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Old 09-10-10, 01:48 PM   #1
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Highish speed and bumpy = autoshift?

So I was pedaling along with minimal effort at probably about 80 or 85 rpm going about 20 mph and the path got bumpy and wham it my rear derauler shifted into a smaller cog. Happened twice. Is that normal for bumpy areas? I'm running all shimano 105 components except for the rear derauler which is a cheesy plastic suntour model. I'll allow that this may also be the culprit.
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Old 09-10-10, 01:58 PM   #2
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Suntour and Shimano drivetrain components generally don't work very well together. Install a Shimano derailleur from the same era as the shifters.
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