Technical FAQ: Rear drop out variation

Why does my rear derailleur pinch my chain on the largest cogs?

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Follow up regarding Jim’s jockey wheel pinching the chain to the cassette in the large gears:

I built a new Mongoose Ti frame up with all XTR components and had the same problem. No amount of B-screw adjustment would fix it .I measured the distance from center of axle to center of derailleur mounting bolt on my bike and on others. There was a surprising amount of variation. I spoke to Shimano and they said that in spite of published build specs, many manufacturers did not comply.

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