12 speed XT cassette replacement.

[Sean0711]

Hi all,

After all the drivetrain issues I’ve been having! I now have more issues. Yay!

So first was the front sprocket cutting into the chain stay, then the chain itself snapping last week. I have been constantly checking it for stretch after each ride so that I don’t shag out the rear cassette. The chain was just below the 0.5 mark so I decided as I had a spare I would replace it yesterday evening. After fitting it along with stripping down checking, cleaning and adjusting the rear derailleur. It was changing lovely on the bike stand. I went out today and done about 25 miles. From the get go the chain was skipping in the mid range gears. So now I’m thinking the cassette is scrap.... 2 questions. Is there anything else that could be causing the chain to jump? And if not, where the hell do I find a 12 Sd Shimano XT or SLX cassette in stock! (I’m Uk based)

Thanks in advance!

 

[Doomanic]

How many miles have you done?

I've done nearly 2000 on my original chain and cassette and until it starts skipping I'm not changing it. It does have 2 quick links in it now though...

I got a Deore 12 speed cassette from Merlin recently.

 

[Gary]

From the get go the chain was skipping in the mid range gears.

Skipping?
or
Slipping?

The former is most likely an issue with gear (hanger or mech) alignment, set-up and possibly poor cabling
The latter is wear.

Take it to a bike shop and have a drivetrain service done.

 

[Sean0711]

Skipping?
or
Slipping?

The former is most likely an issue with gear (hanger or mech) alignment, set-up and possibly poor cabling
The latter is wear.

Take it to a bike shop and have a drivetrain service done.

Sorry I meant slipping but only under load, the alignment seems good it selects all 12 gears well. It’s only covered 281 miles!! And the drivetrain has been cleaned and lubed after every ride.

 

[Doomanic]

t’s only covered 281 miles!!

What do you lube it with, grinding paste?

 

[Sean0711]

What do you lube it with, grinding paste?

Im starting to think so!! I really don’t understand why this drivetrain is giving me so much of a headache! I had Shimano XT on 2 of my previous bikes (non Emtb) and had them set up lovely. Never Replaced the cassette on my 2014 Trek Stache. that got a load of abuse. Still changed perfectly every time and didn’t skip. ?

 

[Gary]

Slipping under load means the chain is not synchronising with the sprocket teeth.
Try bringing the top pulley wheel closer to the cassette by adjusting b tension. It may give you more chain wrap. But If you've managed to wear those sprockets down it may be past saving.

Ive worn a 13t sprocket to the point of slipping in just 100miles but it was a shite Box components cassette

 

[Sean0711]

Slipping under load means the chain is not synchronising with the sprocket teeth.
Try bringing the top pulley wheel closer to the cassette by adjusting b tension. It may give you more chain wrap. But If you've managed to wear those sprockets down it may be past saving.

Ive worn a 13t sprocket to the point of slipping in just 100miles but it was a shite Box components cassette

after adjusting the B tension its slip free and changing perfectly! im not quite sure how the b tension un adjusted itself though? as you have to wind the screw in to slack it off ?

thanks for the helps guys. ?

 

[Gary]

It would have been too far in all along. And that's why there would have been less chain wrap. And that's why it started slipping so early.

#science

 

[bsquared]

I am a Clydesdale and had slipping / switching under load... switched to the BOX 9-speed single shift and love it... more room for the chain to pull and not ride up a gear... IMO.

Very happy I switched to the Box.

 

[dixie600mhz]

I have slipping with the XT 1x12 in 12th after 400 miles on the cassette and 200 miles on the chain. B screw fixed it a bit but now it's slipping like crazy again.

In these covid times buying the single cog replacement or even a new cassette is a challenge. Nothing is in stock anywhere. Although I'm running the 10-51T cassette with the issue, due to the only thing in stock being the 10-45T I'm switching.

I just read the 10-45T uses the M8120 derailleur with a shorter cage. Has anyone used the stock M8100 long cage derailleur with the 10-45T cassette? I can't even find the short cage parts in stock to do a quick switch. It's like try one thing to find stuff in stock then realize you need something else that's also not in stock.

 

[RickBullotta]

I have slipping with the XT 1x12 in 12th after 400 miles on the cassette and 200 miles on the chain. B screw fixed it a bit but now it's slipping like crazy again.

