Changed derailleur but...???

[Frimley111R]

Just changed the derailleur on my Boardman MTB but the top jockey wheel is hitting the cassette, no idea why. What am I doing wrong?...

[Davie]

Wind in that little Allen headed bolt that pushes against the derailleur hanger on the frame. That'll drop the rear mech down. There's alignment tools for most set ups but go with about 3mm clearance for starters. You'll likely need to tweak the cable tension etc afterwards again.

[frisbee]

Shimano have really detailed setup instructions for every component they make. Just Google the part number.

[Frimley111R]

Davie said:

Wind in that little Allen headed bolt that pushes against the derailleur hanger on the frame. That'll drop the rear mech down. There's alignment tools for most set ups but go with about 3mm clearance for starters. You'll likely need to tweak the cable tension etc afterwards again.

Ah got it, thank you.

Yes, it goes to the smallest cog on the cassette but misses the three largest.

[Frimley111R]

frisbee said:

Shimano have really detailed setup instructions for every component they make. Just Google the part number.

Ok thanks, nearly there. if only I was 12 years old again, when this type of thing took me 5 minutes!

[POIDH]

As above, you need to pull derailleur backwards using the 'B-tension' screw.
Download the Shimano instructions or fire up a Shimano derailleur instruction on YouTube

[Xenoous]

On a side note, is your hanger bent?

[Discendo Discimus]

Xenoous said:

On a side note, is your hanger bent?

Looks like it!

[_Hoppers]

I'd start by turning the bike the right way up before deciding what adjustments are needed.

[_Rodders_]

Fighting gravity won't be helping but the B tension screw needs adjusting.

[RicksAlfas]

A cheap bike maintenance stand is a revelation.
Mine was about £30 in an Amazon deal and it just folds up when not in use.
You will wonder how you managed without one!

[Frimley111R]

Discendo Discimus said:

Xenoous said:

On a side note, is your hanger bent?

Looks like it!

I don't know, it looks ok. If it is it is only a fraction. Gears are working ok now, I just need to adjust the derailleur to reach the largest gears.

I do have a bike stand but it is wall mounted one and I don't find it that easy to work on

[Xenoous]

Frimley111R said:

Discendo Discimus said:

Xenoous said:

On a side note, is your hanger bent?

Looks like it!

I don't know, it looks ok. If it is it is only a fraction. Gears are working ok now, I just need to adjust the derailleur to reach the largest gears.

I do have a bike stand but it is wall mounted one and I don't find it that easy to work on

Can you get a photo of the rear of the bike from the back? Mine for example (albeit a gravel bike) is completely straight and inline with all cogs

[Frimley111R]

Will do but prob tomorrow