Author Topic: 11sp cassette/RD compatibility question  (Read 3132 times)

multispoke

11sp cassette/RD compatibility question
« on: October 06, 2016, 04:22:46 PM »
I would like to run a 11-46T cassette (SunRace), but need to pick a RD that would work with it.
On the product page, Shimano claims that the 11sp XTR and XT RDs can only handle 40T at the most. Interestingly, they released their own 11-46T cassette and claim that it is compatible with their XT and XTR drivetrains. Would I need to do any modifications to the derailleurs to handle a 46T rear cog?

Similar question on SRAM offerings. All of their 11sp RDs are listed as 10-42T compatible. Would they be able to handle a 46T cog without some kind of mods? Anyone have experience?
As a data point, WolfTooth claims their 49T cassette expander will work with SRAM 11sp RDs.
http://www.wolftoothcomponents.com/collections/cassette-cogs/products/49t-gc-cog-for-sram-and-sunrace

Is this just a case of manufacturers (Shimano and SRAM) being overly conservative and/or protective of their own product lineups?



Carbon_Dude

Re: 11sp cassette/RD compatibility question
« Reply #1 on: October 06, 2016, 04:38:32 PM »
FYI, for SRAM I know you need the XD freehub to run that cassette.
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multispoke

Re: 11sp cassette/RD compatibility question
« Reply #2 on: October 06, 2016, 07:30:59 PM »
I know I'd need a xD driver to run a 10-42, but what about running a 11sp SRAM RD with a 11-46T cassette? The cassette will not need a xD driver in and of itself. My question is will the SRAM RD handle the 46T cog? And, afaik, there are no 10-46T cassettes (wish SRAM would release one in 11sp).

Carbon_Dude

Re: 11sp cassette/RD compatibility question
« Reply #3 on: October 06, 2016, 08:47:26 PM »
After the SRAM 10-42 cassette came out on the market, several companies started selling larger replacement cogs for people to convert their drivetrains to a 1x setup.  Some of the kits were just one, two, or three cogs, others included upgrades to the rear derailleur.  Some people reported they thought the shifting was okay, others said jumping to a substantially larger cog was a bit rough.  You can search around and read the reviews yourself.  However, I guess most of those conversions were 42T or 44T options.  46T is pretty big.

E-thirteen had some options, Wolftooth, and if I remember correctly, OneUp had some of the better reviews.  I believe OneUp also sells longer cages for use with the big cogs. Not all of them even expect you to have an 11-spd rear derailleur so I guess that would mean you can use an existing 9-10 spd derailleur with the larger cogs.  Although, I would think you would need a long cage derailleur to take up the extra chain slack you will have.

For your question if a new 11-spd derailleur would work with a 46T cassette, my guess is probably, you might just need to adjust your b-screw tension until you get the upper jockey wheel far enough away from the large cog, or you might need one of those OneUp cages.  You may not get the 12mm gap SRAM recommends, but it might work anyway.
« Last Edit: October 06, 2016, 08:54:27 PM by Carbon_Dude »
2019 Stumpjumper Expert 29/27.5+
2017 Santa Cruz Stigmata
2017 Trek Stache 9.8 (29+)
2016 Specialized Stumpjumper FSR Carbon Comp 6Fattie (27.5+) (Sold)
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2014 -036 Full Suspension Chiner (Sold)
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Atlanta, GA

SportingGoods

Re: 11sp cassette/RD compatibility question
« Reply #4 on: October 07, 2016, 02:57:44 AM »
I'd say that any Shimano 11 sp RD with a longer B-screw will do it. Some shops sell this screw but you can find it in any hardware shop.

Here is one:
 http://www.moilutin-cycles.fr/vis-acier-pignon-vtt-m-4x07-mm-x-25-mm-noir-c2x18198542

RS VR6

Re: 11sp cassette/RD compatibility question
« Reply #5 on: October 07, 2016, 03:13:08 AM »
The only SRAM cassette that will work with the Wolf Tooth 49T is the NX that uses a standard Shimano hub body.

Wolf Tooth and OneUp both have third party derailleur add ons to go above 42T.

http://www.wolftoothcomponents.com/collections/derailleur-optimization/products/goatlink-11

http://www.oneupcomponents.com/collections/products/products/50t-shark-sprocket-18t-1x11

carbonazza

Re: 11sp cassette/RD compatibility question
« Reply #6 on: October 07, 2016, 07:05:18 AM »
I've installed an 11-46 XT cassette with the XT RD-M8000-GS(short cage) on the bike of a friend.

It is the first time that I put the cable on the derailleur with a little tension, and nothing else.
Perfect shifting the first time without fiddling with the shifter barrel.

We did align the derailleur hanger before as it was a bit off.

multispoke

Re: 11sp cassette/RD compatibility question
« Reply #7 on: October 07, 2016, 12:02:16 PM »
I've installed an 11-46 XT cassette with the XT RD-M8000-GS(short cage) on the bike of a friend.

It is the first time that I put the cable on the derailleur with a little tension, and nothing else.
Perfect shifting the first time without fiddling with the shifter barrel.

We did align the derailleur hanger before as it was a bit off.

Thanks all for pitching in. This is what I was looking for. So if it works with the XT, I suppose it will work with the lighter XTR derailleur also.

carbonazza

Re: 11sp cassette/RD compatibility question
« Reply #8 on: October 07, 2016, 02:32:26 PM »
....So if it works with the XT, I suppose it will work with the lighter XTR derailleur also.
Sure, they are interchangeable.
Beware, 60g less for 120€ more is about 2000€/Kg :)

multispoke

Re: 11sp cassette/RD compatibility question
« Reply #9 on: October 08, 2016, 02:00:36 PM »
....So if it works with the XT, I suppose it will work with the lighter XTR derailleur also.
Sure, they are interchangeable.
Beware, 60g less for 120€ more is about 2000€/Kg :)

Oh yeah, it's super easy to slip into the WW rabbithole! Heck, I'm drilling holes in my seatpost bolt holder to save 3 grams :/
Fortunately, I'm not in a rush to buy, so I'll only get one if I find a deal :)
Actually, the weight savings are even less that you quote. XT is listed at 270g, and XTR is 225g.
Kicking myself for missing out on a SRAM XX1 RD for $85 on eBay yesterday! But then, I'm not sure if it would've worked with a 46T. Wolftooth make it sound like it would...
« Last Edit: October 08, 2016, 02:09:36 PM by multispoke »