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8 Speed Shimano Brifters with 7 Speed Cassette?

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8 Speed Shimano Brifters with 7 Speed Cassette?

Old 02-04-13, 09:29 AM
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TampaRaleigh
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8 Speed Shimano Brifters with 7 Speed Cassette?

Since the difference in cog spacing is only .2 mm, is there enough "play" in the setup to be able to run an 8 speed Shimano Ultegra brifter with a 7 speed cassette?
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Old 02-04-13, 10:12 AM
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6 gaps, that's a total of 1.2mm discrepancy, meaning 0.6mm undershift at each extreme.

Might work. Probably less than perfectly.

Actually, you can prolly disregard the last gap as there's likely enough cable slack to allow the derailleur to rest against its stop, so 0.5mm undershift at the big cog and second smallest. Failing that, there's still another chance you can swing the 0.5mm by moving the thin metal spacer (if present) from behind the smallest cog to behind the biggest.

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Old 02-04-13, 10:14 AM
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Originally Posted by Kimmo View Post
6 gaps, that's a total of 1.2mm discrepancy, meaning 0.6mm undershift at each extreme.

Might work. Probably less than perfectly.
So... if I wanted crisp shifting AND wanted to keep my 126 mm spacing, I'd be better off to get a 9 speed brifter and run an 8-of-9 cassette? Or a 10 speed brifter and a 9-of-10 cassette, right?
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Old 02-04-13, 10:22 AM
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Yeah, or you could use a 130mm hub with 126mm spacing / 126mm hub with 8/9/10 cassette body laced into an off-centre rim for great victory.
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Old 02-04-13, 11:19 AM
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I have tried to use 7 speed shifters on 8 speed cassettes in the past and had less than perfect results... I would call the performance barely acceptable - a lot of pushing the shifter 2 shifts up then one shift back. I have heard others say they got it to work perfectly.
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Old 02-04-13, 11:26 AM
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I ran 8-speed Shimano RSX brifters with a Sora rear derailleur on a 7-speed cassette briefly. It worked, but I wasn't able to get the shifting perfectly adjusted. Your results may vary.

Respacing your frame (if it's steel) to take a 130mm hub would be fairly easy, if you do want a modern setup on there.
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