[Closed] Am I doing something wrong - Rear derialleur

B tension screw?

Derailleur not compatible with size and/or speed of cassette?

Groupset should be fine, I was running it before. The only difference is I have changed wheels everything else is the same.

I altered the B screw so there is enough room for the derailleur to shift across but still no luck, the H & L screws are out and its not changing to the bigger cogs unfortunately.

Are you 100% certain you put the chain through correctly....

Have you loosened the cable at any point and not had the shifter in the correct gear when it's been re-connected?

I didn't even touch the chain, I took the original rear wheel off and removed the cassette then fit that on to the new wheel and put back in the frame.

After that I ran a new cable through the shifter and that is still loose on the bike now (I havent clamped it with the allen bolt yet) until its set up.

Hope that makes sense?

What do you mean by the H&L screws are out???

John

You are stretching the lower jockey wheel forward and you push the mech across?

EDIT: do you mean you have the chain on the bike right now? But you have changed the cable?

Did you reattach the rear mech to the rear mech hanger properly? I've made the mistake before where I attached it wrong (too far forward so tabs didn't align) and it would shift in the lower gears making me think it was on right, but wouldn't shift into the bigger rings.

Sorry probably not the best term, they are loose not physically out the derailleur. I have tried tightening them in the correct formation but still no avail.

Yes I am manually pushing the mech across by hand to get it in the biggest sprocket via the jockey wheels.

Rear mech was never removed/touched (see above).

Thanks everyone

IF you can push it to the sprockets by hand, the L screw is ok. Usually it's cable tension that stops the mech moving far enough. I'd remove the cable from the shifter, check shifter is shifted to the right gear and re-cable it.

so the only thing you have changed is the cassette and the new cable?

i would go with you havent enough tension in the cable then?

shift to the smallest rear cog, undo the cable clamp and pull the cable as tight as possible. Undo any of the tensioning screw that you have before tightening so that you pull thru the most cable.

then try and re-index if needed.

Thanks Dez.

I will remove the cable and start again, to fit the cable through I have to be in the lowest gear on the shifter.
Hopefully I have cocked something up whilst doing it and its an easy fix!

Start again. Undo the cable, adjust the High and Low screw stops first and then in the smallest sprocket pull the cable taught and do it up.

John

Back again!

I undone the cable and started again;

- Ran the cable through then adjusted the H screw so the chain aligned with the smallest sprocket
- Manually pushed the rear derailleur to the biggest sprocket so I could adjust the L screw but no luck, its on gear 3 and the derailleur is out of line.

Pic attached, any other ideas?

Thanks again everyone who has replied.

<img src="https://preview.ibb.co/h76XD5/IMG_3209.jpg" alt="IMG_3209" border="0">
place to upload pictures

You've undone the L screw all the way?

If you turn the pedals and push the mech by hand, can you get it to shift into the big sprocket?

Chain off and cable undone so it's loose.

Adjust H&L so the jockey wheels aline with smallest and largest sprocket.

Tension the cable and tighten it up.

Check the mech moves up and down the cassette in line for each click. Adjust tension in cable until it does.

Chain back on. Make sure it shifts into all the gears ok, use adjuster on shifter for minor tweaks.

Check B-limit screw and adjust if need be.

Ran the cable through then adjusted the H screw so the chain aligned with the smallest sprocket

Maybe I've misunderstood, but it sounds like you are using the H screw, when you should first be taking the slack out of the cable (pull the end with pliers or use a 4th hand tool, and then use the barrel adjuster* to take out the last bit of slack), and only then tightening the H screw to limit movement of the mech beyond the smallest sprocket.

* The barrel adjuster should be tightened down when fitting a new cable, so that it has the full range to move to tighten the cable when it stretches over time.

and only then tightening the H screw to limit movement of the mech beyond the smallest sprocket.

Thats not right, you set the high screw before even touching the cable

In your case - ignore cable altogether, undo it, then remove chain. Then push mech back all the way with your hands. Undo the H screw until it will go allthe way to the big sprocket without fouling it.

[i]Undo the H screw until it will go allthe way to the big sprocket[/i]

H screw for High gears and the L for Low..

Park's dubry wotsit page might help - got diagrams n stuff
http://www.parktool.com/blog/repair-help/rear-derailleur-adjustment

Take the new cable, old chain, old derailleur, new wheel, old cassette to a bike shop. Ask them to repair it.

.. and take up knitting 😆

Undo the H screw until it will go allthe way to the big sprocket

H screw for High gears and the L for Low..

That's what I meant!

I'm not helping very much am I dad?

[img] [/img]

I will remove the cable and start again, to fit the cable through I have to be in the lowest gear on the shifter.

you sure ? you need to have the shifter set at the highest gear, and the chain on the smallest sprocket, so that the cable is just under tension when you have it connected and torqued up, then you shift up the cassette to bigger sprockets/lower gerars

If the mech will not shift to the 2/3 largest sprockets, then not enough slack has been taken out of the cable when it was clamped to the mech.

OP, have you operated the shifter for the rear mech to ensure it is in the position for the smallest sprocket, [u]before[/u] clamping the cable in the rear mech?

OP, have you operated the shifter for the rear mech to ensure it is in the position for the smallest sprocket, before clamping the cable in the rear mech?

When doing this, you may need to pull gently on the cable whilst operating it.

After clamping the cable, press the down shift button once, and then unscrew the barrel adjuster whilst turning the pedals until the chain is on the second smallest sprocket.

What slowster said. Some mechs have the cable holes line up when not in the top gear. Put cable in, then pull trigger a few times with light tension on the cable. Then finish setting up.

Just one more from me to check...

Have you checked you have routed the cable correctly from shifter to mech and round the right bit of the pinch bolt on the mech?

Some frames/mechs it is easier to muck this up than others.