Pipe down MTB conspiracy theorists, it turns out that SRAM's UDH gear hanger was a truly brilliant idea after all

SRAM UDH hanger being worked on in a workshop
(Image credit: GuyKesTV)

Where the f**k is it? It’s not in the tin mug on the workshop bench. It’s not in the other tin mug. It’s not even in that Ibis Cycles pint glass I blagged from Interbike in 1995. Definitely isn’t in the drawer of ‘small things that need to be kept close because I’ll use that soon’. I’ve searched that three times now. I even did that thing where you creep up and open the drawer suddenly before whatever it is you’re hunting can scuttle into a dark corner. Not in the box of ‘things that need to be tested next’. I’ve checked that twice. I’ve behind most of the places such small but vital things like to live, crawled around on the floor looking for fresh perspectives while embedding dropped brake bolts into my knees. All the flat ‘I’ll put that there for a minute’ surfaces, random tubs, even the ‘well ordered spares box that never actually gets used' and the internal storage sausage of the bike itself have been frisked, beseeched and sworn at to no avail.

And the more frantic and further away from likely success, the more the swearing increases and the more I realize that if I can’t find it, then I can’t fit that entire drivetrain I need to test. And that converting that wheel to the correct freehub was a waste of time. Obviously, after fitting the tire I had in mind for that specific build beforehand. Idiot.

A selection of gear hangers

Keeping track of spare hangers on the transitory test bikes in my life has always been a nightmare so god knows what it was like working in a bike shop (Image credit: GuyKesTV)

Does what it says on the tin

Almost certainly being a Trojan horse for a SRAM-specific ‘Transmission’

And then it hits me. The Specialized bike I’m looking to convert to a TRP rear mech from a SRAM XO T-Type mech uses UDH. Of course it does, most new frames do. And Universal Derailleur Hanger means exactly that. And I know that. I’ve read the press releases. I’ve probably told people what a brilliant idea that is regardless of it almost certainly being a Trojan horse for a SRAM-specific ‘Transmission’ attachment standard change (which it was). But until now – like the price of an $11k superbike I’ve blithely called ‘good value’ because it’s better specced than the $12k one I tested – the real world reality hasn’t sunk in. If this is genuinely universal, then I can just unbolt the UDH hanger from that frame there and slide it straight into the frame. 

SRAM UDH hanger on a pink frame

Presumably, someone has already ordered a soy milk, vegan caramel salted, no lacto, skinny puppaccino with one of these wedged in their ear? (Image credit: GuyKesTV)

Dawning realisation

As I unbolt the SRAM mech, pull out the hipster ear lobe insert thing and slide the composite (nylon?) UDH hanger into place, I’m filled with the same ‘dawn of mankind’ awe.

But even as I pick up the hex key and approach the bike I’m still not wholly convinced. I come in cautiously like an ape about to prod a stick into a termite mound for the first time, creating a live lollipop but also the first tool that will kick-start the eventual development of the entire human race. And as I unbolt the SRAM mech, pull out the hipster ear lobe insert thing and slide the composite (nylon?) UDH hanger into place, I’m filled with the same ‘dawn of mankind’ awe. 

I do that thing where you look around the room to see if you can share that amazement with someone else and make do with giving my rusty old stove a silent “WOW” and a thumbs up. I snug the hanger up tight but I’m still not convinced because it hasn’t quite keyed into the cutout on the inside of the Specialized dropout. But then I check other bikes and the setup looks exactly the same. Once it’s tight, it’s at exactly the right angle and it doesn’t wobble or swing back and forth. It’s perfectly positioned and my next test build is saved.

Universal Derailleur Hanger means exactly that, an end to frame specific gear attachment and all the spares stress that created. My mind does that ‘realization back track’ sequence they love in murder mysteries where it replays the significant scene. Sure enough, when I re-open the ‘well ordered spares box that never actually gets used’, among all the variety of gear hangers there are three more UDH hangers sat there ready to go. Two unbranded – because the whole point is it doesn’t matter – but one ironically tagged with a Nukeproof logo. So I guess that brand can live on for a bit longer in my testing world, if only as a gear dangling link to the past.

SRAM UDH hanger

Yes I know they do exactly what I said they did, it's just taken me a while to have the actual Eureka moment, OK! (Image credit: GuyKesTV)

A literal gear changer game-changer

Obviously since then I’ve told many people about how incredible this is and they’ve all been way less impressed than when I told them you can cook fish fingers in a toaster. Because let’s face it, the clue as to what the Universal Derailleur Hanger does is in the name. But as often occurs with the wizened little walnut rattling round in my skull, the true significance of SRAM’s smallest, simplest innovation took a while to register. Even amongst the first popular suspension fork, single ring gearing, electric suspension, wireless gears etc, the fact they’ve made all modern frames (not much of a spoiler alert as it’s already on gravel, and road UDH is on the way) cross-compatible in terms of gear fit, is probably their most significant real world ‘game-changer’ yet.

Guy Kesteven
Technical-Editor-at-Large

Guy has been working on Bike Perfect since launch in 2019. He started writing and testing for bike mags in 1996. Since then he’s written several million words about several thousand test bikes and a ridiculous amount of riding gear. To make sure he rarely sleeps and to fund his custom tandem habit, he’s also penned a handful of bike-related books and talks to a GoPro for YouTube, too.

Current rides: Cervelo ZFS-5, Specialized Chisel, custom Nicolai enduro tandem, Landescape/Swallow custom gravel tandem

Height: 180cm

Weight: 69kg