We can not simply judge this by brand, but rather specific tyre itself. Soft compound vs soft structure particularly sidewall are different as well.
Generally eco tyres have softer sidwall but stiffer compound for longevity.
Moving higher up UPH, UUHP, MP, you get stiffer and stiffer structure, but softer and softer compound.

Michelin UHP (PS4/PS5) sidewall is typically softer than Continental UHP (PC6). Difference is about 2-3 psi.
From Continental UHP PC6 to UUHP SC7, I drop 5 psi, and SC7 is still stiffer.

You are absolutely correct. The key is software.

I'll break things down to 4 category - 4x4, old school mechanical AWD, modern common AWD, and special design.

4x4
Manual select. Lock center diff to fix 50:50 front rear. Open the center diff become 2WD. The left right can be locked or LSD depends on manufacturer, car.

Old school mechanical AWD
Think Audi Quattro when it first introduced. Use Torsen LSD on center diff, front diff, rear diff.
Fast, reliable, always on, automatic torque distribution.
No control of torque split by software.

Modern common AWD
Most falls there, including Audi new Quattro Ultra. The center diff is multi-clutch, computer control the lock ratio for torque split.
Some manufacturers has own design, but most FWD layout AWD (transverse engine layout) use Haldex.
Here's the 2 most important parts, 1) the front and rear axle have open diff. 2) For FWD, center shaft get input through front diff.

As a result when the car is airborn, front wheels are free spinning and no torque is send to rear at all.
Up to 50% torque to the rear come at condition front wheel has some resistant.

So how is it done? The answer is BRAKE, use brake for torque vectoring front to back + left to right (remember all axles open diff).
So there need different logic, different threshold for off road vs tarmac. Different car makers have proprietary algorithm. Thus they key is software + quality/precision/resolution of the ABS sensors.

Subaru Symmetrical also fall in here, the only different is the both front drive shafts have equal length. Eliminate the torque bias to one wheel due to unequal flex of the drive shaft (Cause of FWD high power hot hatch torque steer), but modern material greatly reduce this.

For RWD bias like BMW xDrive, this is generally not a problem, because the limitation is reversed. Can't send or limited torque to the front wheel, the target buyers usually don't mind. But the control is still the same, use brake for models without LSD.

Special Design
Electrical rear axle like the Volvo. No center shaft, computer control rear wheel electrical directly. Close to 4x4, except left to right torque split still use brake due to no LSD.
Another special like Ford Focus RS, Toyota Yaris/Corolla GR, VW Goft R Mk8. They allow center diff slip, to allow rear wheel spin faster than front wheel to get >50% torque to rear wheel despite transverse engine layout (details, how, I posted before, not to repeat here. That itself is another lengthy write).
That's how they enable drift mode for FWD based AWD.
I suspect newer A45 also the same, but I haven't read the technical document. So this one is just my personal guess.

This post has been edited by constant_weight: Aug 27 2024, 10:07 AM

When a car turn, the outer wheel will spin faster than inner wheel. When car goes straight, no different between left right..
On tarmac, we need to compensate for the difference, thus the differential. On slippery road, the tyre slip can compensate the difference.

Same for any car. ICE, hybrid, EV.... differential is differential.


Most cars on the road has open diff, except high performance/extreme off-road variant.
Any electronic control (use brake, or eLSD separe hardware on the drive shaft) to simulate LSD, torque vectoring, has some delay.

This post has been edited by constant_weight: Aug 26 2024, 01:49 PM

Don't have a lot of AWD experience, but on the few I've driven the differences are pretty obvious.

V40 Cross Country, Mazda, close to FWD. When you give large throttle input, they understeer. Don't help the car rotation mid corner.
This is the default you should expect from most FWD bias AWD.

Subaru XV. Accelerate hard mid corner, the rear will kick more and help the car rotate.
More fun and than the Mazda for sure. Should be more capable to split more torque to rear than competitors.

Volvo T8. Very capable to push from rear, if you jolt really hard rear wheel get wheel spin. Need to reduce steering angle, but not to the point of counter steer.
But there is lag before the rear push to rotate the car.
Switch to Constant AWD, all 4 wheel get driven 100% all the time. But no longer do the tail kick, the software become tune to maximize traction/stability.

Depends if your butt can feels the car rotation (as oppose to turn). If you can't, probably all of above totally not making any sense to you.

Heavy rain, AWD help tremendously.