Most of the "P is better" comments have come from people saying the bike's too stiff in the back and gets unsettled over rough pavement as a result. P does soften about the first third or so of the stroke, but the middle ratio's about the same as in F and the last part of the stroke is stiffer than F. That's what it's designed to be like. Bit of compliance for solo riding on real world roads, with enough resistance at the end for two-up riding.Great topic guys, please correct me if I misunderstood some of the comments. The manual recommends “F” for track usage but are you all say “P” is actually is better? My Pani will be a track only bike so I’m trying to get the best advised from some of you guys that have put some miles on your bikes. Thanks!
Did a quick-n-dirty measure on mine in both positions recently just to see the difference. Pulled the shock and measured eye-to-eye distance at different wheel travel positions with the link in F and P. Not really accurate enough to post graphs or hard numbers (really need about .1mm accuracy to make that worthwhile), but in F it looks to stay at 2:1 all the way through (2mm wheel travel to 1mm shock travel). So F really is flat, or at least appears so on my crappy 1mm scale. P ends up creating a pretty straight line too; a very slight arc with the upward bow towards the middle rather than the end like you tend to see. In any case it's nowhere near as progressive as some bikes (my Daytona, for instance). Think two lines, one flat, and the other starting out lower but angled up a bit, so it crosses the flat one in the middle, and you have a good idea of how the two linkage positions compare to each other terms of effective spring rate. Think in the neighborhood of a 1.5:1 (stiffer) to 2.5:1 (softer) range instead of flat 2:1 and you'll be pretty close, but don't quote me on that. Need.better.measure; 1mm scale means +/-.5mm accuracy at best.
Anyway, with stock springs, that softer 1st 3rd will make the bike more compliant over bumps, but I didn't like what it did to chassis control. Felt like the rear wanted to squat and then pack, so I went back to F. I do need a little lighter spring on the rear of my base model at around 150lbs dry, but am trying to figure out what to go with. Dan Kyle said 8.0-8.5N/mm, so I was thinking 8.5 since everyone says the rear is a 9.0 and I'm not far out on my sag. However I'm thinking the base already has about an 8.5 on it. Coil, wire diameter & # of coils looks a LOT like 8.5 to me. Anyone have definitive numbers on the OEM base spring rates, or have measured them?
I tend to think F with the right spring is what you're going to be best off with for solo riding on relatively smooth surfaces (road or track), but I reserve the right to be full of it. Gnarlier roads might well favor P overall, even if you end up with a bit of wallow in the corners. But aren't those roads what Hypers are for?