Index, you barsteward!

[Karlt]

I replaced the wheelset on my elderly MTB because the hubs were dying and the wheels weren't expensive enough to consider rebuilding; a replacement set costing £60 was an upgrade... Anyroad, I took the chance to move from screw-on (where 7 speed means 14-28 and that's yer lot, barring megarange with that big jump which the mech might not cope with) to cassette, where there's more choice and put an 11-32 on. But will the bugger index? Will it chuff! If I adjust the mech far enough towards the small cogs for the 1-2 change to work, it jumps around between 5 and 6 when the shifter's in the 5 position, and jumps into 7 when it's on 6. If I adjust it so that 5-7 are working, then it won't shift from 1 to 2, and may jump from 2 to 1 with the shifter in position 2

I presume that the spacing on 7 speed cassette is the same as on a 7 speed FW - I can't find owt to the contrary. So what do we reckon? Mech can't cope with the wide range cassette? Bent mech? Sticky cable? I don't think it's the last because the mis-indexing is so consistent. Should I start by replacing cable outer? I've got a length of gear outer handy.

 

[Bollo]

Worn chain?

 

[gbb]

One quick thing worth trying...take the wheel out and re-insert it, then try indexing again.
I has a similar problem once, soddin thing would NOT index after I fitted a new wheel. I went over and over it, no joy.
Left it to sleep on it...next day I took the wheel out for a different reason. Refitted it, carried on attempting to index.....whoa, it worked . I didn't even have to adjust anything.
I can only assume the wheel wasnt straight In the dropouts or something...

 

[fossyant]

Change the inner and outer cables. Always worth doing on a regular basis.

 

[Tim Hall]

I can't see how a worn chain will do that. Cable stiction is always a good bet, although if it worked before, it's a bit more puzzling. Bent mech hanger is also a good call.

 

[Bollo]

I can't see how a worn chain will do that. Cable stiction is always a good bet, although if it worked before, it's a bit more puzzling. Bent mech hanger is also a good call.

It is a bit of a punt, but the last time I had something like that it was a new cassette with an old chain. It was the last thing I thought and I couldn't quite explain it, but a new chain fixed the issue. It'd be best to try the cheaper stuff first anyway.

 

[raleighnut]

It's that season again, ready @screenman ...................................................................All together now.

Check the Hanger Alignment.

But seriously it is worth checking Mech/hanger alignment.

 

[Yellow Saddle]

Worn chain?

How will a worn chain affect indexing? A worn chain is not the cause of all gear problems.

 

[Yellow Saddle]

I replaced the wheelset on my elderly MTB because the hubs were dying and the wheels weren't expensive enough to consider rebuilding; a replacement set costing £60 was an upgrade... Anyroad, I took the chance to move from screw-on (where 7 speed means 14-28 and that's yer lot, barring megarange with that big jump which the mech might not cope with) to cassette, where there's more choice and put an 11-32 on. But will the bugger index? Will it chuff! If I adjust the mech far enough towards the small cogs for the 1-2 change to work, it jumps around between 5 and 6 when the shifter's in the 5 position, and jumps into 7 when it's on 6. If I adjust it so that 5-7 are working, then it won't shift from 1 to 2, and may jump from 2 to 1 with the shifter in position 2

I presume that the spacing on 7 speed cassette is the same as on a 7 speed FW - I can't find owt to the contrary. So what do we reckon? Mech can't cope with the wide range cassette? Bent mech? Sticky cable? I don't think it's the last because the mis-indexing is so consistent. Should I start by replacing cable outer? I've got a length of gear outer handy.

The spacing is the same but the start and end points not necessarily the same. Re-do the limit screws and re-do the indexing.

 

[Karlt]

The spacing is the same but the start and end points not necessarily the same. Re-do the limit screws and re-do the indexing.

Done those; it's the indexing that won't work, regardless of adjustment. Since I've got cable handy I'll replace that first.

 

[Deleted member 1258]

Is the rear mech knackered?

 

[gbb]

Fingertip on each cog on the rear and feel for any wobble...which might indicate a slightly mis mounted smallest cog being nipped by the lockring, leaving the others slightly loose.
Had it happen to me before.

 

[shouldbeinbed]

Sticky cable, incorrect wheel alignment, bent hanger, derailleur spring FUBAR?

 

[accountantpete]

Check that the there is no play in the freehub and cassette.

If not turn the bike upside down and check the alignment of the upper jockey wheel (now the lower one ) with each sprocket in turn. It should be directly in line with the sprocket every time.

 

[screenman]

Start from the beginning, rear mech alignment first, and you cannot get that bang on by eye.