Newbie rear mech upgrade

[Maark]

Hi all,

I bought a 2005 Marin bobcat from a friend for using over the winter and to start to get into MTBing. Second ride out I managed to break the rear hanger and bend the rear mech, after replacing hanger I straightened the mech as best I could but although it works it doesn't seem to shift as well and is noisy most of the time so I am looking to replace it. The bike cost me next to nothing and is not special enough that I am going to throw a load of money at it replacing the whole gear set up but wondered if there is a rear mech of better quality than the current 8-speed shimano acera that will bolt straight on? The shifter on the bars is an 8 speed shimano v-brake? and the front mech is a 3 speed shimano nexave.

On another point, I seem to have the chain rubbing slightly on the front mech if I am on the large or small gear at the front and the opposite on the rear cassette (does that make sense?) I have tried adjusting the front mech but there just doesn't seem to be enough room between the cage on the front mech, is this normal?

Many Thanks
Mark

[Maark]

Thanks for the advice on the gear shifting, that makes sense.

Didn't realise the bike was maybe worth spending a few quid on, so on a different tack what would be the worthwhile upgrades I can do to the shifters,mechs, cassettes etc?