The Toyota GR Yaris uses GR-FOUR, an all-wheel-drive system that actively controls torque distribution between the front and rear axles. But how effectively that torque reaches the road also depends on the differentials at each axle.
When I bought my GR Yaris, I chose the RZ High Performance (RZHP) over the standard RZ because I believed that front and rear limited-slip differentials (LSDs) were the logical choice for getting the most out of a performance AWD system.
For me, choosing a serious performance-oriented AWD car meant choosing one with LSDs.
However, I have no firsthand experience driving an open-differential GR Yaris in the snow.
This article examines how open differentials and LSDs work, how they affect traction on snowy roads, and what influenced my decision.
The discussion focuses on the original Japanese-market GR Yaris introduced in 2020, including the RZHP, RZ, and RC grades.
1. What Do GR-FOUR and LSDs Actually Do?
GR-FOUR uses an electronically controlled multi-plate clutch to manage torque distribution between the front and rear axles.
The differentials at each axle handle torque delivery to the left and right wheels.
Their roles are distinct:
- GR-FOUR: Controls front-to-rear torque distribution.
- Differentials: Transfer driving torque between the left and right wheels on each axle.
For example, GR-FOUR may send torque to the rear axle, but if the rear wheels have very different levels of grip, the type of rear differential affects how much driving force can actually reach the road.
2. Open Differentials vs. Torsen LSDs
An open differential allows the left and right wheels to rotate at different speeds while delivering essentially equal torque to both.
That works well during normal cornering, when the inside and outside wheels need to turn at different speeds.
But consider a situation where the left wheel is on ice and the right wheel is on packed snow.
If the left wheel starts spinning with very little torque, an open differential cannot deliver much more torque to the right wheel, even if that wheel still has plenty of grip.
The original RZHP was equipped with front and rear Torsen limited-slip differentials.
A Torsen LSD uses internal gear friction to bias torque toward the wheel with more available traction.
This helps the car put power down when grip differs between the left and right wheels.
However, a Torsen differential needs some resistance at the wheels to generate its torque-biasing effect. If one wheel is completely off the ground, for example, its ability to transfer useful torque can be limited.
The GR Yaris also has electronic traction control (TRC), which helps manage wheelspin.
As a result, an open-differential GR Yaris can still provide adequate traction in many conditions, depending on the road surface and how the electronic systems respond.
3. Which Works Better on Snow?
Light Snow on a Flat, Paved Road
When the left and right tires have similar grip, an open differential may provide all the traction the car needs.
With appropriate winter tires and smooth throttle inputs, everyday driving on lightly snow-covered roads may rarely demand the additional torque-biasing capability of an LSD.
However, even a lightly snow-covered road can have patches of ice beneath one wheel, creating a significant difference in available grip.
Rutted or Uneven Snowy Roads
Deep ruts and uneven surfaces can create substantial differences in wheel load.
One wheel may also encounter ice or deeper snow while the other remains on a firmer surface.
Under these split-μ conditions, an open differential’s equal-torque characteristic can limit how much driving force reaches the road.
An LSD can help by sending more torque to the wheel that still has traction.
This is where an LSD-equipped GR Yaris has a useful mechanical advantage.
Winter Tires Come First
On snow and ice, the first priority is choosing tires suited to the conditions.
The original RZHP came with Michelin Pilot Sport 4 S tires, high-performance summer tires developed primarily for dry and wet pavement.
Proper winter tires on all four wheels are essential for driving on snow and ice.
Tires determine how much grip is available at the contact patches. The differential influences how effectively that available grip can be used to transmit driving torque.
4. Choosing Between the RZHP, RZ, and RC
When the original GR Yaris was introduced in Japan in 2020, the RZ High Performance came with front and rear Torsen LSDs as standard equipment.
Here is how I would approach the three grades.
RZ High Performance (RZHP)
For drivers who want to make full use of GR-FOUR and have front and rear LSDs fitted from the factory, the RZHP is an attractive choice.
It makes particular sense if traction on uneven or mixed-grip surfaces, or during spirited driving, is a priority.
The RZHP also came with equipment such as BBS forged wheels and performance tires, so the price difference from the RZ covered more than just the LSDs.
RZ
The RZ suits drivers who prioritize value while still enjoying GR-FOUR in everyday driving.
An open-differential setup can provide adequate traction under many conditions, with the option of fitting aftermarket LSDs later if needed.
RC
The RC is particularly attractive as a starting point for motorsport or extensive customization.
For drivers who want to select their own differentials and build a drivetrain around particular competition rules or driving conditions, it offers considerable flexibility.
5. Why I Chose the RZHP
When I decided to buy a GR Yaris, I wanted front and rear LSDs from the outset so I could make the most of GR-FOUR, including in situations where grip differed between the left and right wheels.
That led me to the RZHP.
Buying an RZ and installing LSDs later would also have been reasonable. So would starting with an RC and building the drivetrain to suit a specific purpose.
For my driving environment, however, the RZHP already had the equipment I wanted.
Beyond the technical advantages, there was also the satisfaction and peace of mind that came from knowing I had chosen the configuration I wanted from the beginning.
Conclusion: Open Diff or LSD — What Matters Most?
An open differential can provide sufficient traction when the left and right wheels have similar grip.
An LSD becomes more useful when wheel loads or surface friction differ significantly, as can happen on rutted, uneven, or patchy snow-covered roads.
The choice depends on where and how you drive, and how much of GR-FOUR’s performance you want to exploit.
For me, choosing a performance AWD car meant paying attention not only to front-to-rear torque distribution, but also to how effectively each axle could deliver that torque through its left and right wheels.
That is why I chose the RZHP.
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