Axle types

axle standards tech

A rare Saturday blog, and a rare short blog. This one is in response to a specific customer request to better explain axle types and our nomenclature for them in product descriptions.

First, we love our new site and hopefully you do too. But each product is limited to 100 variants. A "product" in this instance is something like Al33 with Industry Nine hubs. A variant is any option within that product, so spoke counts, hub colors, drive train options and axle types are each variants. It's a very rare product that naturally fits less than 100 variants. The platform we use is without a doubt the bit fit for what we needed and the constraints we had for it (in plain English this business in no way supports a 6 figure site platform), but that's a thing. 

Rim brake road hubs almost always use quick release axles. These are the standard 9x100mm front and 10x130mm rear. These don't even get a variant in our builds because it goes without saying.

Disc brake road bike front hubs can use quick release, or 12mmx100 or15mmx100 (rare) thru axles. Rears can use 130mm (very rare) or 135mm quick release, or 12x142mm thru axles. There are also 135mm thru axles but they are rare enough that we don't list them. Only a few hubs are available for them, though Chris King and I9 both do it. Same goes for 130mm quick release, except neither CK nor I9 make hubs for that. Honestly I don't know where you can get a hub for that setup. 

We refer to these as QR, 12mm, and 15mm front, and for rears it's QR or 12x142. The option structure in our store is "front/rear," so for example if your bike has a 12mm front and a 135mm QR rear, you choose 12mm/QR. 

Mountain bikes use all of those, but they also have Boost spacing. Boost (for now at least) refers to a 15x110mm front axle, and a 12x148mm rear axle. Although I'm sure people out there have Boost frames with non-Boost forks and vice versa, this is rare enough that we don't list it (mountain bike wheel builds are getting built out currently, so you wouldn't see anything right now).

So that's axles. Confusing all of this further is that some hubs come in center lock or 6 bolt rotor options (watch this to become somewhat less confused on that topic), there are different drive types (Shimano/SRAM 11 speed road, Shimano/SRAM 11 speed mountain [which is the same as the old 10 speed road], XD, Campagnolo, and coming soon to a theater near you is XD-R. Remember how I prefaced this with the 100 variant per product limitation in our store? You get there awfully quickly, and though we try really hard to make these all clear, it's like trying to shovel water out of a pond (which is to say frustrating, hopeless, and never ending). 

So that's how we do our nomenclature for axles. We apologize on behalf of the bike industry if it seems like they have a grudge against their customers. From our perch, it often feels that way. As ever, if this all just makes your head hurt, send us a note or give us a call and we will walk you through how to order what you need. 


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  • Brandon Tyler on

    Your article gave me a couple ideas I had never thought of before. Thanks for the info about axle types.. You’ve done a great job! Thank you for sharing!

  • Dave on

    Jay – we need to figure out cross-locating mtb and gravel wheels but if you go into the 650b subsection from road/cross/gravel disc builds, you’ll see the 660b versions of the majority of mtb wheels. All prices are same for 650b and 29er

  • Dave on

    Jay – Next few days

  • Jay on

    Please update the MTB section. It would be great if you can add the Enve option to mtb as well. Thanks.


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