[Dh builder]

Shock is a FOX DHX RC4 10.5x3.5"

I had a bottom out problem which came out of nowhere. I would easily bottom out on my rear shock over any jump.

I then had a air pump problem, so I am not 100% sure but I believe the boost valve in my coil shock had no air in it. I think the valve in the shock may have been loose because I tightened it and felt it turn a bit, but I can't be sure, but it is holding pressure now.

I got a new pump and pumped it to 200PSI and slowly lowered it down to 140PSI (FOX range is 125 - 200PSI).

My shock does not use the last inch of travel on my 3.5" stroke shock.

I have my high speed compression turned completely counter clockwise or 0. Low speed is same at 0, bottom out control is lowest setting. Everything is turned counter clockwise! and I can't get that last inch of travel.

Something is strange here. I used to get that full travel with my shock, but I can't be sure what the air pressure was in the shock and and what point it had leaked out. I just never checked the air pressure!

Could I have damaged my shock somehow by using it with too low air pressure in the boost gauge and that is why I can't get that last inch of travel?

Or is it possible that I always had too low PSI in the boost gauge?

What do you think? Odd thing is I swear my shock feels better than it ever did, even without being able to use that last inch of travel.

 

[kidwoo]

It sounds like your boost valve thingy is now actually working now that it has air in it.

Try backing off the big blue spinny thing that surrounds the bottom of the piggy back.







-udi bait

 

[HardtailHack]

Is your tire hitting your seat?

 

[Jm_]

And how much sag and travel do you have?

 

[Jm_]

And do you have a beard?

 

[kidwoo]

Did you question his sexuality?

 

[Dh builder]

Tire is not hitting the seat, my sag is maybe 20%.

I guess the thing to do is change the 400lbs shock to a 350lbs shock?

Do you guys check the pressure in your coil shocks often for leakage?

 

[Udi]

I'm with kidwoo, make sure the bottom out adjuster is all the way out and reset the pressure to 125-130psi. It helps to let the air out before trying to turn the knob, as it's much harder under pressure. However, don't cycle the shock with no air in the chamber. It's possibly unrelated to your issue but when cycled without air they do have a tendency to aerate the oil and require a rebuild/rebleed as a result.

Make sure the schrader valve valve is actually tight, they shouldn't leak and you shouldn't have to check often. There is actually a hex key slot in the schrader valve after you remove the valve cap, you can gently tighten it (the key it takes is imperial however, not metric). I say gently because you can break the valve if you go too far, just finger tight is fine.

Hope that's of some use. What's your frame, body weight, and sag % if known? Hard to judge spring rate appropriateness without those.

 

[Jm_]

20% sag for a DH bike is way way too little.

 

[TrumbullHucker]

yeah i run 35%-40%... something in between there

 

[Nick]

However, don't cycle the shock with no air in the chamber. It's possibly unrelated to your issue but when cycled without air they do have a tendency to aerate the oil and require a rebuild/rebleed as a result.

I think the OP mentioned in his previous post that he was riding with no BV pressure.

 

[Dh builder]

I think the OP mentioned in his previous post that he was riding with no BV pressure.

Yeah, I may have been. The shock bottomed out so easily, and I could easily feel it in the rear. I had to go over like a 2.5 foot drop though. Now those same drops I can't use the last inch of travel.

 

[troy]

Remove the spring and check if You can bottom out the shock then. Maybe IFP is in the wrong position or You turned BO knob too far, making ifp chamber very small or You changed BO settings without resetting air pressure...

 

[blindboxx2334]

yeah i run 35%-40%... something in between there

jesus that seems like a lot. i really liked 15-20% when i had the big bike. although, most, if not all of the trails i rode were jump after jump. not a fan of saggy bikes.

 

[TrumbullHucker]

maybe thats why i jump like sh*t

 

[blindboxx2334]

i dunno, i just dont see a saggy bike being fun to ride,(maybe im missing something..?).. let alone trying to take it off some sweet jumps.

 

[TrumbullHucker]

lmfao that gif is great... saved

 

[Dh builder]

So I took my spring off my shock and tried to compress it fully. The shock won't compress fully with no spring on it and I also let the air out of the boost gauge.

Nothing I can do will compress it, still stops above the last inch of travel.

What would cause the shock to not compress fully?

 

[DirtMerchant]

So I took my spring off my shock and tried to compress it fully. The shock won't compress fully with no spring on it and I also let the air out of the boost gauge.

Nothing I can do will compress it, still stops above the last inch of travel.

What would cause the shock to not compress fully?

The IFP depth seems to be at an incorrect height (to shallow). You could try to push in deeper by bleeding off oil (and likely air) at the seal head and IFP bleed port...at the point it might as well get a full rebuild.

 

[Jm_]

Yeah, running it with zero pressure will seriously screw it up.

 

[WestCoastHucker]

beards hide stretch marks...

 

[Dh builder]

Is it OK to use the shock for a little while longer in this condition? I already used it a lot like this.

 

[troy]

If it's locking up , You will probably bend a shaft or damage something else. So... no.

 

[Dh builder]

OK, I just did the stupidest thing in the world.

The shock wouldn't compress all the way because I took too many chain links off while adjusting for my single speed chainline. Was going to send it in for warranty than was looking more at that tight chain when fully compressed. I removed chain and the shock functions normally.

This is what happens when you have over 10" of travel, you need a lot of chain length. My goal was to keep my derail lure pointed a bit more forward so if I hit anything it pushed it up.

Now to figure out how easily the shock bottoms out. But damn, that chain stopped my bottoms out. I wonder what else I could have damaged.

 

[kidwoo]

Jesus. What kind of chain is that?

Send one to neko mulally.

 

[Dh builder]

I think my bike is good to go. Did a test drive today and happy to say that the bottom out seem to be good. IT only bottoms out on my largest drop to flat which looks to be taller than my bike. It is hard to tell just how high it is because it is a small hill, but I launch completely of the hill.

The smaller drop at 2.5 feet leaves about .5" of stroke left, but the higher drop looks to bottom it out.

Anyway, just a concern if anyone knows.

When I had the spring off and shock connected. I can feel the rebound really work as I lift the tire.

However, It is harder to feel the compression. Granted I'm pushing down on the tire to compress the shock.

SO my question is, just how much should you feel the compression when going from lowest setting to highest?

 

[HardtailHack]

Haha awesome, I was joking when I asked about the seat but a tight chain is one better.
Guessing you are using a Saint mech as a tensioner, that would have turned a Sram unit inside out.