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RP23...Help me Understand. Please.

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badgermtb

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Discussion starter · #1 · (Edited)
Hi Folks--

Just got a brand new bike. Have not ridden it yet. Went to set the sag on the rear RP23 and something seems amiss. I come from a rigid SS background, so have limited knowledge of the intricacies of suspension tuning.

In a nutshell, I can't get sag to set up correctly...and I don't want to ride the bike and damage it. Even disregarding the "sagotron" markings on the frame and using % sag does not work. The shock has the same sag (pictured) regardless of propedal engagement.

Facts:
2010-2011 rp23 rear shock
Enduro frame
Boost valve = 250
Rebound = Medium
Velocity Tune = L
running about 220 PSI in shock.


I weigh 210 w/ gear. I am apprehensive to run more than 220 PSI in this shock. But I'm thinking that more PSI equals less sag.

Questions:
How high of pressure is safe to run? Can I go much higher safely?
Is there something wrong with this shock?
How does the boost valve rating impact the shock?
What about the Velocity tune?
Is the stock shock the wrong length?
Other tuning ideas?

I am hoping for some guidance. I will take the shock to the LBS, but want to go there with a little bit of knowledge. I trust them, and don't think they would mislead me...but I am trying to be at least somewhat informed.
 

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#3 ·
What scotth72 said is correct. Set sag with PP off to about 25-30% (the sagathron thing should work) and with the rebound fully open. The RP23 can take up to 300lbs of air so don't worry.

Yes, more air will equal less sag. Once the sag is between 25-30%, set the rebound. Close the rebound completely and count the number of clicks from fully closed to fully open. Go back to fully closed and set the rebound in the middle to start (whatever the number of clicks divided by 2). If you feel the bike is kicking you in the rear, add more rebound. If you feel it is not reacting fast enough, reduce rebound.
 
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Discussion starter · #5 ·
OK...this is all very helpful. I am starting to become concerned that I got a bum shock.

When I empty all of the air out of the shock, it only goes down to 100psi. I can't get any more air out of the shock. Could be that my pump is busted...but I don't think so...it works correctly on all of my other fox suspension.

Does the 100psi thing sound correct?
 
#6 ·
No not really. Every time I rebuild a suspension component, be it a shock or a fork, I always let the air out of the air can. The easiest way to be sure is to remove the valve core! IF there is still 100psi then air will escape. if not, the gage of your pump may no longer accurate and the pump should probably be replaced with a new one.

Question: how can you be sure that your gage "...works correctly on all...." of your other suspension?

Do you have a second equally accurate gage to compare readings against?
 
Discussion starter · #7 ·
Welp, I checked the pump with the rear shock and fork on my wife's bike. Both are Fox. I did not deflate them completely, just slightly, but I did adjust the air pressure for sag and was able to acheive correct sag with what correct air pressure. For instance, her bike has a Float R rear shock. I pumped up the shock to within 10 psi of my body weight according to the shock pump gauge, and then checked sag...spot on. I don't have another gauge to use as a control.

Weird.
 
#8 ·
According to my catalogue, you should be setting the pressure to 250psi to begin with and adjust from there. You seem to be running the pressure too low for your riding weight. I have had the rp23 set up for a lady of more significant proportions and pressurized to 320psi.... One of the guys here weighs in at 275lbs and we have him running 350psi because of the way he rides (hard and fast)...
 
Discussion starter · #9 ·
OK...interesting...

SpecialWarr said:
According to my catalogue, you should be setting the pressure to 250psi to begin with and adjust from there. You seem to be running the pressure too low for your riding weight. I have had the rp23 set up for a lady of more significant proportions and pressurized to 320psi.... One of the guys here weighs in at 275lbs and we have him running 350psi because of the way he rides (hard and fast)...
Click to expand...
That is helpful. I was able to reduce the shock's pressure to zero...so that issue has been resolved.

Took it to the LBS and had them go through it with me. We ended up with 250psi. Funny thing is that the sag did not change from 200-250. Not a bit. ??? Anyhow, I asked about more pressure and they said that i could safely go to 285. They had a chart (looks like it came from Specialized).

Do you have a digital copy of the catalog you are using? Just curious. I appreciate your input.

What I am thinking is that the sag is impacted by the boost valve function. I think the boost valve is supposed to help the shock be consistent through it's travel...part of that is to overcome the "bump" caused when the shock blows past the propedal platform and in to its travel. Does that makes sense?
 
#10 ·
Not sure if this is relevant to your particular questions, but the velocity tune, propedal setting, and boost valve pressure are not going to change the sag the amount of sag for a given shock pressure (unless the PP on it's stiffest setting is so stiff as to prevent movement of the shock).
 
Discussion starter · #11 ·
So, do you think I should jsut keep adding pressure until I get correct sag? Even if the pressure goes up to 280-300 psi for a 200 pound rider?

I am OK with that...but it just seems weird. I thought the PSI would be much closer to body weight.
 
#12 ·
badgermtb said:
So, do you think I should jsut keep adding pressure until I get correct sag? Even if the pressure goes up to 280-300 psi for a 200 pound rider?

I am OK with that...but it just seems weird. I thought the PSI would be much closer to body weight.
Click to expand...
You said you came up with 250psi at the shop? I think you should just ride it at 250 and see how it feels. Sag is really just a starting point. If it feels good on the small stuff, and you are only bottoming on the biggest stuff you drop, and you are not wallowing in the travel, then don't worry about it, that is where you want it to be.
 
Discussion starter · #13 ·
Thanks Kapusta--I think that is what I wil do. My shop wrench gave me a similar response.

With my riding background, I think that maybe I am always tending towards stiff suspension, getting nowhere near bottom out on the fork or shock. I will run it at 250psi (regardless of sag) and see how it goes.

Would it make sense that the sag might change (become less) after the bike is ridden in a bit? Just curious.
 
#14 ·
You should have got different sag with propedal on. You may have a defective shock. Take it for a ride. If you hear any clunking when the shock rebounds or the rebound damping does not work with pro pedal on, then your shock is defective. Not unknown from new.
 
Discussion starter · #16 ·
no difference at all...

No difference in sag between propedal and not-propedal.

I will go for a ride tonight and see what happens. I am hoping that the issues I am experiencing might be a result of the shock being new and unridden.

Maybe when I ride it a bit, it will "break-in" and magically do what it is supposed to. ;-)

I really don't want to deal with the hassle of getting a new f***ing shock or a warranty process. At least I do have warranty and a great shop.
 
#17 ·
Dont worry about sag, or propedal, or anything. If the shock rides well, its good. If it rides bad, adjust it a bit.. if it cant get adjusted to ride well, it needs to be rebuilt.

It doesnt sound like you technically have any issue with the shock.. You wont damage anything with that much pressure in the shock. Zero worries, go hit the trail!
 
#18 ·
^^^^^^^^ What he said. You gotta a least give it a go and see how it feels. The newer linkages on the Spesh bike have given them a much plusher feel. And not necessarly the best thing for bigger riders. You, coming off a hardtail, it's gonna be a bit different but you'll get use to it. If your not happy with it after awhile Fox make a "Volume Reducer" kit that is simple to install and allows you to run lower pressures with a similar feel. There under $30 and might be something to try before replacing/rebuilding the shock.
 
#19 ·
Hes already got a small volume can. I wouldnt mess with the volume reducers, they just ramp up the rate. The real problem with floats is the gross lack of real damping. When you get tired of the way the shock works, upgrade ;) The enduro is a great bike, it deserves a great shock.
 
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badgermtb
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