Derailers that handle 36T cogs: shadow vs. non-shadow

[Jim Bronson]

On the Rivendell site they list several derailers for sale that can accommodate the new(er) cassettes with the 36 tooth low gear.  The top of the line Deore XT is a Shadow derailer and is rated by Shimano for up to 36T.  The other three, two Shimano Deores and a Microshift, are non-Shadow, have published specs that state they only accommodate up to 34T.

Is this just one of these marketing designations that Grant talks about?  Is there any actual technical reason why the non-shadow derailers wouldn't work with a 36T cassette sprocket?  

Is it one of these situations to where Shimano is trying to save ham-fisted operators from themselves and all it really takes to make them operate properly is the good sense to not cross-chain?

I am inclined to trust Grant and staff at Rivendell on this.  However, I am curious to see who else out there is running one of the 36T cassettes with a non-shadow derailer, Rivendell or otherwise.

I can offer one non-Rivendell datapoint for the Shadow derailer not working.  I bought a "Shimano Deore M592 SGS Shadow Long Cage 9-speed Rear Derailleur Black" for my 1993 Burley tandem that I recently acquired, for the sole purpose of supporting the Shimano HG61 12-36T cassette (that Rivendell sells...)  When installed, I discovered that there was interference between the derailer and the chain in several cogs on the casette.  The pictures that are online don't really adequately show how high the derailer will orient when installed on a bike like mine.  So, buyer beware.

I'm thinking of installing the M592 on my Rivendell just to see if it has the same problems that the tandem does with it.  I guess it all depends on the design of the derailer hanger.

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Keep the metal side up and the rubber side down!

[James Warren]

I've been breaking the rules. I have a 12-36 9 speed cassette on 4 bikes, and I know that none of them have Shadow derailleurs. I thought that some had Shimano products (newer XT or LX) that were specifically designated as for 36T, but I could be wrong on that. Either way, I know that two of the bikes use older XT's that are certainly not designated for 36T. Maybe only for 32!

On the Hunqapillar (the one with the oldest XT derailleur), I know I'm pushing it. When I put the bike in lowest gear and pedal backwards, there is some cog-bouncing. But when I pedal the bike in the lowest gear, it works fine. I've climbed a lot of stuff in that gear this past year, and so far so good. Knock on wood.

-Jim

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[Eric Platt]

Am using a reverse rise LX on my Sam Hillborne with a 36t in the rear for over a year with no problem.  Like Jim states, on some the upper pulley might get awfully close to the 36t cog.  But it hasn't been an issue for me yet.  Hopefully it won't. 

 

Am not sure the Shadow designation is for the 36t or more for not sticking out as much from the rear chainstay.  Less chance of it getting dinged on a narrow trail.

 

Eric Platt

St. Paul, MN

[Ron Mc]

Grant makes the point in copy that manufacturers under-rate their derailleur capacity - I've found it to be generally true that you can push a derailleur past it's design goal - I ran a '78 shimano 600 RD with 8-speed freewheel.  I'm running a 29 on my daughter's indexed Ultegra short cage and noticed that even before I adjusted the mount rotation screw to clear the low gear, it would hop right into the low gear just fine.  

[Garth]

It's not even that that MF underrate(or rate at all, how we define "rating") their derailers ..... it's that when they give the spec, they have specific cassettes in mind for each. The "rated" specs then, are not meant as hard ruled limitations , but are based on the MF intended cassettes in mind.  It's a marketing and well, logistical "suggestion" ... lol .  That's what I call it.   It minimizes confusion for some .... adds to it for others, no doubt. Considering ALL the parts made ... ALL the vendors .... ALL the bike shops and manufacturers .... it's an attempt to make some sort of standard that everyone can understand, or at least use a base from which to work from for others.

[Ron Mc]

fair enough, and certainly the truth - goes with the package-and-replace mentality of the industry.  We people who put c. 2006 drivetrains on 1986 steel frames are the exception and not the rule.  

[rperks]

One thing that caught me off guard this past week, and may have flown under the average Riv radar, is the new DynaSys shimano shadow detailers.  I had one show up that was ordered as a regular shadow.  Apparently there was a transition where all being sold as 10 spd are now DynaSys.  I am still sorting out the details, but bottom line is that it would neither index nor friction shift across a new shimano 9spd cassette.  I have had no problem with earlier generation shadow derailer as well as some labeled DydaSys.  I am still not completely sure what has changed, but it was as bad as trying to get a Sram 9spd MTB derailer to work with a retro friction DT shifter.  

I pulled it off and put on a regular new 105 GS cage, and it indexed perfectly across all 9 cogs including the 36 tooth one.  

Apparently there are DynaSys cassettes out there as well with non-uniform spacing between cogs as well, buyer beware

Rob.  

[Jim Bronson]

Update on this:  I found a non-Shadow Deore M591 at the local Performance Bike and put that on the tandem, worked perfect with the 12-36.  Even worked with my Microshift brifters without even fiddling with the barrell adjuster or the b-screw, go figure.  Shifted perfect into every gear.

One thing I do like to do with a derailer when I put it on a new to it bike is to adjust the limit screws before I put the chain on.  I know the directions don't say to do it that way but I've had pretty good luck with it.

[Ron Mc]

on my daughter's Team Fuji build this summer, we went with the Microshift bar ends and Shimano 9-speed (Ultegra short cage, Miche custom cassette).  This was actually my first foray into index shifting - for her - and we're both delighted with the result - it's flawless.  

[Jim Bronson]

I'm pretty happy with Microshift products is general.  The brake levers on the Microshift brifers are canted out far enough so they will not bottom out on the drops.  I like that.  And they cost $106 shipped.  Many bar ends cost that much or more.

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