WTB: Dura Ace 7 speed DT shifters
09-29-21, 08:19 AM
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WTB: Dura Ace 7 speed DT shifters
anyone have a set they can sell? looked on the bay and you would think they were gold plated....
All set, and thanks to everyone for the enlightenment on things dura ace.
All set, and thanks to everyone for the enlightenment on things dura ace.
Last edited by cocoabeachcrab; 10-01-21 at 02:01 PM.
09-29-21, 09:15 AM
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A lot of well-used 7s indexed DT shifters got worn out from riders/mechanics having habitually adjusted the lo-limit screw on the RD on the tight or "safe" side, such that hard pedaling caused the detent to move with every pedal stroke. Essentially, low gear no longer holds an accurate position.
One should inspect such levers for function immediately upon receiving them, for possible return.
Beware though that a good 8s DT lever will often/usually show the exact same symptom if paired with an older SIS RD in many cases, since the derailer may not have quite as long of a linear-accurate actuation throw needed for 8s use.
One should inspect such levers for function immediately upon receiving them, for possible return.
Beware though that a good 8s DT lever will often/usually show the exact same symptom if paired with an older SIS RD in many cases, since the derailer may not have quite as long of a linear-accurate actuation throw needed for 8s use.
09-29-21, 09:41 AM
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A lot of well-used 7s indexed DT shifters got worn out from riders/mechanics having habitually adjusted the lo-limit screw on the RD on the tight or "safe" side, such that hard pedaling caused the detent to move with every pedal stroke. Essentially, low gear no longer holds an accurate position.
One should inspect such levers for function immediately upon receiving them, for possible return.
Beware though that a good 8s DT lever will often/usually show the exact same symptom if paired with an older SIS RD in many cases, since the derailer may not have quite as long of a linear-accurate actuation throw needed for 8s use.
One should inspect such levers for function immediately upon receiving them, for possible return.
Beware though that a good 8s DT lever will often/usually show the exact same symptom if paired with an older SIS RD in many cases, since the derailer may not have quite as long of a linear-accurate actuation throw needed for 8s use.
09-29-21, 09:49 AM
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A lot of well-used 7s indexed DT shifters got worn out from riders/mechanics having habitually adjusted the lo-limit screw on the RD on the tight or "safe" side, such that hard pedaling caused the detent to move with every pedal stroke. Essentially, low gear no longer holds an accurate position.
One should inspect such levers for function immediately upon receiving them, for possible return.
Beware though that a good 8s DT lever will often/usually show the exact same symptom if paired with an older SIS RD in many cases, since the derailer may not have quite as long of a linear-accurate actuation throw needed for 8s use.
One should inspect such levers for function immediately upon receiving them, for possible return.
Beware though that a good 8s DT lever will often/usually show the exact same symptom if paired with an older SIS RD in many cases, since the derailer may not have quite as long of a linear-accurate actuation throw needed for 8s use.
Thanks for the great insight. I similarly have been hunting for Dura Ace 8-speed downtube shifters having had bad experiences and given up on the integrated shifters. Similarly, the prices for 8-speed Dura Ace downtube shifters are astronomical right now.
Would still love to try the 8-speed downtube shifters if anyone has a spare pair but might be resigned to going friction shifting.
09-29-21, 09:56 AM
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Thanks for the great insight. I similarly have been hunting for Dura Ace 8-speed downtube shifters having had bad experiences and given up on the integrated shifters. Similarly, the prices for 8-speed Dura Ace downtube shifters are astronomical right now.
Would still love to try the 8-speed downtube shifters if anyone has a spare pair but might be resigned to going friction shifting.
Would still love to try the 8-speed downtube shifters if anyone has a spare pair but might be resigned to going friction shifting.
09-29-21, 11:07 AM
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09-29-21, 12:42 PM
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Yeah, there's a realm of black art to run a 7400 RD with other components. @rccardr is a DA savant and will hopefully chime in here.
09-29-21, 12:59 PM
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There is a lot of misinformation out there about the entire DA 740X family, but generally speaking it is true that 740X 6-7-8 speed RD’s only index properly with 740X shifters. In my experience, all 6-7-8 speed DA RD’s will index interchangeably with all 6-7-8 speed DA shifting mechanisms. People have reliably reported that DA 9 speed shifters (and by extension any Shimano 9 speed shifter) will index 8 speeds with a 740X RD. I have not experienced any of the faux shift/non shift/low gear issues mentioned by dddd, but he is a reliable source (plus he rides a Pedersen and somewhat competitively).
I can also look & see if I have a complete set of 7 speed DA down tube shifters. Always ensure that all of the shifting tangs on the boss side of the pod are intact, as in my experience one or more of them being broken is the primary cause of poor/unreliable indexing performance.
I can also look & see if I have a complete set of 7 speed DA down tube shifters. Always ensure that all of the shifting tangs on the boss side of the pod are intact, as in my experience one or more of them being broken is the primary cause of poor/unreliable indexing performance.
