How the SRAM UDH hanger changed mountain bikes forever

When SRAM launched the Universal Derailleur Hanger, its aim was to address the headache of replacing frame-specific hangers. The replaceable derailleur hanger was a brilliant idea, but there were hundreds of them and they had become more complex and expensive. So in 2019, the US component giant delivered the SRAM UDH – Universal Derailleur Hanger – and created one of the most highly compatible mountain bike components ever made.

To quote the Shamen's '90s hit Ebeneezer Goode, the humble rear derailleur hanger was 'very much maligned and misunderstood' but this tiny piece of essential componentry is 'something of a genius' designed not only to attach the derailleur to the frame but also be a sacrificial lamb in the event of an impact, protecting the frame and derailleur. It also has the important duty of holding the derailleur in just the right place so that the drivetrain and frame are perfectly synchronized. The SRAM Universal Derailleur Hanger gives a secure and consistent connection essential for crisp shifting and overall drivetrain performance, but the SRAM UDH also has a host of built in safety features.

The SRAM UDH was designed to unify derailleur hanger standards with nearly all the best mountain bike brands designing their frames to use a Universal Derailleur Hanger. This means that if you're searching for what mountain bike to buy, it'll most likely come equipped with a UDH. The genius of this means that should the worst happen they're available globally, with nearly all bike shops stocking them, and they are inexpensive, with a replacement costing around £15. More importantly, by standardizing the position of the derailleur with the cassette, shifting performance is optimized. This means better and more consistent, shifting across all bikes. 

The UDH also has built-in safety features, unlike most older hangers, which are fixed, the Universal Derailleur Hanger can rotate backwards in the event of an impact, allowing the derailleur to pivot away from the frame avoiding more potentially costly damage. The design means it can be easily pushed back forward into position, often without needing to loosen the thru-axle. UDH also features an inner lip, allowing the chain to magically be pushed back onto the cassette, avoiding the chain being jammed between the dropout and cassette, which again all adds up to better-shifting performance.

Will a SRAM UDH work on an older mountain bike?

Only mountain bikes that are designed around SRAM Universal Derailleur Hanger will work with the standard, but unlike other cycling industry standards like bottom brackets or headsets, the adoption of the SRAM UDH among bike brands was rapid with most mountain bikes now using UDH. It's also beginning to appear on the best gravel bikes like the Scott Solace and the ENVE MOG.

However, compatible thru-axles to secure the rear wheel are required. SRAM has made the UDH’s design an open-standard with aftermarket brands offering anodised options, with different color options. SRAM has a very useful bike finder on its website so checking if your bike uses the standard is easy – though the finder is not always bang up to date.

Do you need UDH to run with SRAM's new T-Type Eagle Transmission?

Back in March this year, SRAM launched its much anticipated T-Type Eagle Transmission mountain bike drivetrains. This brand-new Eagle Transmission abandons the derailleur hanger altogether, mounting the derailleur directly to the frame. SRAM cleverly seeded the ground when launching UDH, making future bikes compatible for its incoming T-Type Transmissions which can only be fitted to bikes running a Universal Derailleur Hanger.

With cross-brand simplification benefits for all riders, not just SRAM riders, its safe to say the Universal Derailleur Hanger is the most prolific derailleur hangar of all time, and probably one the most important MTB developments of recent time, like Ebeneezer, it's a 'real crowd pleaser'.