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Discussion Starter · #1 ·
I was banging my head trying to get the shifting dialed on my Eagle setup. the hangar was true, the housing was fresh, and almost everything was adjusted correctly. The problem turned out to be that the B gap was not correct. Sram makes a handy tool to set the distance but you can also set it by measuring 14mm between the cog and pulley in the highest gear. I found it difficult to do this with calipers or a measuring tape because you have to contend with the chain, wheels, frame, etc. the trick I found was a simple wooden carpenter pencil. the width measured exactly 14mm and can be fit through the wheel to take the measurement. If the pencil is bigger than 14mm you can just shave it down to the correct width.
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Don't forget to measure B gap at SAG. So you either need someone to check it while you're on the bike or compress the suspension enough to hit close to your SAG and then check it.
 

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Discussion Starter · #5 ·
Don't forget to measure B gap at SAG. So you either need someone to check it while you're on the bike or compress the suspension enough to hit close to your SAG and then check it.
Good point. My initial measurements were at sag but it was the same unloaded on my bike. Others may vary

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Good tip as I've always got a few of those pencils laying around in the shop and tool box.

We all know that red bikes are faster than green bikes, but then why does red mean stop...
 

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I tried this tonight as my middle gears were slow to shift down the cassette. It worked! The only problem I see is that I had to back the screw out enough to see the blue loc tite sticking out about 1/8”.

Would a longer screw be ok? Or don’t worry about it. I don’t have b gap tool.
 

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Thanks! It cleaned up the shifting quite a bit. I have eagle nx. It shifts slow but much more precise now.

On the other hand I did notice the chain would sometimes start to peel off the 50 tooth ring if I backpedaled in the stand. Never did that before. Doesn’t do it riding either.
 

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The upper pulley needs to be enough below the cog so that when shifting to the next larger cog, the chain and pulley doesn't get jammed into it. The optimal distance depends on the size of the jumps between adjacent cogs. On typical road cassettes a number of years ago, 6mm was sufficient. Current wider range cassettes, particularly 1x mtb cassettes, need a larger gap...like 16-17mm.
 
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