Silver OM-1 Derailer - Any word yet on its capacity???

[Steve]

I'm eagerly awaiting the upcoming release of the OM-1 derailer --  and hoping to use it to replace the current 9 speed Microshift Advent unit on my Platypus. The Platy is running a 44-34-24 triple with  an 11-36 nine speed cassette (45 tooth chain wrap). 

Curious if anyone has heard any details regarding capacity of the OM-1 

Thanks,  Steve in AVL

[der_amerikanische_freund]

I, like you, am curious to find out about the OM-1 derailer specifications. Grant says in his latest blog entry that a he’d like a potential future OM-2 derailer to shift to 42T, so I guess we can infer that the soon to be released OM-1 won’t shift up to that.

I was hoping the OM-1 to be similar, specs-wise, to the Acera M3020 that is so common in Riv’s standard builds. That one shifts up to 40T and has a 45T total capacity, and Russ from Path Less Pedaled has succesfully tested it with a 42T cassette, so it can give you a very wide gear range and a very low granny gear.

[Eric]

If you zoom in on this photo from Eben Weiss' Outside article, you might be able to make something out through the jpeg haze.

I think I'm reading Biggest cog of 36T (with friction shifter) and 34T (with index shifter) and a Chain wrap of 39T. The largest cassette cog numbers sound about what I'd expect, but I have no point of reference for chain wrap. So, I'll let someone else jump in as to whether that number makes any sense.

Of course, all of this is prototypey and, I assume, subject to yaddayaddayadda...

Eric

SF, CA

[Steve]

Thanks Eric. Another group member tipped me off to this photo from the article, but I couldn't quite make it out. Looking at it now I think you've deciphered it.  If this is the final capacity - and I'm guessing it is if Riv went to the expense of having the boxes printed - the current 3x drivetrain on my Platypus will exceed its specified max chain wrap.  I may have to wait for the Sam Hillborne I've been contemplating for my next birthday.  If I hear anything different from the inquiry I finally sent Will at RBW, I'll share it here.

Steve in AVL.   

[Shannon Menkveld]

Exceeding chain wrap on a derailleur isn't a big deal. The worst that can happen is that you upshift into a too-small cog on the granny ring, the chain goes slack and makes hella noise, and you shift the front and feel like a moron.

My 1985 League Fuji is set up 45/42/30 x 14-16-18-20-23-26... with a 1980 Suntour Superbe that's spec'd at 23t of chain wrap and a 23t max cog. Other than the shift up from the granny, which needs to be done nicely and slowly, (but when was the last time you needed to shift up off the granny right fringgin' now!!,) with the Riv Silver 1 shifters on the downtube, it shifts better than I do.

As long as your derailleur can handle it when you boneheadedly try to downshift to the bottom cog on the big ring without locking up your drivetrain and making you crash so fast that time won't have time to slow down before you hit. (I guess that's possible going the other way, if you got the chain so slack, under so much pedal force and speed as to wrap it around the bottom bracket like a fishing reel, but any situation where I can imagine that happening would be really really weird...)

Tl;dr: I'd Just Do It (tm). It'll almost certainly work, and if it doesn't, you'll just hate it and do something different, so no harm done.

--Shannon

[Steve]

Shannon,  I like your advice. Indeed, now that I think about it, the current 3x drive train runs a bit slack in the 24 x 11 combination.   I will confess though to having been "bone headed" enough to once seize a derailleur in the big x big position -- which taught  me to check  the chain in that position when setting up a new drivetrain. 

Steve 

[Shannon Menkveld]

How badly were you and the bike hurt in the crash?

--Shannon

[Steve]

What crash?  

[Steve]

It's Official - Will K. at RBW says, "It won't work unfortunately! The OM-1 can wrap 39t of chain and is compatible up to a 34t cassette, although we've made it work with a 36t easily."  This was in response to my query asking if it would be compatible with the 44-34-24 triple crank x 11-36 cassette on my Platypus.

--- The micro shift Advent 9 I'm currently using works flawlessly -- but it's a bit fugly.  I'll have to give this one some thought. 

[Shannon Menkveld]

The one you were fortunate not to have, although I was also kinda joking.

I've done it, while pedaling pretty hard. Luckily, it was uphill on a mountain bike, so I wasn't going very fast.

I still crashed instantaneously. I just didn't get hurt much.

