Going crazy over FD R8000 setup
 

I wanted to upgrade from the FD 5800 to the new design (FD 5801, R7000, R8000, 9100) because I thought it would reduce the amount of force it takes to shift up.

I tried to install the (braze-on) FD and for the life of me can't get the derailleur to mount with the tail inwards or even parallel. It always turns outwards while I'm tightening the bolt. If I try to hold the derailleur with a reasonable amount of force while mounting it, the tail of the cage ends up about 2 or 3mm outwards despite my pushing the tail inwards. If I grab the chassis and muscle it (to the point where I'm afraid of breaking it) inwards while tightening the bolt it goes down to maybe 1mm. But I sure as hell can't get it to be tail inwards. All the videos I've watched make it seem like it should be pretty easy to align it tail inwards and then push it to parallel with the support bolt. I always start with the support bolt pulled out a bit. I also tried tightening the low limit screw to clear the derailleur away from the frame while I'm tilting it towards the frame.

I had the same issue with my 5800 derailleur except I was able to get it pretty much parallel (though without the help of the support bolt). With the R8000 I can't get it to that point. I tried ignoring the alignment hoping that it wouldn't matter too much but I end up with a case where either a) I can't shift into the big ring or b) there's a lot of rub between the inner plate of the FD cage and chain when in the high trim position while cross chaining big-big.

I reeeally hope I'm missing something because I've spent probably on the order of 30-40 hours over the last month or so trying to figure out my FD situation and the R8000 hasn't been the magical fix I hoped it'd be.

Side note: There's also a substantial difference between the FD position in the trim positions depending on how I enter the trim positions. If I go from high to high trim, the FD is maybe 2mm more outboard than if I go slowly from low trim to high trim. Similarly, if I enter the low trim position from the low position, I can "bump" the lever a bit and the FD will move outboard by 2 or 3mm without changing the index. Is that normal?

So, I read the question and I still have no idea about what bike frame you are dealing with. Maybe you should take this issue up with the framebuilder

Sorry, I thought it'd be in my bio. I have a 2017 Allez Sprint Comp. It's less than a year old and has never been crashed drive side.

Crashes would be almost irrelevant for a front derailleur problem. The fact that you had problems with the original FD sort of makes me suspect that the FD hanger is either defective or that it wasn't properly installed on the frame

So I take it you think installing a braze-on FD should be fairly straightforward? Is there no trick to getting the FD aligned properly? It seems odd that a mass produced bike would have such a glaring defect.

Can you post some pics?

Yes, If you have had trouble setting 2 different front derailleurs up on the same bike, there may be a problem with the frame or the derailleur hanger

Lemons happen. Only thing odd is you don't report shifting problems with your old setup.


New Shimano FD....do you have the bracing screw backed in--or is it all the way out?

R8000 is an odd duck. You have to set the cable tension before you set the limit screws. I would start by getting both limit screws turned roughly halfway through their travel, and then follow this video: You start by securing the cable with the cable tension adjustment screw turned all the way out and the shifter in the very lowest position. Then you shift into the big ring and do the half click to put it in the lower trim position on the upper ring. Then you use the cable tension adjustment screw to add cable tension until the lines on the side of the derailleur line up while the shifter is in the lower trim setting of the big ring shift position. Then you adjust your limits.


here are some better videos:

https://imgur.com/gallery/27GCj

Here's my attempt to get this thing installed tail inwards. You can see that I was beyond unsuccessful. The mount actually has a lot of range. I can install it about 20 degrees tail outward very easily.

Fair enough. I'm going to pull up on a 3rd party bike shop tomorrow and see what they say.

The support bolt was/is backed out all the way. And I definitely had shifting issues on the old FD 5800. I wouldn't drop $50 just to slightly reduce shift effort (which isn't even 100% achieved without the new levers, I believe). I would get some rub in the crossed configurations and less than reliable upshifts in addition to the sticky upshifts.

