Derailer for a 42T outer chainring
05-28-18, 10:02 AM
#1
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Derailer for a 42T outer chainring
I have downsized the chainrings on road bike from 48-38-24 to 42-37-24. The 1990-era Deore XT front derailer still shifts, but I can't lower the derailer on the seat tube to the proper height of ~2mm above the outer ring because the tail of the derailer hits the chain stay. So I'm looking for a derailer with a shorter cage, radiused for a smaller large chainring.
I have two candidates for a new derailer. Both are spec'd for a large chainring of 42T and a total capacity of 18T, just right for my range. The first is a Deore FD-M611-B, and the other is the discontinued Deore XT FD-M781. Both are dual-pull, top-banded, seemingly identical. Do you have any thoughts on one or the other? Or is there another option to consider?
The rest of the drivetrain is Shimano Dura Ace bar-end shifters (friction on the front shifter), a 9-speed 13-28 HG cassette, a SRAM 9sp chain, with an Ultegra rear derailer that is less than 10 years old. It shifts really well, and gives me closely-spaced gears in my favorite range.
Thanks!
BC
Radiused
I have two candidates for a new derailer. Both are spec'd for a large chainring of 42T and a total capacity of 18T, just right for my range. The first is a Deore FD-M611-B, and the other is the discontinued Deore XT FD-M781. Both are dual-pull, top-banded, seemingly identical. Do you have any thoughts on one or the other? Or is there another option to consider?
The rest of the drivetrain is Shimano Dura Ace bar-end shifters (friction on the front shifter), a 9-speed 13-28 HG cassette, a SRAM 9sp chain, with an Ultegra rear derailer that is less than 10 years old. It shifts really well, and gives me closely-spaced gears in my favorite range.
Thanks!
BC
Radiused
05-28-18, 10:18 AM
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I have downsized the chainrings on road bike from 48-38-24 to 42-37-24. The 1990-era Deore XT front derailer still shifts, but I can't lower the derailer on the seat tube to the proper height of ~2mm above the outer ring because the tail of the derailer hits the chain stay.
f it shifts OK what problem will a different derailleur with the "proper" 2mm spacing solve?
05-28-18, 10:50 AM
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Of course, you are right. I hope a derailer designed for a smaller ring will shift sooner/better. Also, the current derailer sits about 5/8 inch above the ring, and it just looks bad.
05-28-18, 11:53 AM
#6
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you fake it ,, friction shifting makes it possible ,
the arc wont match but it can function.
the arc wont match but it can function.
