Bicycle Mechanics - rear derailer problem.

I don't have alot of experience w/ derailers but they seem pretty simple. turn one of the two screws to make the chain go the direction you want.

I have a shimano shifter (the lever part that is on your bars) and it must be for an 8 speed because it only clicks 8 times before it stops when shifting from high or low.

my cassette on the rear wheel (the thing w/ all the gears on it) is a nine speed. I don't care if I can't use all the gears, I usually only use 3 or 4 most of the time anyways.

the problem I have is, when I shift there are a few spots where I have to click the lever twice to get the chain to move. it seems to be in the middle of the gears, not on the high or low end.

I have turned the screws on the derailer so the chain rides on the gears correctly but how do I get rid of this non-shifting thing?

any and all suggestions are welcome.

I don't have alot of experience w/ derailers but they seem pretty simple. turn one of the two screws to make the chain go the direction you want.

I have a shimano shifter (the lever part that is on your bars) and it must be for an 8 speed because it only clicks 8 times before it stops when shifting from high or low.

my cassette on the rear wheel (the thing w/ all the gears on it) is a nine speed. I don't care if I can't use all the gears, I usually only use 3 or 4 most of the time anyways.

the problem I have is, when I shift there are a few spots where I have to click the lever twice to get the chain to move. it seems to be in the middle of the gears, not on the high or low end.

I have turned the screws on the derailer so the chain rides on the gears correctly but how do I get rid of this non-shifting thing?

any and all suggestions are welcome.


First of all, if it ever worked right, you've probably already screwed it up. The limit screws on the derailleur, once they're set correctly, never need to be readjusted. Try this and don't skip any steps:

1. Shift into a middle cog in back - one that will leave the derailleur arm pointed straight down. Stand your bike up vertically against something. Now look at your derailleur from the back. If the arm points straight down, that's good. If it looks like it's pointed toward the tire or to the side, your derailleur hanger is bent. There's no point in doing anything else until you get that fixed.

2. If that's OK, shift into the big chainring in front and the littlest cog in the back. Now disconnect your shift cable. The upper pulley on your derailleur should be exactly under your smallest cog or just a hair to the outside. Fiddle with the high gear limit screw (usually the top one on the derailleur) until it is.

3. Make sure that your shifter is in the highest (hardest) gear position. Pull the shift cable taut with a needlenose pliers and anchor it to the derailleur. You can only shift eight times because your derailleur is already in a gear. The gear that you're in plus eight shifts equals nine.

4. Try to shift into the next gear. If it shifts crisply, try the next one until you get to the biggest cog. Be careful that you don't overshoot the big cog and shift the chain into the spokes. If it makes a lot of noise but doesn't shift, unscrew the barrel adjuster where the cable housing enters the derailleur in 1/4 turn increments until it does. Unless something is bent or crudded up, all rear derailleur adjustments are made with cable tension.

5. Now try to shift back the other way. If it doesn't want to shift, you might try screwing the barrel adjuster in 1/4 turn, but make sure your shift cable and housing are squeeky clean first. Don't forget to check under the bottom bracket.

6. Be extra careful with the low gear limit screw. It has to be out far enough that it will let the derailleur shift into the boggest cog without binding up, but not so far that the derailleur hits the spokes or spoke protector.

If you really have an 8spd shifter and 9spd cassette the discrepancies in the
shifting distance between 8 and 9spd shifters may account for the problem.
9 spd cassettes have a closer spacing between the cogs, and the 8spd shifter
would overshift a little each time to eventually the chain will be between cogs
and not on one or the other and shifting would go weird. On the other hand
you could have a broken 9spd shifter, so that one position on the ratchet no
longer works so you have to double shift to get the next cog. I have two
8spd shifters that lost a ratchet slot and only have 7 actual shifts. So far the
9spds have held up ok, but the risk of a shifter failure begins to go up between
7 and 10k miles. Steve

Your 8 speed shifter is not compatible with the 9 speed cassette. Basically, when you click the shifter once, it moves the derailleur 1/8 of the distance, but the cogs in the cassette are spaced 1/9 of the same distance. This distance is a constant - in other words, a 8 or 9 speed cassette will fit in the same spacing, so the 8 speed cogs are spaced at slightly larger interaval and the 9 speed with slightly smaller intervals.

You will have to buy an 8 speed cassette to match the 8 speed shifter. Or buy a 9 speed shifter to match the 9 speed cassette.

The screws on the derailleur do not adjust it, rather, they set the maximum travel of the derailleur. It prevents the derailleur from moving in too far and placing the chain into the spokes and prevents it from travelling too far outside beyond the smallest cog.

8 clicks <should> = 9 speed

8 clicks <should> = 9 speed

Ok, now what did we learn here class? Anyone? Anyone? :D :p :D

yeah 8 clicks = 9spd

Is your derailleur hanger bent? That causes some seemingly mysterious problems.

As one poster said, the screw only sets limits. Heres how I think of it...

By adjusting the screws you are essentially telling the derailleur your range of motion is from point A to point B so what you want to do is set the appropriate limit (theres two) when you are in your biggest and smallest gear. One screw will adjust when you're in the biggest, the other when you are in your smallest. Shift into the smallest first, and tighten either screw until one of them actually moves the cage. This is going to be the limit you want to set for the smallest gear. Using that screw, get the cage aligned parallel to the smallest cog. Make sure your shifter is also in the smallest gear. Shift up into the biggest gear, and using the other screw, set the limit so you can't shift past the biggest gear into the spokes.

Once this is done, the only other things you should need to worry about are cable tension, and if your hanger is bent. If there is too much tension the derailleur will skip gears, pop out of gear. Too little and it will shift slow or sloppy or stick in gear. Use the barrel adjuster on the derailleur to adjust the tension. Screwing the adjuster OUT increases tension, screwing it in decreases tension. In your smallest gear, typically the cable can be pushed against the frame where it runs to the derailleur fairly easily with some resistance. If the cable looks saggy its too loose, if you can't push it against the frame or there is a lot of resistance when you try to, its too tight. As I said before you can usually tell by shifting patterns anyways.

Theres a few other factors that differ from derailleur to derailleur (like which side the cable is screwed into, housing lengths, etc) but thats more advanced. This is a general guide to work off of so I hope it helps you.... derailleurs mystified me for years until I realized the concept behind limit screws. People make it so much more complex than it needs to be.

well, I learned today that you can't use a SEVEN speed derailer with a NINE speed shifter....oops.

I swapped out the derailer with my good one and guess what, it works correctly. I now just have to mess w/ the tension to get it to shift smoothly.

I learned a lot though so that was good.

limit screws set the range of motion for the derailer.
the tension adjusts how it shifts.

that's pretty much it, and of course, use the correct parts......:D

thanks for all the help, I definitly have a better understanding of derailers now.