What is the Universal Derailleur Hanger or UDH?
The Universal Derailleur Hanger is a system developed by SRAM with the intent of standardising hangers across all mountain bikes.
What was wrong with the old system?
The main issues were that every bike manufacturer used a different design (sometimes even across models), which meant sourcing them could be a pain, as well as inability to share parts out on the trail.
What is a derailleur hanger for? Why not just bolt the derailleur straight onto the frame?
It's main purpose was to be a sacrificial part in order to save the (much) more expensive derailleur in the event of a strike.
Why did we decide to use UDH on our frames?
We chose to adopt the SRAM UDH hanger on all of our bikes early on. This keeps things simple for our customers, with replacements being available at almost any bike shop (not just Chromag dealers).
It also has some advantages over a "traditional" hanger. Mainly that it can rotate out the way in the event of your derailleur taking a hit, which could help to save your derailleur and even the hanger itself. It also has a ramp on the cassette side which can help the chain get back onto your smallest cog in the event of an over-shift. Lastly, having a consistent position of the derailleur can only mean improved shifting.
The only downside being it's not backwards compatible with our older frames.
Is the Chromag UDH compatible on other bikes?
Yes! the beauty of the UDH is that it fits on all mountain bikes spec'd for UDH, no matter what brand. You can buy them here.