Just upgraded from a very nice $2500 '07 Spec Stumpy FSR Comp to a $4400 '08 Spec Epic Carbon Expert. To say the Epic eats the Stumpy's lunch is an understatment. (Disclaimer: I admit the FSR susp sag & damping were never properly tuned & that the Epic susp is very well & finely tuned. Still I think the Epic would run circles 'round the FSR w/ identical tuning. The Epic is THAT much better.)
Second time today on my favorite trail, the Epic's unexpected & unprecendented high speed vs. the FSR is requiring me to look further & make more frquent glances ahead to avoid crashing. Things like the two rocks planted in the middle of the trail that require a quick little zig-zag between the rocks: the speed is too fast to steer through the rocks, meaning I'll probably rather steer around the rocks to the side next time.
Also, I'm climbing hills w/ very rocky terrain at speeds previously thought to be impossible. The Epic is in much higher gears on the middle chain ring vs. the FSR's smallest ring. I'm going so fast today that I'm encouraged to just keep powering even harder & fly even faster up the hills. (The terrain is rocky & rough, same as usual, but last ride, the first time on the Epic, the susp was tuned very well & the bike rode flat as a pancake over terrain that previously had the FSR upset.) So this time I figured just ride harder & faster, right?
Well, I was going so fast today, encouraged to just power as hard as I could uphill, thinking I might even keep up w/ one of the 35 year old jocks that occassionly appear (I'm age 55) that I finally upset the susp. So bad so that the front end bounced into the air, handlebars (& right elbow, thank God only minor ouchy) into the chain link fence, still no crash, but out of control, trying to get my fat butt off the seat to land, can't get my feet down, bounced off the fence, back to the left over some rocks then finally landed w/o crashing.
My analysis: at slower speeds (still flying way faster than ever on the FSR), the Epic susp is well tuned & doing a superlative job. At higher speeds, if/when the rocks are big enough, the limited 4" susp travel & preset comp damping is doing all it can, which isn't enough for the intended speeds, causing a loss of control unless speeds are minimized. (Please spank me if I'm wrongly & dramatically minimizing my lack of riding skills.)
Fork sag is perfectly set via air pressure for 1/4 the travel or 25mm (now 137 PSI; I'm 235 lbs). Shock sag is likewise perfectly set at 11mm. Also, both fork & shock rebound damping appear spot on on all but these very fast very rocky sections. The shock compression/brain setting seems spot on. (Will post all setttings upon request.)
The OEM fork is a Fox F100 RL (RL = rebound & lockout, no compression adjustment); Fox said a "$700" USD fork. Would a better fork help? I'm thinking something w/ a bit more travel (maybe 5") & adjustable compression damping to maintain control at higher speeds over rocky terrain. Must fork & shock travel always match (not the case w/ off-road motorcycles)? If yes, why exactly? As an avid motorcyclist I've always favored the more linear travel of a linear mechanical spring vs. so-called "progressive" or rising rate mechanical springs or the extreme rising rate of an air spring. (Lindemann Engineering/LE & other pro mc race susp tuners tout this philosophy, which may be all wrong on bicycles.)
Am I thinking in the right direction? To summarize, I'm thinking a fork w/:
+1" travel, 5" total
No or extremly low air PSI, again, to maintain linear rate
So-called "straight rate" or "linear rate" mechanical spring (not rising or progressive rate) set for my weight, w/ adjustable preload ramp/collar for sag
Or should I just get the OEM fork modified? What mods? Who?
What's the short list for forks in the so-called "sweet" price range, you know, 90%of the performance of the best race fork for 60%-70% of the cost?