Standard quick-release hubs cannot be converted to thru-axles.
Some wheels have expensive “hybrid” hubs that can go from quick-release to thru-axles and vice versa by replacing the end caps.
It’s also possible to convert a basic thru-axle hub to a quick-release setup with a third-party right adapter.
Why Standard Quick-Release Hubs Cannot Be Converted to Thru-Axles
- Dimensions and Hub Architecture
Quick-release skewers slide into hollow spindles around which the entire hub and wheel rotate.
The spindles are hollow and have a 9.2mm/0.36in inner diameter through which the quick-release skewer is inserted.
Meanwhile, the most common diameters of thru-axles are 12mm and 15mm. Thus, it’s unthinkable to simply replace the skewer with a thru-axle as the latter won’t fit.
You can’t replace the quick-release hub spindle with a thru-axle shaft either because the architecture of the hub doesn’t allow a similar modification.
- Thru-axles require Special Frames and Forks
Another issue stopping a switch from quick-release skewers to thru-axles would be the fork and frame.
Quick-release skewers clamp onto the dropouts whereas thru-axles are threaded into one of the dropouts.
Thus, thru-axles require a dedicated fork and frame.
Some higher-end hubs allow the user to switch from a 9mm quick-release skewer to a thru-axle and vice versa by changing the end caps of the hub. Those models usually come with caps for each of the systems that they support. One example would be Hope Pro 2.
Similar hubs come with end caps designed for a thru-axle of a specific diameter. The user can, however, replace the end caps with units supporting a quick-release skewer.
The end cap essentially narrows down the hub’s “exit” points so that the quick-release skewer is stabilized.
Thru-axle To Quick-release Skewers Adapters
Even if your thru-axle hub doesn’t have special end caps reducing the inner diameter to 9mm, it’s still possible to convert the hub to quick-release skewers via an adapter.
The adapter is inserted into the thru-axle hub instead of the thru-axle itself. At the widest points, the diameter of the adapter should match that of the original thru-axle. In other words, if the thru-axle is 15mm, you need a 15mm to 9mm adapter.
Note: If an adapter is labeled as Xmm to 9mm, then it’s designed for 5mm quick-release skewers, not 9mm. The 9mm measurement indicates the narrowest inner diameter of the adapter rather than the skewers that it is designed for.
Why A Conversion From Quick-release Skewers To Thru-axles Is Not Worth It
If you don’t have hybrid hubs and you want to enter the world of thru-axles, the only viable option is to get a new set of hubs or wheels.
If you get just a thru-axle hub, you will have to lace the wheels around it. If you buy a new wheel, you skip that procedure, but the price tag goes up.
However, as already mentioned, thru-axles require a fork and frame with one threaded dropout.
You cannot install a thru-axle hub on standard quick-release dropouts. Thus, a new fork and frame will be needed too. In the end, you might just as well buy a new bike.
- Questionable Benefits
Quick-release skewers have worked just fine for almost 100 years. Thru-axles are more of a convenience than a necessity as their impact on performance isn’t massive. No one loses a race because they have quick-release skewers.
In general, thru-axles have three benefits over quick-release skewers:
- A consistent position of the hub and consequently the disc brake rotor
I have a dedicated article comparing the advantages and disadvantages of quick-release skewers and thru-axles which you can read here.
Frequently Asked Questions
Can you install a thru-axle wheel on a quick-release frame/fork?
You can, but only after converting the thru-axle hubs to quick-release skewers via the aforementioned methods. Otherwise, you won’t be able to secure the hub to the frame/fork.
Can you convert a solid axle to a thru-axle?
The short answer is no. It’s not possible to simply remove a solid axle from a hub and install a thru-axle. The dimensions and the bearings of the solid axle cannot operate with a thru-axle.
If you want to perform a similar conversion, it will be necessary to replace the hubs or wheels. You will also need a new frame and/or fork because thru-axles thread into the frame/fork.
Should you grease a thru-axle?
Greasing thru-axles is a good practice to prevent them from seizing into the frame or fork. Most people apply a light film on the axle’s body and put slightly more on the threads.
How tight should a thru-axle be?
The safest approach is to follow the torque markings on the axle itself. They’re usually between 8-10Nm and vary between manufacturers.
Why does my bike have a front thru-axle and a QR at the back?
There are two reasons:
- The fork is easier to replace than the frame. Thus, it’s cheaper to use a new fork with an old frame than to re-design a quick-release frame. By switching just the fork, manufacturers can say that the bike has a thru-axle while minimizing the cost.
- The front wheel does most of the braking (80%) and thus the additional stiffness that a thru-axle is meant to provide is more beneficial there.