1. How to Adjust Your Rear Derailleur
Applies to most 3-chainring derailleur systems. Adjust your Front Derailer
Adjusting your rear derailleur can be frustrating. I’m hoping that this tutorial will help you understand how each component of your derailleur works, and how to set up and adjust it properly. Once your derailleur is set up correctly, most future adjustments can be done by hand. Let’s get started!
Almost all modern derailleurs function the same basic way. They are designed to move (or derail) the chain from one sprocket to the next. The upper guide pulley (or jockey pulley) moves the chain in both directions. For instance, when you want to climb a hill, you shift down to a lower gear. This pulls the shift cable and forces the guide pulley to change to a bigger sprocket. When you want to go faster, you adjust the shifter to a higher gear. This releases shift cable tension and allows the derailleur springs to pull the guide pulley back down to a smaller gear. Each time you shift gears, the length of chain changes. The lower tension pulley is spring-loaded to take up this slack.
There are 3 adjustment screws – the B-Screw (B-tension adjustment), the H-Screw (high gear limit stop) and the L-Screw (low gear limit stop). Adjustments on these screws should always be made in 1/4 turn increments.
The B-Screw controls the derailleur body’s angle in relation to the sprocket-set. Shift down to the largest sprocket and check the distance between the guide pulley and the large sprocket. If the guide pulley is rubbing on the sprocket, tighten the B-screw clockwise to increase tension and move the pulley away from the sprocket. If there is a large gap between the pulley and sprocket, loosen the B-screw until the pulley rubs the sprocket, and then tighten it until it just clears.
The H-Limit screw high gear limit stop prevents the guide pulley from shifting any further past the highest gear and into the axle. In order to adjust it properly there must be no tension on the lower inner cable. If you feel tension, loosen the cable adjuster until there is none. Now check from behind how the chain is riding on the smallest sprocket. If it looks like it wants ride off into the axle, tighten the H-screw clockwise until it lines up. If it looks like it is rubbing on the next gear, loosen the screw until the chain is nicely centered on the sprocket. Now re-adjust the cable tension until the derailleur shifts smoothly down to the next gear.
The L-Limit screw prevents the guide pulley from shifting any further past the lowest gear and into the wheel spokes. Shift down to the lowest gear, step behind the bike, and check how the chain rides on the sprocket. If it looks like it wants to ride into the spokes, tighten the L-screw clockwise until it is centered on the sprocket. If it looks like it wants to shift down, loosen the screw until it lines up. As an extra precaution you can use your thumb to gently push the derailleur body and make sure the chain will not run into the spokes, as this could obviously have a nasty effect on both you and your bike.
The cable tension adjuster defines how far up or down the derailleur moves. Step back so you can see the chain and sprocket alignment, and then through the gears in both directions, first shifting up two and down one, and then down two and up one. The chain should look centered on each sprocket. If it is rubbing on a larger gear it means there is too much tension on the cable. Loosen the tension by turning the adjuster clockwise. If it wants to jump down to a smaller gear it needs more tension. Increase the tension by turning the adjuster counter-clockwise.
You can also use sound to check the adjustment. There is always a base-level of noise that can be heard in every gear. This noise will increase in a slightly different way depending on which way the tension is out of adjustment. If there is too much tension you will hear a metallic rubbing sound, but if there is too little tension you will hear a clicking noise as the chain tries to jump to a smaller sprocket. There is usually a cable tension adjuster on your shift lever. With practice you will be able to make small cable tension adjustments while you are riding.
Now that the derailleur is adjusted, always apply a drop of lubrication to the derailleur’s many moving parts. This will help prevent wear from dirt and rust, and it will keep your gears shifting smoothly. Wipe away any excess lube and take your bike for a test ride to make sure all the gears are working smoothly.
That concludes our tutorial on rear derailleur adjustments… have fun!
I've read quite a few posts in other forums about these derailleurs breaking apart while riding. I have one on my 83' le tour luxe in great condition and was interested in finding out more about it. I haven't seen any reference in posts to exactly where the derailleur was breaking apart at. Has anyone had any experience with these and what is breaking apart on them?
Thanks!... Read more >>
New to the forum and it looks like a lot of helpful info here.
Now that that's out of the way,
I have a problem locating a part for my down tube shifter. It's a flat washer that has a small hook or tab on it that sits inside the shifter. The hook part has a crack and is starting to break off. Does anyone know where I can get a replacement part for it?
Thanks... Read more >>
I have just done a complete overhaul on my wife's mountain bike, here is a list of what I have replaced;
Shimano MF-TZ 31, 7 speed 14-34 mega range cog set.
Shimano FC-M 171, 48\38\28T Chain set.
Shimano RD-TX35 6\7 speed rear derailleur.
Shimano FD-TX51 front derailleur.
Shimano CN-HG40 Chain.
