RD suggestion??
#1
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RD suggestion??
I need a suggestion for a shiney RD for a 9 speed friction drive train. I gave a Suntour V-GTLUXE but it does quite reach. Someone on the 650b site suggested filing down the stop a bit.
So I am open to all suggestions.
Thanks!
So I am open to all suggestions.
Thanks!
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I am a fan of the Deore LX 581 which you can find on eBay in the $40 range more matte than shiny though
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Dura Ace 7703 long cage. Checks all the boxes.
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I'm confused: What's the problem with the V-GT Luxe? If you left out the "not" above, what reach are you referring to? Posting a pic would help a lot.
#6
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XTR M900 is a very nice RD. Not sure if it would qualify as shiny; that’s sort of subjective.
VeloBase.com - Component: Shimano RD-M900, XTR M900
VeloBase.com - Component: Shimano RD-M900, XTR M900
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I'm pretty sure he means it can't get to the biggest cog without modification because the parallelogram can't swing that much, hence the part about modifying the stop.
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Campy Euclid. Its the long cage version of the C Record.
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Yep, I have a similar issue with a couple of nearly identical Shimano long cage RDs -- Exage 500 CX and Deore LX. Same derailleur design, very minor mostly cosmetic differences, almost the same model number. Both are nominally 7-speed and will cover an 8-speed cassette with friction shifters, but not indexed. I've considered using a moto tool to modify the stop inside the body.
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Re-spacing the axle to better position the rear hubshell and freewheel can help a lot with any travel-limit problem in one direction or the other I've found.
Sometimes it is the particular chain and freewheel which makes the difference between shifting and non-shifting to that last position.
Stiffer old-fashioned chain may help greatly at the small end of the freewheel, while a modern Shimano chain seems to work best getting to the biggest cog reliably.
Beveling the outer face of every third tooth of the second-smallest cog can help greatly with hitting the shift to the smallest cog.
Derailers can be modified by relieving critical contact points inside of the parallelogram, using paper shim to chase down contact points needing to be ground down. This tends to be an iterative process on a derailer such as the Allvit.
Sometimes it is the particular chain and freewheel which makes the difference between shifting and non-shifting to that last position.
Stiffer old-fashioned chain may help greatly at the small end of the freewheel, while a modern Shimano chain seems to work best getting to the biggest cog reliably.
Beveling the outer face of every third tooth of the second-smallest cog can help greatly with hitting the shift to the smallest cog.
Derailers can be modified by relieving critical contact points inside of the parallelogram, using paper shim to chase down contact points needing to be ground down. This tends to be an iterative process on a derailer such as the Allvit.
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For friction shifters, you should be able to use any RD that has a range adequate for your cassette. I think Shimano 8 & 9 speed cassettes are about 36-37 mm - 10 mm wider than your SunTour was designed for.
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Yep, I have a similar issue with a couple of nearly identical Shimano long cage RDs -- Exage 500 CX and Deore LX. Same derailleur design, very minor mostly cosmetic differences, almost the same model number. Both are nominally 7-speed and will cover an 8-speed cassette with friction shifters, but not indexed. I've considered using a moto tool to modify the stop inside the body.
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Getting the derailer's travel centered with the freewheel/cassette seems to be the bigger issue in most cases, so that the limits are more or less reached at both ends of the cassette so with all 8-9-10 cogs getting into the action if barely.
Even an older Stag's-Head or Exage Pre-SIS unit should span 8 cogs if well-centered. I generally find that removing 1-3mm of driveside axle spacing does the trick while still leaving 3-4mm clearance between the 1st cog and the dropout. This improves the chainline as well so is effort well spent imo.
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@dddd...
i don't recall have any issues with reaching the largest cog and i didn't center the derailleur on the cassette. and, it was on a 135mm spaced hub. that was four years ago, though. i've blinked a few times since
i have a different frame and set up, now, i plan to run the shimergo on, again. so, if i do have that issue, i'll keep your suggestions in mind. thanks!
i don't recall have any issues with reaching the largest cog and i didn't center the derailleur on the cassette. and, it was on a 135mm spaced hub. that was four years ago, though. i've blinked a few times since
i have a different frame and set up, now, i plan to run the shimergo on, again. so, if i do have that issue, i'll keep your suggestions in mind. thanks!
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The good thing about 8s cassette hubs is that the wasted space between the smallest cog and the dropout is pared closer to the minimum versus 7s hubsets.
The most driveside axle spacing that could even be removed would likely not exceed 1mm.
So you're right, no re-centering of the hubshell should be needed when it's an 8, 9 or 10s cassette hub.
It's with older 5, 6 and 7s hubs where older-yet pre-SIS derailers sometimes are fussy about having the axle spacing re-centered WRT the cogs.
The most driveside axle spacing that could even be removed would likely not exceed 1mm.
So you're right, no re-centering of the hubshell should be needed when it's an 8, 9 or 10s cassette hub.
It's with older 5, 6 and 7s hubs where older-yet pre-SIS derailers sometimes are fussy about having the axle spacing re-centered WRT the cogs.
Last edited by dddd; 10-28-19 at 09:38 PM.