Bike problems

[ttora4runner]

I'm having a problem with the cable for the rear gears on bike when I shift gears the cable becomes extremely slack to point where it won't change gears.

This happens when I'm on the second front spocket and when I change to biggest spocket (3rd) I can't shift past a certain point as the cable becomes extremly taunt.

I've tried to adjust the cable on the back derailer pulling up the excess slack when it a lower gear but I'm unable them to go to the lowest three gears.

Do I just need a new cable then or is there an adjustment point I'm missing? The front gear selector works fine, the cable does slip a little when changing gears.

My bike is a Trek 4300, 24 speed.

Hopefully, this makes sense.

[1speed]

I'm having a problem with the cable for the rear gears on bike when I shift gears the cable becomes extremely slack to point where it won't change gears.

This happens when I'm on the second front spocket and when I change to biggest spocket (3rd) I can't shift past a certain point as the cable becomes extremly taunt.

I've tried to adjust the cable on the back derailer pulling up the excess slack when it a lower gear but I'm unable them to go to the lowest three gears.

Do I just need a new cable then or is there an adjustment point I'm missing? The front gear selector works fine, the cable does slip a little when changing gears. My bike is a Trek 4300, 24 speed.

Hopefully, this makes sense.

Sounds like you need new cables. Either take it to an LBS for new cables and adjustment or buy a set of cables and go to Park Tool's web sight and look up how to install them and adjust your derailleurs. It' fairly simple once you know how. You will need bicycle specific cable housing cutters to cut the cable housing cleanly.

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

[ThomD]

Make sure that the derailleur is moving freely. Try just moving it by hand. It might be dirty or it might be damaged.

[ttora4runner]

I think I just need a new cable.

I tried various adjustments but no dice.

[LandCruiserPhil]

I have no technical advise to add but I do own the same bike and if any detailed pictures would help just ask.

[ttora4runner]

I have no technical advise to add but I do own the same bike and if any detailed pictures would help just ask.

Without a photo try to picture this (I'm too lazy to take a photo at the moment, but yet I'm typing this)but when you change the rear gears (8 rear spockets)gears 6-8 the cable goes completely slack you can pull it up about a good 2" gears 5-3 work fine cable is in normal position (taughtness, it that's a word) then gears 2-1 the cable is extremely tight.

Now if you try to pull some of the slack out of the cable, gears 6-8 still don't work gears 5-4 work but you loose the ability to drop down to 3rd gear now.

I tried to follow the adjustments procedure on the Trek website but no avail which is why I think I need a new cable which others have mentioned.

Thanks guys.

[ThomD]

From the sounds of it, you do not need a new cable. If it pulls through most gears, it is probably fine.

From the middle chain ring (front), you should be able to shift across the full range in the back. From either of the other chain rings, you may not be able to easily shift to the opposite side of the back cogs. This is OK because you probably shouldn't any way. Depending on the bike, that cross chaining can be severe and not good for the drive train.

Think about it this way - if the cable is slack, that means that whatever force is supposed to pull it through isn't doing its job. If the cable was at fault you'd have a problem through most/all gears. The pull through comes either from you or the derailleur. Since you are doing your part, the problem has to be at the other end. What you are describing really sound like a derailleur problem. It is either a. dirty (WD-40 does wonders), b. really really out of adjustment (or the cable is) or c. damaged.

I'd drop the chain and move the derailleur by hand to confirm that it can move freely. Then I'd move it using the shifter. Since the cable along the stays is probably exposed, I'd set the cable to as loose as possible and try shifting it by using the exposed cable, instead of the shifter. This will help figure out exactly where in the whole process starts to bind up.

If it is the cable, you should see visible damage somewhere.

[mcgovski]

Here is how I would trouble shoot it:

disconnect the cable at the derailleur.
pedal the bike and see if the derailleur drops into the highest gear. If so push the derailleur up the cassette with your thumb, still pedaling, to ensure the chain will go all the way up to the lowest gear. this will ensure your H and L stops are set correctly. If the chain wont move from the high to the low full range then you need to adjust your stops. For example, if it wont drop in to the highest gear, back out the H stop until the chain will. If the cahin goes into the wheel on the lowest gear, tighten the L stop, to keep the chain from going in the wheel

While the cable is disconnected, remove the cable from all the housing stops, just to the down tube, That way you dont have to cut your cable tip off... not all the way to the lever unless you want to cut your cable tip off, and lubricate the cable and cable guide on the BB. I would just use some chain lube.
Before putting the cable back in the housing stops, inspect the ends of each piece of housing to make sure there are no sangs and put housing/cable back in the housing stops

put the shift lever in the highest gear position before you tighten the cable. Tighten the cable and attempt to shift one gear up(lower)and down(higher). Use the barrel adjuster on the back of the derailleur to adjust your cable tension to make sure the chain moves up to the next lowest gear and back down into the highest gear.

that should do it

good luck

[ttora4runner]

Here is how I would trouble shoot it:

disconnect the cable at the derailleur.
pedal the bike and see if the derailleur drops into the highest gear. If so push the derailleur up the cassette with your thumb, still pedaling, to ensure the chain will go all the way up to the lowest gear. this will ensure your H and L stops are set correctly. If the chain wont move from the high to the low full range then you need to adjust your stops. For example, if it wont drop in to the highest gear, back out the H stop until the chain will. If the cahin goes into the wheel on the lowest gear, tighten the L stop, to keep the chain from going in the wheel

While the cable is disconnected, remove the cable from all the housing stops, just to the down tube, That way you dont have to cut your cable tip off... not all the way to the lever unless you want to cut your cable tip off, and lubricate the cable and cable guide on the BB. I would just use some chain lube.
Before putting the cable back in the housing stops, inspect the ends of each piece of housing to make sure there are no sangs and put housing/cable back in the housing stops

put the shift lever in the highest gear position before you tighten the cable. Tighten the cable and attempt to shift one gear up(lower)and down(higher). Use the barrel adjuster on the back of the derailleur to adjust your cable tension to make sure the chain moves up to the next lowest gear and back down into the highest gear.

that should do it

good luck

Yup, tried that and it does exactly what you first mentioned. You can push the rear derailer all the way though the gears. I retightened the cable and played with the barrel adjuster but still no dice and the cable still goes slack or taught.

[mcgovski]

So the stops are set good, the cable is moving through the housing well and you are tightening the cable with the shift lever in the highest shift position. This would lead me to believe the lever is having an issue. Depending on what kind of lever you are using there could be some problems there. non friction levers (indexing)have ratcheting pauls inside that some times get gunked up or off track so that the throw of the lever is not in jive with the position of the lever
What kind of lever is it?

Chris