Stanchions and springs
So I've got an '08 Fox Float RL, 130mm, and an '01 Marzocchi Bomber Z5 in the garage, that I'm looking at.
I never really thought about it too much, but I was aware of the fact that the air chamber is only on the left stanchion in a lot of modern forks. When I was rebuilding the old marzocchi and saw that it had idential configurations for each stanchion--which seemed to make a lot of sense to me--I revisited the concept. So you would be wise, when filling the marzocchi, to put equal pressures in each to keep the friction down on the pilot bushings.
But so then comes along Fox and Rock Shox and everyone else, including Marzocchi these days, with a heterogenous setup, sometimes with all the spring force completely in one stanchion.
What gives? Doesn't this increase the force on the bushings tremendously? And couldn't they just put an air channel in the crown somewhere, if another schrader valve would be ugly or get in the way of all the whiz-bang knobs?
it's about space afaik - a nice damper is what you want, no?
now double the expensive damper, and double the tuning and ...oh yeah weight..and for??
miniscule differences that the crown cant make up?.
just my thoughts -
Last edited by highdelll; 01-16-2012 at 11:42 PM.
Honestly... ahh I give up
I was thinking you could keep the configuration with the damping/rebound cartridge on one side and just pressurize the space around it, but I guess that would ruin the correct air "reserve" volume, especially if it was equalized with the smaller volume in the air chamber. And then, correctly tuned, it still wouldn't mean equal up-force on both sides.
Further complicating it is that air springs aren't linear, they're a 1/x kind of relationship, so they're only linear-ish with adequate reserve volume; you can't exactly shrink the original air chamber a bit to end up with the exact same result....
but but but me loves symmetry! And no the crown and slider bridge stiffness can't make up for it, it's just a constant opposite radial loading on upper and lower bushings of both sliders, if everything is very rigid with tight tolerances, and some additional twist loading especially in upper bushings if it's not.
On the other hand the rake angle of the fork already puts permanent loads on the bushings, so I guess I just need to declench and let it go. I just wanted to hear from the veteran fork rebuilders that it really is "no thang"
A lefty has has both damper and spring on the same side.
Yes but since the lefty is off-center from the wheel it has the same forces I'm "complaining" about. Additionally it now needs some clever method of dealing with the steering forces... I haven't really inspected one, whether it uses an eccentric stanchion or some kind of notched rod inside the seals or something...
But that had occurred to me before posting here, so, what are the opinions about the Lefty? I know a lot of the nutters that buy them must love them (owner's pride) but how about like a bike shop mechanic's opinion?
The bushings handle it just fine, and many years of use has already shown, provided the fork is serviced regularly. Provided a bushing is designed for it (and fork bushings are), loaded them isn't going to do anything.
Originally Posted by EmTee