I’ve got a Specialized Camber Evo 2015 29er and the Forks are knocking when take hard hits.

Also I set the air pressure for my weight, sit on the bike and there is only 10% sag. There’s supposed to be 25%. They feel very horrible on the rough stuff (lots of frequent but small hits) and when they take bigger, fewer hits, the forks are knocking.

Anyone know whats wrong ?

Also I set the air pressure for my weight,

ignore the suggestions on the side re. weight and just get the right air pressure for whatever sag you want

Oh yes and the forks are Reba’s

Also I forgot to mention they loose air as well sometimes. On a ride I did on Sunday I found they went down to just 30 psi! When they were at least 60 psi when I last pumped them up 2 rides ago.

ignore the suggestions on the side re. weight and just get the right air pressure for whatever sag you want

That’s what I’ve been doing sometimes but it does show that there must be something wrong with the fork when you have to set it at about 30% less than what it says on the side to get the recommended sag

The air pressure chart on the Rebas is weird. If I put in the recommended pressure for my weight they are terrible. Just set it for the sag you want. I’m about 70kg kitted and have them at about 75-80psi currently. Versus about 110psi on the chart. That gives me about 20% sag.

However, sound like they need a service if they’re losing pressure like that. Could just be a faulty schrader valve though.

Best thing I did for mine recently was stick a bottomless token in. Rockshox don’t recommend it for 120 Rebas, but it has made the performance shedloads better.

I’ve had a full service done in April so I’d be surprised if they needed another one so soon. Probably only done about 1,000 miles since then.
I had the lowers serviced a week ago (in response to these problems), didn’t make a difference.

The rockshox manual recommends a full service every 100 hours. That’s 1000 miles at 10mph. I’d say a full service will fix all your woes.

Do you reckon this knock is just the fork bottoming out, or something else?

Do you have full travel, or is the fork a bit sucked down in the travel?

Who did your service?

Big thumbs up for TF Tuned. My Pikes never felt right from new. A service from TF sorted out the harshness and they feel great now. Changed the seals to PUSH seals, tweaked the rebound and upgraded bits on the damper. The difference is unbelievable. Money well spent

Do you reckon this knock is just the fork bottoming out, or something else?

The forks aren’t bottoming out when I hear/feel the knocking. That was my first suspicion but when I checked the ring it showed they hadn’t bottomed out.

Do you have full travel, or is the fork a bit sucked down in the travel?

I’ve got full travel (120mm). I used to have problems of the fork being a bit sucked down in the travel (only getting 100mm) until I pressed the valve under the fork which let all the air out & I pumped it back up and the full travel came back & hasn’t gone down again since.

Who did your service?

A home mechanic who has set up a workshop from home in Hag fold & runs his own business from there. I go to him as he is local to me. Only a 2 minute ride to his house.

If they’re loosing pressure then you need an airspring service kit.

A service could mean anything.

2015? Should still be under warranty, 2 years on Rockshox.

grannyjone – Member
Who did your service?
A home mechanic who has set up a workshop from home in Hag fold & runs his own business from there. I go to him as he is local to me. Only a 2 minute ride to his house.

Honestly, I’d send them to TF. Their expertise is second to none. Anyone can do a service. The manuals are all there and even a home mechanic can do a full service. The TF guys really understand how the forks work and how to make them work properly. Money well spent.

2015? Should still be under warranty, 2 years on Rockshox.

Yep for this I would go back to the retailer who you got the bike from. Speak to them and go from there. You can do a lowers service and not see anything at all of the internals. Not saying anything about the guy who did them. Could also be something not done up right etc.

Hag Fold in Atherton? You’d be lucky to come out alive 😉

With your username, I may be teaching you to suck eggs, but have you checked that your headset isn’t the source of the knock?

TBH though, it sounds like they need a full service. One thing you could do to improve performance and exclude the schrader valve as the source of the pressure loss is buy a bottomless token/air cap kit and swap it over with 1, maybe 2 tokens added. It’s a 10 minute job – all you need is a large socket head to undo the air cap.