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Need to move front derailleur down by the most inconvenient amount

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Need to move front derailleur down by the most inconvenient amount

Old 08-02-22, 08:06 AM
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Need to move front derailleur down by the most inconvenient amount

Hello folks,
I have a carbon fiber bike with one of those bolted on "braze on" derailleur mounts. The chainring is 44T and the derailleur is Shimano Ultegra R8000. Unfortunately, the derailleur needs to be moved downwards enough such that the mounting bolt runs through the metal at the end of the bracket's slot. Which means that I can't use one of those "offset the derailleur below the braze-on because that would now put it too low. In an ideal world, I could get get a different mounting bracket that's lower, but it was probably a proprietary part that comes with the frame. What are my other mounting options if I choose to stick with this derailleur? Also, yes I can make parts in the machine shop.
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Old 08-02-22, 08:40 AM
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Throw the dog a bone !!!!!!

what is the bike?
Exactly how much lower do you need to go?


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Old 08-02-22, 08:55 AM
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8.8mm lower

​​​​​​https://wickwerks.com/products/fit-link-adapter/
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Old 08-02-22, 10:02 AM
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Originally Posted by Barry2 View Post
Exactly how much lower do you need to go?

Barry
about 5mm
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Old 08-02-22, 10:05 AM
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You could try a triple. The lower end of their cage will get you the clearance, clarence.
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Old 08-02-22, 10:13 AM
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Can you remove the braze-on and install a clamp-on mount? Won't work if the seat tube is not round. As mentioned a photo, make/model of your bike would be helpful.
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Old 08-02-22, 10:17 AM
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Originally Posted by Crankycrank View Post
Can you remove the braze-on and install a clamp-on mount? Won't work if the seat tube is not round. As mentioned a photo, make/model of your bike would be helpful.
unfortunately, it's one of those fancy pants carbon fiber non-round and tapered tubes.
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Old 08-03-22, 08:39 AM
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not sure I understand the why there is an issue here, not saying there isn't but it does not make sense to me

ultegra r8000 routinely works with 50/34 cranks, so one would think it should work with a 44. and even if it is a older frame 52/42 was common, so again 44 should not be a problem

how old is the frame, what came on it originally for components ?
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Old 08-03-22, 11:29 AM
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It's a 44 / 28 crankset. Ultegra is not used to chainrings this small.
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Old 08-03-22, 12:27 PM
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Originally Posted by beanbag View Post
It's a 44 / 28 crankset. Ultegra is not used to chainrings this small.
got it, that clarifies, Pics might help

is there any room left on the "braze on" to get a small round file and file down the 5mm ? I have done that when putting a 50/34 5800 cranset on an older steel frame
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Old 08-03-22, 12:36 PM
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Originally Posted by squirtdad View Post
not sure I understand the why there is an issue here, not saying there isn't but it does not make sense to me

ultegra r8000 routinely works with 50/34 cranks, so one would think it should work with a 44. and even if it is a older frame 52/42 was common, so again 44 should not be a problem

how old is the frame, what came on it originally for components ?
Shimano says that 46T is the min allowable large chainring for the FD-R8000. See specifications section at

https://bike.shimano.com/en-EU/produ...D-R8000-F.html

Shimano RD's seem to be rated pretty conservatively re: min/max cog specifications, but I'm not sure how true that is of their current FDs.


Edited to add: apparently you posted your follow-up comment while I was drafting the above.

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Old 08-03-22, 12:51 PM
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Road FDs tend to be pretty tolerant of smaller-than-spec chainrings, but the frame sounds tough to work around. If you could be content with a 46T big ring (and possibly a 30T small to go with it), that might be the path of least resistance...
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