Help with rear derailleur Shimano - GT Tempest

[slicecbr]

Hi guys,

Just bought a GT Tempest today to hopefully replace my Halfords bike. It has a 21" frame and no front brakes. Heres a pic of the bike:



The rear derailleur is buggered and need a new one. Heres a few pics:

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The shifters are 8 and 3. I can't wait to have a go on the bike, can anyone give me a link of a reasonably priced rear derailleur which will work with the bike or point me in the right direction as to what to look for?

Hoping to follow some tutorials on here and DIY it. Aswel as a new rear derailleur I would also need some new line?

Thanks in advance!

[nfmisso]

For safety, get a front brake !!!

Shimano M410, M411, M412 or M413 with hanger is the least expensive current Shimano.

A SunRace M50 is least expensive 8 speed RD that I know; I have one and have not installed it on a bike, and probably never will. The H/L limit screws are thread forming screws for making threads in plastic, unlike the machine screws in metal with a nylon block for locking that Shimano and other use.

You definitely need new cables, lubricate them before using them.