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Bike question

post #1 of 33
Thread Starter 
I have a technical question about my front derailleur for anyone who can offer help.

The thing seems to be having a hard time getting enough range of motion. I have let out the high and low adjustment screws all the way, yet, if I adjust the cable to allow it to get into my big ring, it won't go down into the little ring properly all the time. And, likewise, if I adjust it to get it into the little ring properly, it won't go up into the big ring correctly (sometimes at all).

The problem seems to be in the shift levers (rapid fire Shimano). IS there some way to adjust the levers to increase the range, other than the simple cable screw adjustment which just tightens or loosens the cable? If not, how do I fix this problem?
post #2 of 33
you don't mention what kind of front derailer you have. (not that I can help you much but someone else might).
I have a neat old derailer somewhere in my pile of old parts that would work.
It's pre-cables. A bar with a pivot on it that mounts to the down tube. it has a derailer guide on it and you just move the bar left and right depending on which gear you want. Works great. only problem is you have to take your hands off the handlebars and usually need to glance down to see if it's aligned correctly... all of course without falling over sideways or wandering into traffic. I suspect even harder on a mountain bike

Wait, its not the down tube is it? it's the seat tube? oh heck where ever that derailer is normally mounted.....
Time to dig out my books again. Can you tell I have not worked on a bike in ages?<FONT size="1">

[This message has been edited by dchan (edited May 15, 2001).]</FONT>
post #3 of 33
Thread Starter 
Sorry. I figured all the Shimano rapid fires were the same. It's a Shimano LX.
post #4 of 33
The shimano rapidfire has more working parts than the space shuttle - so be careful if you peek inside.

My experience is that you have to fight with these things for a while and get the right balance of adjustment screws and cable tension. But here are some things to check.

You don't have mud or crud jammed into your derailure restricting it's motion?

Is your cable getting hung up on one of the cable hangers?
post #5 of 33
Thread Starter 
Thanks Jim,

I checked for the cable getting hung up. Nope. I could shoot some water and compressed air at it, even though I don't think it'll do any good. I was able to see inside of it, and the cable was tight. That meant to me, that the shifter was the one placing the limits on the range of motion. The derail. wanted to move further, as evidenced by being able to adjust the cable too tight/loose, and getting it to go into the big or little ring easily - just not both.
post #6 of 33
Here's a totally uneducated thought. Can you run a nine speed chain? They are a bit thinner that than the eight speed chain and might not rub against the derailleur side. Someone else correct me if this won't work, since I'm just guesstimating here.

It's odd that you are experiencing this since you are running an eight speed cogset and LX level stuff. Next time we ride, I can take a look at it (I promise I'll do a look see BEFORE the beers are consumed - heh, heh).
post #7 of 33
There are a number of factors which could cause your problem. If the deraileur is not at the correct height, it could cause the problems you have. There should be a 2mm gap between the outer front deraileur plate and the largest chainring when the outer plate is directly above the outer ring.

Also, if you have a front deraileur where the cable fastening screw is from behind the seat tube (as opposed to being accessable from the drivetrain side), the cable must be on the side of the clamp screw away from the drivetrain. This will move the deraileur more per cable movement compared to if the cable is on the drive side of the clamping screw.

Check to make sure you have no extra spacer between the rings, which would make the distance between the granny and the big to large to accomodate the throw of the deraileur.

New 9spd deraileurs don't move as far as the 8spd kind. Though the shifters are identical, the hinging is different. If you are running 8spd chain and rings with a 9spd deraileur, you WILL have problems with setup.

Of course these are only a few things that could cause your problem, without seeing the bike it is difficult to make the correct diagnosis.
post #8 of 33
Thread Starter 
Thanks for the input, Beta. I'm running a standard 3x8 setup. All stock. It seems that the problem is new. I rode the bike quite a bit last year, and had no problems. It started acting this way on my first ride this year. It seems that about every other time I tried to get into the granny gear, it wouldn't go unless I took ALL the pedaling pressure off the chain. And sometimes, it still wouldn't go. It doesn't make sense to me. I could understand it not going into the big ring if the cable got stretched or didn't want to move smoothly though the plastic cable housing. I could also understand needng to adjust the limiting screws, but it seems odd that it just decided not to have enough travel to it, to get from big ring to granny. One would think that they would build these things with a little extra room to move, then be able to reduce that with the limiting screws.

