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Discussion Starter · #1 ·
RM Instinct, Eagle GX, Absolute Black oval chainring.

Second cassette from new, maybe 2000km on it, have been very mindful of chain stretch since blowing through the first one.
Chain was showing .5 wear on pedros checker. Decided to put a fresh chain on. After chain install, chainring was grumbling like a mofo so decided not to wait for it to settle in and to put the OE round on as it had very low usage before I did the oval. This solved the grumbling chainring.

Now I have a very perplexing skip or slip in the 6th gear. It doesn't change gears, runs smooth under low and moderate load but under higher load there is a very disturbing "skip". It's very hard to see what is happening because I can't look down and wind it up..... B gap is dead on with new SRAM checker tool, hanger is perfect. I set upper and lower limits as per SRAM specs, shifting is good (maybe a tiny bit sluggish on upshift). Only thing I have not done is change the cable. Wondering about chain length?

I sure as F hope I don't need a 3rd cassette after being so careful with chains.

Any suggestions are EXTREMELY welcome.
 

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feel you.

i put two months on a chain for 0.7 stretch.
next chain had a skip on the 10th hardest cog.
this was me using cheap chainlube and poor cleaning.
plus some good power.

use a quality chain lube and keep the driveline clean.
muc off ceramic dry works great for me. its water based and does simple chain wash on the bike w a couple scrub brushes and some mild soap.

rotate 3 chains through.

this driveline is now going on 2000km plus

on my bike, i think front chain ring should go.
but with three chains i think its best to just ride this driveline untill it dies.

im thinking of going shimano next time.
shifts better, and has better lower gear steps

anecdote: one ride last summer i ran out of the muc off so i had to go back to the cheap stuff on both my and my daughters bike. we both commented to each other, in the first 5 minutes, how our chains felt horrible and gravelly. that was an eye opener about how bad the cheap stuff was.
 

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Have a look and see if it skips at the same point every time on the cassette. This can be down to a cassette tooth snagging the chain as it moves past. Bend the offending tooth in the appropriate direction to stop the skipping and all should be well.
 

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Discussion Starter · #4 ·
Have a look and see if it skips at the same point every time on the cassette. This can be down to a cassette tooth snagging the chain as it moves past. Bend the offending tooth in the appropriate direction to stop the skipping and all should be well.
I have had the snag tooth problem but I was always able to see the offending one when on the stand and just rotating the pedals slowly...and that would just be a tick, not a skip. I will see if the crank position can help me narrow it down, but not sure how I will identify the specific tooth. Its in the same cogs that cause the mild snag so maybe its picking up on the lower gear (bigger cog) rather than the higher which is the clicking problem?
 

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Discussion Starter · #5 ·
feel you.

i put two months on a chain for 0.7 stretch.
next chain had a skip on the 10th hardest cog.
this was me using cheap chainlube and poor cleaning.
plus some good power.

use a quality chain lube and keep the driveline clean.
muc off ceramic dry works great for me. its water based and does simple chain wash on the bike w a couple scrub brushes and some mild soap.

rotate 3 chains through.

this driveline is now going on 2000km plus

on my bike, i think front chain ring should go.
but with three chains i think its best to just ride this driveline untill it dies.

im thinking of going shimano next time.
shifts better, and has better lower gear steps

anecdote: one ride last summer i ran out of the muc off so i had to go back to the cheap stuff on both my and my daughters bike. we both commented to each other, in the first 5 minutes, how our chains felt horrible and gravelly. that was an eye opener about how bad the cheap stuff was.
I will order the muc off and think about multi chain rotation. Thanks for the tip.
 

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Maybe I'm looking into the future, as your setup is identical to mine: RM instinct, AB oval chainring, Pedro tool... I'll have to replace cassette and chain in the near future, as it has passed 0.5. I used to have 3 chains, but one got stuck links and the other broke.

When I first got the bike, I had problems skipping a gear. Depending on the adjustment, from 4th to 7th. Read somewhere in this forum that adding a pair of chain links would solve the problem, as it did. My bike had an aluminum rear triangle then. That may be you looking into my past.
 

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Discussion Starter · #7 ·
Maybe I'm looking into the future, as your setup is identical to mine: RM instinct, AB oval chainring, Pedro tool... I'll have to replace cassette and chain in the near future, as it has passed 0.5. I used to have 3 chains, but one got stuck links and the other broke.

When I first got the bike, I had problems skipping a gear. Depending on the adjustment, from 4th to 7th. Read somewhere in this forum that adding a pair of chain links would solve the problem, as it did. My bike had an aluminum rear triangle then. That may be you looking into my past.
Don't assume you need a new cassette. You might get lucky. Also, very hard to find as out of stock in most places (at least in north america) I just found one and ordered a 52 (50 is not available anywhere in Canada) just to have it in case. I also bought a new spare derailleur because they are also like Hen's teeth.

Was yours skipping and staying in the same gear or jumping over a gear when shifting?
 

