derailleur question

shr109

New to the forum and looking for a bit of help.

I recently bought a secondhand Gary Fisher Marlin. I got it cheap because the guy I bought it from said the gears were slipping and it would need some work. I had it serviced but the gears are still slipping and the chain keeps dropping down the back of the bracket.
The bike mechanic I took it to said it might need the front derailleur replacing.

My question is if I replace it with a different derailleur to what is currently on it, what else would I need to replace if anything? Eg do I need to replace the rear one as well or the cassette?

Thanks

Chunkers1980

Take it to a shop that knows its stuff....

cooldad

This ^^^^^^^^
But what needs replacing depends on what is wrong/worn.
Front mechs rarely need replacing.

chuase05

If the gears are still slipping after a service then its probably a worn chain and cassette or a combination of that and the chain rings, like cooldad said its rare that a front mech will need replacing. Get yourself a chain checker, i use the park tools cc-2 well worth the 25 quid.

The Rookie

shr109 wrote:

I had it serviced but the gears are still slipping and the chain keeps dropping down the back of the bracket.

What does that mean in English? It sounds like the chain is coming off on the inside of the chainwheels, in which case it should be a simple indexing job to fix it.

ride_whenever

As above except you never need a chain checker as a 12" steel rule will give you a far more accurate result.

shr109

The Rookie wrote:

shr109 wrote:

I had it serviced but the gears are still slipping and the chain keeps dropping down the back of the bracket.

What does that mean in English? It sounds like the chain is coming off on the inside of the chainwheels, in which case it should be a simple indexing job to fix it.

You'll have to bear with me, I don't really know that much about bikes.
The gears are screwed in a number of ways - noises when riding in certain gears, won't change onto the big front cog, slipping from one gear to another, not changing well onto the big cog on the rear bracket and when it does the chain comes off and goes down between the bracket and the spokes.

The bike mechanic suggested that things were quite worn but the gears were changing up and down ok. Not actually the case unfortunately. I can probably get 8 gears out of 27.

The Rookie

Ok that bracket is a cassette, not sure where you got bracket from!

This is all basic setup stuff, to do what it's doing it's been setup badly, you could do it yourself using the online guide at Parktools.com, start right at the beginning as it sounds like your mechanic has probably made it worse.