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Discussion Starter · #1 ·
I have an 2018 Mach 6 with a Dpx2 on it. Currently I have a .2 spacer inside which gives me a compression ratio of 3.32 to 1 (Stock is 3.08) according to the fox chart.
I am thinking of putting in the .4 spacer which would give a ratio of
3.63 to 1. I could go up to a .6 spacer and a ratio of 4.04 to 1.
In the world of suspension tuning is there an ideal ratio or does one just stick in what works to manage bottom out?

Am I better off with more air and less sag or larger spacers and more sag?

Cheers
 

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Discussion Starter · #3 ·
Shock compression ratio (not to be confused with leverage ratio) is independent of frame design or rider weight as these do not factor. Its the ratio the air is compressed inside the suspension as the shock or fork is compressed. Much like an engines cylinder compression ratio. Eg: swept volume vs un swept volume.

Fox's chart is in the link for all the different shock lengths and spacer combinations.

My Dpx2 is an 8.5x2.5

https://www.ridefox.com/fox17/help.php?m=bike&id=568
 

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Am I better off with more air and less sag or larger spacers and more sag?

Cheers
That's like asking if you'd like a ham sandwich with swiss and mayo more than a ham sandwich with chedar and mustard.

Your weight, how you ride, where you ride, the frame's design....and the shock's internal valving.....all have more bearing than a random ratio you are focusing on.
 

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Yes. There is an ideal ratio. That ratio is the one that just allows bottoming on your biggest hits while running pressure that yields reasonable sag. To put it another way, it's an adjustable parameter used, among others, to optimize suspension performance for specific riders in specific conditions.
 

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Yes. There is an ideal ratio. That ratio is the one that just allows bottoming on your biggest hits while running pressure that yields reasonable sag. To put it another way, it's an adjustable parameter used, among others, to optimize suspension performance for specific riders in specific conditions.
Whos to say thats ideal though?

I think that is a definitive start point, but not necessarily ideal. From that point, especially on modern bikes, Ill take out a spacer and bring up air pressure. Its firmer and rides higher, while preserving bottom out. Firmer and higher is nice on bikes that already ride low and hit pedals. It also has more controlled rebound in general.

The quality of your rebound damping plays a significant role in volume spacers too. That wild undamped feel some shocks have at full bottom out with too many spacers feels extremely unstable.
 

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Discussion Starter · #8 ·
I’m sure just stuffing spacers in can’t be good. I guess if the rebound can control it then great.
Sounds like the ratio doesn’t matter as much as what just works with rebound control and progression.
 

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Whos to say thats ideal though?
Agreed. I chalk up sag and bottom out as arbitrary start points. Everyone seems to live and die by those two but don't care about all the complicated stuff in between that actually matters. Then there are those that take it one step further and will take a well performing efficient suspension and mess it all up to get a different sag, to "achieve" more bottom out, or to out-spacer their riding buddy.

Also, I've been on the anti-spacer kick lately. IMO they are a relic from the early days of suspension- "plush" initial stroke, blow completely through the mid stroke, then have that last 35% of ramp up at the end handle everything from mid size to large hits. Modern suspension lets you run higher spring rates for efficient use of travel yet still have a supple start stroke. Unfortunately this doesn't feel the greatest in the arbitrary parking lot test, and you may bottom out a lot less so most people are unhappy with this closer to linear type of tune. But man does it feel good when you are on the trail at speed.
 

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It's ideal. If you're not running at a reasonable sag and using full travel on your biggest hits because you compromise that for other things being wrong, it's those other things that need improvement.
 
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