As more rider’s transition to indoor training, having the right connection between your bike and your wheel-on trainer has never been more important. With modern bikes now adopting the Universal Derailleur Hanger (UDH) standard, cyclists need a thru axle for indoor trainer setups that matches today’s frame designs—not yesterday’s.
That’s why Saris created the new UDH-Compatible Trainer Thru Axle Adapter Kits, engineered for Road, Gravel, and MTB riders who want a secure, reliable, and trainer-ready fit. These adapters ensure your UDH-equipped bike mounts cleanly to Saris wheel-on trainers and most major wheel-on systems.
What Is UDH—and Why It Matters for Indoor Training?
The Universal Derailleur Hanger (UDH) is quickly becoming an industry-wide standard, thanks to its durability, cross-brand compatibility, and simple replacement process. But as bike manufacturers adopt UDH across Road, Gravel, and especially MTB, the interface and geometry of thru axles change—meaning older trainer adapters may no longer fit correctly.
This shift leaves many riders searching for a compatible thru axle that works with:
- Modern Road and Gravel frames (142×12)
- Modern MTB and eMTB frames (Boost 148×12)
- SRAM Direct Mount Derailleurs
- UDH-equipped dropouts
- A variety of wheel-on trainer systems
Saris’ new thru axle kits solve all of these challenges by supporting UDH while remaining broadly trainer compatible.
Why You Need a Trainer-Specific Thru Axle
If your bike came with a standard thru axle, it likely won’t mount directly onto a wheel-on trainer.
Trainer-specific thru axles are designed to:
- Extend fully through the trainer interface
- Provide a smooth, secure clamping surface
- Support side-to-side load during standing efforts
- Remain stable during high-watt sprint intervals
- Prevent damage to bike frames or trainer hardware
Installation takes under 2 minutes—simply thread the axle through your bike and trainer and tighten per your axle interface (lever or hex). No special tools required.
A proper thru axle isn’t just about compatibility—it’s about safety, performance, and making sure your bike stays locked in during your indoor sessions.
Introducing the New Saris UDH-Compatible Trainer Thru Axle Adapter Kits
Saris offers two models, each optimized for today’s bike standards and engineered for broad trainer compatibility.
Trainer Thru Axle Adapter – Road (SKU 9707TU)
MSRP: $59.99
Ideal for Road and Gravel bikes using a 142×12mm axle (a common 142x12 trainer axle standard).
Features:
- Compatibility with: 142mm × 12mm axle systems
- 1.00 or 1.75 thread pitch
- SRAM Direct Mount Derailleurs
- UDH compatibility for newer frames
- Optimization for Saris wheel-on trainers
- Works with Saris trainers including M2, Fluid2, and Mag+
- Compatibility with most major wheel-on trainer brands
This is the best choice for riders using endurance, racing, aero, adventure, and gravel bikes.
Trainer Thru Axle Adapter – MTB (SKU 9712TU)
MSRP: $59.99
Built for mountain bikes using Boost 148×12mm spacing (your go-to boost thru axle trainer adapter option).
Features:
- Compatibility with Boost 148mm × 12mm axle systems
- 1.00 or 1.75 thread pitch
- SRAM Direct Mount Derailleurs
- UDH compatibility for newer frames
- Optimized for Saris wheel-on trainer fit
- Works with Saris trainers including M2, Fluid2, and Mag+
- Compatibility with most major wheel-on trainer brands
This version ensures any modern trail, enduro, XC, or eMTB remains tightly secured on your trainer.
How to Choose the Right Trainer Thru Axle Size
Use these quick steps:
-
Identify your bike’s axle spacing. Most modern bikes fall into:
• 142×12mm (Road/Gravel)
• 148×12mm Boost (MTB)
-
Check you thread pitch. The Saris UDH adapters support:
• 1.00 or 1.75 thread pitch -
Match Road/Gravel vs MTB. Saris splits the product line so riders can pick the perfect fit without confusion—whether you’re shopping for a 12mm thru axle trainer setup on gravel or a Boost MTB frame.
Frequently Asked Questions
Do I need a special thru axle for a wheel-on trainer?
Yes. Standard bike thru axles aren’t shaped for trainer interfaces. A trainer-specific axle ensures safe, stable indoor riding.
Are Saris trainer thru axles compatible with UDH bikes?
Yes—both the Road and MTB kits are fully UDH-compatible.
Do Saris trainer thru axles work with other trainer brands?
Yes. They are optimized for Saris trainers but also work with most other major wheel-on trainers.
Will these thru axles work for Boost MTB frames?
Yes. The MTB version supports Boost 148×12mm.
Ready to Ride?
Your best ride starts with a reliable connection—and these thru axles ensure you’re always ready to roll.
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