I've watched these 3 videos already and I'm stumped at how they're able to mount the derailleur with the tail in so easily.

A couple of clear pictures (from different perspectives) of the derailleur and it's mount would have been helpful.

From your pics it looks like you're trying to do this with the chain installed. It's much, much easier to get it positioned correctly with no chain in the way.

Any shots of the mounting area?

I didn't see it mentioned, but I'm assuming the shift cable was not connected when you were attaching the derailleur to the frame? On my 5801 FD, I had to hold the derailleur inwards when tightening the clamp bolt, but it sounds like that isn't working for you. Have you made sure there isn't any dirt or buildup where the derailleur attaches to the braze on plate?

I do feel your pain. I had a heck of a time setting up my FD, until I found out the shift cable was not cut very square, and was "shifting" where it went into a barrel adjuster. Once I replaced the housing everything was good. Well that, and completely missing the fact that the high/low adjustments are different for these newer FDs.

I went to a 3rd party shop today and the guy pretty confidently said that I was right - the derailleur mount is crooked. He was a pretty big guy and was able to muscle it just barely beyond parallel. But he said he's worked on other Allez Sprints before and they haven't had this issue. I went to the bike shop that sold me the bike and the mechanic there agreed that he wasn't able to install the FD with much of an inward angle. He said he would try to make "adjustments" to it tomorrow or day after. But he refused to tell me exactly what this entails (because I said I wasn't OK with grinding the mount or the derailleur, which he brought up). He also said if it truly is a defect then Specialized will replace it under warranty, which to me sounds like the only conceivable solution.

I'll post pics when I get the bike back, but something tells me I'm going to have a bad time between now and then.

TL;DR: There's no difference between the low and low trim positions and I was told that this is how it's supposed to be on older cranks with newer mechs because Shimano recently changed the chainring spacing. This gives me crap shifting. Is this normal?

Long version:
OK so I got the bike back from the shop today and I'm more confused now than I was before. My mechanic ended up bending the mount to compensate for "deformities from constantly trying to readjust" the FD. Seems like a very subtle bend, so I don't mind it much.

However, the bike still shifts pretty much *identically* to how it was when I bought it. His explanation was that Shimano changed their chainring spacing with the 5800/6800/9000 generation (and kept this spacing for R7000, R8000, 9100) BUT the Praxis Alba crank on my bike is spaced for the older generations. Shimano apparently explicitly told him that techinically these newer derailleurs are compatible with older cranks, but they sacrifice the low position (also newer cranks are incompatible with older FDs). Clicking down in the low trim position just slackens the cable and barely moves the FD.

The mechanic was kind enough to show me another example of my bike (2017 Allez Sprint comp). He adjusted it and it shifted identically to how mine did back when I bought it and now. It had the same low trim issue.

He also showed me a 2018 which has a 5800 crank. When he gave it to me, it suffered from much of the same issues *BUT* I noticed that there was quite a bit of room between the chain and FD inner plate in the high trim cross chain position so I dialed in a bit more tension and that made the shifting pretty much perfect, though I didn't get to ride it or spend more than a few minutes with it. So this makes me this the mechanic is right.

Can anyone confirm that they've seen someone use an older crank with a newer FD and that this is normal? Because I'm just about ready to go 1x.

My bad. I tried a bit harder this time but I'm not sure exactly what shots would be helpful here.
https://imgur.com/a/4hnjb

I can't see how the chain would hurt when it's on the little ring because I was struggling to get the derailleur far in enough, not out. Please see above.

The shift cable was not connected, yes. Holding did not help. There wasn't any dirt or buildup but the anodization was heavily worn from many failed adjustments.

It appears from your pick, the support bolt is set too deep. This may be preventing the derailleur from rotating into proper position.

See page 9 of the linked Shimano manual;
Front derailleur - Shimano

You've either got derailleur mount where something is bent or the hanger by my thinking.

