I recently put a Fox Van R coil shock on my enduro. 7.875 i to i with a 2.25" stroke that increased my full travel from 5.25" to 6". I used this website to determine the spring rate and ordered a 700# spring with the shock. I got in a few rides before the rains and the shock feels stiff and not as plush as I expected. I checked the sag today and it measures 0.625". This would be between 25%-30% of the shock stroke, but only 10% of the 6" of full travel. I have read places that the sag should be a percentage of the stroke. Fox's online tech video states the sag should be 25% of full travel, but 1.5" of sag seems like too much.

Please help. Anyone with experience setting up rear coil shocks with some good input would be greatly appreciated.

You definitely want 25-30% of the shocks stroke, not wheel travel.

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Ride it until they CDFW it.

You measure %-stroke for shock, %-travel for fork. How much preload you running?

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By choosing not to help the situation, you have chosen to be part of the problem.

Not much more than a quarter turn. Just enough to keep the srping in place. More preload = stiffer spring, right?

Not always. I'm not positive, but I doubt these springs that Fox is making (or having made for them) are progressive. I suspect they are linear, so you won't notice much in the way of a "stiffer" ride if you crank down the collar on the top of the spring a few more turns. Just don't go past two turns trying to get the correct sag reading. Anything past two turns and you need a heavier spring, but damn you've already got a 700 lb'er.

Also, I've noticed that mine sometimes comes loose, and I usually run about 1.5 turns to get the right sag level - just something to be aware of it you only run .25 turns.

If your shock is functioning properly and has the proper amount of fluid and you achieve recommened sag with only 1/4 turn of preload and you're not feeling the love, borrow or rent a couple springs with lower spring rates.

It's not uncommon for 5 springs stamped with the same spring rate to register 5 different rates when properly tested. Don't forget the recom-mended sag % is exactly that, a recommendation. I prefer a spring rate that allows me to achieve 90% of what i want out of my suspension with one turn of preload. Rebound, compression, and end stroke ramp up are tools to dial in your setup and are not meant to compensate for improper base spring rate. As far as sag, I arrive at sag after I've dialed my suspension. Use the "recommendation" % to get you in the ballpark to begin tweaking, not as a % to end up at. You may find that after setting up you end at the recommended %. It doesn't matter if you don't as long as your suspension is doing what you want.

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By choosing not to help the situation, you have chosen to be part of the problem.

That would be the same either way, if the leverage ratio on the stated bike was 3:1 then the shock moves 1/3 of the rear wheel, either way 30% of either equates to the same.Alwaye use someone else with sag measurements to be more precise and use the stroke measurement its easier.

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owner "Independent Suspension Operation" isotuned@yahoo.com 619.760.6261

30% of 6" of wheel travel = 1.8"

30% of the shocks 2.25" travel = .675"

How are those the same? I must be missing your point.

Not what I meant. I meant that when you are measuring the sag on the shaft of the shock you need to use 25-30% off the length of the shock shaft. So on a 2.25" shaft, you would use .56"-.675". I suppose you could somehow measure sag from the wheel travel, and in that case you would want 25-30% of 6" which would be 1.5"-1.8".

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Ride it until they CDFW it.

ok, i am sparking this one up again...

moondog, did you ever get this figured out?

lately i felt like i was blowing through my travel on my Demo...it had a #400 spring when i got it.
I went up to a #450 spring and rode around...it still feels like i am blowing through the entire travel on large hits. i cant exactly confirm that i am indeed blowing through it all since i have yet to feel the harsh bottom out feeling...so i may be exactly using the full travel and not truly bottoming out. regardless it just feel really soft/wallowy,too plush...whatever.
so today i tried measuring the sag and with the 450 spring....i start with 222mm of full shock (i2i) and when i sit on the bike, i read 206mm (i2i)... so just shy of 30%... is this right?

according to the Demo 8 manual,
i2i is 222.3mm (8.75) and correct sag is 30-35% which is 21-24mm of stroke... so technically i am 'oversprung' ???

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'the notorious North County Sancho'

Nope. Didn't get a chance. Within the course of two days my new fork and rear hub blew out, earning them a UPS ride back to Fox and Mavic.

Big Clyde even hooked me up with a 600# spring to try and it is just sitting there. I'll let you know how it feels when I get my bike working again.

What is the stroke of your shock?

i2i = 8.75" or 222.3mm
stroke = 2.75" or 69.9mm
actual rear wheel travel is 8.4"

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'the notorious North County Sancho'

I'm sorry but that has to be the worst suspension set-up video ever made.... If I wanted to listen to a blown back stoner try and tell me how to set up a shock, I'd just ask my buddies for advice, lol. Seriously though, dude needs to sober up before he films at least.