I Built a Free Forza Horizon 6 Tuning Calculator — Gear Ratios, Suspension & PI (60 Cars)

If you've spent any time tuning cars in Forza Horizon, you know the pain: tweak a setting, drive to a race, realize it's wrong, drive back to the garage, tweak again, repeat. Half an hour gone and you haven't even raced yet.

So I built a tool that gives you a bird's-eye view of your tune before you even load into the game.

What it does

The FH6 Tuning Calculator lets you pick any of 60 confirmed cars, adjust 5 tuning parameters in real-time, and see the performance impact on a live radar chart. It estimates your PI so you know if you're about to bump up a class before you commit the tune in-game.

It's not a replacement for the in-game tuning menu. Think of it as your first draft engine — rough in the gearing, tire pressure, and suspension here, then fine-tune the alignment and damping on a test track.

The 5 sliders

Final Drive Ratio is the big knob. Drop it for top speed highway runs, raise it for tight technical circuits. I wrote a whole section about tuning this first, with a real R34 Skyline example where I gained half a second just from not bouncing off the rev limiter.

Tire Pressure actually matters now in FH6. Lower PSI = bigger contact patch = more mid-corner grip, but the tires overheat faster. There's a sweet spot depending on race length.

Spring Stiffness has a weight heuristic I worked out: start at 8.0, add 1.0 for every 500 lbs over 3,000, subtract 0.5 for every 500 lbs under. Heavier cars also need a bigger front-to-rear split.

Anti-Roll Bars are a balance knob, not a stiffness knob. If the car understeers, soften the front ARB. If the rear steps out, soften the rear. Most of my road tunes land around 22 front / 20 rear.

Downforce only works above 80 mph. Below that, it's dead PI budget. Stop putting 250 lbs of aero on B class cars that never crack 90 mph.

Built into the FH6 Wiki

The calculator lives at fh6wiki.com/tuning-calculator, part of a larger FH6 Wiki:

• 85+ car database with full specs
• Interactive Mexico map with 119 locations
• 148+ in-depth guides

Everything is free, no signup, no ads. Built because I got tired of scrubbing through 20-minute YouTube videos to find one stat.

Why I built this

FH6 doesn't release until later this year, but the community is already figuring out the meta. I wanted one place to check car specs, compare builds, and rough in a tune without juggling 6 different tabs and a spreadsheet.

Give it a try and tell me what's broken: fh6wiki.com/tuning-calculator