--Shannon

[Steve]

Shannon, what I experienced by exceeding the capacity of the derailleur was an inability to shift out of the big ring- big cog combo -- the chain was overly taunt;  the hub  continued to freewheel, no drama resulted   Fortunately the derailleur survived the  ordeal   . ;-).     It sounds like you maybe dropped the chain inboard and locked up the rear hub or the cranks??

[Josh C]

I'm glad that they are making this RD, but honestly, I think a good 2x capable FD would be of more use to me. Don't get me wrong, I'm excited for both, but I find it harder to find good quality (and good-looking) 2x FDs. I'd have to go back to the archives and see if they are planning for that FD to be 3x or 2x. 

[Kyle Mitchell]

Merry Sales was showing off a new front derailleur at the MADE show and specifically mentioned Rivendell testing them out in their clip with Path Less Pedaled.

https://www.youtube.com/watch?v=bp19IGyL_HM&t=53s

[Josh C]

Kyle, I saw that yesterday afternoon. I sent them a message asking when it'll be available, and they said, "Maybe winter 2025??".  I don't have any experience with IRD but it looked pretty. Glad it's silver and not huge.

[NYCbikeguy]

Bumping this thread back up:

Did the OM-1 already sell out that quickly???

At the $150 sticker price, I didn't think this would sell out that quickly, but man I was wrong.

Looking forward to candid reviews from the lucky ones who get their hands on this!

Best,

IY

CT/NYC

[Hetchins52]

Time stamp on the weekly Friday news email from Will -- 3:50 pm Pacific -- to yours, IY, at 4:34 pm means they sold out in 45 minutes (or less)!
Incredible!

David Lipsky

Berkeley

[Mike Rossi]

Probably sold out ~20 minutes. I had one in my cart, but noodled around looking for something else to add to get free shipping, and missed out. Oh well, maybe next month.

Mike

On Nov 7, 2025, at 9:46 PM, 'Hetchins52' via RBW Owners Bunch <rbw-owne...@googlegroups.com> wrote:

Time stamp on the weekly Friday news email from Will -- 3:50 pm Pacific -- to yours, IY, at 4:34 pm means they sold out in 45 minutes (or less)!

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[Mike Rossi]

The newsletter said a larger order coming in December. I’m still amazed that 90 of them, at a “one per customer, please”, sold out so quickly.

Mike

On Nov 8, 2025, at 9:35 AM, Tom Goodmann <tgoo...@gmail.com> wrote:

I only saw the message late in the evening, hours to late. I wish there had been an opportunity to preorder; that way, a larger order might have been made and guaranteed. Hope there will be more to come, and eagerly await new users sharing experiences.

Tom

Decorah, Iowa 

To view this discussion visit https://groups.google.com/d/msgid/rbw-owners-bunch/c8f42600-b37a-4c3b-b3b2-44d4853bc96cn%40googlegroups.com.

[Eric Marth]

I checked stock 40 mins after the email was sent and they were all gone. 

[Guy Jett]

According to Rivendell (Derailer - Rear - Silver OM-1 (reverse action) - 1) the capacities are listed as: 

"Biggest cog it’ll shift to: 36t. With an extension tab it’ll shift to at least 42t.
Chain wrap (explained on the box): 39t"

Didn't see anything there about indexed shifting but I do recall seeing that somewhere.

GAJett

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[maxcr]

I'm one of the lucky few who managed to get one. It will replace a Shimano Deer Head RD on my Ram which needs a drivetrain switch now that it's converted to 650b and my 180 WI cranks are too close to the ground for my comfort (going 170).

When I got to the online store (I think I was there very early), I checked and there were only 10 OM-1's available, I think that's all they sold, but I can't be sure.

I'll report when I get it and install it.

Max

[Patrick Moore]

All of you who bought the new OM-1, please report on how it shifts in friction, particularly with 10 or more cogs. 

[Isaak Oliansky]

Patrick- I will be happy to oblige. I snagged one somehow. Good timing as an xtr RR mech wasn’t playing nicely on my ritchey breakaway cross. The gearing is 46/30 with an 11-36 xt cluster, shifted friction. I don’t have problems with a similar setup and an older rr xtr mech on my bombadil, maybe this will be the fix.

IO in Ashland OR

[Patrick Moore]

Thank you, Isaak.

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Patrick Moore

Alburquerque, Nuevo Mexico, Etats Unis d'Amerique, Orbis Terrarum

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