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Check These 7 Things Before Buying a Wheel

Check these seven things before buying your wheel to ensure you'll get a wheel that will work for your bicycle. Use this as a final checklist before submitting your purchase.

1 - Front Wheel, Rear Wheel or Set?

We'll start with the easy one. It's always good to double check.

Front wheels are not drive wheels and have simple hubs with no ability for gears.

Rear wheels are the drive wheels.

Sets are sold as a front and rear wheel and usually use the same model of rim and a very similar hub so they match.

2 - What Diameter of Wheel is Needed?

This one often seems obvious, but there can be many gotchas.

Bike wheels are described by the size of tire they are intended to hold and NOT by the actual measurement of the rim.

Incorrect diameters, even if off by only a little will cause tires not to mount, may not fit the frame and could have issues getting the brakes set properly.

Reading the size from your existing tire is the best way to ensure you get the proper wheel. Even though wheels are described by a common name, you want to look beyond that and look at the ISO number that should be stamped on your tire. ISO numbers are listed as a 3 digit number, followed by or preceeded by a 2 digit number. They may look something like 622-23. The 622 would be the ISO diameter.

The common name for a 622 wheel may be 700c, 29er or even 28", depending on how the wheel is being marketed.

If you do not have a tire to reference and are measuring the rim, use our ISO measurement guide. The guide also lists common names and their matching ISO numbers.

Potential Oddities

In some case, there are conflicting common names.

26”, 24”, 20” are all common tire names that can have different diameters and where the ISO number should be checked every time. The ISO guide is very useful when checking this.

Be wary of fractional sizes. They are generally far less common and it’s best to check before buying a tire or wheel with a fractional size. For example, a 26 x 1-3/8” tire is a special size used on older bikes and will not work on the same rim as a 26 x 1.5” tire.

3 - Is the Wheel the Right Width for my Tire?

There are few firm rules when matching tire widths to wheels, only recommendations. The further you get from the recommended sizes, the more likely you are to have issues like tires popping off or flats.

To help with this, we have a bike tire width to rim width chart.

It's based on the internal width of the rim, which is a spec that can be found for most wheels and rims.

Often, wheel manufacturers will give a recommendation for a size range they suggest using. It may vary from our suggestion chart. When in doubt refer to the rim and tire makers recommendations.

4 - Does the hub spacing and axle type match the frame and fork?

The hub width and axle type must match properly to the fork or frame.

Hub widths are given as an O.L.D. measurement, which is short for over-locknut dimension. This is the width of the hub where it slips into the frame or fork. Essentially, this is the inside-to-inside measurement of the frame or fork at the dropouts where the hub is mounted.

The axle diameter and attachment system should also be the proper type for the frame or fork to ensure a proper and secure fit.

When an axle is described, it is typically described in three parts – the O.L.D measurement, the diameter and the securing mechanism.

Bolt-on axles will vary by diameter and you need to ensure you get the right diameter of axle so it fits through the frame or fork.

Thru-Axles will also vary by diameter. To learn more about thru-axle measurements, see our thru-axle guide. You do not usually buy a new thru-axle when purchasing a wheel and instead continue to use your existing thru-axle.

Quick-release rods are a standard diameter and the actual diameter of the rod may not be listed in description since they do not vary. Many, but not all quick-release wheels will include a new skewer.

Some wheels support multiple axle types and are “convertible”. This is most often done with end caps that change the wheel from a quick-release to a thru-axle or vice versa.

5 - Are my Brakes Compatible?

Wheels need to be matched to the type of brakes being used.

For a wheel to be compatible with rim brakes, the rim should have a braking surface where the pads can touch the rim and apply the braking force.

To use disc brakes, the wheel must have rotor mounts and the frame or fork must have caliper mounts.

Note: If your frame or fork does not have disc caliper mounts you will not be able to use disc brakes even if you change your wheel.

There are two common types of rotor mounts and should be checked to ensure the rotors you buy or plan to transfer will fit the wheel.

Some wheels are compatible with both disc brakes and rim brakes. If the rim has a braking surface and the hub has rotor mounts, the wheel would support both types of brakes.

Rear wheels have two additional options.

One is a coaster brake. A coaster brake is the style you likely grew up with where you pedal backwards to brake instead of using a hand brake.

Another is a drum brake, which is a hub mounted brake that is controlled by a hand lever. These are not as common as other styles, but can still be found.

One Oddity for Down Hill Thru-Axle Bikes

On some downhill thru axle front hubs, the forks have the caliper positioned 5mm outward and require a poorly named “boost” hub which will push the rotor mounts out 5mm. This is poorly named because boost traditionally has meant a frame with 148mm spacing or a fork with 110mm spacing and using “boost” to represent rotor offset can make it confusing to read product descriptions and find the appropriate hub. The best description I've seen can be found in this article.

6 - Will my Gears Fit?

This is only a concern on the rear wheel, but the hub will need to match the type of gears you plan to use. Here are the common types. This should be specificed in the product description of the wheel.

There are several single speed types. Read the product descriptions carefully. Examples include: Threaded 1.37" x 24tpi LH, Threaded Metric 30 x 1mm, Threaded Track

Some BMX wheels use a 9 tooth driver. The 9 tooth gear will be included with these wheels.

Metric 30, or M30 for short, are usually found on one side of 20" BMX Flip-Flop wheels. Typically M30 BMX freewheels are 13, 14, or 15 tooth. 16 tooth and larger are typically 1.37" x 24tpi standard threading.

Threaded Standard 1.37" x 24tpi, is usually referred to as a thread-on freewheel, and is the standard size for 5/6/7 speed thread on style freewheels.

Important: 7 speed gears can be found as either slide on HG cassettes or thread-on freehwheels. If you are planning on using your current gears, check which style you have before buying.

HG splined freehub bodies for cassettes are a very common type. These freehub bodies may be referred to as HG, or Shimano / SRAM. Often they will indicate the number of speeds they support, though this may be misleading as lower speed cassettes like 7 speed can be used with the right combination of spacers. You may even see notes about 11 speed mountain and 11 speed road. 11 speed road cassettes are slightly wider and will require an HG 11 road compatible freehub body. Read the descriptions carefully. If you want more details on spacers, see the cassette spacer chart.

Shimano Micro Spline is a newer style of cassette that allows for a smaller cog. Look for this pattern on 12 speed cassettes.

SRAM XD / XDR is SRAM's standard for some 11 and 12 speed cassettes. XDR freehub bodies are little wider than XD and when using an XD cassette on an XDR body, a spacer may be used. XDR is usually 12 speed. XD is for some 11 speed.

7 - What type of tire do you plan to use?

Clincher Style Tires

Clincher tires are the traditional type. They are intended to be run with a tube. Clincher tires usually have a rounded bead edge that are designed to fit beneath the inner lip of a rim.

Tubeless Ready

Tubeless ready rims and tires are designed to be run with sealant and rim tape without a tube. Tubeless ready tires usually have a more square bead and more square lip rim to help give more surface area contact to aid the sealant.

Tubeless ready tires and rims have the option of being run with a tube just like a standard clincher. In many cases you can even run a tubeless ready tire as a clincher on a clincher rim, however the only time you can run a tubeless ready tire without a tube is on a tubeless ready rim.


Tubular tires have the tube inside a sealed tire that is then glued or taped onto a tubular rim. Tubular tires can only be run on tubular rims.

UST Tubeless

UST is a tire and rim design that requires no sealant. A UST tire bead is designed to be an air-tight seal on a UST rim. They must be used together.