In these covid times buying the single cog replacement or even a new cassette is a challenge. Nothing is in stock anywhere. Although I'm running the 10-51T cassette with the issue, due to the only thing in stock being the 10-45T I'm switching.

I just read the 10-45T uses the M8120 derailleur with a shorter cage. Has anyone used the stock M8100 long cage derailleur with the 10-45T cassette? I can't even find the short cage parts in stock to do a quick switch. It's like try one thing to find stuff in stock then realize you need something else that's also not in stock.

There's nothing special about Shimano 11 speed cassettes. Any 11 speed cassette that is compatible with the Shimano freehub will work, including the SRAM PG-XXXX cassettes.

BTW, I feel your pain on parts. I'm building a gravel bike from scratch (started with a Pivot Vault V4 frame from eBay), and I've had to place 11 separate orders from 8 different sources to get the parts I needed! I am becoming a ninja at Google searching for Shimano parts lately...

 

[Doomanic]

IME Shimano XT 12 speed shifts better than Sram NX 12 speed. I have no idea what you guys are doing to trash cassettes in such a short distance though, I had 2200 miles on mine on a single chain before the chain cried enough and I fitted a new chain.

 

[dixie600mhz]

Doomanic, you must have legs like Kermit. Only kidding!!

I agree that the Shimano system is light years ahead of SRAM. I have two other bikes with the X01 and will never go back to SRAM, even though my XT cassette is wearing fast. The cool thing about Shimano is that you can swap out the smaller cogs as they wear IF they are in stock somewhere.

Rick are you saying the M8100 10-51T derailleur will be just fine as is with the 10-45T cassette? I'm reading the b-screw adjustment can't get close enough to the 45T with the M8100. Some folks are filing the hanger on other forums. I'm hoping it will just work as a straight cassette swap.

 

[Mcharza]

If it is lower gear that are slipping, just bought the new one 10-45 and move the lower gear sprockets from the new one to the old cassette

 

[dixie600mhz]

If it is lower gear that are slipping, just bought the new one 10-45 and move the lower gear sprockets from the new one to the old cassette

Good point!! That would be the quickest fix. Other good news is I found the 10T and 12T sprockets in stock in Singapore with 4 week shipping. Just ordered two batches for $30. I know what you guys mean about becoming internet Jedi's trying to find stuff in stock.

 

[Bac]

IME Shimano XT 12 speed shifts better than Sram NX 12 speed. I have no idea what you guys are doing to trash cassettes in such a short distance though, I had 2200 miles on mine on a single chain before the chain cried enough and I fitted a new chain.

Yes I agree with this, but are having same issue here with the new XT. My previous bike a Heckler was all SRAM drivetrain, done 1800kms not a single issue, no jumping chains or worn cassettes. Now my new Bullit with XT chain is jumping teeth on the cassette in just 220kms, and the cassette is shagged. Weird! Although I prefer the shifting of XT, I'm baffled as to why it's not lasting as long. It never jumps in boost mode, only when I switch to eco, shift into high gear and hit the pedals for the downhill run. It's jumping on all gears in the lower half of the cassette.. quite unnerving.
Would love to know why

 

[RickBullotta]

Yes I agree with this, but are having same issue here with the new XT. My previous bike a Heckler was all SRAM drivetrain, done 1800kms not a single issue, no jumping chains or worn cassettes. Now my new Bullit with XT chain is jumping teeth on the cassette in just 220kms, and the cassette is shagged. Weird! Although I prefer the shifting of XT, I'm baffled as to why it's not lasting as long. It never jumps in boost mode, only when I switch to eco, shift into high gear and hit the pedals for the downhill run. It's jumping on all gears in the lower half of the cassette.. quite unnerving.
Would love to know why

Is the derailleur clutch turned on or off? Make sure it's on.

 

[Bac]

Is the derailleur clutch turned on or off? Make sure it's on.

Yeah it's definitely turned on, and I've wound it up to max resistance too

 

[dixie600mhz]

Just for the record when I switched to a 10-45 cassette I could adjust the b-screw to get much more wrap. I haven't found I ever need a lower gear than 45T even on the worst technical climbs. Another fix was to go to 36T front ring. Then you are almost never in the 12th gear.