Indexing

[yenrod]

What can influence 'indexing'...

I can either set the bike up so it indexes for the last four or the 1st four sprockets on the back.

Somethings stopping the bugger indexing over all the sprockets;

The stops are ok - the cables are lubed: its a Tiagra mech on 9sp. sprockets.

Any suggestions

NB - I do know how to set the bike up and can do everything on a bike other than true a wheel (really good) so I know what the deal is / have skill.

But this has just floored me and Id rather try and sort it myself than take it to the shop unless i have to!

 

[Aperitif]

Weak/worn spring(s) in the rear derailleur?
Are you changing rings at the front as well - or is it not critical re: chainline?
Don't know anything much but particularly nothing about Shiman__o sorry.

 

[oxbob]

this any help ? http://www.parktool.com/repair/byregion.asp?catid=53

 

[Steve Austin]

undo the cable at the dérailleur. screw cable tensioner as far into the rear mech as you can. tighten cable.

put chain into 8th cog. turn cranks backwards, unscrew tensioner until it starts to grate a little .

go for a spin, and check it works ok. if it don't screw in a little or out a little, noting which way you are going, if it gets worse, you gone the wrong way. adjust accordingly

 

[Steve Austin]

sorry. 9th or bottom gear. the idea is to get to a starting point, so you can start again

 

[yenrod]

I reckon this is a 'shop job' - looking tonight and the sprokets are 'sram' - does anyone know if these are supposed to work with Shimano STi's..

I reckon its been a 'bodge it' fitment to the bike and it ACTUALLY needs a S H I M A N O block...!

Saturday, the LBS where i got it, gets a VISIT ! from the local friendly neighbourhood irate cyclist...

 

[Smokin Joe]

If you have recently unclamped the cable, you may have re-connected it to the wrong side of the clamp. I did that once and had the same problem as yourself.

 

[bonj2]

I reckon this is a 'shop job' - looking tonight and the sprokets are 'sram' - does anyone know if these are supposed to work with Shimano STi's..

er... no! I think they're slightly different.
When you say it 'doesn't index' over the first 4 or the last 4, do you mean it doesn't index at all, or it just indexes to the wrong tension? 'cos if the latter than work out whether the index is taking too big or too small leaps in tension. Then there's your answer as to why you can't use different brand cassette/shifters.

 

[Dave5N]

No Bonj, SRAM cassettes are fine with Shimano - I run them ok anyway.

Back to basics, Yenrod. Start by releasing cable and putting adjusters in all the way less two turns. Grab cable, set limit screws - pull cable by hand, don't use levers, then set indexing.

If it still jumps halfway up the block, then your cassette spacing is wrong (or the levers are - I run 7 speed levers on an 8 speed block and it's slightly out, but i don't suppose you are doing that.)

 

[Steve Austin]

Sram cassettes are exactly the same as Shimano, and will work fine.

 

[piedwagtail91]

If you have recently unclamped the cable, you may have re-connected it to the wrong side of the clamp. I did that once and had the same problem as yourself.

I'll second that. it's seems to be more of a problem on campag but club mates have done it on shimano.
for setting up try putting the chain on the middle sprocket, and getting it to run without making any noise by using the cable adjuster.then see if it indexes ok on the other sprockets.
it you set it running on the middle sprocket you're halving the error at both extremities.

 

[yenrod]

If you have recently unclamped the cable, you may have re-connected it to the wrong side of the clamp. I did that once and had the same problem as yourself.

I'm gonna check this out upon getting to the bike...

No Bonj, SRAM cassettes are fine with Shimano - I run them ok anyway.

I thought they were compat. with Shimano too...

Back to basics, Yenrod. Start by releasing cable and putting adjusters in all the way less two turns. Grab cable, set limit screws - pull cable by hand, don't use levers, then set indexing.

If it still jumps halfway up the block, then your cassette spacing is wrong (or the levers are - I run 7 speed levers on an 8 speed block and it's slightly out, but i don't suppose you are doing that.)

I'll second that. it's seems to be more of a problem on campag but club mates have done it on shimano.
for setting up try putting the chain on the middle sprocket, and getting it to run without making any noise by using the cable adjuster.then see if it indexes ok on the other sprockets.
it you set it running on the middle sprocket you're halving the error at both extremities.

The way indexing 'used to be' or the best advice I got once was;

Select the hightest gear - put onto the smallest sprkt then turn adjuster till it scrapes, slightly, the next sprkt up (to the left)...then ytou should be ok...

But, its going, in this case, into the 14t sprkt - 8 (the 13t is the smallest we'll call this 9) and ok into 15t sprkt - 7 & 6 & 5 & 4 but 3, 2 + 1 - jumps all over the place...

 

[fossyant]

You set the gears up with the mech in a middle gear and ensure the jockey's are directly in line with the sprocket, then tweak it a little. You are using a 9 speed shifter with a 9 speed block, 9 speed chain (or 10) and it does have 9 speed spacers betwweeen the sprokets ?

 

[yenrod]

You set the gears up with the mech in a middle gear and ensure the jockey's are directly in line with the sprocket, then tweak it a little. You are using a 9 speed shifter with a 9 speed block, 9 speed chain (or 10) and it does have 9 speed spacers betwweeen the sprokets ?

Foss - i didnt put the block together.

 

[PrettyboyTim]

A while back I was having some problems getting my gears to index properly - if I got it them to index properly near the top end, they wouldn't work near the bottom and vice versa.

It wasn't until the gear cable snapped that I realised what the problem was - the cable had been fraying (inside the gear switching housing), which had been allowing the cable to stretch as it was put under increasing tension. Once I had replaced the cable, the indexing was fine again.

Check the cable along the whole length and see if there's anything wrong with it.