[jacksonpt]

Is there a way to know if your cable tension is too slack or too tight?

I'm pretty good at setting the limiting screws, but I have a hard time getting the cable tension right, so adjusting my derailleurs basically comes down to trial and error - which gets very frustrating.

This is pretty typical for me when replacing the cables/housings for my derailleurs. I get the new cable/housing in, pull it taught, and tighten the nut that holds the cable at the der. Then I check/adjust the limiting screws and run through the gears. Generally speaking, I'll get one or two gears (usually in the middle of the cassette) where the chain moves ever so slightly too far, or not quite far enough. So the chain either jumps back and forth between gears, or takes an extra couple of cranks to move to the next cog.

This happens on both of my bikes - one with shimano derailleurs/levers and one with sram derailleur/triggers.

If the chain is moving to far, does that mean the cable is too tight?
If the chain isn't movign far enough, does that mean the cable isn't tight enough?
Or vice-versa?

Or is there no real rule of thumb with this kind of thing?

Thanks.

 

[Wumpus]

If you are having trouble in the middle of the cog, it could very well be your limiting screws.

I usually adjust the limit screws without the chain or cable attached.

The barrel adjuster adjusts cable tension.

 

[jacksonpt]

If you are having trouble in the middle of the cog, it could very well be your limiting screws.

I usually adjust the limit screws without the chain or cable attached.

The barrel adjuster adjusts cable tension.

hrm... if I play around with the barrel adjusters for cable tension long enough, I can usually fix the problem.

 

[Westy]

If you are talking about the front derailleur just get a SRAM twistshift for the front. For the rear mech I like to hang the bike upsidedown or just put it on the floor. Look at how the chain is riding on the cassette, if it is skipping you can usually see if the chain is catching on a larger ring or trying to hop down, adjust accordingly.

For finer tunning I just go for a ride and use trial and error. If things are skipping I give the barrel a few clicks in one direction, if things get better I try a few more. If things get worse I go back in the other direction.

You may also want to take a look at the B screw tension adjustment. The closer the last pulley is to the cassette the faster things will shift but the derailleur will also be supersensitive. Many frames with shimano derailleurs need to have the screw all the way in or the derailleur will actually hit the largest gears in the cassette.

 

[binary visions]

Dunno if you have rapidrise or not, but when you're pushing w/ your thumb to shift (that is, you're pulling on the shifter cable), and the derailleur doesn't move far enough, then the tension isn't high enough, and you need to turn the barrel adjuster counter-clockwise.

The reverse is also true - when you're shifting the other direction (giving the shifter cable slack), and the derailleur doesn't move far enough, the tension is too high and you need to turn the barrel adjuster clockwise.

 

[jacksonpt]

Dunno if you have rapidrise or not, but when you're pushing w/ your thumb to shift (that is, you're pulling on the shifter cable), and the derailleur doesn't move far enough, then the tension isn't high enough, and you need to turn the barrel adjuster counter-clockwise.

The reverse is also true - when you're shifting the other direction (giving the shifter cable slack), and the derailleur doesn't move far enough, the tension is too high and you need to turn the barrel adjuster clockwise.

That helps... I don't know why I didn't see the logic in that (pulling the cable to shift versus "releasing" the cable... that sort of thing).

THanks.

 

[Wumpus]

hrm... if I play around with the barrel adjusters for cable tension long enough, I can usually fix the problem.

Then it sounds like you are doing everything right. You will rarely hook everything up and have it shift perfectly without adjustment. After a few rides the housing will settle, and you will have to do some minor adjustments.

I remember which way to turn using 'down and out' and 'up and in'. If the chain isn't shifting down(bigger cog to smaller), then turn the barrel adjuster(when viewed from the top) away(or out) from the bike.

 

[jacksonpt]

Then it sounds like you are doing everything right. You will rarely hook everything up and have it shift perfectly without adjustment. After a few rides the housing will settle, and you will have to do some minor adjustments.

Yea, I know... and I don't have a problem making adjustments. I was trying to get away from the hour or so of trial and error I do in my garage, then 10 minutes of on the bike trial and error to get things dialed in.