I think I need to just try to really clean it all out, and re-lube it all.

I wonder if maybe my cables are not sliding properly?? Hmmm, time for a thorough cleaning of all the little parts on the front end. I did the rear gears a couple weeks ago.
post #9 of 33
Is it possible your chain is starting to wear? Too much side flex? I found if the chain isn't rigid sideways, shifting gets harder.
post #10 of 33
the fact that the problem became more pronounced after time and letting up on the pressure of pedaling seemed to help makes me think it may not be the derailer as much as the chain. going to the granny gear means more space for the flex to happen since it's farther away from the derailer.<FONT size="1">

[This message has been edited by dchan (edited May 16, 2001).]</FONT>
post #11 of 33
Sounds like the issues I am having with my STI (road) Shimano Shifters. Start by shifting into the granny, and taking all tension off of the cable via the barrel adjuster on the shifter. Adjust the low limit screw accordingly. Then adjust the shifter barrel again and make the cable taut, not tight. THat will be your ground zero. If it still will not function properly your shifter has probably worn out. The internal parts for the RF shifters are not readily available. You are probably looking at $35.00 to replace the front shifter with a new LX 8 speed which are still available. Another option would be to buy a SRAM Grip Shift front shifter. What is nice about it is that the index notches are closer together so you get a more 'friction' action. You can trim the front derailleur so no matter what gear combo you are in you can rid yourself of the annoying chain rub on the front D.
Oh yea, a worn chain can have adverse effects on your shifting system. If you purchase a new chain, it is important to purchase a new cassette (rear cog set) at the same time. Since these two pieces work and wear together you will optimize your shifting performace by changing them at the same time.

If your chainrings are worn on your crankset as well, you might consider changing those too. Don't rush out and buy three chainrings. Quality chainrings with ramps for set of three can run you up to $100.00 and even more. In some cases it is more economical to purchase a new crankset. A new LX crankset w/rings will run you around $70.00. But agian check the compatibility with your 8 speed system. The new 9 speed systems have narrower teeth and thus narrower chains, an 8 speed chain on a 9 speed ring is not a good match.
Hope any of the above can help you...
post #12 of 33
It might be time to replace the drive components. Chains, rings and cogs wear out, and wear out faster in muddy and dusty conditions. Also, the cables and cable housings wear out and/or get dirty. 9spd LX became available in '99, so I assume your bike is older than that. If you rode it, and still ride often, it is time to get new rings, chain and cogset. You will have to get all the components, since as a chain wears, it will cause the rings and cogs to change shape to accommodate the stretched chain. Get new cables and housings too, they're cheap.
post #13 of 33
Thread Starter 
Okay. Now I'm scared. Everyone is telling me to replace every damn moving part on my bike. It's a '99, bought NEW in May 2000. I doubt I have more than 30 rides on it (one was a 48 mile death ride on a paved path) Yes, I ride muddy, dusty single track, but I don't beat the bejeezus out of it. My gears, front and back, are in perfect shape. My shifters seem to function quickly and smoothly. My chain, however, could be a problem. I noticed that it squeeks a lot as it goes through the rear derail. rollers. I cleaned and lubed it, and only one ride later, it was making noise again. It could be stretched out. Maybe I'll get a new chain, clean and lube all the cables, and ditto the front derail. We'll see if that helps.

Anyone have any tips on installing a new chain? I just put a new one on my hard tail, that I ride to work, and was sort of clueless as to how long to make the chain. I just guessed (used the old chain as a starting point, and made the new one 1 link shorter), and it seems to work okay, but I don't want to be that careless with my good bike. The dork in the bike shop told me something like 1 finger between the rear derail wheel and the gear, when it's in both smallest gears. But that seems odd to me, because as the chain stretches, it'll quickly be too loose. Shouldn't it be tight enough that it can get into both big gears, but not much more?
post #14 of 33
Thread Starter 
Hey Gonz! You scrub! We found out through some deeply burried post on MTBR that you missed your plane. Thanks for the heads-up, slicky boy! Sorry we missed you. It would have been cool to get to ride together. Let us know when you're coming back to town.

