Motomathics

Step response

Front and rear quarter models. Front sees the input at t = 0. Rear sees the same input offset by Δt = wheelbase / speed. Tune wheel rate, compression, and rebound until the traces settle together, then send those slopes to the damper plot as a traditional bilinear baseline.

Inputs

Front

reb/comp 1.33 · 26% / 34% of critical

Rear

reb/comp 1.38 · 26% / 35% of critical

Results

Response vs time

Response rate vs time — climbing (rebound) +, falling (compression) −

Dashed marker is rear-axle arrival. The rear line starts there, shifted by wheelbase / speed. The goal is to sync the two traces in time, not overlay them at t = 0.

Rear delay
0.095 s
WB / speed — rear plot offset
Timespan
1.50 s
plot to 1.60 s
Front wn
1.27 Hz
c_crit 7,032 N·s/m
Rear wn
1.64 Hz
c_crit 6,222 N·s/m
Front ζ
c 0.26 · r 0.34
reb/comp 1.33
Rear ζ
c 0.26 · r 0.35
reb/comp 1.38
Front overshoot
41.2%
settle ~ 1.50 s
Rear overshoot
40.1%
settle ~ 1.30 s from t=0

Damper spec

  1. Tune wheel rate, compression, and rebound until the front and rear traces settle together after the rear delay.
  2. Send those slopes as a traditional bilinear baseline: step rate becomes high-speed, low-speed is 5× HS, knee 50 mm/s, high-speed end 400 mm/s. Front → curve A, rear → curve B.
  3. On the damper plot, trim the knee or slopes if the shop wants a different blow-off, then export the Pro spec PDF for a manufacturer or tuner.
Front C / R
1,800 N·s/m / 2,400 N·s/m
HS on the dyno · k 28,000 N/m
Rear C / R
1,600 N·s/m / 2,200 N·s/m
HS on the dyno · k 32,000 N/m