Been running a 42t Shimano cassette with an Apex 1 derailleur (unsure of medium or long cage model) for some time now. All working perfectly. Cassette due for an upgrade, so went with a Sunrace 46t.
From what I've read, just a fiddle of the B tension was all that's required. However..
Fitted the new cassette. Up shifts (to the larger cogs) with no issue. Trouble is, now, it refuses to shift down from 11th to 10th without dropping about 4 shifts, and even then it's hesitant.
Tried all manner of adjustments. Started from scratch, limit screws, reindexed, everything. Nothing works.
Hanger looks fine.
Cables are recently-ish new and smooth running.
Tried the sometimes mentioned spacer behind the cassette tip. No dice.
Nothing I try works. Is my derailleur toast? Help!
You may need a hanger extender like this:
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.co.uk%2Fulk%2Fitm%2F153325558734
And then you can use less b-screw to get the right position.
Thanks Joemmo. For the price it's worth a punt. Ordered. Fingers crossed.
As above really. It’s a setup issue as you can’t get the b tension to where it needs to be, so you’ll need that sort of adapter to have a chance
Cool. I use one to get a max 34t rear mech to work with a 11-40 cassette and the b screw is not even half in. The other plus is you get more chain wrap around the sprockets which should reduce wear.
Remember that you don’t set b-tension on modern Sram stuff the same way as you used to on Shimano and the like. Starting point is to set a 15mm gap between the top jockey wheel and the largest cog. Chain length also needs to be spot on too
Did you change the chain with the cassette as I'd assume that the chain would need to be a tad longer to accommodate the extra teeth?
Yeah, new, longer, chain as well. Have left the derailleur, hosed in lube, overnight to see if that could possibly be causing problems. I've ordered the extender on a fast track type thing and hopefully should arrive soon. Itching for some steep gravel climbs!
Just to update.. Derailleur hanger extender arrived yesterday. Installed, along with a new gear cable, and shifts perfectly. Happy days!