Power oversteer happens when the rear tires lose grip under acceleration and the back of the car steps out as you get back to throttle. The fix is to reduce differential lock under power, soften the rear anti-roll bar, or ease off throttle application in the corners where it happens until the mechanical changes catch up.
Here’s what’s happening, and how to work through it.
What power oversteer actually feels like
You’re through the apex and getting back on the throttle, and the rear starts to rotate faster than you asked for, requiring opposite-lock correction to catch it. It’s most noticeable in slower corners where you’re applying a lot of throttle relative to the car’s speed, and it gets worse the earlier or harder you get back to power.
Why it happens
Applying throttle asks the rear tires to convert engine torque into forward grip, which uses up some of their total available traction. If the rear tires are already working near their limit from cornering load, adding torque on top of that can push them past the point where they can hold the car’s line, and the rear steps out. A locked-up differential compounds this by forcing both rear wheels to spin at closer to the same speed, which fights the car’s natural rotation and can make wheelspin on the inside wheel translate directly into a slide.
The whole problem: your rear tires don’t have enough spare grip to both hold the corner and put down the power you’re asking for.
How to fix it
The differential and rear mechanical grip are the most direct levers here, since this is specifically a throttle-phase problem.
- Reduce differential lock on power. Less lock lets the inside and outside rear wheels spin at speeds closer to what the corner actually demands, reducing how hard the diff fights rotation and cutting down on sudden traction loss.
- Soften the rear anti-roll bar. This keeps more rear mechanical grip available under load instead of concentrating it on the outside rear tire alone.
- Stiffen the rear springs slightly if the car is squatting excessively. Too much squat under power can unload the rear at the exact moment you need grip, so controlling that motion can help.
Start with the differential. It’s the change most directly tied to how torque reaches the rear tires, and it’s usually the fastest way to feel a difference.
What not to change first
Don’t jump to front-end changes like front springs or front anti-roll bar. Power oversteer is a rear-grip problem under throttle, and front changes won’t touch what’s happening at the rear tires once you’re back on the gas.
How to test the change
Run the same corner and apply throttle at the same point as before. Check whether the rear still steps out as sharply, and whether you’re still needing the same amount of correction. If the car now feels reluctant to rotate at all on exit, you’ve reduced diff lock or rear grip too far in the other direction.
When the diagnosis changes
If the rear steps out the moment you lift off the throttle rather than when you apply it, that’s lift-off oversteer, which is caused by a different weight-transfer mechanism and needs a different fix. If the car oversteers throughout the whole corner regardless of throttle input, check overall rear grip balance rather than treating it as a throttle-specific issue.
The bigger picture
Power oversteer is a phase-specific problem: it exists because the rear tires are asked to hold a corner and put down torque at the same time, and it eases once you rebalance how much grip is available for each job. Name the phase (throttle application on exit) and the imbalance (rear tires overloaded) and the fix list above is the fix list.
This is the same phase-and-balance framework built into onRails: identify the corner phase, identify the grip imbalance, apply the smallest effective change. If you’re diagnosing this by feel across a dozen setup sheets, onRails does that process for you.
Related phases
Related questions
Is power oversteer the same as exit oversteer?
They’re closely related. Power oversteer specifically points to throttle application and differential lock as the trigger, while exit oversteer can also include cases where the car is loose on exit even before full throttle is applied, driven more by weight transfer than by torque.
Will more rear wing fix power oversteer?
It can help at speed, since more rear downforce adds rear grip that’s available for both cornering and traction. But in slow corners where power oversteer is most common, aero load is too low to matter much, so mechanical changes are usually more effective there.
Should I just apply less throttle instead of changing the setup?
You can as a short-term fix, but it costs lap time everywhere that corner exit matters. Treat easing off the throttle as a stopgap while you dial in the differential and rear grip, not a permanent solution.