Talk:Torque steer

Quite Obviously BS

Im going to delete the following section: "In many cases, torque steer is the result of a bad upper facited regulation modulator control homogonizer with a pasturizing bypass linked to the incorrent absent placement of 14 seperate lost bolts that become dislodged in the inner twinings of the "rotary gurter" which hang down below the maximum tollerance for substantial weak point physicallity. THEREFOR resulting in unwanted movement of the anterior section of purified transients that make up the common shoe" because its quite obviously BS... unless ive been lied to about cars for the past years of my life. - Nereth (talk) at 21:53, 13 September 2006.

Ony in FWD cars?

If you have a transverse engine in a rear or mid engined car (or indeed unequal lenght driveshafts in any rear wheel drive car) shouldn't they also display torque steer, but with the rear wheels instead? // Liftarn

No, in general. The torque around the steering axis generates a force in the tie rod, and because the steering system is not rigid, that generates a steer angle in the wheel, so the car turns. With a rear suspension the steering system is much more rigid. If that explanation does not tie up with this article, well, that is sad, this article is pretty bad. Greglocock 20:46, 13 January 2007 (UTC)

Ok, now I see, but I have no idea how to incorporate this in the article. // Liftarn

You raised a perfectly good question, but, I think, rather beyond an encyclopaedia. Put it this way, in the technical papers there is no generally applicable theory of torque steer. So, when you ask a good question, it is quite possible that there is no succinct answer. And I would love to see a detailed answer as well. In practice I just model it, but modelling things is much less efficient than analysing them. Greglocock 10:57, 15 January 2007 (UTC)

Open differential

I am a bit confused by this statement: "The open differential cannot fairly distribute torque between the two driveshafts, the power may be transmitted to only one driveshaft." How can an open diferential apply more torque to one driveshaft than to the other? The power can certainly be different when one wheel is spinning faster than the other, but I fail to see how one side could receive more torque than the other. Aij 22:26, 19 May 2007 (UTC)

I think, that in reality, the torque distribution really IS equal, the problem is that there is very little torque going into the differential in the first place. If you go WOT in an attempt to feed the diff lots of torque, the wheel with very little traction will spin up, hence the speed of the diff, driveshaft, transmission, will all have to speed up to match it. The angular inertia of these components will suck all the torque out of the drivetrain. That was a good slang-filled physics explanation. Doesn't happen often. Keep in mind, I have no sources for that except my own reasoning. Nereth (talk) 15:55, 15 December 2007 (UTC)

---

The basic premise of whole article is wrong Torque Steer is generated by the drive reaction couples within the CV joint acting at different distances from the road wheels (virtual) steering axis when viewed in front elevation, Using equal length drive shafts minimizes the over all effects of torque steer because the left and right drive shafts enter their respective outer CV joints at mirror image angles and the torquesteer generated by each wheel should be equal and opposite and therefore cancel out. —Preceding unsigned comment added by 78.86.101.67 (talk) 19:26, 10 June 2008 (UTC)

The whole article is almost 100% wrong obviously the original was written by someone with no knowledge of mechanical engineering mechancs and has spent a lot of time reading reading poorly researched articles in US car magazines awm

And *I* am confused by this statement: "Either way there is a tendency for the slower wheel to receive more torque." How is that not a stabilizing effect? I think this whole article has actually made me a little bit dumber. I would correct it if I had any clue why torque steer occurs, but that's why I looked at this article in the first place! —Preceding unsigned comment added by 98.209.18.24 (talk) 15:21, 2 February 2010 (UTC)

Incorrect statement?

As the torque steer effect is directly related to the engine torque capabilities, this problem becomes more and more evident with high output engines with strong torque in the low RPM range.

