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Replace Shimano 105 (rd-1050) with Dura-ace rd-7400

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Replace Shimano 105 (rd-1050) with Dura-ace rd-7400

Old 06-06-22, 12:59 PM
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chuckybb
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Replace Shimano 105 (rd-1050) with Dura-ace rd-7400

Took a fall yesterday on my '87 Trek 560 and the 6 speed rd-1050 seems to have taken the brunt of it. My body protected most of the bike from the road, haha. I'm just wondering about replacing the Shimano 105 (rd-1050) with Dura-Ace rd-7400. Would the current 105 shifters need to swapped out? Is there any significant benefit with the Dura-Ace?
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Old 06-06-22, 02:09 PM
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Might work. But the rd-7400 has a max rear cog of 26 teeth. I don't think you'd have to swap shifters. But I didn't look to find out the stuff to be certain.

Why not just put all new something else on it. With a new wheel you could be 10 speed Tiagra. And have your shifting on the bar where you don't have to take your hand off for times when you need both hands but also have to shift. Even new 8 speed Claris or 9 speed Sora will have you thinking it's a new bike.

https://si.shimano.com/api/publish/s...000-00-ENG.pdf

https://si.shimano.com/api/publish/s...000-00-ENG.pdf
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Old 06-06-22, 02:22 PM
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Dura-Ace rd-7400 will not work properly with your current shifters unless you like friction shifting
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Old 06-06-22, 05:22 PM
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Oh... many times falls don't tear up the DR itself other than make it look scratched up. So if the cage with the pulley wheels isn't bent, then your issue might be a DR hanger bent. A bike shop can easily fix that usually. Sometimes you need a new hanger and that'll add some cost to the repair.
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Old 06-06-22, 11:15 PM
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Dura Ace RD-74XX has an actuation ratio of 1.9 to 1mm of shifter cable pull.

Standard cable pull up to 9 speed, and road 10, is 1:7 to 1mm of shifter cable pull.

You can use an alternate cable routing (Hubub) that moves the attach point further out from the pivot.

I’ve run the opposite alternate routing, DA shifters and a non-DA rear derailleur.

I have run a 28t max cog on an RD-7400 with a double chainring setup. A triple crankset would probably not work due to chain wrap and capacity.

John
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Old 06-07-22, 07:08 AM
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Did the same swap, no crash just simple aesthetics, and even with just friction shifting, you will not be impressed with the DA 7400 rd. It does look nice though, but ended up going back to the 1050.
Tim
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Old 06-07-22, 07:59 AM
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You could use most Shimano derailleurs up to 10 speed, with a few exceptions. Here's a chart. Look at the column that says "pull ratio". Your shifters work with a 1.7 PR. Bicycle Cassettes & Drivetrains - Google Sheets Check back here for confirmation if you find one you want to buy as I have found a mistake or two in this chart in the past and there are some other factors that need to be considered.
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Old 06-07-22, 10:07 AM
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If you dan’t have the RD-7400 and want a very nice upgrade, that comes with a price, look into an XTR RD-M900 or M910.

It is compatible, shifts great, and can accommodate larger max cogs and capacity if you ever want it. Basically DA on steroids.

And then there is DA RD-7700…

John
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Old 06-07-22, 03:26 PM
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Thanks! Just feeling-out the options.
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Old 06-07-22, 03:28 PM
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Excellent! Thanks!
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