Indexing gears for a newbie

[Twowheelsbetter]

Hi, first post, please be kind etc... I've been riding for about a year and have discovered I love tinkering almost as much as the riding itself!

I've an issue with my son's gears. His twist shifter got stuck and then cracked when he tried to force it(!), so I bought a replacement and fitted it today along with a new cable. The gears were pretty out so after fitting the cable I've had to adjust the derailleur and index the gears from scratch. Thing is as I move up the gears I'm using the barrel adjuster, then having to use it again to move down and so on, over and over. I'm not hitting the sweet spot where they move without any assistance. I'm assuming it's simply a case of continuing to fine tune it until it's right, which might take a while since I'm new to it. But I wondered if anyone had any tips, or suggestions for something fundamental I might have missed? I will take it to a bike shop if need be but thought I'd nothing to lose by trying to fix it myself first since it was a well used bike I got for peanuts. Thanks in advance.

 

[raleighnut]

There are loads of vids showing how but I suspect that you are overadjusting. The barrel adjuster only needs fractional movements.
That is assuming you've got a compatible shifter for the rear mech.
https://www.youtube.com/watch?feature=player_detailpage&v=Bbk5RcH0bbQ

 

[Twowheelsbetter]

That could well be it. Going to look at it with fresh eyes today and give it another go. The shifter is exactly the same as the one I removed, and it's working - just not quite right yet. Thanks for your reply.

 

[shouldbeinbed]

Just make sure the hardware is aligned properly: hanger isn't bent, derailleur jockey wheels & cage are straight, the cable is not kinked & is running freely from grip to mech. Did you fit a new cable outer too, if not could be a bit of grit or corrosion in there.

@raleighnut is likely on the money tho, barrel adjustment is a 1/4 twist at a time, often the adjuator will have 4 notches and click out of and into place each 1/4 turn.

Usually I'll use 1 full turn on an unfamiliar bike or to really take it out of kilter to make an appreciable difference and idea which way I'm going.

 

[Twowheelsbetter]

Thanks. I'm pretty sure it's all lined up - looks the same as on my bike, although that's not to say mine's perfect! It's getting there - it's the two extremes, ie first and fifth it's having trouble shifting to without adjusting every time.

I didn't replace the cable housing, so that could well be it, although the new cable fed through very easily. I've given the derailleur a clean in case that was an issue. It's an interesting, if frustrating process!

 

[roadrash]

this should help you out


View: https://www.youtube.com/watch?v=SkzvfCaIbyQ

 

[Twowheelsbetter]

So after much adjusting I've reached this point -
Bike is in 4th gear whether the twist grip says 5th or 4th
Shift to third - fine
Shift to second - fine
Shift to 1st - jumpy but does it.
Back to second - fine
Back to third - Nada
Back to fourth -takes it to third
Back to fifth - takes it to fourth.....

I am carrying on with the fine tuning but if the above suggests something obviously wrong to any of you that'd be helpful. In spite of not being able to get this quite right I am rather enjoying myself....

 

[roadrash]

did you start with the gear selector in 5th if its a( five speed block) and the chain on the fifth sprocket when you attatched the cable, same as in the video above.

 

[Twowheelsbetter]

Yes, attached it on fifth, wound the barrel adjuster all the way in and then started working on shifting up, adjusting a tiny bit at a time. I suspect I need to change the cable housing.

 

[roadrash]

outer cable replacement certainly sounds like a good idea

 

[bikingdad90]

On the rear derailleur itself there should be a black thumbscrew which the cable feeds through. Try winding this in and/or out depending on where it is sticking/not changing to sort the indexing then use the barrel adjuster to fine tune as the cable stretches.

DO NOT TOUCH THE H and L SCREWS - they do not index on the back only change the stop positions of the mech when you go into lowest and highest gears.

 

[Twowheelsbetter]

Well it's still not liking the highest/lowest cogs. I will try changing the outer cable once I've got hold of some but I suspect it could be the cheapo shifter at fault. It's a learning curve that I'll carry on with!

 

[Twowheelsbetter]

@chris harte - in thought the thumbscrew and the barrel adjuster were the same thing - what have I missed??

 

[shouldbeinbed]

@chris harte - in thought the thumbscrew and the barrel adjuster were the same thing - what have I missed??

I think Chris has assumed you're adjusting the gear at the shifter end.

On some bikes you can do this in addition to what you, I & others are referring to as the Barrel Adjustor & Chris is referring to as the thumbscrew on the derailleur. We are all singing from the same hymn sheet, don't worry.

 

[steve50]

I have just done the gear indexing on my project bike after replacing the cables and fitting a bigger chainwheel and it was a bit of a faf. I followed the video posted above and after a few attempts it all just kind of dropped into place. Make sure your chain is on the biggest chain wheel at the crank and on the smallest cog at the rear wheel, slacken off the cable clamp at the derailleur and check the tension of the gear cable, it doesn't want to be too tight or too slack re tighten the cable clamp when you are happy with the cable tension.turn the pedal with the chain still in 5th, it should run smoothly with no clicking or jumping. I f you have moved the two little grub screws in the derailleur you will have to follow the instructions in the video to set them up again, each adjustment has to be minimal otherwise you will move the derailleur to far,