I have adjusted and indexed the rear mech. The problem I have is with the front mech, I can change from smallest to largest cogs OK but when I change from the largest it changes to the middle cog fine but will not go to the smallest cog no matter what... Read more >>
I want to convert my Raleigh Rapide from downtube shifters to STI shifters.
So I have Campagnolo 980 derailers, 6 at the back and 2 at the front.
Sanwa Road Bike. 10 Speed. Had for about 10 years. I only have one speed 5th gear. I know videos all over. I watch them and just can't get this thing correct. Thought I'd head here for help and I have a new Schwinn coming. That's pretty inexpensive also. Looks like a nice web site also.
Problem: Start with something simple. Getting from 5th to 10th. When I push the Front Derailleur by hand it snaps back. I can pull the lever on top of bike down to shift to 10th and the lever snaps back. If I put the bike in 10th the derailleur snaps back toward the bike causing the chain to go to ... Read more >>
I've recently bought a women's Schwinn Continental at a garage sale. We think it's a 1975, but we aren't sure. Anyway, I'd like to get a totally different rear (and possibly front) derailleur for it because no matter what we do, it doesn't like to switch into all of the gears. We read that the original derailleurs on the bike don't really work well with it, so we were looking at maybe a Suntour or Shimano, but we have no idea were to start or anything. Could some one give us some information that could help? Thanks in advance.... Read more >>
Hi all, I'm a bit new to the maintenance of a bike so would really appreciate any help. I have a road bike that needs a new rear derailleur fitted.
My current rear derailleur just says shimano on it but my gears are shimano sora triple deck. I've looked online for a replacement shimano sora derailleur which are all 9 speed but mine is an 8 speed. Will this cause a problem?
Also, I've seen that you need to know the total tooth capacity. Can you just confirm how you work this out?
Thanks for any help!... Read more >>
So today I ordered some new wheels for my 700c conversion. The wheels come with a 7 speed freewheel which is just what I need. However, my current cassette is 13/23 and the new one is 14/28. What adjustments will I need to make to the rear derailleur so that it will shift smoothly and accurately on the new cassette.
Jamin... Read more >>
I've encountered a very strange problem I've never had before. I have a Fischer mountain bike with shimano acera 8 gear derailer. About a week ago it suddenly developed a very strange problem, the derailer only travels part of the distance it should to give me the full gear range. Now I only get it to go to gear sprocket 2 at the low end through to sprocket 5 or 6 towards the high end.
I've tried making various forms of adjustment to the derailer, but this has only very limited effect. Has anyone here had this problem, and any ideas about how to fix it and how it... Read more >>
I'm a bike tech at dicks sporting goods in Bloomfield, MI and I'm having trouble with replacing the cables on an old 10 speed freestyle. I've only been working at this job for about 3 months now, so I don't have a ton of experience working on bikes yet, and I can't tell how to get the cable out of the shifter.
It looks like the cable should just be able to pop out of the end of the shifter (I have already removed the housing), but I can't get it to budge. Is there something else I need to do first before I can take the cable out, or is it just that this particular one is likely j... Read more >>
We just bought a hyper havoc within the last 2 months and have only ridden it a handful of times. My issue is the other night as we were riding along the chain snapped off. Looked like it broke? We just started riding again recently so we're not familiar with these new bikes at all. Do I need to buy a new chain or can this one be fixed? I snapped it back together but I just don't know if it'll last or what. Lol I apologize for my ignorance about anything mechanical lol.... Read more >>
On the weekend I crashed and managed to destroy one of my shifters. I've got an old Cannondale 105 with 105 components - double and 9 speed. I'm wondering if any other Shimano double/9 speed shifters would be compatable or do I need to try and find an old set of the 105 ST-5510?
Thanks!... Read more >>
So I took my bike out for a ride and neither of the gears seem to shift, pressing the shift bottom (sorry dont know the name for it) next to the brakes doesnt do anything, no clicks or sounds, nothing happens.
I have no clue whats wrong with it so please help me, I'll upload more pictures if needed and do any tests
here are some pictures
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At age 43 I recently have taken up cycling, it's been about 20 years. I had found a 1982 Free Spirit 10 speed, Sears brand by Murray I think, at a junk store. $15 and everything seemed to work, couldn't pass it up. I put new tires on it and was riding, wheels fairly true, all 10 gears, no squaking or squealing, decent stopping. Then the other day, the left lever snapped off. No surprise being 32 year old plastic, I remember new bikes doing that in my younger days. So my question is, what's a good source to order this part from? I'd want to go metal and replace the whole assembly, I'm gues... Read more >>
I have a Trek 7000 (93/94) still with tons of original parts on her.
A few weeks ago, the rear shifter broke, not shifting to the lighter gears, but was still shifting to the heavier ones.
When I opened it, I saw that a little spring inside it was broke.
Just like the one seen here:
I can't find this spring anywh... Read more >>