Replacement for Shimano Deore Rear Derailleur

[wbmkk]

My grandson has just broken the rear derailleur on his bike (GT Aggressor) and I have been tasked with the job of fixing it

Sadly the local bike shop closed early this year.

The current one is a Shimano Deore derailleur but I am wondering whether there is a cheaper alternative to this. My daughter bought him the bike last year 2nd hand for only £30, so i don't think i want to be spending more than that on a small part.

he's not that keen a rider and was probably only using the bike recently during the summer holidays ... it's quite possible it won't be used again until next year, even when fixed.

I see many derailleurs online .. are all 7-speed units the same ?

Any recommendations please ?

thank you for any advice

 

[Petrichorwheels]

you need to post the drivetrain specs for better advice.
It's 7 speed?
How many chainrings on the front and what are the teeth counts?
What's the number of teeth on the smallest rear cog and the biggest?

On the general point, assuming that it's quite an old bike I would think that you'd be fine with something from the "lower" ranges - shimano trickle down being a real thing (unlike Truss's version - and I wouldn't let her anywhere near any bike of mine anyway)

 

[wbmkk]

3 chainrings at the front

back .. smallest 14 ... biggest 28

 

[Cycleops]

Given it's a mountain bike it's rather odd to have a 14-28 on the back, so maybe it was changed. Deore derailleur is meant to handle up to 34 t.
Just about any cheap 7 speed derailleur you can find in Decathlon or Halfords will do.
https://www.decathlon.co.uk/p/7-to-9-speed-rear-derailleur/_/R-p-100594
This is £13

 

[wbmkk]

many thanks !

I'll try this one at Halfords as kit's nearer than ecathlon

 

[Cycleops]

Don't forget to adjust the Hi-Lo screws which limit the swing. If you don't the chain may run off into the spokes or get caught between the gears and frame. Plenty of videos on YouTube . No special tools needed.

 

[wbmkk]

I suppose I could go to Decathlon and have a look .. I quite like the shop and have bought a few things there in the past.

Of the two you mentioned, which is the better one in your opinion ? B'Twin have always had a good reputation if I recall correctly

 

[Cycleops]

I only posted posted one at £13. Should suit your purpose absolutely fine.
The Halfords one would do the job too. You need to see which one has the fixing to attach to the GT, a C type fixing or a bolt which would connect to the derailleur hanger on the bike. I suspect the latter.

 

[Big John]

https://www.chainreactioncycles.com/microshift-rd-m26-7-8-speed-mtb-rear-derailleur/rp-prod205116