The right bolt-on thru axle depends on matching its length and thread pitch to your frame. The MRP Race Axles are the most relevant choices for replacing a rear MTB axle, with options listed in several sizes. For transporting a bike with a 15x110mm thru-axle fork, the Kuat Dirtbag is a mounting alternative rather than a replacement axle. Check your bike’s specifications before choosing any axle or mount.
| Product | Best For | Key Specification |
|---|---|---|
| MRP Race Axle | Rear MTB axle replacement | 180mm x 1.75 thread |
| MRP Race Axle | Rear MTB axle replacement | 174mm x 1.75 thread |
| MRP Race Axle | Rear MTB axle replacement | 178mm x 1.5 thread |
| MRP Race Axle | Rear MTB axle replacement | 198mm x 1.75 thread |
| Kuat Dirtbag | Bike storage or transport | 15mm x 110mm thru-axle mount |
MRP Race Axle, 180mm x 1.75
Best for: Riders whose rear MTB axle requirements match 180mm length and 1.75 thread pitch. This is a bolt-on replacement option intended to take the place of a standard, bulkier thru axle.
MRP describes this Race Axle as a lightweight upgrade designed to provide a secure, rigid connection between the frame and rear wheel. That makes it a relevant choice for riders prioritizing the axle connection and a streamlined replacement.
Limitation: The listed dimensions must match your frame’s axle requirements. Do not choose it based on length alone; verify thread pitch and other manufacturer specifications first.
MRP Race Axle, 174mm x 1.75
Best for: Mountain bikers who need a rear axle measuring 174mm with a 1.75 thread pitch. It is a better fit than the other MRP options here only when those measurements agree with the bike’s requirements.
The product is presented as a lightweight, bolt-on Race Axle intended to replace a standard thru axle. MRP highlights a secure, rigid frame-to-wheel connection, so this option is selected for riders seeking that style of replacement in the specified size.
Limitation: The product information does not list compatibility by frame model. Confirm the exact axle standard with your bicycle manufacturer or current axle before ordering.
MRP Race Axle, 178mm x 1.5
Best for: Riders whose rear axle specification calls for 178mm length and a 1.5 thread pitch. Among the listed choices, this is the one to consider when the frame requires that particular thread size.
Like the other MRP Race Axles, this model is described as a lightweight bolt-on replacement with a focus on a rigid, secure connection. It gives buyers a distinct thread-pitch option rather than assuming all MRP axle versions are interchangeable.
Limitation: Thread pitch is not interchangeable by assumption. Verify both the 178mm length and 1.5 pitch before selecting this axle.
MRP Race Axle, 198mm x 1.75
Best for: Riders who have confirmed that their rear axle needs a 198mm length and 1.75 thread pitch. This is the longest listed MRP option in this selection.
MRP describes the axle as a lightweight bolt-on upgrade designed to replace a standard thru axle and provide a rigid frame-to-wheel connection. Choose this version if the measured specification matches your bike; the longer length does not make it a universal option.
Limitation: The listing does not provide a frame compatibility chart. Check the required axle length and thread pitch rather than inferring fit from the product name.
Kuat Dirtbag 15x110mm Thru-Axle Mount
Best for: Bike owners who need a fixed mounting point for a 15x110mm thru-axle bike in a truck bed, van, trailer, garage, or other flat surface. This is a transport and storage mount, not a replacement axle for the bicycle.
Kuat describes the Dirtbag as a one-bike, bolt-on mount made from steel with a resistant finish. Its ability to attach to a range of flat surfaces makes it a practical alternative when the goal is to secure a bike for storage or transport.
Limitation: This model is specified for 15mm x 110mm thru-axle bikes. Avoid it if your fork uses a different axle standard or if you need an axle for riding.
Buying Guide: How to Choose a Bolt-On Thru Axle
Which measurements should I check?
Confirm the axle length and thread pitch specified for your frame. The products listed here include different lengths and two thread pitches, so similar-looking axles should not be treated as interchangeable. Consult the bicycle manufacturer’s documentation or compare the specifications of the axle being replaced.
Do I need an axle or a bike mount?
A thru axle is part of the bike’s wheel and frame connection. A bolt-on fork mount, such as the Kuat Dirtbag, is attached to a vehicle or storage surface to hold a bike. Choose a replacement axle for riding; choose a mount for transport or storage.
How do I compare the MRP options?
- Choose 180mm x 1.75 or 174mm x 1.75 only if that exact size matches your bike.
- Choose 178mm x 1.5 if your frame specifies that length and pitch.
- Choose 198mm x 1.75 only when the longer listed size is confirmed as correct.
The product descriptions share the same general lightweight, bolt-on design positioning. The key comparison is the listed axle size, not an assumption that one model fits more bikes.
What should I check before buying a transport mount?
Match the mount’s stated fork standard to your bike. The Kuat option in this article is specified for 15mm x 110mm thru-axle bikes. Also consider where the mount will be installed and whether the mounting surface suits a fixed, bolt-on setup.
Frequently Asked Questions
Is a bolt-on thru axle the same as a quick-release skewer?
No. They are different axle systems. Confirm which type your bike uses before buying a replacement; a quick-release skewer is not a substitute for a thru axle.
Can I choose an MRP axle by length alone?
No. Match both the listed length and thread pitch to your bike’s requirements. Verify any additional specifications provided by the frame manufacturer.
Is the Kuat Dirtbag a replacement axle?
No. It is a one-bike mounting base for storage or transport, specified for 15mm x 110mm thru-axle bikes.
Will the 1.5-thread axle fit a frame requiring 1.75?
Do not assume that it will. Thread pitch must match the frame specification; the 178mm MRP option listed here has a 1.5 pitch, while several other listed options use 1.75.