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Hi all, I'm in need of some advice..
Running shimano12 speed on my Bird AM160 and i cannot get it to shift properly.
It'll either go up well, or down well.. not both
If I'm in the 51 and pedal backwards it was dropping down the rear cassette, Its now started falling off the bottom of the Bergtech NW front ring.
Drivetrain is a couple of months old, the front ring thing has just started in the last month or so
Mech hanger is aligned. Rear Mech set up with the shimano instructions. Everything else to the spec on the Bird site
The chain drop is a real issue. I can't rotate the cranks backwards at all which is a problem round here with gates on climbs and you need to get the pedals in position. The fact i can't get a good shift up and down is a worry.
The wife has an Ather7 and I've set that up the same way and she doesn't have these issues so I'd think its not my setting up/mechanics that's at fault.
I was putting it down to 12 speed tolerances being really fine but again I'm becoming less convinced of that.
I’m beginning to wonder if my frame is misaligned because i’ve done everything i can and its spoiling rides as I’m just waiting for the inevitable issue
Any wise words oh hive mind??
Anyone any thoughts or advice??
Having been through everything you described there - it was the mech that was slightly twisted. Unfortunately it’s annoyingly difficult to tell as there is a slight intentional twist in the cage from new. However, as soon as the mech was swapped it took minutes to setup for perfect shifting again
Mech went on with the drivetrain.. that’ll be annoying if it’s buggered after only a few months use…
I’ll check it out though!
ta
Does 'playing' with the B Tension screw make any difference?
I have a memory that on my previous Kona Hei Hei I had issues like you, but playing with that altered things.
Shouldn’t need much playing with - the marking on the inner cage makes correct set up straightforward.
bent mech hanger?
B screw/mech aligned with cassette marking on mech cage.
hanger is straight and true..
Mech hanger checked with the proper tool?
Cable on the wrong side of the clamp screw? that gave me similar issues
Mech hanger checked with the proper tool?
Cable on the wrong side of the clamp screw? that gave me similar issues
yep.. mech hanger tool and I’ve made the cable clamp mistake before, but not this time!
I've got my chainline at 51mm using a Blackspire snaggletooth chainring and can backpedal all day long, every time I've had unexplained shifting issues after checking everything over n over again it turns out to be the chain, even if it's relatively new and unstretched,I initially wonder if some teeth got damaged on the cassette but it turns out a new chain solved it, god knows why or what goes wrong with them, I always keep them well lubed. Could be twisted mech or dodgy jockey wheels in your case though.
Jockey wheels… forgot that bit.
quite frequently chain derails the top (guide) pulley, again with the slightest backwards movement on the chain.
i know worn jockey bearings can cause this but its only a few months old.. they can’t be knackered can they??
Ive found a brand new chain in the spares cupboard so i might chuck that on just to see
current chain is +.75 wear according to my checker
If I’m in the 51 and pedal backwards it was dropping down the rear cassette, Its now started falling off the bottom of the Bergtech NW front ring.
Unless you're in a gear with a fairly straight chainline, backpedaling is always going to be a problem.
As for the other problems, buy a derailleur alignment tool and check to see if the hanger is straight. It's quite astonishing how bent they can be but look straight when you eyeball them.
current chain is +.75 wear according to my checker
That's worn out then isn't it? - should be replaced at 0.5 and is overdue by the time it reads 0.75 as I understand it...
buy a derailleur alignment tool and check to see if the hanger is straight.
I have one.. it is.
current chain is +.75 wear according to my checker
That’s worn out then isn’t it? – should be replaced at 0.5 and is overdue by the time it reads 0.75 as I understand it…
I might have mis-represented what I read off the checker. It's one of those lifeline tools ones where you hook the back into the chain links and swing it down. What I should have said is it's more than .75 but less than 1.0. So I've always understood that to mean once the 1.0 gauge passes through the link the chain needs replacing.
However I've found a new chain so I'm going to fit it and see what difference that makes. If a new chain cures this then the existing one has only lasted a few months which really isn't that good in my opinion..!
That’s worn out then isn’t it? – should be replaced at 0.5 and is overdue by the time it reads 0.75 as I understand it…
Shouldn't cause the issues reported though.
OP - did you mean the chainring is also only a couple of months old?
If it's older, I find the chainring is usually what's causing dropped chains.
Can you swap a different one on to rule the chainring out at least?
Well.. this is interesting
Had a really close look at the drivetrain again. I’d put the chain on with the writing on the outside however I noticed that the writing was upside down when looking at it going onto the front chainring
Flipped chain so writing is the right way up and the chain drop issues have gone.
re-tweeked the gears and in the stand at least, everything is fine.
i guess the proof is in the ride once its all gummed up with the finest peak grinding paste!!
So the writing is now the right way up on the top (cassette to chainring bit) of the chain, and upside down on the bottom (chainring to rear mech) bit?
IHN
yep