Let’s do this! £120 for fork tokens that are probably printed?!

Could you just drill a load of holes in your current fork tokens?

Rickon they don’t do what fork tokens do, so you could drill tokens, but you’d have to fill them with activated carbon ™

So I ran mine at tweedlove in some really grim slop and came away very happy, amazingly didn’t crash once, even on hammertime! Brand new T9 butcher helped but forks felt really nice, tons of grip and plush without being divey

Been thinking about the physics of these. I have my doubts that it is adsorption, air would have to be adsorbed and desorbed multiple times a second and I just don’t think it’s that fast a process. I couldn’t find any useful literature discussing speed of adsorption, papers tend to concentrate on total volume rather than speed. People seem to be getting some benefit, so I wonder if it is the friction of the air moving in and out of the pores in the activated carbon. This would act like additional damping but more rapid and I think more progressive than oil moving through a nozzle would provide.

These things do seem quite interesting and the science is quite mind boggling. I did assume they were manufactured from “solid” activated carbon but it appears that the “token” is a 3d printed canister containing the activated carbon. Now the science might be funky, but activated carbon doesn’t actually appear that expensive, £106 for 25Kg. Unless there is something techy about the spec of the carbon, it’s does seem kind of pricey. The fact they also have a finite lifespan is a downer too.

I’m struggling even with the initial premise that large negative chambers “cause” greater progressivenessivitude
Surely that’d only be the case if the relative sizes of +ve vs -ve had changed ?

I suppose maybe in a 180/190mm single crown fork there might have to be a trade off between the two and I also suppose that manufacturers might generalise that a typical owner of such a fork might be heavier than Benji and might be expected to ride mighty hard, all of which would mean prioritising -ve over +ve (for the mid- and end-stroke support (err, bro) but also feeling nice in the car-park)

If so, I bet a 40mm DC air fork would piss on the Zeb – are DH forks ever air-sprung these days ?

@scaredypants 99% of the uci dh teams run air forks

I suppose maybe in a 180/190mm single crown fork there might have to be a trade off between the two

Yep, I had a 190mm Zeb v1 and it was impossible to get full travel, way too progressive.

V2 Zeb at 180mm is actually a lot better and I’d only try one of these out of curiosity – I don’t feel driven to by a performance issue IYKWIM.

PS. “Tardis token” is very good Ben

“I have my doubts that it is adsorption, air would have to be adsorbed and desorbed multiple times a second and I just don’t think it’s that fast a process.”

I can’t see why adsorption couldn’t happen this quickly – you’re dealing with a pressurised gas and molecules attaching themselves to the surface of a solid. It’s not like you’re having to push a high viscosity fluid into a porous sponge. Despite the name, adsorption is very different thing to absorption.

I’m not finding much on adsorption timing. The few bits I saw looked slow but with a faster start.

Presumably a shokwhizz (?) would tell you if the pressure was ramping up less quickly.

I wonder if a simple screw on piggy back chamber would work?

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I find I have to run Zebs with loooads of sag to get the most out of them… so was interested in trying this… ’till I got to the price. I’d still like to try one… but would need to try for myself before handing over the folding stuff.

Go on Ben, lend it to Kelvin to try.

Then he can lend it to me.

My Zeb feels pretty good at 180mm to be fair, but could it be better? I don’t know.

From my cold dead hands.

I am fascinated by the idea of these, since seeing the demo at Tweedlove a year or so back. I’d potentially be curious to try one out if I could ignore the price.

What I can’t work out is how it would be affected or not by a light covering of suspension oil. Rockshox recommend a bit in the air chamber, presumably over time at least some would end up in the carbon bit? Would that reduce the adsorbtion properties? Does that make it a wear part?

Does that make it a wear part?

Yes, they give it a lifespan.

But this it the bit I’m not convinced about, carbon filter beds are used to remove dissolved HC from aqueous liquids (that’s how Britta filter jugs work). In my mind something that small is going to be polluted quickly, but apparently isn’t.

I wonder if a simple screw on piggy back chamber would work?

Not in the same way.

This is essentially removing air at compression, and putting it back in at extension. A bigger chamber would ramp up less all through the travel (an infinite volume wouldn’t have any progression, as soon as the pressure under the piston exceeded the air pressure above it it would start moving and not stop).

So this (in principle) keeps some progression through the middle of the curve but takes the ramp up out at the end.

Trek did something similar with their rear shocks, the air chamber opened a 2nd chamber further into the travel.

Would be good to see some testing behind the facts, i.e. pressure charts for the claims, as well as over a period of time to see how effective they are when they’ve been used several times. It all appears to do what it claims, and over time, i’m guessing it’s got a healthy factor against the amount of activate carbon required and the amount used, so deterioration due to doing what it’s meant too won’t cause an issue for a fair few cycles, again mainly assumptions without the data.

Everything inside my forks is plastered in oil. Once plastered in oil I fail to see the material absorbing anything but oil, even if it can.

Every time I rebuild a fork it feels better, for a while. It’s all clean, lubed and smooth running. For a comparative you need to do some in-out testing, Ben.

As a light rider with a lighter wife (65kg and 53kg) I’ve found these things help:

running the fork at pressures well below what is recomended; up to 2bar less than the minimum on a Rockshox for Madame, except for Ainsa

thin oil: 2.5w or 5w  motorcycle fork oil

very little air in the negative chamber, 1 or 2bar or nothing at all.

turning the bike upside down now and then to wet all the seals

There was a chap that said his had fallen apart and ruined his forks. Was that a one off or just a rumour? I haven’t heard anything else like that, has anyone else?