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Now I have a very perplexing skip or slip in the 6th gear. It doesn't change gears, runs smooth under low and moderate load but under higher load there is a very disturbing "skip". It's very hard to see what is happening because I can't look down and wind it up..... B gap is dead on with new SRAM checker tool, hanger is perfect. I set upper and lower limits as per SRAM specs, shifting is good (maybe a tiny bit sluggish on upshift). Only thing I have not done is change the cable. Wondering about chain length?
It sounds to me like your b-tension is not as spot on as you want it to be. It can be a wee bit tricky since b-tension must be adjusted under sag, which is difficult to achieve on the stand. I can disconnect the shock and approximate where I think my sag is or should be, but under riding conditions that can fly out the window. Since it happens in 6th gear, which is right where a b-tension issue would present and since it has a slight lag on upshift, I would hypothesize that there is too much b-tension, preventing a smooth upshift. I suggest backing the b-tension off 1/4 turn and going on a ride, and would do this until there is no lag.

As for chain length, it absolutely affects the b-tension adjustment. Removing even one link will necessitate a re-adjustment. Chain stretch will also affect the b-tension--as the chain grows, it exerts less tension on the derailleur.

Will new cables and housing work? It can't hurt, but is unlikely the culprit in this scenario. Crimped/frayed cables or damaged housing do affect shifting performance, but are not likely to only affect the 6th gear. You would more likely see sluggish unpredictable shifting across the range.

Best of luck. ✌
 

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Discussion Starter · #9 ·
It sounds to me like your b-tension is not as spot on as you want it to be. It can be a wee bit tricky since b-tension must be adjusted under sag, which is difficult to achieve on the stand. I can disconnect the shock and approximate where I think my sag is or should be, but under riding conditions that can fly out the window. Since it happens in 6th gear, which is right where a b-tension issue would present and since it has a slight lag on upshift, I would hypothesize that there is too much b-tension, preventing a smooth upshift. I suggest backing the b-tension off 1/4 turn and going on a ride, and would do this until there is no lag.

As for chain length, it absolutely affects the b-tension adjustment. Removing even one link will necessitate a re-adjustment. Chain stretch will also affect the b-tension--as the chain grows, it exerts less tension on the derailleur.

Will new cables and housing work? It can't hurt, but is unlikely the culprit in this scenario. Crimped/frayed cables or damaged housing do affect shifting performance, but are not likely to only affect the 6th gear. You would more likely see sluggish unpredictable shifting across the range.

Best of luck. ✌
good info thanks! I will check B with sag. I will also look at chain length. I have seen the "2 extra" links when bypassing the derailleur. What is your recommendation?
 

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Search the site for GX eagle cassette issues. Sounds like you have the classic slight bent/twisted teeth.

Sent from my Pixel 4a (5G) using Tapatalk
 

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GX cassettes have skipping and noise issues like that when they rack up the miles.

Not sure if SRAM ever fixed these problems but I have a 10-50 X01 with 2000 miles with no issues and my 10-52 XX1 with almost 1000 miles also has no issues. Except for the fact that tuning the 10-52 to shift perfectly is a complete pain.
 

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Wow, the chains wear out that fast? I guess I better get out my chain checker.

I have similar issues but I've been blaming it on the SX derailleur.
XX1 and XX0 chains go forever, pretty much the best out there.

Also you're not wrong in blaming part of the issue on the SX derailleur, I would recommend upgrading to GX minimum at some point.
 

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XX1 and XX0 chains go forever, pretty much the best out there.

Also you're not wrong in blaming part of the issue on the SX derailleur, I would recommend upgrading to GX minimum at some point.
I actually have a GX sitting on my shelf. I was going to change it out when I change the chain.

I have an NX chain also, because that was what I could get while placing an order for something else. I'll pick up an XX chain of some kind next time (if I can).
 

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GX cassettes don't last long for me. Maybe 500 miles? Then bent or broken teeth.

XO1 cassette is a different story altogether. I think I am on about 4000 miles now with no noticeable wear.
My GX 10-50 cassette in the past lasted 700 miles until it started ticking and shifting wonky.

OP, if you're in it for the long haul and ride a lot, it makes more financial sense to buy an XO1 or XX1 chain and cassette over a GX and below simply because you'll spend more money replacing chains and cassettes over time. The entry cost to higher level components are very high but they are more durable and lasts many times the miles you'd get out of anything GX and below.
 

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Discussion Starter · #19 ·
GX cassettes don't last long for me. Maybe 500 miles? Then bent or broken teeth.

XO1 cassette is a different story altogether. I think I am on about 4000 miles now with no noticeable wear.
OK, I have heard enough. I have a broken 50t tooth already (doesn't seem to impact) but I am ordering an x01
 

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Discussion Starter · #20 ·
My GX 10-50 cassette in the past lasted 700 miles until it started ticking and shifting wonky.

OP, if you're in it for the long haul and ride a lot, it makes more financial sense to buy an XO1 or XX1 chain and cassette over a GX and below simply because you'll spend more money replacing chains and cassettes over time. The entry cost to higher level components are very high but they are more durable and lasts many times the miles you'd get out of anything GX and below
Just submitted my order on an x01
 
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