FRont mech on a hybrid

cskasofia

Have got a Merida Crossway hybrid bike, whose front derailler is gubbed after a few years of commuting through winters. I was thinking of having a go and replacing it myself, so looking for a bit of advice.
On the existing front derailler it says Shimano SIS index. There are 3 gears at the front, and 8 at the rear.
Do I have to replace it with the same part, or are all MTB deraillers suitable? (i would probably be looking at a budget price part wise)I assume it is going to be an MTB part as its a hybrid?
All replies appreciated!

Wooliferkins

There are quite a few Shimano front mechs out there, but a fair guess would be a Tourney MTB Front Derailleur FD-M190 or FD-M191

What you need to know, how many teeth on your chainrings (M190 for 42 / 34 /24) (M191 for 48 / 38 /28 )

cskasofia

Fitted the new front mech (it was the M191), by following a couple of you tube guides. It shifts between the small and middle gear OK, but I can't get it to shift onto the large gear. I noticed the barrel adjuster, up at the shifter, is damaged.

Do you think this could cause this?

Also, seen a shimano rear mech barrel adjuster on the chain reaction website, it looks the same as the front one that is damaged. Would this be the same part?

Thanks

benpinnick

Is it damaged, or just hanging out? If its hanging out just screw it back in.

cooldad

The screwy bit disappears inside the plastic bit because of the spring - so can look broken.

Wooliferkins

Starting from scratch. Cable disconnected from mech.
1, Check gap as outer plate passes over outer ring (1.5-2mm)
2. Adjust inboard limit stop screw so with chain on little ring and big sprocket at the back, the inboard plate just clears the chain.
3. Adjust outboard stop screw so when on big ring and little sprocket outboard plate is just clear of the chain.
4, Set barrel adjuster on shifter about midway through range.
5, Ensure shifter selected to inner chainring
6, Connect cable, ensuring correct routing, removing slack but without moving mech.
7, This SHOULD now shift OK. If not then usually the mech is not travelling far enough to lift chain on outer ring. Adjust outboard limit screw slowly until it will.