Fork bottoms out at about 50% of its travel

[Craig Armstrong]

I have a Rockshox Revelation 120mm fork and I noticed that I'm only ever using about 50% of the travel.

 

I figured my pressure was too high, so I reduced it and it didn't help at all.

Eventually I removed all air from it, and to my horror, its bottoming out at about 50% travel.

 

I've only owned the bike for about 6 months (bought second hand), but I'm fairly certain that at some point in the not-so-distant past, I was using all of the travel.. So I suspect that its not an issue of too much oil or something, because I haven't serviced it since owning it. There's a slight chance that I just didn't notice that it was always behaving this way, but I think its unlikely.

 

I suppose the obvious answer is to service it, which I will most definitely do, but I was hoping for some opinions on what I should possibly look at in the process.

[Jewbacca]

I have a Rockshox Revelation 120mm fork and I noticed that I'm only ever using about 50% of the travel.

 

I figured my pressure was too high, so I reduced it and it didn't help at all.

Eventually I removed all air from it, and to my horror, its bottoming out at about 50% travel.

 

I've only owned the bike for about 6 months (bought second hand), but I'm fairly certain that at some point in the not-so-distant past, I was using all of the travel.. So I suspect that its not an issue of too much oil or something, because I haven't serviced it since owning it. There's a slight chance that I just didn't notice that it was always behaving this way, but I think its unlikely.

 

I suppose the obvious answer is to service it, which I will most definitely do, but I was hoping for some opinions on what I should possibly look at in the process.

It might be dry.... no oil.

 

Just get someone to have a look. Best case it needs fresh oil and a good once over, worst case you have an issue with the damper. 

 

Either way I don't think you can fix either personally, so best to just give it to someone who can.

 

Those revelations are nice forks. I run a 120mm on my XC bike and I love it.

[splat]

I have the same/similar fork my Camber, and it's doing the same thing.

Not the first time either.

Oil has leaked past a seal and is now filling the air chamber, thus restricting your travel.

A service will sort that out.

[Craig Armstrong]

I have the same/similar fork my Camber, and it's doing the same thing.

Not the first time either.

Oil has leaked past a seal and is now filling the air chamber, thus restricting your travel.

A service will sort that out.

 

Funny, my bike is a Camber too. 

Thanks, will just do a service then and hope it sorts it out. 

[Meezo]

Let out all the air and see if it bottom's out all the way.

 

If it does, pump 25psi try and again 50psi and try again and so on...

[Bos]

Sounds like to much oil in the damping system and causing hydraulic lockout. It could theoretically also be what Splat said, on the rebound right leg side, If the oil drained from the damper and is sitting in the bottom of the lowers, when the stanchions. comes down into the oil there's nowhere for it to go but up the fork leg..with big hits this might push through the dust wipers onto the exposed part of the stanchions.

[Vetseun]

Let out all the air and see if it bottom's out all the way.

If it does, pump 25psi try and again 50psi and try again and so on...

Read the original post.

[Meezo]

Read the original post.

Oops my bad

[andydude]

It might be dry.... no oil.

 

Just get someone to have a look. Best case it needs fresh oil and a good once over, worst case you have an issue with the damper.

 

Either way I don't think you can fix either personally, so best to just give it to someone who can.

 

Those revelations are nice forks. I run a 120mm on my XC bike and I love it.

Slight hi jack. Out of interest, on what bike are you running the 120 fork? Was it initially/standard a 100 or 120?

 

Asking because I want to build a normally aggressive alloy ht which would normally come with a 100 fork. But not sure whether I should try 120 instead.

[Me rida my bicycle]

Just had a similar problem had it serviced and all perfect again. Rockshox luckily very simple.

[Tankman]

Have you checked to see if there are any tokens in the air chamber?

Let all the air out.

Use a 24mm socket, remove the air cap and see what is inside.

[Jewbacca]

Slight hi jack. Out of interest, on what bike are you running the 120 fork? Was it initially/standard a 100 or 120?

 

Asking because I want to build a normally aggressive alloy ht which would normally come with a 100 fork. But not sure whether I should try 120 instead.

It's the older Lapiere XR929.. It was essentially a 100mm front and rear race bike, but with a 120mm fork set with more sag you don't really change much at all except being able to step away from race forks and improving the smashability of the bike.

 

It is my 'do it all' fun bike that really does 'do it all'. Trail day at Jonkers yesterday was great. world champs AR last year was also great. 

 

100mm set to 25% sag vs 120mm at 35% is same same but better. Weight penalty but I'm not racing anyone so yeah nah.

 

I know their test fleet had a 120mm Pike on, so I think it is a 'thing'. The frames are long and slacker than traditional XC/XCM bikes so it works nicely.

[NotSoBigBen]

Sounds like to much oil in the damping system and causing hydraulic lockout. It could theoretically also be what Splat said, on the rebound right leg side, If the oil drained from the damper and is sitting in the bottom of the lowers, when the stanchions. comes down into the oil there's nowhere for it to go but up the fork leg..with big hits this might push through the dust wipers onto the exposed part of the stanchions.

I had that just a week ago and it was as you say that the oil had drained out of the rebound into the 'lower' ... a quick service and it's working a treat again!

[Quagga]

I have the same/similar fork my Camber, and it's doing the same thing.

Not the first time either.

Oil has leaked past a seal and is now filling the air chamber, thus restricting your travel.

A service will sort that out.

Not sure I understand, air is on left side and oil is not right side. How would the oil leak to the air chamber?

[Headshot]

Not sure I understand, air is on left side and oil is not right side. How would the oil leak to the air chamber?

Quite so. This sounds like some form of hydraulic lock  - perhaps because oil has indeed entered the lower leg i.e below the damper on the right hand side. If that did happen I'd imagine that the damper stopped working too which would have meant a very fast undamped rebound and the first sign that something was wrong.... When my damper popped it was the first thing I noticed.

[Adr!@n]

Not sure I understand, air is on left side and oil is not right side. How would the oil leak to the air chamber?

 

Sounds like to much oil in the damping system and causing hydraulic lockout. It could theoretically also be what Splat said, on the rebound right leg side, If the oil drained from the damper and is sitting in the bottom of the lowers, when the stanchions. comes down into the oil there's nowhere for it to go but up the fork leg..with big hits this might push through the dust wipers onto the exposed part of the stanchions.

 

 

The air spring is the one side and the damper on the other. The lower leg on the the damper side is just a chamber and the oil has moved to the wrong side of a seal.