Chain slip with Shimano XT 12 speed in top gear

[flightrisk86]

How have you done that to a cassette in 300 miles POWERING up step hills in turbo?

I have 1k miles on my orginal chain and cassette with hardly any wear and I ride in the Welsh mountains ⛰

I must of forgot to mention, the cause for the chain breaks was due to the front chain ring. Some kind of issue with the Stamped Steel Chain Ring kept bending the chains side plates. LBS broke the last chain in the parking lot doing a test ride. LBS got the upgraded version from e13 under warranty, but it took 3 chains to figure out the cause. BTW 12sp chains are expensive.

 

[dixie600mhz]

From the last picture you can clearly see that the smallest gear has been worn.

I have the new 10T rings and am carefully comparing old and new. There's two posts saying the wear is obvious. Considering that each tooth has a unique shape, when I compare old and new exact tooth for tooth I can't see any significant wear. Maybe at the very tips of some there is slight burr. It's not clear to me that the old one is badly worn. Keep in mind it does only have about 400 miles on it.

For the record I'm usually in eMTB mode but I'm quick. Trails in Texas are usually hard packed and fast and flowy so I spend most time in the higher gears just to keep pace with other riders. 36T front spider and chainring can't arrive soon enough.

See old vs new below.

 

[Gary]

36T front spider and chainring can't arrive soon enough.

Learn to spin and you won't actually need the 10t nevermind wear it out quickly.

a 10t cassette sprocket has no place on an Ebike in the first place

 

[Gary]

Another 30 miles in and the slip is back. It's definitely chain slip. Check out the video. Ignore the rust and the sandals. It was a spur of the moment gopro clip just after washing the bike tonight and was about 35C outside.

Your video shows your chain riding up onto the edge of the 12t sprocket rather than slipping

is your mech or hanger bent/damaged?
and are your limit screws adjusted properly?

 

[Jubby]

Or check your hub, mine was bone dry

 

[Richiefromboston]

with my time on ebikes a chain every 6 months is mando think of the stress and I use XTR 12 speed chains

 

[Link]

i am running AXS and just replaced the cassette at 600 miles, same issue, slipping in 10th gear (2 up from smallest), I am sure the wear started when I first got the bike and the 'b' screw setting was not near enough which def caused the issue coupled with the fact that this is a gear I use often.

I am coming from years and years of analogue mtbs and infrequently wore out a cassette as I would change the chain etc well before, I think the key difference here is the torque the rider plus motor can deliver, likely there is no way this amount of wear would slip with just rider power, so for me it's a different way to ride and be aware you can prob create slip and wear if you even infrequently mash big gears. As someone else said keep the cadence up, 80 is the optimal for the motor. Saying that I am sure my cassette would have been fine with the correct 'b' gap.

I have measured the chain and its not even 0.5 wear, its like new, same for the chainring, its literally that one sprocket which has gone. I should add i am pretty meticulous about cleaning and lubricating the drive chain, its def not a lack of care, as i said the chain is like new.

I had a hell of a job finding a new chain and cassette, finally managed to get them but paid through the nose, so will be much more conscious of gear, torque and 'b' setting.

I also looked into getting a 36T chainring, that would have solved the problem and moved the popular gear up the block, however everything i have read is that the rail wont take a 36T as its already close to the chain stay, this is a right pain, a 36 would literally remove any possible issues and i never use the 52T sprocket.

I really hope someone finds a way to fit a 36T without some sort of spacing hack that puts extra load on the motor shaft etc

 

[Randomscruff]

Anyone know why I would only get slipping across roughly the high half (descending cogs) of gears when the XT 12 speed clutch is turned on. Turn the clutch off and no problem.

 

[flightrisk86]

Anyone know why I would only get slipping across roughly the high half (descending cogs) of gears when the XT 12 speed clutch is turned on. Turn the clutch off and no problem.

Things to check:
1. Drivetrain clean and lubed
2. B Screw set per XT instructions
3. Frt chain ring might be holding the chain for too long with clutch tension - if so you need a new frt ring.

 

[aviserated]

My Rail 5 came with 11 tooth Sram cog. Sometimes it will slip, but not often enough to worry (read it is common issue). Recently discovered chain was very loose. Tightening and better alignment should help. Maybe chain oil works too well, waxing may work better at preventing slippage...I don't know. Maybe Trek will chime in and comment.

 

[Expidia]

Old thread, but @dixie600mhz did a new 10T ring solve your slippage issue? Looks like you never updated us?

 

[BobMtnBkr]

Same here. I trashed 2 gears on my OEM cassette on my ’21 Rail 9.8XT in less than 300 miles. Wasn’t slipping yet, but notice the extensive play while cleaning/lubing the chain. Seems I spend 80% of my ride in those 2 gears. Time to find a stronger cassette.

 

[Kanitfastan]

This thread is not new - so you see, this topic is an every-day-trouble.
So for me.

I bought my Giant Reign in autumn 2020. At the 70 km at riding from dealer to home I experienced first time chain slip on the 10T gear. (The fastest gear, smallest cog)

I am going to solve it as follows:
Chain is brandnew, the to smallest cogs are also nearly new.
The derailleur is adjusted perfectly! (B...)
I testet longer Chain, higher preload angle on the derailleur and the gap between 1st and 2nd gear and different chain manufacturer.
Nothing could solve the slip - it only disappeared with the wear and elongated chain and high preload angle of the derailleur.

Now I proved my theory with a friends bike.
See pics below. ("nn Z" means "nn Teeth")
Draw your own conclusion!

My conclusion is a "home grown" hanger, so that the derailleur is finally about the length of one chain link in driving direction positioned.
Discussion welcome.

 

[Kanitfastan]

The "home grown" hanger has been done.
Solution works.
No "chain slip" any more. See pictures.

 

[skinnyboy]

Good idea Kanitfastan, thanks for posting!

I had no skipping issues with my bike (YT Decoy 29), 2000 km on chain and cassette, B tension set as per Microshift. Chain had no measurable wear when removed.

Today with a new chain, same brand but e specific, skipping. Had to adjust B tension to increase chain wrap to eliminate it. (Not sure how the new chain caused this. Fresh grease on rollers, very tiny difference in pitch?) No issues with reduced clearance between jockey wheel and large cog.

I was curious, so adjusted my daughter's bike (Orbea Rise), with the exact same drive train, to the same clearance. It was very unhappy going to large cog set up like this.

The difference must be down to the position of the derailleur hanger. The YT with a UDH has derailleur hole 26 mm below and 30 mm from axle centre. The Orbea, 31 mm below and 33 mm to centre. Chain lengths on both bikes are correct.

It certainly seems the B setting, and prevention of chain skipping, are dependent on hanger placement, as you have advised. May be why some specific models of bikes seem more prone to the issue. Going forward, when I am setting the B tension, I will only treat the measurement from the manufacturer as a starting point, especially with the highly loaded (overloaded) e bike drive trains.

Cheers.