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Decreasing the Chainline on a Shimano GRX Crank

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Decreasing the Chainline on a Shimano GRX Crank

Old 04-30-23, 02:52 PM
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Originally Posted by SoSmellyAir
I don't get the half step between the 50T and 46T chain rings. What is the shifting philosophy?
Even spacing.
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Old 04-30-23, 03:07 PM
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Originally Posted by SoSmellyAir
I don't get the half step between the 50T and 46T chain rings. What is the shifting philosophy?
It's something from back in the day when there were only 5-6 gears in the back, called "half-step gearing". If you wanted "wide range" on the freewheel in the back, like 14-34, you'd end up with huge jumps in between gears. So, the big and middle chainrings were very close to each other, about half the gap between each of the cogs in the back. Therefore, by using the FD to fine-tune, you could get a big gear range and also small increments between gears. The downside being that you're shifting in the front constantly. And in those days with downtube shifters, every other shift being a double-shift (front+rear) was a huge pain. It was a thing on touring bikes, not racing bikes. In the end, the gears available sort of approximated a 1x11 or 1x12 setup today but not as smooth.

It was often paired with a granny gear ("half step + granny"), the thinking being that if you're in the bailout gear, you won't mind the huge steps as much.
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