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Gimme my MOJO!
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Discussion Starter · #1 ·
Bike is an NRS with a giant proprietry air shock. Added on the SGF rocker arms, but as a result, had to pump the shock up to around 260psi. Just yesterday, I noticed that I didnt feel any difference in the rebound damping with the knob either full on or full off. Before, when I was using the normal rocker arms, I was doing fine at around 180psi, and at that point in time, in full on damping, I could literally hear the hiss as the damping worked.

Do I have a problem with my shock now? Or is this normal at that high pressures?
 

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Actually it is quite normal at higher pressures....

for some shocks. Most manufacturers set their shock damping range for an "average rider" as far as oil weight, vlaving etc. It is possible with some shocks to push the rebound force of the air spring beyond what the damping system is capable of handling. With the rocker that you installed you increased the compression ratio of your suspension (I am assuming that this increased travel as well). That would account for the requirement to run higher pressure in the shock. This is quite often a problem when increasing the rear travel through the replacment of rockers. Anyway, while not stricktly normal, it is not uncommon when increased compression ratios are invloved. Custom valving of the damping system my be an option. There are outfits like Push Industries that can do this for you. The other option of course is to return to your original rockers. Which may not be that bad of an idea. Going from 180psi to 260 is quite a jump!

Good Dirt
 

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Gimme my MOJO!
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174 Posts
Discussion Starter · #3 ·
Squash said:
for some shocks. Most manufacturers set their shock damping range for an "average rider" as far as oil weight, vlaving etc. It is possible with some shocks to push the rebound force of the air spring beyond what the damping system is capable of handling. With the rocker that you installed you increased the compression ratio of your suspension (I am assuming that this increased travel as well). That would account for the requirement to run higher pressure in the shock. This is quite often a problem when increasing the rear travel through the replacment of rockers. Anyway, while not stricktly normal, it is not uncommon when increased compression ratios are invloved. Custom valving of the damping system my be an option. There are outfits like Push Industries that can do this for you. The other option of course is to return to your original rockers. Which may not be that bad of an idea. Going from 180psi to 260 is quite a jump!

Good Dirt
I sold the frame. When I sold it, I switched back to the standard rockers. I also let the air out and repressurised it for the new owners weight. Then upon testing, rebound damping was non existent also. Have I fooked up this shock?
 

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MattSavage
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leleklegrunt said:
I sold the frame. When I sold it, I switched back to the standard rockers. I also let the air out and repressurised it for the new owners weight. Then upon testing, rebound damping was non existent also. Have I fooked up this shock?
Rebound could just have been blown. Not necessarily a result of anything you did. It happens.

I hope the guy you sold it to was aware of this...
 

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Gimme my MOJO!
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Discussion Starter · #5 ·
mattsavage said:
Rebound could just have been blown. Not necessarily a result of anything you did. It happens.

I hope the guy you sold it to was aware of this...
Oh yeah, he is. I called the LBS immediately and arranged for him to take the shock in for warranty claim. Also arranged for the LBS to have a loaner SID shock in the meantime.

Any idea how to "fix" this, if we could do it ourselfs or not?
 

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Probably not, most oil dampers in shocks...

are presurized with nitrogen gas to preven cavitation or foaming of the oil as the valves pass throgh the oil. This nitrogen is at realtively high pressure. To rebuild the damper, the nitrogen must be released. Upon reassembly the damper MUST be repressurized with nitrogen to prevent foaming and cavitation or you end up with VERY poor rebound and/or compression damping. So, unless you have the hardware necessary to do the nitro refill, you can't really do it yourself. Another issue is that if you don't know what your are doing, that damper can come apart rather violently if you don't follow a specific procedure for disassembling it. This and result in quite a mess, as well as damage to surroundings and possible personal injury. So it's better to leave it to the pros. So send it into the shop, they'll either take care of it, or send it into RS for service.

Good Dirt
 
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