I would have thought torque steer would be directly related to the torque at the wheels - after gearbox multiplication, not what comes out of the engine. Otherwise you'd get torque steer in all gears - in reality it's only the lower gears. (usually only 1st and 2nd are noticeable). So a high revving but geared down vtec engine should experience more torque steer then a high torque diesel but average power diesel. Least that's what I would have thought.. Themania (talk) 09:39, 13 November 2009 (UTC)

I think the issue is that in gears 1 and 2 people can expect a bit of torque kickback through the steering wheel. The disconcerting thing is when you are cruising on the freeway, and accelerate in top gear, and the car drifts sideways. I have only noticed that in powerful FWDs Greglocock (talk) 00:14, 14 November 2009 (UTC)

Most FWD cars I've driven have been too weedy to exhibit much in the way of torque steer, but a Peugeot 205 GTi 1.9 demonstrated a disturbing wish to visit the opposite side of the road every time brisk acceleration was called for. That had 128 bhp and 111 ft lb. My current diesel has 105 bhp, and 178 lb ft, and doesn't do anything like it, so I suspect Themania's assertion is correct.Mr Larrington (talk) 13:06, 14 July 2010 (UTC)

Would we be more correct to say:

1. Torque steer effects are directly related to differences in the forces in the contact patches of the left and right drive wheels.
2. The effects become more evident when high torques are applied to the drive wheels either because of low transmission gearing or high engine torque.

Compared to the current text: Torque steer effects are directly related to the forces at the contact patch. The effects become more evident in vehicles with high torque engines. -AndrewDressel (talk) 16:12, 25 March 2011 (UTC)

Well, I'll give it a try it and see what critics have to say. -AndrewDressel (talk) 15:44, 26 March 2011 (UTC)

RWD

Various editors with more interest than knowledge have attempted to explain why RWD cars don't have torque steer. The article as it stands is more or less correct. In a FWD car the driver senses and attempts to control the difference in force between the two wheels. With a RWD he is no longer directly involved. The difference in forces/torques are actually quite small in a typical torque steer event but because the steering system is very soft in comparison with a suspension, they ar ebifg enough to affect the front.Greglocock (talk) 05:01, 7 April 2011 (UTC)

Almost everything within this article is wrong it needs edited down to a stub and re-written by a car design professional mechanical engineer. Please lets get back to real engineering science, the turning moment that creates torque steer is created within the outer CV joints. With equal length drive shafts the left and right drive shafts should enter their respective outer CV joints at equal but opposite angles and therefore the torque steer moments about the respective steering axes are equal and opposite and cancel each other out. -AWM — Preceding unsigned comment added by 80.229.136.112 (talk) 19:58, 13 August 2012 (UTC)

True as far as it goes, but sadly insufficient as an explanation. Greglocock (talk) 04:47, 15 August 2012 (UTC)

I agree. This article is once again degenerating into complete nonsense about drive shaft stiffness and tyre sidewalls etc. Drive shaft stiffness is only relevant to NVH (noise, vibration and harshness), and the drive shaft resonant frequencies are always so high that they can never have any effect whatsoever on steering feel. And, with proper Ackermann geometry, and a matched pair of tyres, there should be no net effect from sidewall flexing.

I hope to be back later (maybe a week or so) with a reference to a reputable magazine article on this subject, which unfortunately is stored elsewhere right now. It will confirm that the effect is indeed largely torque vector summation at the CV joint, due to the angle between drive shaft and stub axle, the third (steering) axis carrying the resultant torque when they are summed in 3 dimensions. The other significant effect is that, due to most vehicles having a non-zero scrub radius, the drive thrust or braking drag acts either outboard or inboard of the tyre to road contact patch centre, however this effect is generally very much less than the torque vector summation effect because, in normal circumstances, equal drive or braking torque is applied to both wheels. Hopefully we will get rid of the guff in this article soon. Sadly much of it is regurgitated from the mainstream motoring press, who do a great deal of damage to people's understanding of what should be simple things, by publishing articles written by complete incompetents. We should be able to do better here. -Tiger99 (talk) 12:30, 21 February 2014 (UTC)

OK I'll throw away my engineering textbooks, get rid of my multi body simulations, and we'll wait and see if your magazine article is better. I've just reread this article and it is not too bad in its current state. Some manufacturers were or are of the opinion that halfshaft stiffness differences side to side are part of the issue with torque steer. I, personally, don't, but reputable professionals do. The sidewall stuff sounds like someone with a bee in their bonnet about one experience. Greglocock (talk) 23:57, 21 February 2014 (UTC)

