Jolt Vehicle Tuning Guide

Realistic is quite a big world in hindsight. The biggest impact of all is that jolt out of the box threads longitudinal and lateral slip separately.

This leads to stable cars that can wheelspin, or breakout in curves on slip loss. It does however not match reality where a power induced wheelspin also reduces lateral grip. So the single biggest impact was adding the CustomTilerMaxImpulseCallback.

gist.github.com

https://gist.github.com/zzuegg/9a3687cbbb081394d856ce47231020d6

gistfile1.java

/**
 * Enforces a friction-ellipse constraint per wheel: the total grip budget is
 * shared between longitudinal and lateral forces, so when a tire is saturated
 * in one direction it has less grip available in the other.
 *
 * <p>Jolt's solver normally clamps each direction independently (rectangular
 * region), which means a wheelspinning rear tire keeps full lateral grip and
 * the car can't power-oversteer. This callback scales the max longitudinal and
 * lateral impulses down together whenever the normalized slip vector lands
 * outside the unit circle, mimicking the real-tire friction-circle:

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everything else i think is fine tuning. nice to have but not neccessary. with only the added callback you get a really unstable car if you use rear wheel drive. and it comes close to what i was used to in other games. AWD and RWD now drives / drifts completely diffently.

At least this part is what took me quite a while to figure out.

in this video you can see it nicely. the awd spyder is quite easy to handle and recover, while the senna is not. both cars with traction control off

Screencast From 2026 04 24 05 48 31

I can’t share a working demo because everything is currently done with a lot of custom stuff, the biggest issue is that even jme is not stock. Jolt is stock.