"Side note: There's also a substantial difference between the FD position in the trim positions depending on how I enter the trim positions. If I go from high to high trim, the FD is maybe 2mm more outboard than if I go slowly from low trim to high trim. Similarly, if I enter the low trim position from the low position, I can "bump" the lever a bit and the FD will move outboard by 2 or 3mm without changing the index. Is that normal?"

To me this sounds like there is some sticktion or slack in the cables. I have had trouble with my FD on account of excessive friction between the cable and the BB cable guide and less than stellar cable routing. Reading throught your posts, its a bit opaque what exactly the problem is outside of the FD tail sticking out a bit. Now that is sorted, what trouble remain?

Sorry I forgot to mention - those are pics of the bike AFTER the mechanic set it up how he considers "perfectly".

The mechanic bent the FD hanger and claims that now the derailleur is aligned fine. As far as I can tell the FD is attached perfectly parallel to the chainring.

The cables are brand new - I had the mechanic replace them while fixing/adjust the new FD. The problem is this: I don't have a low trim position. I can't use the small ring with the smallest 3 gears without the chain rubbing the FD. I also can't use the big ring with the biggest 3 gears without the chain rubbing the FD (even in the high trim position). This leaves me with a very limited number of gears. The mechanic tells me the Praxis Alba crank is to blame here and it doesn't have the same spacing as newer Shimano groups. Can anyone confirm that this is indeed true? Would replacing the crank with R8000 or R7000 fix my issue?

In the last pic
https://i.imgur.com/1buBiQc.jpg
Are you saying the cable is completely slack and still rubbing in small-F/big-R? Can you back out the lower limit screw and get more clearance? If there is tension in the first low position and then slack in the second position but no movement then your low limit screw is set incorrectly. You can even detach the cable completely to eliminate that variable

So the mechanic is telling you that the spacing between the two rings is different? If you take a measurement and post it, we can compare to the spacing on an Ultegra 11 speed crankset. I read that the new R8000 components are compatible with Ultegra 6800 and Dura Ace 9000, so it should be easy to get a reference measurement.

However, having set up several Shimano front derailleurs with the trim feature I can tell you that there is a lot of adjustment that can be made. If the way it's currently set up in your pics is the closest the derailleur can get to your top tube, then maybe it's more of a chainline issue. If you can add spacers to move your crank a mm or two on the drive side you might be good to go.

It shouldn't matter. The change in chain ring spacing in R9000/8000 from 6800 is 0.4mm. Which is pretty darn close to machining tolerance....nvm the tolerance with which the FD braze needed bent back to align right.


6800 vs. 8000 - Chainring Spacing - Weight Weenies

Sorry I should have made this clearer. He said 5800/6800/9000 also have a different spacing from the Praxis crank. I didn't realize 6800 and R8000 were different. I already said this but another bike with a Praxis crank had the same issue as my bike and the same bike with a 5800 crank was at the very least significantly better.

There is <1mm of clearance between the chain and the FD when in easy-easy in the lowest index. I was mainly trying to illustrate how little of a difference there is between the low trim and the low positions. There is almost none - just like when I had the FD 5800. The cable just tightens up in the low trim position.

Using a crappy technique of holding a ruler to my seat tube I measured maybe 37mm to the little ring and 46mm to the big ring... maybe. What is it supposed to be?

The reason I'm so confused is this: The low trim position currently puts the FD cage too inboard (rub in small x hardest 3 gears). There are two solutions to this: move the crank inboard (ie change the chainline) or turn up the tension. Both solutions push the inner plate of the FD closer to the chain when cross chaining big-big. I already have rub in big x easiest 3 gears. So neither of these solutions seem like they'd be better than what I currently have. It feels like there's supposed to be a bigger gap between the rings? Maybe? I didn't notice such a conundrum with the bike that had the 5800 crank.

Back off the support bolt, set the derailleur to the correct position, lock it down, and then snug the support bolt. If I am not mistaken, you mentioned he basically forced the derailleur into the position where it currently resides. If that was the case, the derailleur is likely bent and proper fit and operation is not likely to happen now.