Yes – I fitted this latest 2021 air spring to a 2016 Pike B1 (160mm) that already has the previous Debonair spring upgrade in it and a Charger 2.1 damper as well. Used the same pressure and can confirm the fork sits that bit higher at rest and so I effectively have 20-25% sag whereas before it was nearer 30% to get the ride feel I wanted.
The change from the original solo air to the fist Debonair was very noticeable with a definite increase in small bump plushness.
This latest ‘2021’ or C1 upgrade felt good, subtly different but riding the same trails (Peaks – Winhill/Ladybower ‘offpiste’) this weekend just gone on the 2021 air shaft compared to the previous weekend on the other air shaft definitely felt better. Same trails, same conditions, very dry, dusty, rooty and sometimes rocky. Strava also logged a few PR’s and I’ve ridden those trails a fair bit over the last two years or so. I didn’t notice much, if any, change in small bump but I think there was something useful going on in the mid stroke that maybe held the front up a bit and improved confidence on some of the steep bits. Of course some of that is probably down to a freshly serviced fork (the small bump always feels a bit better in the fist few rides!). Overall it felt good and I liked it, so better, but hard to pin down exactly what. Certainly nothing adverse stood out.

I’ve got about 10 hours of dry weather lumpy riding on the new debonair c1 in my 140mm Pike.

So far I think the armchair theorists are correct – it is a bit more reluctant to move off the bat on the small stuff.

I didn’t like it at all at my B1 debonair pressures, so I dropped the pressures by 5 to 10% and installed an air token.

Set up like this there’s the tiniest suggestion of a bit more reluctance to move off the top (it’s pretty negligible) but they are much better than the B1 air spring when you’re pushing on.

Weirdly doing a static sag setup they appear too soft, but when you’re actually riding the bike they’re perfectly fine.

Overall for my style of riding the pros outweigh the cons.

My reading of that is it’s less about changing the volume and more about changing the pressure in them at sag?

So at top out you still have similar pressure (and therefore sensitivity)

At bottom out it’s irreverent.

At sag or mid-travel there’s less pressure in the negative spring because you’ve started with a smaller volume but stretched it by the same amount. Effectively making it begin ramping up sooner?

I’m a couple of rides into my updated fork(202Pike Ultimate) and my thoughts are very much inline with @scienceofficer.

Trundling up a fireroad, maybe not so keen to move off small stuff…but it feels more poppy, composed at speed and holds a line better i think.

I really couldn’t get the previous spring set up to my liking…i think this is going to be much better for me and most riders I would say.

Anyone know any more info on the new Rockshox Zeb fork yet?

I’m finally taking the plunge on a ’21 ebike as I can get one early & it comes with the above. The models relate to the Lyrik (as in it’s still called the Ultimate RC2) so i’m just assuming its a bigger, beefed up version?

So it seems that something has recently changed from Rockshox with regard to the compatibility of the C1 Debonair upgrade to A1 & A2 Pikes (2014-2017)

From the current spare parts catalogue (SPC) 2020 revh – this is the compatibility chart;-

But the ‘Debonair upgrade and travel change kit manual revD’ advises that they aren’t compatible and instead advises the previous debonair shaft;-

I bought my 160mm C1 shaft from TFTuned so I’ve asked them. Apparently something might start tapping not sure what. Seeing that I bought it from them when it was compatible but now it isn’t it seems a bit of a concern?