showlow

The mil bolt to adjust my r8000 FD, the one that is supposed to push against the frame, doesn't push against anything. It seems like this just adjusts the left/right angle of the cage? Can't I just do that by loosening the clamp on the frame to get it lined up?

WizardOfBoz

If I'm not mistaken, that screw is to brace the whole assembly to make the mechanical coupling from the FD to the seat tube stiffer.

showlow

So, the 25 page manual for this FD seems to suggest it's mandatory to use this "support bolt", but doesn't really explain what it does beyond moving the back of the cage outboard. The problem is probably this "problem solvers" brand band that I'm using. It seems to move the derailleur further back than it normally would be.

Andrew R Stewart 

The R8000 is offered in a clamp on version that does not use the support bolt (because of the stiffer clamping design) and will also locate the cage exactly as Shimano intended (as no third party adapter clamp is used). Andy

showlow

Seems like an expensive solution but maybe the best one. I see here that the 31.8 size comes with the 28.6 adaptor I need.

dr_lha

Maybe rotate your braze on adapter a bit counter-clockwise, so the screw can be closer to the frame. I have this setup on my steel road bike (OK with the 6800 FD, but it has the screw) and it works just fine.

dsaul

Shimano makes braze on adapters that are specifically designed for Di2 use. It has a flat for the mounting bolt to prevent any rotation, so the frame bolt is not necessary.

https://www.universalcycles.com/shop...97&category=71

dr_lha

Do these work for non-Di2 FDs?

Andrew R Stewart 

It's only more expensive if you didn't get the clamp on to begin with. This is one example why having an experienced person guide one through the many options of selection. The suggestion of the Shimano adaptor is a good one if you must use a braze on der when the frame calls for a clamp on. Andy

dsaul

Yes, they do. I prefer them, because the derailleur mounts securely to it and then acts just like a band clamp FD.

dr_lha

Nice.

I used the same clamp as the OP, and didn't have any problems with it. I wonder why that is? I need to go take a photo of my setup to see what the difference is.

WizardOfBoz

I got the clamp version for my '99 Lemond Zurich. IIRC, same thing: the support screw wasn't long enough to do anything. In fact, on my CF bike ('14 Domane) I don't recall the screw being long enough either, The Dura Ace FD on that bike also works without the backing screw. On CF frames, you're suppose to tighten the screw down on a provided plate (about 8mm square I think). But again, didn't need to.

squirtdad

Mine too.... instruction on my 5800 105 Front derailler (braze on and bike has braze on mount) were to adjust the derailler than put a supplied little metal piece on the frame and make the set screw touch the frame..... not to be used as and adjuster

I would have just gotten a banded derailler rather than use an adapter

Metaluna

Shimano also sells a braze-to-clamp-on adapter that has a built-in stop for the support bolt on it. I use one with an R8050 Di2 FD and it basically turns it into a clamp-on FD, unlike the Problem Solvers style adapter that tries to mimic a braze-on tab like the one the OP appears to have.

I'm not sure if the bolt is in the same place on the mechanical FDs though, so the Shimano adapter might not have the intended effect.

https://www.competitivecyclist.com/s...illeur-adapter

cpach

It isn't necessarily necessary, but in addition to adjusting the yaw of the derailleur it preloads the pivots and provides support to the derailleur on upshifts. It'll upshift better if you use it

showlow

I just bought the clamp on one. The braze on FD is going on eBay.

WizardOfBoz

A bit of a hassle, but the upside is that you get a nice clean installation, and the setup is as the Shimano engineers designed it. As I said, my r8000 works da bomb.

Good riding.

showlow

Definitely. Getting another clamp would feel a bit like a bodge, and I want this build to be dialed. Thanks for the reply.

showlow

I missed this reply somehow. Thanks. Ended up ordering the clamp on FD anyway.