How to Measure Rim Width Correctly

As a bike owner, you’ll notice that along with the fun of riding your bike, comes the responsibility of taking care of it. This is probably why you’re reading this guide on how to measure rim width. You’re looking for a new tire for your bike and want to make sure that you buy the right sized one the first time around.

Now, the issue arises with most people due to having too many options to choose from. The problem is that each manufacturer uses different components to make their rims so you oftentimes can’t really tell exactly how large or small a tire’s rim width is by eyeballing it.

This is where rim width measurement comes in. Read on as we share with you tips on how to measure a bike rim width effectively.

How to Measure a Bike Rim Width

This is important because you want to get it right the first time! The last thing you want is to purchase the wrong size tire rim as that can compromise your ability to enjoy riding your bike.

You ideally want a tire whose width is similar or the same as the old one. How do you determine that? By learning how to measure rim width with tires on.

Measure Rim Diameter 

First, it’s important to understand rim diameter and why it matters as it relates to rim width.

You can’t have one without the other and you want to start by placing the rim on the ground and measuring its diameter using an appropriate tape measure. The tape measure should be aligned on the long wheel points which you can do by passing it over the hub.

This makes it easier to spot the longest points which you can determine by running the tape back and forth. To convert rim diameter measurements into millimeters, then all you have to do is multiply the result by 25.4.

Measure Rim Circumference 

Another thing to consider is rim circumference. All you have to do here is to place the tape measure around the rim, preferably a metal tape if you can because fabric tape tends to stretch which can lead to inaccurate results.

It’s also advisable to opt for a tape that measures 6mm in width to ensure that it will fit on the rim properly.

Here’s how to measure wheel circumference using measuring tape.

  • Prior to cycling the tape measure around the rim well, place it onto the hole of the valve.
  • Divide the well circumference by 2.142 in order to determine the diameter.
  • If the tape measure that you’re utilizing for this process is calibrated in inches, then you’ll want to multiply the result by 25.4 in order to convert your findings into millimeters.

If you don’t have access to a metallic tape measure, then you can always use a wire or a cable instead to get reliable readings.

All you have to do here is to wrap said wire or cable around the rim’s inner well and then make a mark on the end of the two points. Thereafter, place the cable on a flat surface.

Measure Rim Width 

Want to find out how to find rim width? First determine both inner width which refers to the interior of the rim and outer width which refers to the exterior, or the rim.

Both are vital determinants of the bike’s aerodynamic performance so you’ll want to pay attention to these variables. Interior width also affects the bike tire’s shape as it can infringe on the side walls. Rim width can, therefore, play a huge role in determining tire width.

To make sure that you end up with a comfortable tire and bike, use a ruler to measure rim width. Make sure the rule is laying flat against the rim so that you can take down the measurements while keeping the measuring scale aligned.

Final Thoughts

From learning how to measure bicycle rim size to finding out about rim diameter, we’ve taken you through the whole cycle of learning how to measure rim width in as little as a few minutes.

You’re now equipped to measure your tire’s rim width so that you can go out and purchase a new tire with the confidence that it’s the right size.

This is important for your own safety and comfort while riding your bike. Plus, it plays a significant role in your bike’s aerodynamics and overall performance so it’s not something to take lightly or overlook.

With that said, we hope you’ll find your bike tire sooner rather than later so you can get back out on the road!

Shailen Vandeyar

A proud Indian origin Kiwi who loves to plant trees and play with my pet bunny when not out cycling through the best routes, reviewing the latest gear, and sharing tips on everything biking.

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