Fox RP2 rear shock - rebound knob problem

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Fox RP2 rear shock - rebound knob problem

Postby Skonk » Tue Jul 07, 2009 09:36 am


I have a Fox Float RP2 rear shock on my GT i-drive bike.

Last night I noticed my rebound was off (too springy) so I tried to adjust it but the rebound knob would hardly move.

It felt like it was full of grit (which didn't supprised me, my last few rides had been in very muddy conditions).

So I slackened the grub screw on the Pro Pedal switch and removed it, cleaned the area and tried to get a bit of lube in to see if it would free it up... which it didn't.

So I then slackened the 2 grub screws which hold the actual rebound knob in place (behind one was a spring and a ball bearing which went flying accross the room. I found them though).

It was indeed full of dirt, so I gave it a good clean and it looks fine now.

The problem is... I cant get the soddin rebound knob back in now, there seems to be a spring-loaded piece of metal which needs to be moved slightly out of the way so the knob can drop in, but I cant work out how to do it.

Has anyone removed the rebound knob on their RP2 and successfully re-assembled it? and if so, how would I go about getting mine back in?



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Postby cgarossi » Tue Jul 07, 2009 10:25 am

I have exactly the same problem! It has become hard to turn.

I haven't taken the knob off as I wasn't exactly sure what I was doing. There are two alen key nuts on the top and 90 degrees. Are these the ones you removed?

Perhaps remove the shock entirely from the frame so you can get to it?

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Postby Skonk » Tue Jul 07, 2009 10:54 am

The grub screw which runs along the same direction as the shock is the one which has a spring and ball behind it and then the one at 90 degrees holds the knob in place.

I considered taking the shock off the bike but it was 3am by this point so I figured I'd goto bed :) I'm at work at the moment.

I did try releasing all the air from the shock, and I detached the shock from the frame at one side.

Basically, on the bottom of the rebound knob there is a curved shape which gradually gets closer to the edge of the knob, which I assume is what pushes the rebound control in and out when you turn the knob. The problem is I cant get this curved bit into the correct place (it's sat ontop of the sprung metal bit rather than being sat at the side of it).

Not knowing the names of all the bits is making it hard to explain what I mean :(

Here is a doodle of it I knocked up in paint: Here

Dunno if this will help explain the issue or not.


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Postby cgarossi » Tue Jul 07, 2009 11:07 am

I see. So the knob moves the cam using its curved surface which actuates the rebound mechanism. So it seems that while the cam is outwards the rebound is completely off.

Looks like you need something to hold back the cam while you put the knob back on?

I think im going to just take the Pro Pedal lever off and blow through the adjuster with some compress air and WD40.

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Postby garrrymac » Thu Nov 26, 2009 17:02 pm

did anyone ever find out how to fix this problem, as mine is now doing the exact same thing. i took off the propedal adjuster then the rebound adjuster and bits came pinging out. i didnt find them so i have no idea what parts they even were.

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Postby sailor74 » Fri Nov 27, 2009 02:30 am


hey folks,

i had the same problem with 2 RP2 shocks and recently the additional problem of refitting the rebound knob.

First of all this is really i suspect a job for Mojo, the cam requires quite a bit of pressure to hold it back so the easiest method is to de-pressurise the rebound system (a job for Mojo).

Having said that there is a method which does work but also requires a bit of patience and some luck!

First of all remove all grub screws, the one on the front houses a small spring and tiny ball bearing, dont loose them!! The second one is just a lock for the rebound knob.

There is a third grub screw at the back of the shock which acts as a stopper for the pro-pedal, you will need to remove it, just leave the pro-pedal in the off position. Next using a small screwdriver or allen key lever the 'spring loaded piece of metal' (rebound circuit) down and wedge the screwdriver/allen key between that and the rebound knob spindle.

Now for the tricky bit, you will need to get a needle and bend it (into sort of a U shape) so that you can put it through the hole that the 3rd grub screw fits into, the idea is to get the needle to pass from the grub screw hole at the back past the pro-pedal tab inside and sit it next to the screwdriver/allen key currently holding the spindle and rebound circuit apart. you should then carefully remove the allen key so that the pin is now holding the spindle and rebound circuit tab apart. This will then provide just enough of a gap for the rebound knob to slip between the two whilst pushing the pin out of the way.

Its very tricky, be careful not to loose the pin inside the shock body, but it does work, it is much easier if you first remove the shock from the bike.

once the rebound knob is back in place put the pro-pedal lever back on and lock it down so that it cant fall off again!!

Drop the ball bearing through the front grub screw hole, then the spring then the grub screw. Finally replace the other two grub screws. Put the shock back on the bike, re-pressureise it and job done. I would also take the opportunity to add some float fluid to the main air can whilst its off the bike.

For future reference the best way to clear the grit etc is to loosen the grub screws just a turn then use a spray lubricant between the rebound knob and try and flush the dirt out by spraying and rotating the rebound knob.

Garrymac, it sounds like you will be missing a small spring and an even smaller ball bearing, you would be best to take it into your LBS, they will probably send it to Mojo.

I have found with the RP2 it was best to set it and then lock the rebound down, it should then be fine assuming you dont either loose a lot of weight or put it on and have to significantly adjust the shock pressure.

I have had 2 RP2 shocks both of which have had gritty and or limited movement of the rebound switch. I have also had 2 RP23 shocks both of which have had zero problems.

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