Torque steer explained
You’ve probably heard or read something in a car review about torque steer, but what is it and does it actually matter? Torque steer explained…
What is torque steer?
TORQUE STEER is the tendency of a vehicle to pull to either the left or right under acceleration. You may notice when applying the throttle the steering wheel tug in your hands as the car tries to pull to one side. It is most common in front-drive vehicles, and caused by one side of the drivetrain being easier to turn that the other.
There are a whole of reasons that can cause torque steer, and most car companies spend a lot of money on design and fixes to keep their sporty front-drive cars from torque steering. While torque steer can be caused or exaggerated by things like unequal inflation in the front tyres, it’s more commonly caused because of the nature of a front-drive car, the transversely mounted engine (as distinct from in line, facing forwards to backwards).
Most front-wheel drive vehicles have the engine, transmission and differential all wrapped up in one package. And because it’s all got to be stuffed in the engine bay with the engine in the middle of the two front wheels, the transmission and differential are pushed to one side, which means the half-shafts to each of the front wheels end up being unequal in length – and so they react to torque loads differently.
In short, this results in drive from the engine being transferred to one wheel more efficiently than the other, which is torque steer. And because the front wheels are being driven as well as also dealing with the steering, you get the slight tugging at the wheel in some front-drive cars.
Should I care? Probably not. The only people that should worry about torque steer are car enthusiasts who own higher-powered front drive cars that they are intent on driving hard and fast. Everyone else can stop now and read something like this.
Is it dangerous? No. It would be if it was severe, but no modern roadcar has it bad enough to worry, and those with the potential for torque steer get plenty of engineering attention lavished on them with everything from suspension to power delivery tweaks to help keep the steering wheel straight under hard acceleration.
What does it feel like, what do I need to do? You probably don’t even notice it, because you’ll naturally apply the small amount of pressure to keep the car straight without even feeling anything unusual. But in high-powered front drive cars you may notice, in the first couple of gears, a tugging or a tendency for the car to deviate off line. The more powerful the car and the more quickly you accelerate, the greater the torque steer.
If you’ve never experienced torque steer before, then find yourself a big wide open space where you can test the off-the-line acceleration in first gear without hitting anything or causing an accident, or being considered a hoon. Then, bring the car to a stop, take your hands off the wheel and give the throttle a decent but brief squeeze. If your car is a front driver you’ll have likely seen the steering wheel jerk to either the left or right and the car lurch to the corresponding side. That’s torque steer.
Obviously, depending on the surface you’re on, the effect can be exacerbated by the camber on the road – the road is slightly angled for drainage.
In the video below, you’ll see two instances of torque steer. One at low speed and one at higher speed.
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6 Comments
I understand that Honda fits equal length drive shafts to some models. What was the 4 wheel steer Honda called? Integra? Prelude?
Subarus are AWD so they’re not likely to be affected by torque steer. But if they were FWD the symmetrical nature of the mechanicals under bonnet would probably rule out torque steer (assuming equal length drive shafts).
I’ve driven a few V6 FWD rental cars that suffer from torque steer. It’s an annoyance that presented itself without driving like a hoon. The other issue is that the front wheels are pretty much placed on the white line at traffic lights. The combination of weight transfer to the rear and poor traction on road marking paint invariably resulted in tyre chirps … until the driver learns to compensate for these FWD quirks.
The last rental car I drove was a few weeks ago. A Toyota Corolla. I didnt notice any torque steer and it handled well so it’s an improvement on the V6 FWDs I hired 18 years ago. It’s obvious that some of the buzz box FWDs have controlled torque steer by crippling torque in the lower gears – there’s a noticable pickup in grunt at around 20kmh. I don’t regard that as a fix.
I could live with the Corolla I recently rented. But if Toyota shoe horned their V6 under the bonnet that’s the one I’d buy because I am an enthusiast. If I wasn’t I’d haunt gardening web sites. And if a Corolla V6 FWD had torque steer and traction well sorted I’d be happy. It’s nice to be able to tighten a car into a corner wiyh throttle. And this does not require hooning or drifting etc.
If throttle lift off in a FWD does the tightening I can live with that. But I’d prefer the tightening with a whisker more throttle in a RWD. And I am prepared to pay the extra to get what I prefer. But with the WRX price equal to ir cheaper than a hot hatch I see it as a no brainer.
In the video the torque steer does look dangerous. The Alfa crosses the centre line. I guess the driver should just prepare for it when accelerating, but not having it torque steer would seem a safer proposition.
…just adding to this, Ive changed my mind. I don’t think it’s acceptable to expect the driver to prepare for torque steer. I wouldn’t find it acceptable for a new car to veer right under heavy braking and I don’t think it’s acceptable for it to do it under heavy acceleration. It’s worth testing for this on the test drive. Good article and video.
LenF. I agree. If car makers are hell bent on FWD then let them engineer their system to eliminate torque steer. And let them do it with equal length drive shafts rather than through the use of the PCM to mask the problem by crippling torque. Add an LSD to equal length drive shafts and the RWD purists might have little to moan about?
Car makers obviously have a preference for the trsnsverse engine configuration.
It’s a shame that it’s difficult for them to package their transverse mechanicals over the rear axle. Imagine a Camry with a transverse V6 driving the rear wheels. Why is it difficult to do? It’s not a new idea. It’s what Toyota did with the MR2 (MRS in France! ; – ). The VW Beetle had a front boot so why wouldn’t it work for a Canry? A Camry with a transverse RWD V6 would be a real driver’s car. And with this cinfiguration adding a blower would not run the risk of torque steer or traction problems.
Hi Ben, well I really appreciate the information you’ve provided in your posts. Very detailed and informed and things aren’t as straight forward as I thought with RWD. Pros and cons with each, but I still would prefer not to have that tug of the steering wheel that FWD gives.
I see the benefit of FWD being primarily cost of production. Manufacturers like it because it’s a cheaper way to build cars. I understand there is supposed to be some space savings as well but I’ve never really understood how the same model can be FWD and AWD without affecting space.
Another point. With LSD equipped big power RWDs theres a need for steering correction under radically hard acceleration (wheelspin). That’s because both driven wheels are loosing grip and they tend to slide towards the lowest point on the road. And that’s the left edge of the road. The road of course is high in the centre and low at the edges fir drainage. And so the rear axle slips away from the road centre. AWD pretty much eliminates this problem. I doubt that this has much to do with torque steer but the end result is similar – the need for steering correction. I think it’s a valid point that this RWD issue only occurs under extreme provication and that’s where it differs from the video that illustrates FWD torque steer.
Before we were blessed with ABS brakes we needed steering correction under panic braking situations and for a similar reason. When the back axle went light due to weight transfer under hard braking it slipped towards the road edge steering the car towards oncoming traffic!! ABS does a good job of controlling wheel lockups and the car steering where we don’t want it to go.