Shimano 105/ FD-R7000 Fr. Derailleur Tuning Conundrum!

johnkopp6

*This is NOT a problem related to cross-chaining.

I'm a junior tech at a small LBS in the Midwest and none of my experienced peers have been able to help me resolve an issue on my bike.

After tuning and re-tuning my "new-style" Shimano R7000 front derailleur, I cannot get it to operate without rubbing in the reasonable extremes of BIG ring/ SMALL cog or SMALL ring/BIG cog. Adjusting the H/L adjustment bolts to move the derailleur inboard for the SMALL ring position or outboard for the BIG ring position makes the problem worse for the other chain ring. To say it another way, adjusting the H adjustment bolt outboard so that there's less rubbing in BIG ring/ SMALL cog actually prevents the derailleur from resting all the way inboard when in the SMALL ring/ BIG cog; no matter how I then try to adjust the L bolt, the derailleur won't move inboard because the H bolt is actually preventing it from moving. Again, I'm not talking about cross-chaining; I'm talking about using the chainrings in combination with the correct cogs. So at best, I get to the SMALL ring/ 2nd BIG cog and BIG ring/ 3rd SMALL cog before rubbing starts.

I've meticulously followed the Shimano DM-RAFD001-05 Dealer's Manual, including the specifics of the cable adjustment "barrel," H/L adjustment bolts, and specific trim positions for each step.

Do I have an unreasonable expectation that both extreme ends of the drivetrain (BIG ring/ SMALL cog or SMALL ring/BIG cog) won't be accessible without rubbing on the derailleur guide inner and outer plates? In my mind, I should be able to have a straight chain-line and no noise at the extremes of BIG ring/ SMALL cog or SMALL ring/BIG cog. Why have an 11-speed drivetrain if you can only access ~7-8 of the cogs without noise in either chainring???

Thanks for any help or ideas!

chris_bass

i think i followed that

if things are rubbing don't you undo the adjustment bolts, se i fail to see how that would then get in the way? If you loosen them all the way is there still rubbing if you move the mech by hand and spin the cranks?

can you upload any pics of how the bolts are stopping it moving?

johnkopp6

Thanks!

chris_bass said:

i think i followed that

if things are rubbing don't you undo the adjustment bolts, se i fail to see how that would then get in the way? If you loosen them all the way is there still rubbing if you move the mech by hand and spin the cranks?

can you upload any pics of how the bolts are stopping it moving?

I don't think I can actually photograph that part of the issue, but maybe I can paint a better picture of what's happening. The chain rubs on the BIG ring/ smallest 3 cogs, so I tighten the H adjustment bolt to move the derailleur outboard. The rubbing is less, now only on the smallest 2 cogs. I could tighten the H bolt further, moving the derailleur outboard so far that there is no more rubbing on the smallest cog/ BIG ring.

BUT... now when I shift into SMALL ring/ BIG cog, I get rubbing on the largest cog. I try turning the L adjustment bolt CCW to move the derailleur inboard, but it cannot move because the H bolt is tightened so much that it holds the derailleur in that position. I loosen the H bolt and watch miraculously as the derailleur moves inboard off the chain. The rubbing stops. I shift back to the BIG ring/ SMALL cogs and have rubbing again in the smallest 3 cogs! Am I completely missing something and fighting myself?

The new-fangled "barrel" adjusting bolt is trimmed perfectly (the lines are 100% aligned in the upper trim position, as described in the manual). Throughout all of this, I've un-done and re-tightened the cable and done the whole setup process several times (thinking perhaps, that the derailleur was physically unable to move far enough inboard or something). But with the cable un-done, the mech moves more than enough in/outboard so that there shouldn't be any rubbing on the H/L extremes.

david7m

Did it work with previous FD, or it a new build? Have you tried another FD?

johnkopp6

david7m said:

Did it work with previous FD, or it a new build? Have you tried another FD?

It's a brand new, stock bike (Trek Checkpoint ALR 5), assembled by me at the shop. I'm out of town in a big city visiting my family right now and even thought about going to their LBS and test-riding the same bike to see if they were able to set it up any better.

What I think it comes down to mechanically, is cable tension: it's almost like I need a little MORE tension to get the derailleur to move farther outboard on the BIG ring so that I don't have to compensate so much with the H adjustment bolt. But maybe I'm understanding the H bolt's function incorrectly?

chris_bass

is there any chance you have the H and L screws mixed up?

as you loosen the L screw it should move towards the bike and as you loosen the H screw it should allow the mech to move further away from the bike.

johnkopp6

chris_bass said:

is there any chance you have the H and L screws mixed up?

as you loosen the L screw it should move towards the bike and as you loosen the H screw it should allow the mech to move further away from the bike.

