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I have 2 sets of Pike Ultimate's with the newest C1 spring (one mine, one the wife's) and I'm not sure if the transfer ports are getting blocked or if I'm misunderstanding.
The set on my bike feel pretty harsh but they're still showing the correct amount of stanchion. If I let all the air out, they suck down so there's maybe half the stanchion showing. The wife wouldn't notice if hers felt harsh but hers do the same if I let all the air out. I've also watched a couple of travel change vids on YouTube which look to have C1 springs and they do the same.
I also have another set of older Pikes but they don't suck down letting the air out and neither do any of the vids on YouTube which look to be older air springs.
So is this a C1 thing or do I need to take apart and investigate. I've already had mine apart and put back together about a month ago.
The air valve is only connected to the positive side. The negative side will equilibrate with the positive, but only at full extension. Which means if the fork was sagged, even slightly, when you let the air out (of only the positive side), it'll suck down because the negative side expands against no resistance. If you forcibly extend the fork, you should hear a hiss as the sides equilibrate.
Just a guess?
Thanks @Superficial
I've been and pumped them up, making sure to equalise as doing so, and let the air out slowly with no weight on them and they still sucked down.
The wife's are due a lowers service anyway so I'll pull the air spring out as well. Hopefully nothing untoward going on.
It'd still be good to know if anyone else has noticed the same when letting air out with a C1 spring.
The transfer port sits above the piston, if you let the air out of the main chamber, the negative chamber will force the air spring up, causing the forks to compress.
The newer air springs (B1 and C1) have a much larger negative volume, so will suck down a lot more.
I've found the C1 airhsaft to be harsher than the B1, so run B1's in both my Pikes and the other halfs Lyriks,
Have you tried forcibly extending them (push the brace and crown in opposite directions)? If they still suck down even after you've extended them to the top-out point, then you have a problem with pressure equalisation.
SirHC Full Member
The transfer port sits above the piston, if you let the air out of the main chamber, the negative chamber will force the air spring up, causing the forks to compress.The newer air springs (B1 and C1) have a much larger negative volume, so will suck down a lot more.
@SirHC thanks, that makes some sense and is basically what mine & the wife's are doing. So a good chance it's normal with the B1/C1 springs. My older Pikes (2019) forks will probably have an older spring, though the spring was new in April last year.
@Superficial yep, foot on the axel, yank the bars. I get a small pop type noise and they sit at full extension less some sag.
sounds like the spring is fine, though they can get blocked with grease if you go a little over the top when servcing, changing air rod, etc. But, i was experiencing the same harshness, albeit with the A1. Changed to the B1 and it did make a difference, but still found it too harsh (or when run with little enough air to get the early stroke sensitivity then it lacked mid stroke support) - in the end I put a Fast Suspension 3 way damper in it, so that I could adjust the mid-stroke damping for more support and keep a lower air pressure and early stroke sensitivity.
I’ve got no answer to your solution as such, but my 140mm travel Pike Ultimate RC2s always seem lovely and plush.
Just to check you aren’t running too little pressure in them - if so you might sag all the way through the initial stroke and be hitting the mid stroke where it starts to firm up earlier than you should?
I’m not sure if my Ultimates have the B1 or C1 spring in them.
I also have what was a Yari but is now effectively a Lyrik with a charger 2 rct3 damper / skf seals / C1 air spring in. I can’t say moving from 140mm B1 to 150mm C1 that I felt the fork get any harsher. Still seems fairly decent to me.
On the C1, the seal crossing the transfer port pretty much happens with the piston resting/compressing the top out stop.
When you release pressure it is possible for the piston to pass above the transfer port (suck down) with no chance of any of the negative air releasing. This leaves the fork in a state very different from its intended working state.
Definitely cycle the fork pulling out to a hard topout and nudging it a bit into its travel when adjusting pressures.
equilibrate - I thought that was a made up word so had to google it, you live and learn eh. I would still say equalise though.
Thanks all, sounds like the forks are working pretty much as they should and I need to play with pressure etc. It's just odd that I thought they felt good till recently!