Yeah, I played with those damn screws for an hour, maybe two! It's not them. I think dchan may be onto something with the chain. Being 200#, and sometimes standing on my pedals in a wrong gear, not going anywhere, may have stretched my chain enough to make it loose. Read my last post.

Could I just take a link or two out of my chain? Maybe I'll do that, just to see if that's the problem, before I go out and buy a new one. Although I do think I need a new one.<FONT size="1">

[This message has been edited by JohnH (edited May 16, 2001).]</FONT>
post #15 of 33
everytime I have replaced my chain I use the old one as a guide and account for the strech so one link removed would be about right unless you see an extreme amount of distortion. I don't think I've ever replace a cog set unless it shows distortion or excesive wear but I'm not as fanatical about my bike as some.
Do you clean and lube your chain regularly? I think it was about every 20 hours of riding or something like that.. I think I lubed about every 15-20 hours and cleaned and lubed every third time or something like that. I'm sure the "standards" have changed by now. I'm interested in this question now that I have a new bike. It's probably different on road bikes compared to mountain/off road..
post #16 of 33
post #17 of 33
Thread Starter 

Yeah, I was pretty obsessive about cleaning my bike last year. After every ride, I'd clean the bike, head to toe. Including scrubbing the chain and re-lubing.

I think it may be very different with a road bike. I may be way off base here, but since I use my hard tail as a road bike, I lube the parts with WD40. I know it's a big no-no for a mountain bike, because it collects dirt, but it's a very good lube, otherwise, and doesn't build up the way the teflon MTB lubes do.

edit: Thanks for the link! It seems like they like a tight chain. I've never seen a rear derail pull that tight when in both largest gears.<FONT size="1">

[This message has been edited by JohnH (edited May 16, 2001).]</FONT>
post #18 of 33
Thread Starter 
Hey Gonz.

The jockey wheels aren't squeeking anymore, it's the chain, as it goes around them. From the Park reference, that dchan posted, one of their methods for sizing the chain is what you mentioned. Only 2 links bigger than big/big isn't much. But then how often are you in that combo of gears?

I have one of those 28 pound Topeak Aliens. It's a frickin' anvil, but a great tool. I used the chain tool in it to do the chain on my HT, and it works pretty damn well. The only thing that's a major pain, is getting a chain rivet started into a link. Is there some sort of trick to that? They don't want to start straight in. I used a pair of pliers to at least get it holding in the hole, but couldn't, for the life of me, get it to stand straight. It wanted to go in crooked. I finally got it straight enough that the chain tool could push it through. Maybe I'll just use a bench vise next time!

Another Q: How can you tell which link is the "master" link? Is it the one stating it's superiority over the others? (I am the master link!!) And does it really matter which link I pop out?<FONT size="1">

[This message has been edited by JohnH (edited May 16, 2001).]</FONT>
post #19 of 33
I dohn't know if anyone has mentioned this but you might check the alignment of your front deurailluer (sp), sometimes they get bumped or squished, make shure that it's parallel with the BB, also if it has been squished you can use a pr of pliers to widen it back out, or vice versa. As for your chain, spend the extra couple a bucks and buy a new one, a worn chain will just cause you problems in the future,and can cause premature wear on your rings and sprockets.
as for which link to pop, it dosen't matter, a masterlink is nice to take the chain off but you still need a chain break to pop a link.
post #20 of 33
If JohnH is the Master Link and Gonz is the Missing Link, does that make me the Weakest Link?

