UDH is the large bike buzzword as of late – with SRAM’s newest direct-mount Transmission derailleurs requiring it – however Bitter thinks they’ve discovered a greater option to future-proof their metal bikes. As an alternative of absolutely adopting the common hanger customary, Bitter tweaked it a bit so they might nonetheless make a light-weight dropout well-suited for small-diameter metal tubes, however with T-type direct mount derailleur compatibility. And importantly for some journey riders… Tailfin compatibility, too.
Bitter goes Virtually-UDH for Transmission compatibility
OK I do know, I do know…
We lastly acquired a common derailleur hanger customary that manufacturers had been whole-heartily adopting, and these metal bike builders determined to screw with it and make one other customary!
What are they pondering?
Nicely…
What they’re pondering is that UDH is absolutely not fairly as ‘common’ as effectively all thought. And it was actually optimized for the flat broad dropouts of carbon bikes.
It requires a 13mm thick dropout with a fairly large 30x40mm flat space on the within and 25mm diameter flat spot on the skin. Transmission derailleurs merely require ~30mm in diameter flat on either side. That’s fairly customary on carbon bikes. And alloy bikes with massive machined dropouts may also simply make that work.
However many high quality metal and titanium bikes use a lot smaller (usually hooded or flat plate dropouts), optimized to weld or braze-on small diameter seatstays & chainstays. They usually merely don’t have sufficient free actual property to work with UDH.
Sure, it’s attainable to make it work. Some metal bikemakers have switched to larger or interchangeable dropouts, utterly rearranged the structure of their stays to suit, or some have provide you with a good UDH-ready compromise.
Bitter’s resolution was to tweak the usual, only a bit.
What’s that imply?
Which means, the Bitter Not-UDH is just about the identical as an everyday UDH, simply with a little bit of that inward-facing plastic higher fin chopped off. Bitter says it’s about 15% smaller total. That lets them match it right into a compact hooded dropout, and doesn’t get in the best way of their integral rack/fender mount.
And on the skin, there’s simply an alloy spacer since metal dropouts aren’t 13mm thick. As a result of, metal is simply stronger, so that they don’t should be so broad, and might save fairly a little bit of weight.
Plus, not like the SRAM UDH which is partly plastic, the Bitter Not-UDH is solely made from machined aluminum. So, the Bitter one may even supply extra exact shifts?
Of observe: Bitter’s Not-Fairly-UDH is all aluminum – very like Robert Axle or Wheels Mfg‘s all-alloy UDH replacements. Bitter’s additionally makes use of an ordinary M17x1 lefthand thread pitch to assemble the two hanger halves. An enormous driver of this was simplified manufacturing. But in addition, lots of people (certified bike outlets included) have been breaking a few of SRAM UDHs when putting in them. A very good portion of that may be due to the excessive UDH torque ranking, the non-standard left-hand thread pitch between the bolt & hanger, and the truth that many (most?) torque wrenches weirdly sufficient don’t work or are inaccurate for reverse threads. That and the truth that they’re about half plastic.
Some extra bits of ‘common’ hassles…
One is that the SRAM UDH hanger is a ‘customary’ and works with 12mm x 1.0 thread pitch thru-axles. However some OEMs use the UDH interface, however their very own hangers have a unique thru-axle pitch (since that’s not technically a part of the agreed-upon ‘customary’). Why some would use a M12x1.75 axle inside a UDH is inexplicable to me, however it exists. Bitter sticks with M12x1, like SRAM, and like all of SRAM’s Transmission derailleurs (which additionally curiously every have totally different meeting bolts, presumably due to barely totally different hangers built-in into every T-type derailleur).
The final bit is that SRAM’s customary UDH resolution isn’t Tailfin-friendly, as a result of they require particular axles that stretch by means of the hanger (or T-type derailleurs) to mount the distinctive bikepacking racks. Since Bitter is fashionable amongst bikepackers and journey cyclists, they reworked their axles to bolt along with a 12mm hex wrench as quickly as they realized this problem. So, lots of the pictures I’ve for instance this present a 8mm hex interface, however they’re now constructing bikes with the 12mm (and a 8mm adapter) and can ship the brand new bolt to everybody who wants it.
In the long run, the Bitter ‘Virtually-UDH’ is “100% Transmission appropriate”, since SRAM direct mount derailleurs don’t make contact with the portion with the fin anyway.
Bitter Not-Fairly-UDH – Availability
All new made-in-Germany Bitter frames welded since final fall function the brand new Not-UDH dropout. Bitter says the brand new dropout & hanger can also be a bit lighter than their earlier dropouts, even with the added compatibility.
However YES, you’ll be able to simply match any SRAM T-type derailleur or any typical derailleur to your new Bitter bike. And even a Tailfin rack with their particular M12x1 thru-axle. Plus, Bitter will ship all of their new metal bikes with an additional spare hanger, too. (And it feels like you might use it as a alternative to your common UDH-equipped bike for those who injury a hanger there.)
Decide a Bitter metal gravel or hardtail mountain bike if you’d like broad mountaineering Transmission gearing. Or, now that Purple went Xplr 13-speed, you will get a tighter-spaced 1x race setup for a gravel or all-road Bitter.