There’s a lot of debate amongst cyclists about whether or not bike allen keys should be metric. Some people argue that metric is the standard for bike parts and that allen keys should be metric to avoid confusion. Others argue that bike allen keys don’t need to be metric because they’re not used on other parts of the bike.

Ultimately, it’s up to the individual cyclist to decide what size allen key to use.

As someone who loves to ride bikes, I often get asked if bike allen keys are metric. The answer is yes! Metric allen keys are the standard size for bike components and are therefore the most common size for bike allen keys.

This is because metric allen keys are slightly smaller than standard allen keys, making them less likely to slip and damage bike components.


What size Allen keys do you need for a bike?

Assuming you are referring to the size of the wrench needed to loosen/tighten the various bolts on a bike: There are four main types of bolts found on a bicycle: 1. Pedal threads (9/16″)

2. Bottom bracket threads (1″) 3. Rear axle threads (9mm, 10mm, 12mm or 14mm) 4. Front axle threads (3/8″)

The most common size of Allen wrench is the 5mm, but you will also see 4mm, 6mm and 8mm wrenches. The larger the number, the larger the wrench. A 5mm wrench is going to be too small for the rear axle bolts, so you’ll need a larger size for those.

For the pedal threads and bottom bracket, you can use a 4mm, 5mm or 6mm wrench.

Are bike Hex bolts metric?

Yes, bike hex bolts are metric. The metric system is a system of measurement that is used in many countries around the world. In the metric system, the unit of length is the meter.

The metric system is used to measure the size of bolts and screws. The metric system is also used to measure the size of washers and nuts.

Are Allen keys metric?

Yes, Allen keys are metric. Metric Allen keys are available in a variety of sizes, ranging from 2mm to 10mm. The most common sizes are 4mm, 5mm, and 6mm.

Metric Allen keys have a hexagonal shaft with a hexagonal head, and are used to tighten or loosen screws with a hexagonal head.

Are most Allen keys metric or imperial?

Most Allen keys are metric, meaning they are measured in millimeters. This is the most common measurement system used in the world, so it makes sense that most Allen keys would be metric. There are some imperial Allen keys (meaning they are measured in inches), but they are less common.

are bike allen keys metric


Bike allen wrench size

When it comes to bike allen wrench size, there are a few things to keep in mind. First, the size of the allen wrench should be based on the size of the bolts being used. Second, allen wrenches come in different lengths, so be sure to choose the right size for the job.

Finally, it’s always a good idea to have a few different sizes on hand, just in case. Now that you know the basics, let’s take a closer look at bike allen wrench size. As mentioned above, the size of the allen wrench should be based on the size of the bolts being used.

The most common sizes are 3mm, 4mm, 5mm, and 6mm. If you’re not sure which size to use, it’s always best to err on the side of caution and go with a larger size. When it comes to length, allen wrenches come in two different varieties: short and long.


Most bike allen keys are metric, meaning that they are measured in millimeters. This can be confusing for people who are used to measuring things in inches, but it is actually quite simple. Just remember that there are 25.4 millimeters in an inch, so you can easily convert between the two.

For example, a 6mm allen key is the same as a 1/4 inch allen key.

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1 Comment

  1. […] on the back of the pedal. It will be either a small knob or a Phillips head screw. Next, use an Allen key or a Phillips head screwdriver to turn the tension adjustment screw clockwise or counterclockwise. […]

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