More likely is that those who had beta versions of the game are just faster
than the rest of us, or at least more experienced with GPL. Expect them to go
as quickly, or moreso, with higher ride heights & longer bump ***s as setup
knowledge grows. From posts I've seen, I think the GPL bump ***/ride height
issue is misunderstood, and understandably so, as there are a number of factors
unaddressed in the game or manuals. I've seen posts that suggest that a 1 inch
ride height and 1.5 inch bump ***s means you're running "on the bumpers" all
the time; I don't believe this to be the case; that logic is likely based on
the old GP2 model with it's "packers" and doesn't apply to GPL, which
(surprise!) seems to model bump ***s more accurately, as illustrated by the
following observations. Note that these observations relate to the Lotus; I
haven't experimented with the others much. And forgive the length (of this
post, not the bump ***s :-)).
1) Ride height is independent of wheel travel. We don't know the mechanics in
GPL, but a common real-world way to set it is adjustable-length shocks. The
travel doesn't change, just the length between shock mounting points. You set
it after you dial in the spring rate, damping, sag, etc. (in a
no-ground-effects setting)
2) Bump ***s are not actual bump "stops". Bump ***s are pliable, and
effectively limit suspension movement by geometrically ramping up the effective
spring rate at the end of travel. The bump ***s(br's) deform, compressing
to a fraction of their static thickness, depending on the force applied. As
their length/stack height is increased, the slope of their spring curve becomes
shallower, though starting earlier in the travel and ending higher. The choice
of short or long br's affects the point at which the spring rate rise changes
from linear to geometric, and thus the force required for a given amount of
compression at a given coil spring rate. Given a steep enough curve, you never
actually hit a hard bottom; you just reach equilibrium between spring rate and
force applied by driving - a "soft" bottom.
3) Positive, or "bump" wheel travel of the Lotus is over 5 inches. To see
this, go to Spa and set your static ride height at 5.0in., your springs at
50/70, dampers at 1/1, and br's at 1.0. Run from La Source down into Eau Rouge
without lifting, apexing at about 165mph. Before you crash, you WILL
bottom-out, having used all of those 5 inches, in spite of the br's. Repeat
with br's on max, 2.5in. You still hit bottom - not enough steel/*** spring
rate yet. If you then raise the spring rates 5lbs. to 55/75, you'll clear,
barely. Go back to the pits and drop your ride height from 5.0in. to 1.0in.,
max the spring rates at 100/120, and br's maxed at 2.5, and go at it. You'll
bottom again. You'll need to raise the ride height to 1.5in. to clear the dip
at 165mph.
So; what's all this mean? For one, with a "low-rider" one-inch ride height,
br's won't make the suspension rigid, even at 2.5 inches long. In the example
above, the difference in coil spring force on the two setups, one at 5 inches
of compression on 55/75lb. springs and the other at 1.5in. on 100/120's, both
with full br's, is 640lbs., by my conjuring. That has to come from the br's,
by bringing them into play much earlier in the travel. Since actual shock
travel and geometry is unknown, we just have to wing it as to how much earlier.
But we're not limiting the travel with some kind of "stop", just increasing
the spring rate by another means.
There; I feel better now. Thanks for listening.
Steve B.
