Need to move front derailleur down by the most inconvenient amount
#1
S*v* J*sus
Thread Starter
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.
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.
#2
LR÷P=HR
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Throw the dog a bone !!!!!!
what is the bike?
Exactly how much lower do you need to go?
Barry
what is the bike?
Exactly how much lower do you need to go?
Barry
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#3
SE Wis
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#4
S*v* J*sus
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#5
Thread derailleur
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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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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.
#7
S*v* J*sus
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#8
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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 ?
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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Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
#9
S*v* J*sus
Thread Starter
It's a 44 / 28 crankset. Ultegra is not used to chainrings this small.
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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
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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Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
#11
Senior Member
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 ?
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 ?
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.
Last edited by Hondo6; 08-03-22 at 12:39 PM.
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#12
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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...