vol

I have a few dumb questions (as always ) re derailleurs.

On my bike (Raleigh detour), the front derailleur cable tension barrel adjuster is on the left handlebar; the rear one is on the rear derailleur. There is no barrel adjuster on the right handlebar. (Are these standard set up?)

While trying to adjuster my derailleurs, it seems to me that the front and rear barrel adjusters are turned in opposite directions for the same purpose; i.e. to increase the front derailleur cable tension, I need to turn the barrel adjuster on the left handlebar counter clockwise; whereas to (also) increase the rear derailleur cable tension, I need to turn the barrel adjuster on the rear derailleur clockwise. Is this normally the case?

When properly adjusted, should both the front and the rear derailleurs' cables feel about the same tension (by hand, on the downtube)?

I seem to always have trouble remembering which way to turn the limit screws and barrel adjusters for a given goal (clockwise or counter clockwise). All the tutorials only tell you which way to turn, but don't explain why or give a thumb rule. Is there an easy way to remember them once for all?

Thanks in advance.

P.S. My derailleur is Shimano SL-RS35 Revo 7spd.

FBinNY 

OK, usually the levers are mirrors of each other, so the FD adjuster is on the left, and there's one on the right for the RD. The RD also usually has an adjuster built in, so it ends up having adjusters.

All trim adjusters work the same way, and I hate calling them tension adjusters, because they don't really change tension. What they do is change the effective length of the housing, so if you turn them outward from the body, the housing is longer, which effectively makes the cable shorter (tighter).

The perceived cable tension isn't affected by the trim adjuster, it's related to the tension in the derailleur's return spring, and you can't change it.

I hope this helps. You might also dig up some tutorials of derailleur adjusting.

vol

Thanks. I did read/watch several derailleur tutorials on the Internet, but didn't find answers to my specific question. When you say "outward", what do you mean? It's vague. Do you mean clockwise? (and again my right handlebar does not have barrel adjuster. In its place is a dead integral part (not even ribbed---see attached picture). Is it in fact a defective part??? (I've bought the bike new for 3 years now!)

Any answer re my specific questions in 3rd paragraph above? (front: counter clockwise, rear: clockwise: both to increase tension?)

The rear derailleur shift seems to be the same as this one. As you see, it has no movable barrel adjuster.

FBinNY 

In a simple adjuster the entire barrel turns, so like any right hand screw, turning counter clockwise backs it out from the body, lengthening the housing (shortening the inner wire - remember longer housing = shorter inner wire so we don't have to repeat).

However some adjusters, particularly Shimino, are trickier. The barrel itself doesn't turn, the nut surrounding it turns and acts like a screw jack lifting the barrel out. In this design, turning the outer barrel clockwise lengthens the housing.

So don't think clockwise or counter clockwise, think in or out from the lever body or derailleur, or in other words, longer or shorter housing.

vol

In that case, the front barrel adjuster works that way, but the rear one works the opposite way (counter clockwise=loosen the cable=shorter housing=longer inner wire). Is there anyone who has the same Shimano SL-RS35 Revo 7spd and can confirm this, please?

FBinNY 

I can't confirm, but your eyes can. Watch the effect of your action.

If you're still not sure, hold your thumbnail against the housing near the adjuster, and turn the adjuster, counting turns, until you can tell if it's moving toward or away from the lever (or derailleur) body. Then turn back to where it started, and begin adjusting by degrees.

Or you may decide which way you wan t to trim the derailleur, try the adjuster in one direction. If it improves you're going the right way, if it worsens reverse course.

curly666

Your rear adjuster is on the other end of the cable right where it goes into the rear derailler if that helps you any.

vol

I know where it is. I just confirmed with FBinNY's method that indeed, for the rear barrel adjuster, clockwise=increasing tension (shorten inner wire), which is different than how the front barrel adjuster works. My front and rear cables don't feel the same tension, though, the rear being tighter, after they seem to both work for shifting right. Is this ok? How tight should it feel by hand at the down tube area, if there's a way to describe? (e.g. if I press the cable at the down tube area, should it be able to touch the down tube, or so tight that it can't touch down tube--think about a string on a musical instrument?)

Bill Kapaun

Who cares how tight they "feel" if they shift properly?
You are obsessing about something so minor..........

cny-bikeman

Again, derailleur trim adjustment is not the same as tension, as FB indicated. All that's important is that the effective cable/housing length be correct for the derailleur to shift properly. How tight the cable feels at any one point is a combination of the particular derailleur spring tension (which varies according to what gear it's in, and cable/housing friction between the derailleur and that point(comprised of factors like housing length, how tight the bends are, whether or not the cable is die-drawn, lubrication, etc.). If your cable moves freely and the trim is adjusted correctly don't worry about "tension."

As for cable adjusters, both the adjuster at the lever and at the derailleur tighten the adjustment by moving counter-clockwise in relation to (or looking toward the stop. That is, if you are looking toward the place where the adjuster screws in you will always turn clockwise to lengthen the length of that portion of housing.

FBinNY 

STOP feeling tension. It's determined by the springs that the manufacturer put into the derailleurs. You can't change it, and it doesn't matter anyway as long as it's enough to pull the cable back when you shift to smaller sprockets.

You're adjusting cable LENGTH, to set the position of the derailluer relative to the click position in the lever.

In my first post I said I hated it when people refer to adjusting cable tension. It leads to exactly the kind of confusion you're feeling.

vol

My front (lever) adjuster works the green way, rear adjuster works the blue way.

My problem with the rear derailleur now is, it's very hard, sometimes impossible, shift from 5 to 6, but all other shifts are fine (upward or downward, 6 to 5 also ok). Is this the the cable adjustment problem? The cable is already quite tight/short, I'm afraid shortening more will risk breaking it some day---maybe a dumb worry?

P.S. Just saw your post, FBinNY. Sorry, I said "tension" because that's the word the tutorials use (such as this one).

FBinNY 

You don't say how many speeds your RD/cassette have. In any case ALL shifts except the outermost ones are he same. They're controlled soley by the trim adjuster, and when one is trimmed, all of them are. The innermost and outermost sprockets are also affected by the limit screws.

On the outermost, the cable is slack and the limit screw determines the position by itself. The innermost is controlled mainly by the trim adjuster (like the others), but an overly restrictive limit screw can hinder shifting.

BTW- you live in NYC now (don't you?). If so there are a number of good basic repair courses available. Drop in at Bicycle Habitat sometime and ask when their next one is, they do a decent job.

vol

There are 7 speeds on the rear, 3 in the front. So it's not the outmost gear.
Yes, NYC .

Edit:

Just a note: I found a past thread on the same topic.

I shortened the rear cable a bit and it seems to help shifting from 5 to 6.

The only conclusion I can draw is that my front (lever) and rear adjusters work differently as far as the screwing direction is concerned because, maybe, they are meant to be "mirroring" each other, to borrow FBinNY's word for a different occasion.

Many thanks for all the replies, especially FBinNY and cny-bikeman.