Rear Derailleur stuck in first gear

[Smurf2]

Hi.
After I changed new wheel with hub motor and cassette, rear shifter worked a while, then I stucked in first (climbing) gear.

The shifter stuck? When remove HIGH lever, it moves, but when move LOW lever, it not moves, it is hard to move it.

The cable is very tight.

When remove chain by hand to higher back gear (smaller Cog), and turn pedal, its return back to the lowest first gear again (the biggest Cog).

I hope that is only cable tight, but if is, I have only 1 cm cable to adjust, or buy new one.

 

[RunForTheHills]

It is most likely because the cable is tight, but you need to find out why the cable is tight. Is the battery mounted on the downtube interfering with the cable?

 

[Smurf2]

Yes, I checked hundred times, battery zip types are there, but not touching any cable. It seems in is his place.
Only now the cable is on wheel axes..

Sorry, it is not too tight now, the front is tight then rear cable. Don't know how but is, maybe I moved something.

So, I must open a shifter then? Or loose cable, or rotate screws, which I did?

 

[99t4]

Chain may be too short. If the chain is too short, the derailler pulley can get jammed up in the chain up against the largest cog and won't want to move away. What happens if you shift to the smaller chainwheel up front?

 

[Chalo]

You replaced a smaller cassette with a larger one, and the chain is now too short to work with the new gearing. There's no slack available to derail from the big sprocket to a smaller one.

 

[Smurf2]

You replaced a smaller cassette with a larger one,

Not really. I had before 8 gear Freewheel, now have same gear cassette, only with much bigger first Cog.

Chain may be too short. If the chain is too short, the derailler pulley can get jammed up in the chain up against the largest cog and won't want to move away. What happens if you shift to the smaller chainwheel up front?

Yes, I thought too that chain is too shoort.
Btw I got spare chain with that cassette.
But see how looks in smaller cog on front, seems normal?

 

[Smurf2]

Also, I checked a lenght of booth chains, on the bike and spare one, they have 56 outside plates, so seems are identical.

I opened a shifter, but don't know where is mistake.

EDIT: I seee in videos in most cases is Grease, and can repair like with wd40 spray.

 

[E-HP]

Seems like you broke the shifter while jamming it into a gear where you didn't have enough chain.

 

[Smurf2]

Why you think is broken?
I just shift from 2. to 1. gear with bigger lewer which stuck when played with limit screws.
Smaller lever, for return gears back is free move by hand, no resistance.
If that hepls.

 

[Chalo]

You replaced a smaller cassette with a larger one,

Not really. I had before 8 gear Freewheel, now have same gear cassette, only with much bigger first Cog.

That's what I meant by "larger". More teeth on the big sprocket means you need a longer chain to wrap all the way around. This should be self-evident.

When you run out of wrap like that, it can bend the derailleur hanger or the derailleur itself when it shifts into or out of that gear.

https://www.sheldonbrown.com/derailer-adjustment.html#chain

 

[99t4]

Yes, I thought too that chain is too shoort.
Btw I got spare chain with that cassette.
But see how looks in smaller cog on front, seems normal?

Yes looks better. Does the rear derailler shift normally when the chain is on the smaller front chainwheel? Bet it does. Therefore, the chain is too short to be used on the large front chainwheel.

 

[Smurf2]

That's what I meant by "larger". More teeth on the big sprocket means you need a longer chain to wrap all the way around.

Ok.
Before I made/extend new longer chain with dad, see now please how looks all situations of chain. Still think need longer?
See first and second picture, if I put a longer chain, how that position will looks?

My rear shifter cable was out and impossible return it back, so I use good longer cable feom another bike.

I found mistake on right shifter, there is a little pin which not rotate full when you push it, so need extra push with hands.
Btw shifting UP workng fine.
See my video:
https://youtube.com/shorts/jsnN-WDxvpM?feature=share
I saw many videos and almost all that can be repair with spray for rust, but seems not worked with me. Must figure out what to do.

Does the rear derailler shift normally when the chain is on the smaller front chainwheel? Bet it does.

Sorry, not yet made fine adjustment.

 

[Chalo]

Before I made/extend new longer chain with dad, see now please how looks all situations of chain. Still think need longer?

It looks okay-- but if it's too tight to come down out of big/big gear, then you need another link. And if adding another link makes the chain rub or sag in small/small, then you've exceeded the derailleur's wrap capacity.

I think the capacity of your model and year of derailleur is 43 teeth. So if you have an 11-34 cassette (which is what it looks like) and a 48-38-28 crank (which is what it looks like), then you're right at the derailleur's wrap capacity. 23 tooth range across the cassette + 20 tooth range across the crank = 43T.

So if you're in your derailleur's range, and the cassette and chain aren't worn out, the next thing to check is the derailleur hanger alignment. There's a tool for this the bike shops have, but you can give it a rough inspection by removing the derailleur (leave the cable attached) and using a ruler to see if the mounting face of the derailleur hanger is parallel to the plane of the wheel. If it's not parallel, you can get shifting anomalies. Check with the ruler vertical and horizontal.

 

[Smurf2]

So if you have an 11-34 cassette (which is what it looks like) and a 48-38-28 crank (which is what it looks like)

That's correct!

23 tooth range across the cassette + 20 tooth range across the crank = 43T.

Is that you calculate first point on cog where chain is touching cog tooth? It have more than 20 touching tooth on front 48 cog, I calculate 26+.

Btw my chain have 56 outer plates.

 

[Chalo]

23 tooth range across the cassette + 20 tooth range across the crank = 43T.

Is that you calculate first point on cog where chain is touching cog tooth? It have more than 20 touching tooth on front 48 cog, I calculate 26+.

Wrap is the difference in chain length your derailleur has to take up between big/big and small/small gears. You subtract the small sprocket tooth count from the large sprocket, front and rear, and add the two differences together. So,

(48 - 28) + (34 - 11) = 43

The longer the derailleur cage, the larger the pulleys, and the larger an angle the cage can swing through, the more wrap capacity the derailleur will have.

 

[Smurf2]

Oh, that is it. Thank you.

Ok, the mission is first check the derailleur hanger alignment with ruler, then found answer on 99t4 question about changing the gears. But need some time for adjust gears without noise (if I made it), and also will be difficult shifting with screwdriver