Problem with drivetrain

[Sander23]

I ride a shimano axs drivetrain.
I recently replaced my drivetrain, exsiting of a slx cassette with xtr chain , a new fsa 38t chainring/spider and some hope jockeywheels. So basically all new.

When new it shifts fast and good

Has done 3-4 rides of 300-400km and my smallest when putting power on the pedals it skips.
Chain/quicklink is in good rotation, everything is well tightened
At first I thought my chain was a little to long so I shortened it a little. That diddnt fix it.

I played with the bgap diddnt work either.
Smallest sprocket also looks like new..

The only thing was the difference between the old en new drivetrain are in the micro adjustments in the sram axs app.
Micro adjustments on the Old drivetrain was at 15, the new is at 22.

New at 15 is t rideable.

What else can I try to solve it?

 

[Sander23]

Also checked the cassettebody, wich is also good .

 

[Mikerb]

1. did you set the b gap with the shock at SAG?
2. Not sure how you set the B gap when using a shimano cassette but when on a SRAM cassette you use the white tool on the largest cog with the chain on the next cog down and with the shock at sag, get the pointer of the tool pointing directly at the centre of the bolt of the jockey guide wheel.
3. Next step is set the limit screws. Upper limit is set by changing up to largest cog then backing the limit screw off 1/4 turn....same then on the smallest cog.

That just leaves the fine indexing. I dont both with the app. Start with the chain on the second largest cog and check how well it changes to the next smallest cog. If it is slow change the chain back to the second largest cog and whilst pressing and holding the button on the shifter, press whichever button you have programmed to move to the next smallest cog.......try again.....repeat if still slow to change. I have found that invariably if you get the gear change sweet from the second largest cog to the next cog down, the rest of the changes will also work well since what you doing is adjusting how much the mech moves for each gear change....and the gap between all cogs is the same.

That said if your only issue is with skipping when using the smallest cog it suggests a lack of mech tension.......and it is the chain length and B tension that sets that......or possibly the low limit setting. The only other potential reasons would be a mech that is not moving freely due to trail dirt etc.

 

[theremotejuggernaut]

How much wrap have you got around the smallest cog? Can you post a pic?

Also, where did you buy the cassette and chain? So many fakes out there on Ebay and Amazon etc

 

[irie]

How much wrap have you got around the smallest cog? Can you post a pic?

Also, where did you buy the cassette and chain? So many fakes out there on Ebay and Amazon etc

I will not buy any drive train parts from eBay or Amazon unless I can see that the seller is a reputable supplier. In which case going to the supplier directly is often cheaper.

 

[Sander23]

1. did you set the b gap with the shock at SAG?
2. Not sure how you set the B gap when using a shimano cassette but when on a SRAM cassette you use the white tool on the largest cog with the chain on the next cog down and with the shock at sag, get the pointer of the tool pointing directly at the centre of the bolt of the jockey guide wheel.
3. Next step is set the limit screws. Upper limit is set by changing up to largest cog then backing the limit screw off 1/4 turn....same then on the smallest cog.

That just leaves the fine indexing. I dont both with the app. Start with the chain on the second largest cog and check how well it changes to the next smallest cog. If it is slow change the chain back to the second largest cog and whilst pressing and holding the button on the shifter, press whichever button you have programmed to move to the next smallest cog.......try again.....repeat if still slow to change. I have found that invariably if you get the gear change sweet from the second largest cog to the next cog down, the rest of the changes will also work well since what you doing is adjusting how much the mech moves for each gear change....and the gap between all cogs is the same.

That said if your only issue is with skipping when using the smallest cog it suggests a lack of mech tension.......and it is the chain length and B tension that sets that......or possibly the low limit setting. The only other potential reasons would be a mech that is not moving freely due to trail dirt etc.

I haven't set it at sag point. I might try that now. I indexed it before and it shifts very smooth in all gears , no rattle and very fast.

 

[Sander23]

How much wrap have you got around the smallest cog? Can you post a pic?

Also, where did you buy the cassette and chain? So many fakes out there on Ebay and Amazon etc

No it's from bike discount.de. it was a cheaper cassette because I bought it without package but it was brand new.

 

[Sander23]

 

[theremotejuggernaut]

Chain wrap looks good.

Is it definitely the chain skipping? Could it perhaps be the freehub slipping under load?

 

[Ark]

is your bike supposed to fit a 38t chainring? I know some bikes I've seen have limits "max 36teeth chainring" etc

soemthing to do with the gap between the chainring and chainstay though, so if you had a problem because of that. maybe it'd be obvious.


If the cassette isn't one peice, are you sure you lined all the indicator marks up properly?

 

[Sander23]

Chain wrap looks good.

Is it definitely the chain skipping? Could it perhaps be the freehub slipping under load?

The freehub pawls you mean?

 

[Sander23]

is your bike supposed to fit a 38t chainring? I know some bikes I've seen have limits "max 36teeth chainring" etc

soemthing to do with the gap between the chainring and chainstay though, so if you had a problem because of that. maybe it'd be obvious.


If the cassette isn't one peice, are you sure you lined all the indicator marks up properly?

Yes cassette is well installed. Bike came with 38 T

 

[theremotejuggernaut]

The freehub pawls you mean?

Yeah, the pawls can get stuck if there's dirt or damage inside the freehub or hub shell. Depending on the hub, itd generally an easy thing to check. Most of the time, you can just pull the cassette and freehub off as one unit so minimal disassembly.

Getting it back in can be a bit more tricky. I use an old gear cable wrapped around the pawls to pin them in place and the wiggle the freehub into the hub body. Once it's engaged, you can whip the old gear cable out and push the freehub in fully.

 

[Mikerb]

View attachment 146378
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not easy to tell exactly from the photos but the high limit does look to me to be too far towards the mech. The high limit is set so that the chain just moves securely onto the smallest cog then the limit screww backed off 1/4 turn. Your guide pulley looks to be aligned with outside of the smallest cog. On my AXS ( v1) bike the guide pulley is directly in line with the cog.

 

[Sander23]

Yeah, the pawls can get stuck if there's dirt or damage inside the freehub or hub shell. Depending on the hub, itd generally an easy thing to check. Most of the time, you can just pull the cassette and freehub off as one unit so minimal disassembly.

Getting it back in can be a bit more tricky. I use an old gear cable wrapped around the pawls to pin them in place and the wiggle the freehub into the hub body. Once it's engaged, you can whip the old gear cable out and push the freehub in fully.

They seem okay. The pawls move freely.

 

[Sander23]

not easy to tell exactly from the photos but the high limit does look to me to be too far towards the mech. The high limit is set so that the chain just moves securely onto the smallest cog then the limit screww backed off 1/4 turn. Your guide pulley looks to be aligned with outside of the smallest cog. On my AXS ( v1) bike the guide pulley is directly in line with the cog.

When I look at it, it look straight in the middle. Picture shows it wrong