Sag is usually thought of in terms of percentage of travel, so it won't vary based on your weight.

Everyone has their own preference for sag, but a good rule of thumb is about 20% front and rear. Give it a couple weeks to see how you like it, and then try adding PSI if you're bottoming out too easily or drop PSI if you're not utilizing the full range of your shocks.

I prefer a more stiff suspension, so I run 10-15%.

 

I prefer just enough sag

 

I'd start at 20%, and see how much travel you're actually using during a ride. If you're only using 50% of your travel, take sag to 25%. If you're blowing through all travel, go to 15%.

 

I don't see much value in measuring sag anymore. I add or remove to try to use up most of the available travel on the roughest trail I normally ride. I then fiddle with rebound and compression to keep the tires on the ground while minimizing brake dive.

 

Watts mentions the correct procedure. With that said, on an FSR Stumpy, I'd use 25% as the starting point, and consider the full range of 15% up to 35% as valid options.
As long as you're happy with how it pedals, and you're not blowing the o-ring off the shock on big hits, going closer to 30% sag is usually a good thing on the CTD Evo shocks.

 

As mentioned by others, your weight is irrelevant. Set your bike up so you bottom out maybe once a ride.

Sent from my XT1585 using Tapatalk

 

Also consider this, for about $35 and a few minutes on the work stand: SHOCK- Air Volume Reduction (FLOAT, FLOAT X, and DHX Air) | Bike Help Center | FOX

Generally, it's suggested that you run your front with 5-10% less sag than the rear. For a short travel bike, 20-30% is the norm for rear sag. Spec's suspension design generally doesn't really care how much sag you run, unlike some other designs which tend to have tighter sweet spots for sag (ex. older VPP bikes). 15% sag is actually recommended for some of Fox's forks.

 

I am right at about the same size (height and weight, been a little heavier as well as a little lighter) as the OP, and I own a Stumpjumper FSR 29, and have ridden a number of other Stumpjumper FSR 29ers.

I run mine at 30-32% on both the rear shock and the front fork. I tend to run most bikes at about that same sag. I also tend to run the rebound at a fairly 'fast' setting. Usually somewhere between half way and full 'fast'. I usually find a rebound setting on the rear shock that I like and then adjust the rebound on the fork to 'match' so that it stays pretty neutral in the air. Then, if the rear end is coming up too fast/far when jumping, I will speed up the rebound on the fork. If the front end is coming up to high when jumping, I will slow the rebound on the front fork until it gets neutral in the air.

If the rear shock has Pro-Pedal or CTD, I may use the stiffer setting while climbing, but usually leave it open. I always leave the CTD open on the fork unless I am standing up on a steep climb.

Factory recommended air pressure settings are usually too stiff for my taste.

 

20% in attack? Sitting? Standing? Leaning? Do you hunch over or sit straight?

These can double your fork sag. Or not change it. Stiction can reduce it in half, sometimes.

With all those variable, and such a wide range of discrepancy between them, you gotta wonder how valid any claim of fork sag really is.

Set the fork pressure so it feels appropriate to you. Not harsh, not wallowly. You have to check this while riding. If its 10%, or 30%, its right.

 

IMO, setting your fork pressure by sag is pointless for the reasons already stated. Setting your pressure with sag in the shock makes sense if you have adjustable high speed compression damping. Otherwise you're stuck setting the pressure to prevent harsh bottom outs.

 

Don't underestimate air spring volume tuning. You can get a fork/shock to be more supple, yet have more bottom out resistance, by decreasing the positive air volume.

 

Good point. Volume reducers are great for us heavier riders. My Pike is basically unusable without a bunch of reducers.