We Like The Trojan Horse
The introduction of the SRAM T-Type Transmission has shed a light on why the Universal Derailleur Hanger (UDH) standard exists and why SRAM worked to slip a Trojan Horse of a standard through the gates of the bicycle industry. While this new frame standard has caused some headaches among framebuilders, it does bring with it a few benefits for the handbuilt bicycle that we think outweighs the negatives.
UDH = Good
Adaptable To Suit Your Needs
The Universal Derailleur Hanger (UDH) standard has been designed to be just that: universal! It doesn’t matter where you are, if you happen to break off a derailleur hanger, you can always find another. AND, if you want the latest and greatest from SRAM in the Transmission type drivetrain, you can have that too. Just pop out the derailleur hanger and mount it straight up. It’s that easy.
Large Surface Area for Brazing
Typical dropouts are small diameter circles that are good for tapered chainstays and small seat stays but if you want larger diameter tubing for stiffness, you’ll need a dropout that can accommodate that. Enter our Fastback Flange which is contoured to reduce weight but has a large surface area for attaching those tubes.
Improves Tolerances
Derailleurs are one of the most precise components on a bicycle and they require very accurate alignment to work properly. The UDH standard is based on a tightly-toleranced bore that provides a wide area to align the hanger while the axle threads into the hanger itself assuring the least amount of misalignment possible.
Works with the Latest from SRAM
UDH was the Trojan Horse that allowed SRAM to create their latest series of derailleurs, the AXS Transmission. Unfortunately, if you do not have a UDH-compatible frameset, this means you won’t be able to run the new derailleurs and take advantage of any other new products that SRAM will release in the future. Good thing we have a UDH dropout eh?
UDH = Not so Good
Optimized for Carbon Full-Suspension Bikes
UDH was designed to work for the entire bike industry. This means it needs to work with featherweight road bikes all the way to downhill bikes and in every kind of material possible. From an engineering standpoint, you choose the worst-case scenario and design to that. In this case, that means a carbon fiber full suspension bike with a pivot at the rear axle. Do you need all of that width and size for a steel dropout? No. So you end up carrying a few extra grams when compared to a steel-optimized design.
SRAM Only Derailleurs (At the moment)
The UDH Standard was optimized to work with a SRAM Direct-Mount derailleur ahead of all other derailleurs and so that technology is not available to other companies at this point. The good news is that Shimano has been working on their own mount that uses this standard. It’s just not ready yet. If you want to make the most of the UDH dropout, you will need to run a SRAM drivetrain.
Verdict
After all of that description, here’s the short version: we like the Trojan Horse. While there are some downsides to this new standard, the base idea is good and it will only improve with time as we continue to develop and adapt our designs to work with this standard. It works with the latest drivetrains (sorry, TRANSMISSIONS. . .) on the market, solves some pretty critical tolerance stack issues, and the range of compatible drivetrains will only grow over time.
