Front Derailleur NOT Staying In Gear

[ATX760]

Hi I'm new to the forums and need some info about my front derailleur. The further I push the shift lever on the handle bar the further the derailleur moves toward the biggest sprocket. The only problem is the chain will slip off the two bigger sprockets and stay on the smallest. Pretty much i cant keep the bike in gear. I have read a few other posts that touch on the topic, but they don't give me enough information. Does anyone know about or had this same problem?

THANK YOU

[Bill]

Do the chainrings on the Middle and the Bigger look at all bent or the teeth look "shark toothed"?

[ATX760]

(01-19-2010, 09:01 PM)Bill Wrote:  Do the chainrings on the Middle and the Bigger look at all bent or the teeth look "shark toothed"?

No none of the teeth are shark toothed but i did notice that some of the teeth are worn a little in some places. I didn't worry about this because the chain doesn't slip gears at the worn teeth point every time. And i can also see the derailer physically pulling the chain off of the bigger two gears inward toward to the smaller gear. What do you think?

[Bill]

Ok sounds like your Derailler needs to be adjusted. Here is Alex's video on how to do that http://bikeride.com/adjust-front-derailer/ . If this doesn't seem to be the problem can you take a couple photos of the derailler?

Also, from reading your post, when you are pedaling per say and you shift into a larger "sprocket" the chain goes goes there. But right after does the derailler seem to retract back pulling the chain back to the small sprocket?

[ATX760]

(01-20-2010, 12:47 AM)Bill Wrote:  Ok sounds like your Derailler needs to be adjusted. Here is Alex's video on how to do that http://bikeride.com/adjust-front-derailer/ . If this doesn't seem to be the problem can you take a couple photos of the derailler?

Also, from reading your post, when you are pedaling per say and you shift into a larger "sprocket" the chain goes goes there. But right after does the derailler seem to retract back pulling the chain back to the small sprocket?

I've watched the movie earlier today, just watched it again, and went through all the steps again, and it is the same.

Also when I am pedaling and i push the shift lever on the bars in, the further i push it in the further the derailleur moves toward the big sprocket from the small one. So when the lever springs back out the derailleur moves back toward the small again. This is instead of just pushing the shift lever in just a little and it shifting the derailleur and the shifter coming back to its original position awaiting the next shift.

How much of the shift lever in = which sprocket the derailleur is on
1/4 = Small
1/2 = Medium
3/4 = Large
If this helps at all

I can stay in 2nd and 3rd gear if i hold the shift lever in the 1/2 and 3/4 position

[Joe_W]

Either the shifter is broken or just gummed up. There is a little ratchet mechanism inside. First, try to get some penetrating oil inside, let it sit for a while and then try shifting. Repeat. If nothing helps, some shifters can be serviced, though with all the small springs and ratchets and stuff this is nothing for the fainthearted. If nothing helps, get a new one, I am not sure, but I think most MTB type shifters should be ok (since this is for the front derailleur). You might even be able to get a used pair somewhere.

[JonB]

Shimano Deore Shifters like the one you have are pretty easy to service, I've done one myself (Alex's video uses a very similar one to what you have). http://bikeride.com/rapid-fire-shifters/. I have to agree with Joe_W it does sound like it's gummed up and jammed. You may need to repeat the service process several times (I had to when mine did something similar)

It's only SRAM shifters you don't want to take apart unless you like fiddly stuff and springs flying everywhere, the shimano ones are much easier to service.

As for replacing the shifter, Joe_W you are right any 3-speed shifter will work for MTB. It's only on the rear that you don't go mixing manufacturers.

[ATX760]

(01-20-2010, 03:53 AM)Joe_W Wrote:  Either the shifter is broken or just gummed up. There is a little ratchet mechanism inside. First, try to get some penetrating oil inside, let ist sit for a while and then try shifting. Repeat. If nothing helps, some shifters can be serviced, though with all the small springs and ratchets and stuff this is nothing for the fainthearted. If nothing helps, get a new one, I am not sure, but I think most MTB type shifters should be ok (since this is for the front derailleur). You might even be able to get a used pair somewhere.

I've tried cleaning and lubing my shifter before and I'm going to do it again a couple times today. Also you guys made me realize that the ratcheting mechanism in the shifter is not catching. Duh!!! Should have figured that out right away ya know. I'm going to work on my bike today and tell you guys what I find, and if you guys have any more info please let me know.

THANK YOU

[Bill]

Thats more then likely your answer. Please do update

Thanks

[ATX760]

Finally I have figured out that my derailleur was not wanting to stay in gear because the shifter was gumming. To fix the problem i first; removed the cover form the shifter. With the cover off i soaked the insides off the shifter with WD-40. On a tip from a friend, I took a small flathead screwdriver and wiggled back and forth what he said were called "Paws" (Correct me if the word "paw" is wrong). The "paws" are small spring loaded ratcheting mechanisms, and in case they are gold. After freeing the paws from the gunk I followed up with more WD-40 and some Marvel lubricating oil. While applying the lube I pushed the shift lever in and out until the paws caught and the bike was changing gears once again. So thank you for all your guys help, I would have never figured it out.
THANK YOU

White arrow pointing to "Paw"

[Alex Ramon]

Good to hear you got it working! I know you've already done this, but as Jon said <a href="http://bikeride.com/rapid-fire-shifters/">here is a video</a> that may help others with the same problem.

They are called "Pawls". Here is the definition from good ol' Sheldon: http://www.sheldonbrown.com/gloss_p.html#pawl

[jr14]

Damn you Alex! You beat me to the pawls correction!

[ATX760]

(01-22-2010, 07:26 PM)jr14 Wrote:  Damn you Alex! You beat me to the pawls correction!

He is quick isn't he

Paw = Pawl
THANK YOU

[jr14]

Sure is. Might have something do with him owning the site and all.

[ATX760]

(01-22-2010, 07:53 PM)jr14 Wrote:  Sure is. Might have something do with him owning the site and all.

I think you might have something there

[jr14]

hehe.

---

Hey cool...I just realized I got 5 stars...Wonder how I did that.

[jack1]

I was able to fix this issue by raising the front derailleur higher than the 2-3cm recommended by everyone. "It's a suggestion, not a rule."

That helped my problem.

[wheindl]

I am having the same problem, only with a road bike STI shifter (Tiagra). The front shifter, for tightening the cable and pulling the chain onto the big chainring, moves the front derailleur and will shift the chain; but when you release the shifter the derailleur moves back and the chain downshifts. Also, there is no "click" in the shifter when it moves the chain, so I suspect that's where the problem is.

The bike is relatively new (8 months, but with 1000 miles on it), and all of this started to happen while I was adjusting the barrel adjuster on the downtube to stretch the chain a bit, as it was having a hard time shifting onto the big chainring.

Any ideas?

[Joe_W]

To me it sounds like it is gummed up. You might try to squirt penetrating oil in it or take it to the bike shop where you bought it and ask them. It should not gum up after only 8 months (well, depending on where you ride and store the bike...).

[Archey Sturmer]

(04-10-2010, 02:10 AM)Joe_W Wrote:  To me it sounds like it is gummed up. You might try to squirt penetrating oil in it or take it to the bike shop where you bought it and ask them. It should not gum up after only 8 months (well, depending on where you ride and store the bike...).

Either it's gummed up, which is less common on STIs than on mountain bike pods, or it could be that the cable is way too tight and the shifter just isn't making it all the way to the ratchet point. Based on this happening when you were fooling with the barrel adjuster, that would be my first suspicion. Try turning the barrel adjuster back in a couple turns and see if that helps.