USDA substrate profile calibrating for this pin. Open Garage for class-specific setup guidance.
Grattan Raceway Park is a dirt oval in Belding, MI. On dirt, three numbers decide your night: density altitude (shown live above), stagger and cross weight, and where the surface sits in its dry-down. Nail those and you are racing, not guessing.
As temperature, humidity and barometric pressure shift across the day near Belding, the density altitude above moves with them — and so should your jetting and tune. racer.wiki uses uncorrected station pressure for the real number, the same math a Kestrel runs. Read the full density altitude guide →
Custom race shirts, pit crew hoodies, and all-over print jerseys for Grattan Raceway Park fans and drivers. Search 725 dirt tracks for logo art, add your number, live mockup — no MyRacePass $72/yr or design fees.
Open Merch Studio →