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Shimano XT RD-M8100 SGS issues


Muishond
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Looking for opinions on course of action with regards derailler issues being experienced.

 

Bike was purchased new Nov 2019 and used as per normal for an mtb, in other words on road and gravel trails.

The use case would also include possibly riding in the rain, or through water..

 

The bike experienced chain drop/slack in May 2020 and I googled to find this a "common" issue on Shimano deraillers?

Upon opening the clutch housing, I found it to be containing a fair amount of dust mixed with moisture, rusting and slowly eating away at the metal parts, causing the clutch to slowly seize.

 

The rusting was no doubt helped along by the bike not being used for the lockdown period in April.

 

I cleaned, lubed and closed up the cover and thinking I may need professional advice, contacted CL Lynnwood where the bike was purchased, and arranged a service. I specifically queried the issue around the derailler and dust and water entering the housing. The Tech admitted it should not happen, but can if I washed or sprayed bike and derailler with high pressure washer directly on the derailler or if I ride in the rain.

 

I assured him I do not wash with high pressure washer, but I do sometimes as would be normally acceptable end up riding in the rain or through water. They serviced and lubed the clutch and I was cautiously confident the problem was dealt with.

 

Alas, today I opened the cover to check and would you believe, the clutch mechanism and cover is covered in dust and moisture - on the INSIDE! 

 

I already contacted CL Lynnwood to complain about the part and it's poor quality in this case. I requested exchange as the bike should be under warranty (?) or at least the part should be.

 

What else can I do or expect in this case? To me the derailler has a flaw and must be replaced as it is definitely not normal wear and tear.

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A friend of mine has the same derailleur and a similar issue. Clutch seized and ended up loosening the cage bolt and he thought he had actually broken it. Mechanic pulled it all apart and put it back together, said that everything was quite rusted inside.

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Is there a gasket or runner membrane between the cover and housing?

 

If not then obviously nearly anything o. The roads will get in there over time

 

If yes then it might be damaged or the housing might just be poorly designed, I know on the old 10 spd ones you were supposed to take it out and give it clean yearly (maybe more often but I only did mine once a year) and I never had dust or rust of that level present

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I have a 11 speed shimano deore and had it seize on me after about 16,000km in mud , rain and regular washing  (some times with hi pressure ) I opened it and found only dirt mixed with the grease ( grime ) in it . I washed it all clean , re greased it with water proof grease re adjusted the the clutch to my liking and have not had a problem since and already done another 12,000 km . I think the trick is to use  a better grease than original and adjusting it carefully .I punish my bike, that is i ride through sandy /dusty areas , water puddles and streams , up and down pavements ( lots of derailleur movement ) and rocky gravel roads .  

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Unfortunately this is common on the Shimano derailleur design. Dura ace, ultegra 105, XTR XT Deore.. It's quite irritating as it detracts from what is otherwise very good product..the dust cover doesn't help much to be honest. If the bike gets wet then that mechanism gets gunked up. On the mtb dérailleurs it's both the clutch mechanism and the jockey pulley cage pivot shaft that requires regular maintenance and Shimano doesn't warranty the derailleur.

Best solution if you chose to keep the groupset is to just add it to the regular maintenance checklist

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The gasket can be seen in the pic. Rust shows there was not enough or no lubrication at all. Almost doubt the bike shop even did anything with it at the service.

 

Never had that issue with mine, have had the clutch ring snap on 2 occasions, first was sorted under warranty.

 

My current bike strangle had to much grease in the mech when I opened it, and as it had broke down over time and gathered metal dust, actually lubricated and polished the mech to well that it the it was not giving enough friction! Cleaned up and all sorted.

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Thanks for all the responses.

 

So took it in to CL Lynwood, and service dept. tech said he will send it in as it may be a warranty claim.

Didn't ask if he's sending it to Scott or Shimano?

 

He agreed that it should not be as bad as in my case but he does see it occur now and then - his opinion was I'd still be "better off in the long run" sticking with Shimano...fwiw...

 

So from hubbers it seems to range from some who have no issues like this, and others who see it as a maintenance item to check and clean regularly.

 

Personally I think this particular part should not have to be maintained after every ride/2nd ride or cleaned after every wash as is the case now.

I would not have a issue with maintaining it every 1000-1500km or perhaps 200 hrs like the front shock. 

 

Anyway will see what they come back with.

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  • 4 months later...

Thanks for all the responses.

 

So took it in to CL Lynwood, and service dept. tech said he will send it in as it may be a warranty claim.

Didn't ask if he's sending it to Scott or Shimano?

 

He agreed that it should not be as bad as in my case but he does see it occur now and then - his opinion was I'd still be "better off in the long run" sticking with Shimano...fwiw...

 

So from hubbers it seems to range from some who have no issues like this, and others who see it as a maintenance item to check and clean regularly.

 

Personally I think this particular part should not have to be maintained after every ride/2nd ride or cleaned after every wash as is the case now.

I would not have a issue with maintaining it every 1000-1500km or perhaps 200 hrs like the front shock. 

 

Anyway will see what they come back with.

 

 

From more recent interactions with peeps using these parts It appears to be far more frequent so I'm thinking that sticking with a product that is starting to indicate a design problem is not good advice.

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