Forum: bicycles.stackexchange.com
Tags: <mountain-bike><derailleur><cassette><derailleur-rear><compatibility>
Title: Fitting a 9-speed 11-50T cassette on MTB: which derailleur?
Question: I'm trying to understand if its possible to fit a 9-speed 11-50T cassette (found one on Ali) on my MTB. The plan is to go 1×9. The problem is that I can't seem to understand the if a specific derailleur can handle that.  The rear derailleur in mind is Shimano M4000 long cage. Should I use a hanger extension? Will 11-42T be better for that?  Thanks for the help

Answers:
sents: text: https://bike.shimano.com/en-EU/product/component/alivio-m4000/RD-M4000.html says that derailleur will handle Low
text: sprocket_Max. 36T Low sprocket_Min. 32T ANSWER : You cannot run a 50 tooth cog with that derailleur.
text: You might be able to use a hanger extension, but that will make the small gears even worse.
text: Wolf Tooth's Roadlink allows up to 40 tooth, and Wolf Tooth's Tanpan says 44 or 45 tooth is the maximum cassette size supported.
text: Note
text: these are for 10 and 11 speed.
text: If you're absolutely stuck on a 50 tooth rear cog, then you're looking at a SRAM 12 speed Eagle setup, which will not be cheap.
text: Cassette and shifter must change, and its very likely your freehub won't fit the cassette, and then the OLD will be too large to fit in your frame.
text: Not a good plan.
answer_details: author: bicycles.stackexchange.com/users/19705/Criggie
score: 10
sents: text: Derailleur will not handle that, as Criggie says in his answer.
text: Apart from that, an 11-50 9 speed would have horrifically big jumps between gear ratios.
text: 1x systems only really became feasible with the advent of 11 speed drive-trains, and still sacrifice ratio jumps to get a full spread of ratios to some extent.
text: If you really want a 1x 9 speed, get a cassette a 9 speed derailleur can handle, then get a small enough chainring to give you the low gears you want, and forgo the higher gears.
text: BTW, Shimano provides tech specs for all their products (as Criggie linked to).
text: This page is a good place to start looking for specs of a particular product.
answer_details: author: bicycles.stackexchange.com/users/24228/Argenti Apparatus
score: 6
sents: text: I run a shimano m4000 with a 9spd goat link on a 9spd 11-50t cassette with no problems b screw doesn’t need to be fully wound in.
text: More recently, I’ve reverted to a 10spd SLX shadow+ mech sgs cage which I run with a sram x7 9spd shifter, giving even better shifting.
answer_details: author: bicycles.stackexchange.com/users/40653/Andy W
score: 6
sents: text: I have to agree with Dave - 11-36 works like a charm, gear spacing is just right.
text: A 11-40 cassette just works OK with the B-screw screwed in all the way or using an even longer replacement screw.
text: I also tried an 11-42 which didn't really work well.
text: AFAIC the issue with the wide range cassettes reg.
text: 9-Speed is that they have the cassettes but there are no (Shimano) derailleurs to shift it.
text: At least not out of the box.
text: You could try a Shimano 10-speed derailleur and if it doesn't work ok (which it likely won't), try tweaking it.
text: There are howtos online with re-routing the cable for a different pull ratio.
text: 11-speed derailleurs might be too narrow, chain-wise.
text: You could also use a Sram 9-speed shifter with a Shimano 10-speed derailleur.
text: Trouble is, all of these solutions are rather expensive if you haven't the parts in the spares box.
text: Rather than spending that much money on an exotic 9-speed solution that doesn't get better over time, invest it in a Sunrace 11-speed cassette and Shimano SLX derailleur plus shifter.
text: What you don't want is a solution based on hanging your derailleur lower and the Wolf Tooth link extensions don't work with 9-speed derailleurs.
text: I tried it (and it's rather expensive too).
text: Best to stick to inexpensive 11/12-36 and a 30 or 32 NW chainring.
text: Or try the 11-40, but that's the max you will be able to get working properly.
answer_details: author: bicycles.stackexchange.com/users/40420/Simon Adventures
score: 4
sents: text: 21% gear spacing is not a problem.
text: Shimano has over stated the need for tight ratios.
text: The shifting won't be quite as smooth, I have an 8spd 11-40, but will be well within acceptable standards.
text: 11-36 has never been a problem with 9 speeds and I usually have to double
text: shift my 11-36 10 spd because the ratios are too tight.
text: You will have to use a hanger extender with a long cage derailleur.
text: The warnings that the extender doesn't allow the RDR to track the cassette properly is also over stated.
text: Shimano claims they do no testing with components other than their own.
text: If you believe that Shimano wouldn't know.
text: Obviously that is ridiculous.
text: Shimano has stubbornly lagged 2 to 3 years behind the market in the area of gear ranges.
text: They don't belive in it and only participate well behind the market because they have no choice so pick another brand of RDR.
text: There are many options.
answer_details: author: bicycles.stackexchange.com/users/39946/Dave
score: 2
sents: text: I looked at some offerings of such cassettes and what a vendor suggests as a derailleur for them.
text: An example of a cassette: Compatibility chart from the same page:
text: It looks that no 9- or 10-speed dérailleurs are compatible with that cassette, but they claim that some 11-speed ans 12-speed parts from both Shimano and SRAM may be used instead.
answer_details: author: bicycles.stackexchange.com/users/26917/Grigory Rechistov
score: 2
sents: text: Box Components have released a 9-speed 11-50 drivetrain (cassette, RD, and chain) for EMTBs (thicker chain and cassette to cope with the torque), and I think the gear jump ratios don't matter when it comes to mountain biking.
text: Even Seth's Bike Hacks uses it, and he's a very nitpicky kind of guy.
text: What I don't know is if it's compatible with a standard 9-speed system.
text: Box Components says it isn't compatible with Shimano and SRAM 9-speed systems, but I have a feeling they're just saying it for marketing purposes.
answer_details: author: bicycles.stackexchange.com/users/39963/Gregory Leo
score: 2
sents: text: I have used a RD-M2000 and 11-50 on 9 speed with hanger, but the very connection of the gear wire on the inside just touches the bigger cog when in 1 gear, otherwise ok (almost :-)
text: Would probably try the RD-M370 instead next time
answer_details: author: bicycles.stackexchange.com/users/43823/Max
score: 1

Summary of the answers:
A number of derailleurs are recommended when fitting a 9-speed 11-50T cassette on MTB: Wolf Tooth Roadlink and Wolf Tooth Tanpan, SRAM 12 speed Eagle setup, Shimano 10-speed derailleur, Sunrace 11-speed cassette and Shimano SLX derailleur. Note that Shimano states it does not test on components other than their own.
A 9 speed cassette is unlikely to support a large range, so switching to an 11/12 speed might be a better option. Having said this, some commenters claim that Shimano overstates the problems with wide gear spacing, and that this setup could work with a hanger extender and long cage derailleur.