rhm

These are 8-speed "brifters" from the early 1990s. I am using the matching crank (1055) with 42-52 biopace rings, and the matching 1055 front derailleur.

Stainless steel inner cable, Jagwire LEX housing.

The problem is: the shifter doesn't pull enough cable. I have the derailleur lower limit screw set loose enough that when I release the shifter all the way, it's cable tension rather than the limit screw that keeps the chain from hitting the cage. Even so, I can only just barely shift into the big chain ring, and the shifter will not pull enough cable to get the cage to stop rubbing in the big ring.

As close as I can measure it, I'm now pulling the cable about 9 mm, and I need 4 or 5 mm more.

My only guess is: the shifter isn't releasing the cable all the way. I've tried squirting WD40 in there to free it up, but it hasn't done anything yet. I suspect I'm not getting it where it's needed. Where exactly am I supposed to spray it?

All trouble shooting suggestions are welcomed.

dddd

I've never seen the case where the spool released cable but not enough cable.

A set of BioPace rings sounds like earlier stuff, likely from the 6-speed era. Spacing might be significantly wider, and these rings usually lack the sort of shifting-assisting features that proper front indexing somewhat rely on to effect a proper shift.

I somewhat suspect that the hi-limit range of motion might be where the problem lies, not because of the limit screw but possibly the shifter not engaging the top-gear position but rather the close-by "trim" position. If this is the case though, one should still be able to achieve the shift to the large ring with a full swing of the lever, though with the derailer then just not holding the full reach indexed position.

Is the height of the front derailer cage within a 1-3mm gap above the tips of the large ring's teeth? I often find front derailers set much higher, making shifting less likely to occur.

I don't think it is possible for the exact routing of the cable pinch/binder attachment to lower the actuation ratio of this front derailer, but if the cable is pinched to the wrong side of the bolt or if it is not routed around any guiding nub, then the derailer would move too far, such that the shifter might not be able to quite reach it's top-gear detent because of the cable going full tight.

You didn't mention what chain you are using, but a modern chain is crucial to the proper functioning of Shimano's Dual-SIS derailers.

3speedslow

Quick guess, the spindle for the BB might be too long?

From the hip...

RobbieTunes

This often happens with the R shifter, but can happen just as often, and just as easily, with the L shifter.
It's only two things: the shifter, or the FD. I'm going to assume your cable path is clean and free of things that bung it up.

OK, here we go:

1-The FD, mainly because the FD is the simplest, and I've seen it before.
-Take the chain off the bike.
-Disconnect the cable.
-Back out both parameter screws to where they are not a factor.
-By hand, move it in/out and eyeball the inner and outer limits.
-By eye, set the cage with the parameter screws.
-By hand, move it in/out, see if the range is reduced a bit, or a lot. If it's a lot, you have to back them out a small amount.

This by no means indicates the FD is bad, but you've now got that out of the way. If, for some reason, you are not getting the range of movement you need, back off one of the parameter screws, generally the outside. This model of RD could easily "jam" up where it was hitting both parameter screws far short of it's potential range. I've seen it happen, on that model FD, over and over. I discovered the issue when I took it off and tried moving it by hand, off the bike. I solved it by backing the screws out, seeing the full range of movement, and then slowly advancing each one until I noticed the range of movement was unnaturally small. There seems to be a point at which they may "overlap," if that is possible. The limit screws, inside the FD, hit the curved plates on the cage pivot. Definitely happens. If this is the fix, fine, lube it up and go. You may elect to do this with the FD off the bike, but while it's easier to see the problem occurring, it's a real pain to move the cage in and out.

2-Assume the FD is now right with the world, let's move to the L shifter.
-Generally, the only time the shifter doesn't pull enough cable, is when the cable was inserted after the lever had been inadvertently moved off of the "zero" position. It happens all the time. You can still insert the cable, but it's never going to "zero out." The real issue with this is that it often makes getting the cable out a challenge. It can get pretty bad, but if it's pulling cable at all, at least the cable was not inserted at the "end" of the lever travel. The only way to fix this is to remove the cable, zero down that lever to where it can release no more cable, and insert the cable. When it is zeroed out, inserting the cable is quite easy and a direct insertion, visually, on a horizontal plane. You should be able to see the cable stop plate, and inserting the cable should run it right out the exit flange on the shifter body. I continue, while I'm running cable, to check that the lever is zeroed down. I do this over and over until I've got the cable cinched down at the FD. Call me crazy, but it's a lot of work to re-do it. At least it's not the new 5700/5800 setup, where you've pretty much got to unwrap the bar unless you are lucky and the cable end is not compromised in any way.

I'd bet a dollar it's one or the other, and a dollar on top of that it's the FD. Why? Because I know rhm is an excellent mechanic, and this sort of thing happens to excellent mechanics. They generally know what they are doing and this is not a skill failure, it's a characteristic of that FD (and the following 105 FD's, I do not know why). This issue was brought to me, to fix, by two local riders, one on 8-sp 105 and one on 10-sp 105. Both had been to other mechanics, real mechanics, far exceeding my skills, who simply went by the book and couldn't figure out the issue. I also saw it on a 9-sp Ultegra FD.

And generally, 9mm of cable pull will be more than enough. Really, that's a lot. You should have no problem setting the parameters so wide that the chain is clear when on the small front/large rear, and still be able to throw it past the big ring. Really, even if I overuse that word.