YOU are the weakest link, goodbye... (heh, heh). Funny show.
post #21 of 33
anyone remember way back when master links on bike chains were actually designed to be removed and replaced. no driving out the pin. just remove the "lock clip" like a little c clip and pop out the link.
That and the stingray 5 speed with playing cards in the spokes to make them sound cool.

oops . dating myself..
never mind...<FONT size="1">

[This message has been edited by dchan (edited May 17, 2001).]</FONT>
post #22 of 33

My friend has an LX front derailer that sucks noi matter what he does to it.

Scrap it and get an xt or xtr. Those work well.

Cheap bike parts are notorius for just not working well and can be a real pain to adjust proplery.

About 45 bucks for an xtr front at a place like supergo, I think.
post #23 of 33
Thread Starter 
space monkey,

Yeah, that thought's been running though my brain. The rest of my components are XT. If I did, I'd probably go XT as opposed to XTR. The extra ounce or two won't kill me. And it'll be cheaper.

Gill - Too frickin' funny!!! I've never watched the show, but every time I see a clip of that lady saying {in stong British accent} "You ARE the weakest link... goodbye!", I practically burst out laughing, and can't stop repeating her for the next 10 minutes!
post #24 of 33
Even though I may have suggested getting a new drivetrain, do that only as a last resort. Since you don't ride that often, the chances that something is out of alignment or dirty.

Here's a way to diagnose the problem better. Disconnect the cable from the deraileur. Check the movement of the deraileur by activating the lever which gets pulled by the cable. If you have full motion, that part is OK. Check to see if the deraileur is properly alinged and the right height. Even a small crash con knock the deraileur around. The outer plate should be parallel to the outer ring, and have 2mm clearance. Though it is awkward to do, you can test to see if everything is aligned and working properly at the deraileur end by fasting a piece of wire onto the cable fastening bolt, and pulling it as you pedal. If the chain goes through its range properly, you have fixed that end. The rapidfire shifters are pretty much unservicable. There are tons of tiny parts within the body, and it is not recommened that they be opened and worked on. WHat you can do though is get some Teflon lube (Finishline or TriFlo). The lube can be sprayed or dripped into the access hole where the cable gets installed through. Keep the cable inside while you lube the shifter body. Once you have a quantity of lube inside, activate the shifter so that it pulls the cable. Once you have done the 3 clicks for the front (and 8 or 9 for the rear, since you might as well do both), release the tension with the finger lever and pull the cable at the same time. Keep adding lube and clicking the shift levers until all is running smoothly. Once you have got the shifters and the deraileur to go, replace the cable housing and cable. Use the old housing as a guide for cutting length.

To check if the chain has been stretched too far, each roller is 1/2" apart. The stretch of the chain should not exceed 3/32" over 12". if the chain has more stretch, you will have engagement troubles when using a new chain with old rings and cogs. Though there is nothing wrong with Shimano chains, I suggest using Sachs/Sram chains with a PowerLink connector. This allows the chain to be removed when doing regular service and cleaning without any extra tools or link pins. Once you have mastered how to open the PowerLink, you'll take it off whenever you have to do a thourough cleaning. The cahin develops side play which is related to chain stretch. The stretch is more critical to the operation of the bike than the side play.

In the future, try to limit cross chaining. Too much side load is generated when going from big ring to big cog, and this combo can also shear off the rear deraileur if the chain is too short. If you go from granny ring to tiny cog, the chain will be too slack and could cause damage by chain slop. When possible, try to stay in the half of the cogset that corresponds to the ring. If in the granny ring, use the 4 easiest cogs. When in the big ring, use the 4 hardest cogs. When in middle ring try to limit the 4 or 5 cogs within the middle of the cogset. There is enough overlap in ratios.
post #25 of 33
Thread Starter 

I think I understood that. Thanks. I know the derail has full range of motion, since I can adjust it too far either way. I'm going to take it to a LBS this afternoon, for them to look at it.

I took the chain off, and did the big ring to big cog test. I had 4 extra links there, as opposed to the 2, that is recommended. So I took 2 out. Before I did that, when I set it in little ring and little cog, the chain was so loose that it drooped about 2 inches. Enough, that, with the bike upside down, the bottom side of the chain was laying on the top part, and the rear derail, was completely loose. Because the derail was folded up so much, the chain would bind when I tried to spin the pedals.

