Shimano Derailleur RD-M8000-GS vs. RD-M8100-SGS Cage Length and general longevity.

DrStupid

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Iv'e worn out the pivots on my RD-M8000-GS derailleur. Its still working OK, but getting sloppy.

I'm considering giving an RD-M81000-SGS a try, but I'm curious if it's as tough as the M8000 and how much longer the cage is?

Does anybody have an opinion after using them both?
 

Zimmerframe

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Jun 12, 2019
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Using this simple hack you can use the XT8000 with 8/9/10/11/12 speed chains and even motorcycle chains ..

xt.jpg
 

urastus

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I have the XT RD M8100 Shadow+, if that is what you're talking about. I think I bent the bit that holds the jockey wheels months ago, and straightened it by eye. It has just worked, no trouble. I have 52 / 32 (12x) set up.
 

urastus

⚡The Whippet⚡
May 4, 2020
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It does look short. I'm sure stealth gray makes up for that :ROFLMAO:. I think it might be a good idea to look up those derailers and see what length you need for your cluster size ie from largest cog to smallest.

I just looked - that model is good for 10-45 12x. The sgs is for 10-51. Sometimes you might read "total capacity = 41". That means the difference between largest and smallest sprocket ie smallest is 10, largest is 51, the difference between the two is 41.
 
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RickBullotta

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I always use the shortest cage that can accommodate the gear range I plan to use. No point in having extra stuff hanging out there to be destroyed nor the additional "slop" from the derailleur swinging back and forth (even with a clutch derailleur).
 

DrStupid

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That's the 12 speed Shimano Rhythm Step derailleur made specifically for the 10-45 cassette. I believe it may be the best possible ebike system ever made, but dam it cost as much as a rohloff.
 

Dan63

Well-known member
Feb 4, 2019
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Brisbane
I have seen quite a few people complain of the 8100-SGS cage folding in half and grenading for no particular reason. Maybe the extra stress of an ebike, but the longer cage seems to be prone to bending. The 9100-GS would be a better option i think,
 

urastus

⚡The Whippet⚡
May 4, 2020
1,548
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Tasmania
I have seen quite a few people complain of the 8100-SGS cage folding in half and grenading for no particular reason. Maybe the extra stress of an ebike, but the longer cage seems to be prone to bending. The 9100-GS would be a better option i think,
The stress via feet and motor is on the top part of the loop. The only stress the bottom part of the loop will experience is when the chain slaps up and down, no more or less than a non e bike.
 

DrStupid

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It appears as though this guy likes the medium cage xtr and the 10-45 Slx cassette.

 

Dan63

Well-known member
Feb 4, 2019
289
170
Brisbane
The stress via feet and motor is on the top part of the loop. The only stress the bottom part of the loop will experience is when the chain slaps up and down, no more or less than a non e bike.
That is correct, i can only speculate. Perhaps it is happening on analogue bikes too, however i have seen numerous mentions of the problem on different emtb groups.
 

DrStupid

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I will be trying something different soon.

Its finally over, my best ever, longest lasting, most beloved derailleur is dead. It was a complete and spectacular way for a mech to go.

20200919_092732.jpg

Seen as the new Trance X is on it's way, I'll have an XTR 12 speed destruction test subject soon enough.

Also

I've still a Box Components 8 speed to wear out or break, and few special modified Zees with One-Up RadR cages to fiddle with.

I'll have something cobbled together one way or another tomorrow morning.
 
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