Hi folks, I currently own a Fairlight Secan 2.5 and have it built with Sram Rival AXS XPLR 12 speed - 40t x 44/10. I ran the bike like this for over a year without issue.
A few weeks back I replaced the chain when it was showing as 0.5 wear. Ever since changing the chain (stuck with Sram flattop) i’ve found that the gears are slipping in the 19, 17 and 15 cogs at the rear. The gears are indexed and the b limit screw is correct (i used the Sram guide). Fearing that the cassette was worn i swapped that for a part worn one i had on another bike, but still have the same issue. I’ve since changed the front chainring and chain but the chain continues to slip (now in the 17 and 15 tooth cassette cogs). It doesn’t jump into another gear but slips in the selected gear whilst under torque.
I’ve checked chain length, cleaned the mech, checked for stiff links, checked the hanger with a dag and spoken to a pal whose an experienced home mechanic and we’re both scratching our heads.
Does anyone have any suggestions to try and resolve this issue? Cheers, Ed
Hi, the only constant you have is worn cassettes, and along with that you state it doesn’t skip gears, it just slips, points towards them as well. Modern high end components can wear very quickly once a chain is out of tolerance through wear.
Is there any sign at all of teeth rounding or opening up in the cogs you mention?
As those are high gears, it could also be a slipping Freehub perhaps due to the amount of torque.
Also, check for dirt in the cassette that could be preventing the chain engaging correctly - although unlikely this is the issue if you have tried a second cassette.
If the chain is the correct chain and is properly installed, then it’s likely the cassette wear that is the issue here. Try lifting the chain away from the cassette with a fingernail - if it comes away easily and more than a couple of millimeters then it’s definitely the cassette.
Thanks for replies. I’ve tried two sets of wheels and same issue. Cassettes are in good condition. Chain is installed correctly with power links pointing in the right direction.
What you describe sounds like a classic case of a worn cassette. Very often, wear on the chain rings or cassette becomes apparent once you change the chain. The old, worn chain has already stretched and fits like a glove into the worn grooves. The new, tighter chain will then not be completely seated in the valleys and thus, you get chain slip.
There is no good way to judge the condition of cassettes. Cassettes can wear if e. g. you ride a lot in dirt and grime and/or tend to use the same gears a lot. The cassette on my trainer wears fastest in the gear I use the most, the one for rest intervals (I use resistance mode, not erg mode).
This does sound like my borked cassette on my trainer - chain is within the wear limit and the cassette looks mostly fine, but riding several hundred virtual kilometres in two gears led to skipping on those. I can actually see/feel that my 13/15 have a slight edge to them not present on other gears which is likely the cause of my issue.
If my memory is right, on a previous chain article Dave has stated that top level SRAM stuff really needs replacing at 0.3% wear. Do you ride those cogs that are slipping predominately?
I think the issue isn’t “longitudinal” wear, but “transversal” wear. My last Force chain was within specs length-wise, but it felt very sloppy going from side-to-side. So when my LBS replaced my chainrings, I had them replace the chain as well.
I have made the mistake of only replacing the chain and then ending up with an unusable bike way once too often and have learnt from it.
I’ve checked the cassette visually and doing the chain pluck technique mentioned in a previous post. I’ve also run it on two different cassettes. I’ve ordered a new cassette and will let you know how it goes.