Just trying to find something more efficient, especially if/when I have problems on the trail and have to make adjustments.

 

[Wumpus]

Yea, I know... and I don't have a problem making adjustments. I was trying to get away from the hour or so of trial and error I do in my garage, then 10 minutes of on the bike trial and error to get things dialed in.

Just trying to find something more efficient, especially if/when I have problems on the trail and have to make adjustments.

Holy cow. It should only take about 15 minutes tops.

Make sure you're not inadvertently pushing the derailluer when you are attaching the cable.

Make sure you get it shifting up (little to big) good if you have non rapid-ride derailleur. When you are riding, shifting down is aided by the pedaling forces so it doesn't need to be as crisp when on the stand.

I really think you should fiddle a little with the limiting screws if you are having trouble just in the middle of the cassette esp the high(small cog) limiter.

 

[Wumpus]

I really think you should fiddle a little with the limiting screws if you are having trouble just in the middle of the cassette esp the high(small cog) limiter.

The indexing is set by the shifter. When you push the button, it releases/pulls a set amount of cable. So pretty much once you get one gear adjusted properly they all should work. Then you only have two other adjustments that will have any effect.

1) The cable attachment screw. Sometimes you can pull the cable too tight and cause problems(won't shift into the little cog) or not tight enough(won't go into the big cog.

2) The limit screws. Took me a while to figure out that they could affect the shifting in the middle of the cog ,too.

 

[jacksonpt]

Holy cow. It should only take about 15 minutes tops.

It's probably really only like 20-25 minutes... but I fiddle around with it, get frustrated, way over adjust or whatever, then work backwards... get frustrated again, etc.

 

[DßR]

Try this -- set your limit screws with the cable un-attached, then put the der. in smallest cog. Pull all the slack out of the cable and tighten the cable fixing bolt.

Hit the shifter one time to go to next-to-smallest cog. If it makes that shift (even if it's noisy or a little hesitant), you're ready for next step. If it doesn't make that shift, you didn't do a good job of pulling the slack out of the cable in step 1. Try again. A 4th-Hand tool may make that task easier.

Then look at the der. from the back of the bike, and see how the der. pulleys line up vertically with the 2nd cog. If they're to the right of the cog, turn the barrel adj. CCW to tighten the cable and line them up. If they're to the left, turn the barrel adj. CW to loosen the cable and line them up.

Spin the cranks and look to see if the chain rubs on the next cog up or the next cog down from the one it's in (look at the bottom of the cogset, between cog and der. pulley to see this). If it rubs a cog to either side, turn barrel adj. to correct.

If you get perfect alignment at one end of the cogset and it's all nasty and grinding at the other end, your derailleur hanger or your derailleur is bent.

All told, the process should take 5min or less.

 

[jacksonpt]

Try this -- set your limit screws with the cable un-attached, then put the der. in smallest cog. Pull all the slack out of the cable and tighten the cable fixing bolt.

Hit the shifter one time to go to next-to-smallest cog. If it makes that shift (even if it's noisy or a little hesitant), you're ready for next step. If it doesn't make that shift, you didn't do a good job of pulling the slack out of the cable in step 1. Try again. A 4th-Hand tool may make that task easier.

Then look at the der. from the back of the bike, and see how the der. pulleys line up vertically with the 2nd cog. If they're to the right of the cog, turn the barrel adj. CCW to tighten the cable and line them up. If they're to the left, turn the barrel adj. CW to loosen the cable and line them up.

Spin the cranks and look to see if the chain rubs on the next cog up or the next cog down from the one it's in (look at the bottom of the cogset, between cog and der. pulley to see this). If it rubs a cog to either side, turn barrel adj. to correct.

If you get perfect alignment at one end of the cogset and it's all nasty and grinding at the other end, your derailleur hanger or your derailleur is bent.

All told, the process should take 5min or less.

Cool... thanks for the tips.

 

[jacksonpt]

Try this... blah blah blah

I took your advice last night and things went very smoothly. Took me about 10 minutes, if that, to adjust my drivetrain front and rear. On the stand, the shifting is dang near perfect - far better than it was. Hopefully it will stay that way with me on the bike.

Thanks man!