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How do 18mm shock shaft affect dampening

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how does the 18 shaft affect dampening compared to a 16 shaft or if it does affect anything at all.is it that The 18 shaft has 16 Id shims and the 16 shaft has 12 Id shims. Or does the clamp control everything no matter what?If you were to some how have identical everything, which of the two would be stiffer/softer. Just interested to see and help me understand the difference in valving the two different shafts.

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John curea wrote up a lengthy comparison on the 16 and 18 mm shocks on his dyno. It's titled "2006 yz250 shock unfolded"

His results were the 06 had 15-20 perfect softer in comp damping compared to the 05 yz250 shock

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Strangely the inner diameter of the shims does have an effect even through they are clamped by the clamp shim , I think the bigger id shims are softer as they have less meat

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The shaft diameter also makes a difference as it pushes less or more fluid through the cadj , then as well as that the shaft diameter determines how much fluid has to run over the main piston , ie a 16mm shaft displaces less but flows more oil across the main piston

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Mog good point i didnt think of the amount of oil that the shaft displaces through the adjuster. So a 16 shaft with 12 id piston and shim would see more oil through the ports then the 18 with 16 id piston?

I w

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Yes exactly on the shaft size , not 100% sure on the id of the shim , I remember using restock or and it made the curve change and not perfectly up or down

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so which 18 mm shock shaft has 16mm id shims?

 

my 18 mm yz shock has 12mm id shims.

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