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09-29-21, 01:30 PM
#10
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Old Dura-Ace had a derailleur actuation ratio that was higher than the lower-tier SIS systems. So whereas the rest of their systems had an actuation ratio of 1.67: 1, old Dura-Ace was about 1.9: 1.
Shimano 9-speed systems (including Dura-Ace 7700 and later) pulled 2.5mm of cable per 'click'. Non-Dura-Ace Shimano 7-speed pulled 2.9mm of cable per gear.
So the math works - Shimano 9-speed shifters should index correctly with old Dura-Ace over a 7-speed block. Bicycles are simple machines; if the math works, then the shifting will index correctly. I have created all kinds of franken-drivetrains - if the math worked, the shifting has always worked. Conversely, the few times that I have attempted to hobble together something in which the math did not work, it never indexed acceptably.
Shimano 9-speed systems (including Dura-Ace 7700 and later) pulled 2.5mm of cable per 'click'. Non-Dura-Ace Shimano 7-speed pulled 2.9mm of cable per gear.
So the math works - Shimano 9-speed shifters should index correctly with old Dura-Ace over a 7-speed block. Bicycles are simple machines; if the math works, then the shifting will index correctly. I have created all kinds of franken-drivetrains - if the math worked, the shifting has always worked. Conversely, the few times that I have attempted to hobble together something in which the math did not work, it never indexed acceptably.
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09-29-21, 01:53 PM
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Myrtle Beach Crab
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Old Dura-Ace had a derailleur actuation ratio that was higher than the lower-tier SIS systems. So whereas the rest of their systems had an actuation ratio of 1.67: 1, old Dura-Ace was about 1.9: 1.
Shimano 9-speed systems (including Dura-Ace 7700 and later) pulled 2.5mm of cable per 'click'. Non-Dura-Ace Shimano 7-speed pulled 2.9mm of cable per gear.
So the math works - Shimano 9-speed shifters should index correctly with old Dura-Ace over a 7-speed block. Bicycles are simple machines; if the math works, then the shifting will index correctly. I have created all kinds of franken-drivetrains - if the math worked, the shifting has always worked. Conversely, the few times that I have attempted to hobble together something in which the math did not work, it never indexed acceptably.
Shimano 9-speed systems (including Dura-Ace 7700 and later) pulled 2.5mm of cable per 'click'. Non-Dura-Ace Shimano 7-speed pulled 2.9mm of cable per gear.
So the math works - Shimano 9-speed shifters should index correctly with old Dura-Ace over a 7-speed block. Bicycles are simple machines; if the math works, then the shifting will index correctly. I have created all kinds of franken-drivetrains - if the math worked, the shifting has always worked. Conversely, the few times that I have attempted to hobble together something in which the math did not work, it never indexed acceptably.
09-29-21, 05:56 PM
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I have a set of Dura Ace 7-speed 7401 downtube shifters that worked fine with a long cage Deore LX RD and a Shimano 600 Tricolor (Ultegra) 8-speed RD, last time I used that combo on an early 1990s Trek 5900 in 2019. I later switched to MicroShift integrated brakes/shifters for convenience. But that particular Dura Ace downtube shifter worked fine with those non-DA Shimano rear derailleurs.
I'm saving the DA 7401 downtube shifters for my Ironman, now that I have a spare Dura Ace rear derailleur to go with it.
I'm saving the DA 7401 downtube shifters for my Ironman, now that I have a spare Dura Ace rear derailleur to go with it.
09-29-21, 08:43 PM
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I have a set. I looked at some online and it looks the chrome-ish ring that goes onto the braze-on has more of a curve than mine. Also, if it looks like anything's missing from the pics, let me know, but I pulled these off a bike recently and put them in a bin together. Anyway, send me PM if you're interested.
Here are some pics:
Here are some pics:
10-01-21, 02:00 PM
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actually, i'm all set! diomekes had a set of 7401's that just needed curved mating collar thingies that i have in my stash, but thanks for searching the bay for me!
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10-02-21, 09:07 AM
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A lot of well-used 7s indexed DT shifters got worn out from riders/mechanics having habitually adjusted the lo-limit screw on the RD on the tight or "safe" side, such that hard pedaling caused the detent to move with every pedal stroke. Essentially, low gear no longer holds an accurate position.
One should inspect such levers for function immediately upon receiving them, for possible return.
Beware though that a good 8s DT lever will often/usually show the exact same symptom if paired with an older SIS RD in many cases, since the derailer may not have quite as long of a linear-accurate actuation throw needed for 8s use.
One should inspect such levers for function immediately upon receiving them, for possible return.
Beware though that a good 8s DT lever will often/usually show the exact same symptom if paired with an older SIS RD in many cases, since the derailer may not have quite as long of a linear-accurate actuation throw needed for 8s use.
