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Rear shock bottom out question.

6 years 7 months ago #2538 by ratcat
Let say, how do I know if my rear shock had reach it bottom out condition? How can I tell? I have Fox RP23 high volumn and when I set it up to 30% sag it feel nice on trails. And on the way home there are these really cool stairs that I alway go down and at the bottom I felt a kick back. The ring is just at the very edge of the shock. So I pump it up to 20% sag the feel on the trail is definitely harsher. Went down the same stairs same thing happen, a kick back was felt and the ring right at the very edge like if I had 30% sag. How do people know if the shock had reched it maxium compression? And if it did, can the shock bottom out once is a blue moon without causing damage?

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6 years 7 months ago #2539 by bikesteve
How fast is your re-bound? If it is too slow chances are the shock may not be returning fully between steps so gradually it uses up all of its travel. -It's called 'Packing Up' -Steps are by nature pretty extreme compared to usual trail conditions.

I've over shot the rubber O ring plenty of times both on my Maestro & RP23 shock and it hasn't stopped working just yet but I do wonder how much abuse they can take.

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6 years 7 months ago #2543 by enzoferrari
how long have had the shock / how many hours riding ? Fox state that the RP23 should be serviced every 100 hours of riding.
The shock should handle the bottom out without a problem, it is the stress it puts through the frame you need to worry about - particularly if you can feel the 'thump' of the bottom out.
Sounds like the shock could be low on damping oil, as you should not really feel the bottom out.
You could consider sending the shock to TF-tuned in UK, it would be set up for you and you riding style with special custom damper - will make a 1000% improvement in the ride :woohoo:
or get it serviced localy - although not sure if there is a Fox Racing service center in HK :huh:

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6 years 7 months ago #2544 by Jeff
Ratcat- if you want to measure full travel on your shock, just take all the air out of it and see how far it will compress.

If you are blowing through your travel, then perhaps you should be running a standard sleeve instead of the high volume one.

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6 years 7 months ago - 6 years 7 months ago #2545 by enzoferrari
Jeff,s advice throws up a good point.... because on a standard shock the 'o' ring normally would come off the shaft at full travel.
Let the air out of the shock and check full travel and check that the frame / wheel / chain etc are not at max travel before the shock
here is a good thread on such a topic
singletrackworld.com/forum/topic/why-can...l-travel-on-my-shock

there is also a 'mod' you can do to make the spring rate more progressive if that is the problem... google RP23 air can mod... it will bring up lots, basically putting some shims into the air can to reduce the volume

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6 years 7 months ago #2548 by ratcat
Thank dudes!! I have an ornage five (Diva) and the label on the shock said Boost Valve. I am timid rider and not particularly heavy. I get a nice 20% sag when it is at 160 PSI and a 30% at 150 psi. Even when I am running 30% when I finish Hoi Pu I still have a nice 10-15% left. It is only when I go down the stair at the end of Stubbs Road beside the hospital that a kick bacl on the pedal is felt. I assumed it is the safety stop build into the shock. Since I am not a memeber of the communist party nor I am a share holder of multi-billion corporate, I like my shock to last for a long long time.

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6 years 7 months ago #2549 by Jeff
If you only notice it at the end of a long flight of stairs, then Steve is probably right and you've got your rebound set too slow, causing the shock to pack down after repeated fast hits.

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