Hi all.
I've fitted 2 new shifters for 3 cog front and 6 speed rear freewheel.
I've also fitted a new derailleur.
Setting up is impossible although I'm having another go today.
Watched loads of YouTube videos but none show what I need to look at. Turn a few screws and its all smooth changing they say. No chance.
Either chain jumps off or sits on wrong cog.
I'm thinking it's likely to be a bike mechanic job Vs DIY?
Any thoughts or advice before I try again. Tbh I need cheering on a bit with it. Ha
There are 6 separate adjustments you have to make in the prescribed sequence below. It's best to do them with the chain on whichever front cog that you will mainly be using, which is normally the big one on an electric bike:
1 High gear stop screw. There are two screws together normally marked H and L, sometimes not marked. You select high gear on the cable, then slacken off the cable by unfixing it. You adjust the scre until the derailleur holds the chain in the middle of the hich gear (smallest cog).
2. Cable length. You pull the cable end around its fixing until it is just tight, then fix the clamp screw.
3. Cable length adjuster. You select the next gear and adjust the sleeve adjuster on the end of the cable outer until you can shift consistently and correctly between top gear and the next.
4. Low gear stop screw. It's the one next to the high gear stop screw. You select bottom gear on your shifter and adjust the screw until the derailleur holds the chain in line with the low gear sprocket (largest cog).
5. Check that all gears shift correctly. if they don't, you use small adjustments of the cable length adjuster until they do.
6 B-screw. The B-screw is on the back of the derailleur, and it sets the chain tension. The idea is to get the top idler wheel on the derailleur close to the gears with enough room for the chain to be able to shift properly. Normally, there's no need to adjust it, except if your chain is the wrong length. It's not a critical adjustment. in theory, the closer it is to the gears, the more accurate the shifting, but sometimes shifting works better if there's some tolerance on the shifting accuracy. In other words, you only adjust it if you get problems shifting when everything else is OK.
The procedure is the same for the front derailleur, except there's no B-screw, and it's the other way round - big cog with cable slack. It's probably better to do the front first.
