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.