I need to get the bike on a hill and grind hard to check it, since the problem didn't happen every time. I need to be in the granny gear with some pressure on it to really test it. I'll see what the guys in the LBS say about the chain and derail this evening. I have the feeling I may replace the chain even if I do have the tension set right.

Here's a question...

The chain I bought for my hard tail cost me $14. It's the chain the guy handed me in another LBS. I think it's the only one they carry. The chains they have in this LBS run $18 and $24. I don't know the difference. What makes one chain worth 70% more than another?
post #26 of 33
LBS? Little Bike Store?
post #27 of 33
Well, John,

I just caught up on this post and there is nothing like a lot of information to really mess things up. Have you considered buying a brand new bike and putting your malfunctioning front derailure on it? That way you'd know if it was really your derailure. Anyway, in my experience the front derailure is about the last thing to wear out on a bicycle.

I've been using the same front derailure on my once competition mt. bike and now my commuter for about 10 years now - despite many chains, chanrings, BB's, shimano and sram shifters and cranks. Still works like a champ. So I am going to go out on limb and say it's your shifter.
post #28 of 33

The differences in chains is how they are riveted. The more expensive the chain, the more the pin ends are flared, such that the most expensive and best quality chains have a full mushroom rivet end. Plating and materials, and weight saving features also increase price.

The chains I would suggest to you are either the Sach/Sram PC 61 or PC 91. Both have cross step rivets, which is almost full mushroom, a durable plating, and the Power Link connector, and are for 8speed systems. The 91 is lighter because the side plates have holes machined into them. A reduction in material = a reduction in weight. As to which lasts longer, I don't know, since I replace my chains before they actually fail.
post #29 of 33
Thread Starter 

Those SRAM chains are the ones in this LBS! The 61 was the $18 chain, and the 91 was the $24 chain! There did seem to be some difference in material, because there was a slight color difference to some of the parts.

jimpd - Yeah! That's it! Replace my 1 year old bike with a new one to check the front derail! I like it. This LBS has a $3000 Gary Fisher Sugar 1 that is OHHHH so sweet! I guess that's why they named it "Sugar". But it has these stupid tubeless tires. I don't see the point of saving a couple ounces on the weight of the tube, and risking a blowout. And come on! $800 for the wheels?!?! I think NOT.

dchan - that would be "Local". However, this one also qualifies as Little. They got some rockin Gary Fisher bikes though. There is something oddly comforting about a shop who's cheapest mountain bike is $1000. All the shop employees have these monster DH rigs. I don't get it. There isn't a real place to run DH within hours of here. Yet Gill and others all have these 35lb sleds with 8" of travel at both ends. Maybe they're just making up for their shortcomings. I got that much "travel", and it ain't on my bike! (It's a *joke*, Gill!, from when I said, to your friend "what do I need 8" for?")

<FONT size="1">

[This message has been edited by JohnH (edited May 18, 2001).]</FONT>
post #30 of 33
JohnH - yeah, I remember that comment! Heh, heh... when mountain biking, I've always heard that it's not the size of that appendage that counts, but another set of appendages - and whether they're brass or not.

With my bull in the china shop finesse, I just wanted a durable bike. As I kept breaking and replacing parts, the bike's weight just seemed to grow. Besides, hauling that fat rig up all the hills we have around here just makes me more of a man, right? Right? Come on, RIGHT?!?

Keep in mind that the guy who finished first (by a long shot, by the way) was riding an Intense Uzzi DH bike that came in around 35 pounds. I've also seen some of the local bike shop guys ride an RM9 up stuff I couldn't get up if I were riding the lightest bike on the planet. Riding is 90% rider and 10% equipment. I keep telling myself that to avoid the serious case of upgradeitis I'm coming down with. That Ellsworth Truth looks sooooo good hanging there in Galyans!!!<FONT size="1">

[This message has been edited by Gill (edited May 18, 2001).]</FONT>
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