Nope, I've got 'em straight, but it's good to double check From my experience on the bike and what's shown in the dealer manual, tightening moves the derailleur outboard for both the H and L bolts and loosening moves it inboard for both H/L bolts.

When you first route and secure the cable, the brifter should be in the lowest position, correct? That's one detail not listed in the manual, but obviously makes a big difference. It would make sense for it to be like this since with the lowest cable tension, the mech rests inboard.

Thanks for the help!

figbat

Only one of the limit adjusters should have any effect at a given time and neither should impact the effect of the other. For example I don’t understand this:

johnkopp6 said:

I try turning the L adjustment bolt CCW to move the derailleur inboard, but it cannot move because the H bolt is tightened so much that it holds the derailleur in that position.

Are you trying to use one bolt to move the FD inboard and the other to move it outboard? If so, that’s not how it works. You use one bolt for the little ring and the other for the big ring. There’s no situation where both should be up acting on the derailleur at the same time.

david7m

Have you tried setting H and L without cable attached?

photonic69

As I see it, it is the function of the H and L screws to limit the range of motion of the derailleur as that is why they are called Limit Screws. It is a function of the tension in the cable and the shifter to provide the correct range of motion for the derailleur.

Tightening the H screw is only going to prevent the cage from moving further out. Tightening the L screw is only going to prevent the cage from going further in. You need to have correct cable tension to get the cage to the right place in the first instance.

I suggest that your cable runs are not optimum and/or your cable ends are not seated firmly/cut squarely. Pay particular attention to pages 17/18 of the Dealer Manual to get the slack out of the cable and to seat the outers properly before attempting any adjustments.

I've got 105 R7000 FD on my winter bike and can pretty much get all 11 cogs on the back without rub. Maybe the 11 rubs a bit but then I don't cross chain much.

Good luck.

chris_bass

johnkopp6 said:

chris_bass said:

is there any chance you have the H and L screws mixed up?

as you loosen the L screw it should move towards the bike and as you loosen the H screw it should allow the mech to move further away from the bike.

Nope, I've got 'em straight, but it's good to double check From my experience on the bike and what's shown in the dealer manual, tightening moves the derailleur outboard for both the H and L bolts and loosening moves it inboard for both H/L bolts.

this is not the case.

tightening the L screw means the mech can't move as far towards the bike, tightening the H screw means the mech can't move as far away from the bike. they don't act in the same way. if you think about what the screws are doing the H screw is there to stop the mech going too far out so the chain doesn't fall off the outside of the chainring - so tightening it stops it going as far out.

as others have said one should never affect the other.

you seem to have set it so that the screws are both done up to tightly so the mech can't move at all.

if i was you i'd loosen both screws off as far as possible. not attach the cable set the L screw by gradually tightening it, move the mech by hand and tighten the h screw then sort thew cable tension out.

johnkopp6

I really appreciate all the ideas... and after a few more tries setting it up from the start, it's started working normally without noise. That H adjustment bolt is still a mysterious beast (it's not like any other H bolt I've ever worked on... it moves the derailleur without the cable attached and when you're in the small chainring), but I must have done something differently this time.

chris_bass

what did you do differently that sorted it?

johnkopp6

I have no idea! It could be something as stupid as more fully engaging the shifter when shifting from the small to large chainring and getting into the actual high position instead of just high-trim, but I thought I was getting both those detents before. At any rate, nothing seemed different or felt different in the last successful attempt, it just worked. I guess the bike gods were smiling on me.

mr_evil

Can you see how the screws work, mechanically? On older Shimano front mechs, you could see two little nubs that rotated as the mech moved, coming into contact with one limit screw at each of the two extremes of travel. I couldn't find any good photos of the internals of the newer ones to see for myself.

david7m

Congrats on sorting it, but it would bug me not knowing how

The Rookie

johnkopp6 said:

chris_bass said:

is there any chance you have the H and L screws mixed up?

as you loosen the L screw it should move towards the bike and as you loosen the H screw it should allow the mech to move further away from the bike.

Nope, I've got 'em straight, but it's good to double check From my experience on the bike and what's shown in the dealer manual, tightening moves the derailleur outboard for both the H and L bolts and loosening moves it inboard for both H/L bolts.

Indeed, it seems the latest mechs the high stop worsk 'back to front' compared to the older ones, page 1 lists only the latest mechs, page 20 that you screw in the H stop to allow it to move out further.
https://si.shimano.com/pdfs/dm/DM-RAFD001-05-ENG.pdf

tsarouxaz

what brand is the crankset?

thecycleclinic

It's mostly assumptions that cause problems.