This may be rambling, and hard to follow, but I'll proof it after I've posted it. I can't wait to get up there for the twin ride....

PaintItCeleste

+1. Definitely check your angle of your front derailleur and the spacing between it and the large chain ring. I have had the same feeling before, where it seemed like my (in my case, 5500 105 stuff) wasn't pulling enough. Once I "reset" everything (zeroed out barrel adjusters, properly angled the FD and set height to 1-3mm above the large chainring, and re-attached the shift cable to the FD), I was able to dial everything back in and everything worked swimmingly.

Any pics?

Slash5

Just checked a set I've got here and show approx. 8.4 mm cable pull.

wrk101

Setting up front STI can be a royal PITA. I have found no matter what I do, some FDs just don't seem to cooperate. Everything has to be perfect: derailleur height, angle, cable tension, limits, you name it. And yes, you have to have the right BB for your crankset too. No margin for error.

The most aggravated I ever got was on a pair of Cannondales. One had Shimano 105 8 speed components, one had RX100. I started with the 105 bike. Tried every single 105 FD I had, swapped one out after another, finally got an RX100 unit to work. Then I went to work on the RX100 bike. Tried every single RX100 FD I had, none of them worked. I finally tried the 105 FD I had REMOVED from the other bike, it worked flawlessly.

It seems like the Shimano fronts move the bare minimum amount of cable. Tension has to be perfect. So does everything else.

Meanwhile, rear derailleur set up is a snap. Setting up a front triple is even worse.

rhm

Thanks for the ideas!

To answer some questions:
@dddd, you may be right about the BioPace rings. I believe they came on this crank, but indeed the big ring does not have the pins that help the chain climb. The spacing may be an issue. But also, I like BioPace, so maybe that's my problem.

Your suggestion about the shifter not engaging its highest setting, that's what I've been thinking. As I keep moving out through all the gears, I think it's moving a little better now... just a little.

The height of the derailleur is a little under 3 mm, and I've been trying different angles, rotating it a little around the seat tube, looking for the sweet spot.

The chain, yeah, good question. Definitely something sold as an 8 speed chain, but beyond that I don't remember.
@3speedslow, the spindle may not be right, but the derailleur can move it over the whole range, so I don't think the spindle is the problem.
@RobbieTunes,
The derailleur moves okay. But I take your point. I will try this later.
While I was messing with the derailleur and shifter and shifting through all the gears on the stand, the cut end of the cable hit the spinning tire and got the end badly frayed. I hadn't put a cap on the cable end yet, and now I can't. So now I have to find a new cable before I remove this one.
@PaintItCeleste,
No, lighting here is not good enough for photos right now. But you know what this stuff looks like. Picture out on a white Ironman frame, and you've got it.

Honestly, I'm thinking I might put a down tube shifter on the left side, or maybe a bar end shifter. Friction is so much easier to deal with!

Slash5

Are you sure you have the cable anchor point as low as it can be? Could you run the cable up the wrong side of the bolt? That would increase the travel.

rhm

I have the cable on the right side (that is, the wrong side) of the bolt. The correct side appears to be the left. So this way should increase derailleur travel as much as possible. This helped a little....

noglider 

I had this problem a few months ago, and to be honest, I'm not sure how I solved it. I think you need to check once again the angle at which the cable enters the pinchy thing in the derailleur. It's probably too far from the fulcrum. I think I changed the derailleur, and I know I changed the spindle at least once, so it may be the spindle length.

STI systems are not as easy to build as some people claim.

TimmyT 

The outer part of the fd cage should be exactly parallel with the big ring when the cage is all the way out. For Biopace, aim for 2mm of clearance at the closest part of the big ring, so lower than a typical fd. The ramps-and-pins don't matter except that they make shifting faster and crisper. The set up you have should work fine.

You can unscrew the big ring limit screw as much as you want to get started. It will not matter. Ideally, you want the limit screw for the small ring fairly close to where it will be set but a little loose. With both of the screws in this position, you should be able to move the entire cage across both rings with no problems using your hands.

Click the brifter to its lowest position while tensioning the cable with your other hand (and needlenose pliers, if necessary). Re-lace the cable to the fd.

Make sure your cable is crossing the bottom bracket correctly as you loosen and tighten these. I think this frame has a bottom-routed cable. Make sure the cable is seated on the plastic guide properly.

If your housing is cut too small from the brifter to the downtube stop, you might have problems in the long term but probably not during initial set up.

This isn't the cable housing you got from me, is it? That was brake housing.

Edit: The "wrong side" should be over the top of the arm or as near to the top as possible.

rhm

Little by little the problem is going away. A few details:

No, @TimmyT, I'm using the brake cable for the brakes; matching derailleur cable for the derailleurs.
I cut extra pieces of housing and extracted the liberty and inserted that in the steel guides under the bottom bracket. I have the two derailleur cables crossing under the down tube, which I think gives a slightly more elegant cable line.

I also spent a fair amount of time bending the big chain ring to get it absolutely as straight as possible, which is a little tricky with a biopace ring.

clubman 

It could be bottom bracket related. I once had a BB shell that had never been faced on the drive side and kept the crank just out of reach. Check the shell to see if it measures up correctly.

On another occasion the shell was faced too much and the fixed cup needed a spacer under it. This was on an ergo double to boot. Bad mechanics!