Adjusting a Zeb
16/11/23 21:28 Filed in: Gear
After having a couple of Fox 36 forks on past bikes, and really liking the Boxxer forks on my DH bike, I selected a Slash with Flight Attendant; meaning Zeb forks.
My experience with the Boxxer has been ideal from day one. Set the pressure to that recommended for my weight and one or two minor tweaks to make it feel "right". And then nothing since. It was so "right" I didn't bother to install a ShockWhiz for feedback.
The Zeb began in much the same vein. I put in the recommended air pressure and ended up removing a few psi. It was great. Big hits would use up almost the entire travel, riding along it seemed to sit not-too-far into the travel and the Flight Attendant lockout was a very solid lockout. On my final day of a week riding in Tasmania, something changed. The lockout was soft - the fork visibly moved a lot under pedalling and there didn't seem to be the same amount of rebound damping as I'd had up until that point. I thought the Charger cartridge had blown.
The fork went to RockShox and their dyno said it was 100% as intended.
My shop just happened to have a new customer's Slash being built at the same time, so they set both forks up for the mechanic and he rode them both back-to-back and couldn't discern a difference.
I got the bike back and did all my riding over winter on shorter travel bikes. The Slash mostly sat. And with Spring on us and Thredbo opening in sight, I pulled the Slash out and started riding it again. I had to set up the pressures from scratch because of all the experimenting by RockShox and the shop. I put a ShockWhiz on the fork this time. With the same pressure I used in Tassie a few months ago, I found it very stiff and impossible to get more than about 1/2 travel. The ShockWhiz concurred:
Too much air pressure.
Too much compression damping.
Too many tokens (there were none!).
Dropping the air down incrementally until it was about 1/3 less, I was still not getting full travel and while the fork felt soft, it was also not settling into travel with sufficient sag.
The Flight Attendant's function of locking out the shock when pedalling isn't fit for purpose with the ShockWhiz measuring damping and spring rates, so I have had the fork in manual "open" mode the whole time. Thus, I can't comment on the firmness or lack thereof for "locked" mode.
A suspension fork is a pretty simple device, really. I cannot imagine what could have changed that effected such a significant change in the fork's behaviour.
It is going back to the shop for a strip-down. Shop owner has put a Zeb on his own bike recently and went through the fork lubricating seals and checking torque on bolts to get the best possible performance out of his fork - he's going to check everything internally is good with my Zeb.
Fingers crossed he finds something to "fix" because I'm almost out of ideas.
There is a British company that makes negative tokens for forks. Effectively reducing the compression ratio in the air chamber, perhaps it will permit me to run more baseline pressure and still achieve full travel? Check out Trutune.co.uk if you're curious. Obviously, I haven't tried one yet so I can't comment on how much difference it makes. The science seems sound, if a little bit like magic.
I want my "new" Zeb back.
My experience with the Boxxer has been ideal from day one. Set the pressure to that recommended for my weight and one or two minor tweaks to make it feel "right". And then nothing since. It was so "right" I didn't bother to install a ShockWhiz for feedback.
The Zeb began in much the same vein. I put in the recommended air pressure and ended up removing a few psi. It was great. Big hits would use up almost the entire travel, riding along it seemed to sit not-too-far into the travel and the Flight Attendant lockout was a very solid lockout. On my final day of a week riding in Tasmania, something changed. The lockout was soft - the fork visibly moved a lot under pedalling and there didn't seem to be the same amount of rebound damping as I'd had up until that point. I thought the Charger cartridge had blown.
The fork went to RockShox and their dyno said it was 100% as intended.
My shop just happened to have a new customer's Slash being built at the same time, so they set both forks up for the mechanic and he rode them both back-to-back and couldn't discern a difference.
I got the bike back and did all my riding over winter on shorter travel bikes. The Slash mostly sat. And with Spring on us and Thredbo opening in sight, I pulled the Slash out and started riding it again. I had to set up the pressures from scratch because of all the experimenting by RockShox and the shop. I put a ShockWhiz on the fork this time. With the same pressure I used in Tassie a few months ago, I found it very stiff and impossible to get more than about 1/2 travel. The ShockWhiz concurred:
Too much air pressure.
Too much compression damping.
Too many tokens (there were none!).
Dropping the air down incrementally until it was about 1/3 less, I was still not getting full travel and while the fork felt soft, it was also not settling into travel with sufficient sag.
The Flight Attendant's function of locking out the shock when pedalling isn't fit for purpose with the ShockWhiz measuring damping and spring rates, so I have had the fork in manual "open" mode the whole time. Thus, I can't comment on the firmness or lack thereof for "locked" mode.
A suspension fork is a pretty simple device, really. I cannot imagine what could have changed that effected such a significant change in the fork's behaviour.
It is going back to the shop for a strip-down. Shop owner has put a Zeb on his own bike recently and went through the fork lubricating seals and checking torque on bolts to get the best possible performance out of his fork - he's going to check everything internally is good with my Zeb.
Fingers crossed he finds something to "fix" because I'm almost out of ideas.
There is a British company that makes negative tokens for forks. Effectively reducing the compression ratio in the air chamber, perhaps it will permit me to run more baseline pressure and still achieve full travel? Check out Trutune.co.uk if you're curious. Obviously, I haven't tried one yet so I can't comment on how much difference it makes. The science seems sound, if a little bit like magic.
I want my "new" Zeb back.
