I have a 2022 Polygon Xtrada 5 10 speed XC. OEM derailleur (Shimano RD 4120) somehow was sucked into the spokes recently after I bent the hangar back after noticing it was tweaked somehow. Anyway, fast forward to somewhat current times, after some research (I think I incorrectly read something) I opted for a new RD 5100 10/11speed bc of this der having a clutch. I primarily ride as a commuter but occasionally go off roading on local trails, hence vying for the clutch version. Plus this derailleur looks much cooler and was dirt cheap. I peeped the official Shimano compatibility chart and swore this derailleur is compatible with my 10 speed cassette, 11-42 teeth. Shown in the picture is the derailleur all the way on the first cog and all the way on the last cog. My problem is the first couple of cogs, the highest gears (smallest) I'm getting major chain slippage. The first few calls do not appear to be worn as I do not ride this bike very very hard as I depend on it solely for my transportation. I got a new chain with the derailleur, KMC X10 with the anti-rust protection added. And when I shift further down the gears towards the biggest cog, to chain sounds like it's stretching so to speak. Also the bike was once a 2×10 and I have converted it to a 1×10, only instead of a regular round chain ring, I'm using an oval narrow wide chain ring. That also does not seem to be worn. Did I get The wrong derailleur? I noticed the difference between my old one and this new one is what I think is called the goat link the extra link between the hanger and the derailleur itself. This has been going on for a week now and I've exhausted all efforts and I'm now turning to my redditor family for help. thank you in advance.
by Cautious-Village1501
7 Comments
Not an expert but the bike is in different gears
I would start by turning the B-screw counter clockwise so the top pulley wheel sit closer to the sprockets. This will significantly increase the chain wrap around the smaller cogs, preventing chain slip. Do this while shifted in the lowest gear (biggest sprocket). Turn it out only so much that the top pulley wheel does not touch the biggest sprocket (around 5 mm clearance).
You can try adjusting the limit screws for the skipping into the spokes. As for going from a 2x to a 1x you may need to add a spacer to the bottom bracket
It looks like the chain is not properly run through the jockey wheels. Take a look there
Not sure why people downvoted you. I’m sure the derailleur works, you don’t have a problem there. The slippage is probably the new chain. I’ve had this problem when I just replace the chain. You may want to try a different chain and/or replace the cassette (cogs in the back).
New chain on a old cassette creates the exact problem you are describing, slipping in the smaller cogs, personally I’d change the cassette and go from there. You may not have ridden it hard in your opinion, but wear happens over time wether you are smashing it or going easy. Actually I’d check there are no stiff links in the chain first, then change the cassette if there are not.
All the b-tension or lomit screw turning will not magically make the chain go though the top pulley properly. Start with routing the chain properly and go from there.