the diameter to get what’s right for the bike.
The reason why we recommend getting the size of the stem bolt diameter right is because you want the bolt to fit and be tight enough. If the bolt isn’t tight enough, the stem is likely to shake and the handlebar won’t be in the right position.
What Size are BMX Stem Bolts?
BMX bike stem bolts are available in different shapes and sizes. The most common ones that you’ll come across include the 5/16”, M5, M5, and M8.
To make sure we’re on the same page, M is a designation Metric for bike bolts and the number denotes the diameter of a bold measure in millimeters. Moreover, each bolt has a thread pitch, which varies quite significantly depending on its diameter.
For example, the M5 bolt is 5 millimeters in diameter and has a standard thread pitch of 0.8 millimeters. The M6 stem bolt has a diameter of 6 millimeters and a thread pitch of 1.0 millimeter.
The M8 is unique a little more detailed in my view. To say the least, it can have a standard thread pitch of either 1.0 or 1.25mm, although the latter is the standard. Not only is the diameter of the head 11mm, the threaded portion can have a length of 24 or 33mm, with the latter being the most common.
Keep in mind that these are standard measurements and don’t very on bolts of the same size.
BMX stem bolts are unique in the sense that they’re only suitable for BMX bikes. Therefore, we can’t guarantee that they will work well for other types of bikes.
How Tight Should a BMX Stem Bolt Be?
A BMX bike stem bolt shouldn’t be too tight or too loose. Rather, the tightening should just right so that the stem doesn’t twist.
From what I understand, you should tighten the bolt a few turn in the clockwise direction, making sure you’re doing so as recommended. In other words, the right approach is to tighten the bolt as stated on the stem.
Tighten the bolt to the 75-inch per pounds point and then stop it at that. To be clear, the 75inch/pound load applies to all the BMX stem bolds and you should therefore observe it as a strict tightening rule.
Tightening to the right load ensures the bolts last longer, but doing the opposite can cause damages to the stem.
How Can I Replace BMX Stem?
If you have the right toolset and the time to do the job, replacing the current BMX stem with a new shouldn’t be difficult.
First, understand that a bigger percentage of BMX stems have a similar structure. Whether you wish to get a front or a top-load model, they all feature a four-bolt system.
With that said, here’s what you need to do to replace the BMX stem:
- Untighten the bolt that clamps to the fork, the compression bolt that holds the headset, and the handlebars bolt
- Pull the loose bolts and remove the handlebars, the top cap, and the step
- Put a spacer in the fork followed by the step in the right position
- Make sure you line the stem so that it’s in the correct position with the fork and then put the compression stem bolt back
- Remove the front stem cap and install the handlebar
- Fix the front stem cap in position, apply some grease to the bolts’ threads, and then fix the bolt by tightening them to the right load.
Keep in mind that if the stem you wish to attach to the BMX bike has a different thickness from the older one, you will need to add or remove spacers to get it to fit right.
Make sure you tighten the bolts properly until there’s no space between the stem and the cap.
Also, make sure all the bolts have the same level of tightness. My recommendation is that you tighten up to the 8nm load.
What are the Best BMX Stem Bolts?
Upgrading your BMX stem bolt may also mean getting new stem bolts. So some examples of the best BMX stem bolts can go a long way to make your search easier.
One of the best-rated BMX stem bolt is the Wanyifa M8 x25mm.
It’s made of grade 5 titanium alloy and weighs only 6 grams per piece, so you aren’t going to add too much weight to your BMX with these.
The golden finish makes the bolts element and scratch resistant, but the Allen head of these ones look smaller compared to the old ones. The package includes 6 pieces of bolts at a price that’s downright a bargain.
SUNLITE stem bolts are also great. They are made of strong materials and they have a gray finish that makes them element and scratch resistant. The Allen head has a good diameter, so these should serve you well.
Some BMX riders may find the Allen head a little too big and somewhat intimidating. Should that be the case, consider a model made by Wanyifa.
Frequently Asked Questions
1. Can I Tighten The BMX Stem Bolt Past The Required Load?
You should not tighten the BMX stem bolt beyond the suggested load. Doing so can easily damage the stem, so much so that you may have to buy a new stem. Stick to the required load, making sure you don’t exceed 75 inches per pound.
2. How Do I Measure The Stem Bolt For A BMX Bike?
You can measure the stem bolt of a BMX bike starting from the end of the thread to the bottom of the head. You get the length of the shaft, which doesn’t include the head.
You also should get the thread pitch, which is the distance between the thread. The result should be the value in millimeters.
3. What Tool Should I Use To Tighten A BMX Stem Bolt?
You should use a torque wrench to tighten the BMX stem bolts. Any other tool will more than likely damage the stem.
Based on what we’ve learned in this guide, BMX stem bolts are not universal for all bikes. However, bolts sizes such as M5, M6, and M8 are universal only for the BMX bikes.