Not criticising you, because I think you understand, but some clearly don't. It really is NOTHING AT ALL to do with drive shaft stiffness. Drive shaft resonance is at far too high a frequency to cause any discernible effect. Fiddling with drive shaft stiffness, and putting a damper on the longer one is to fix NVH and possible fatigue problems by damping an unwanted resonance, but you don't feel torque steer as a few 100 Hz to KHz at the steering wheel, which is likely where the resonance lies. The torque at the steering wheel is MOSTLY due to the different vector sums of the hub torque and drive shaft torque where they meet in the CV joint, and are reacted by the steering mechanism about the virtual king pin axis. Make the torques different (very bad to use an LSD in a FWD car, it GUARANTEES very unequal torques in many situations) or make the vector summation different by different shaft to hub angles, and they don't cancel, so you get the difference fed back to the steering wheel. You also have a significant effect if the effective contact patch of each wheel is a different distance from the virtual king pin axis, as it will be in various bump, camber change or cornering load conditions, because you also have traction or braking force exerting a moment about the axis unless the virtual king pin exactly intersects the centre of the effective contact patch. But someone on Wikipedia, somewhere else I think, asserted that steering does not work if you do that, you allegedly need some offset, whether positive or negative. Actually, you don't, but it is usually needed to get the kind of handling that you want. But almost everything ever written anywhere about torque steer is utter guff, one journalist copying another with the same errors. A few years ago the same bunch of incompetents used to say that you could affect static weight transfer by fitting anti-roll bars. Well no, weight transfer depends entirely on cornering speed and radius, and centre of mass height above ground. But you CAN adjust the balance, front to rear, and the DYNAMIC weight transfer, i.e. at which end it happens first, by tweaking roll bars and dampers. Just don't believe anything that you read in any motoring journal, work it out from first principles of engineering, and you will not go far wrong. I will attempt to fix the drive shaft stiffness bit in the article again, let's see how long it takes before someone messes it up.....

Tiger99 (talk) 20:30, 14 September 2015 (UTC)

Oops, never noticed that the article remains correct and the error is just in the talk page. I feel silly, but my comments still stand, and there remains abysmal ignorance on this subject in many places. And why did we ever allow rear wheel torque steer into the article? Should it be there at all? I think it should be called something else, but what? It is of course non-existent on the majority of modern cars produced worldwide, which are FWD, although that may be changing as there seem to be a pointless number of 4WD vehicles about now. — Preceding unsigned comment added by Tiger99 (talk • contribs) 20:39, 14 September 2015 (UTC)

Intentional torque steer

This article needs expansion to cover vehicles that use differential torque to actually steer vehicles (usually caterpillar drive ones) The new Tesla Roadster also uses it. --- 70.51.45.76 (talk) 09:34, 17 November 2017 (UTC)

Could this be correct? Is there not already an article about how vehicles intentionally use differential torque to steer? I checked tracked vehicle, skid steer, and even Skid-to-turn, but non seem to cover the topic. Anyone else have information or an opinion? -AndrewDressel (talk) 14:22, 17 November 2017 (UTC)

Steering production cars via differential action is a real thing, often called torque vectoring or active differential. Greglocock (talk) 23:15, 17 November 2017 (UTC)

Started Differential steering article today, for better or worse. -AndrewDressel (talk) 15:53, 23 November 2017 (UTC)

Page Title

Seems to me the title of this article should be "Torque Steer" as this is how I have seen it referred to in automobile publications for as long as I can remember. "Torque Steering" suggests intentional steering action facilitated by torque, which is not what is being addressed here. Unknowntouncertain (talk) 21:37, 29 November 2017 (UTC)

Agreed. Andy Dingley (talk) 21:52, 29 November 2017 (UTC)

Absolutely, definitely, positively, yes. Greglocock (talk) 05:13, 30 November 2017 (UTC)

• Listed at WP:RM/TR Andy Dingley (talk) 10:52, 30 November 2017 (UTC)

Dubious

This statement about worsening of torques steer by LSDs may only apply to plated LSDs. Geared LSDs aim to reduce torque steer, at least Quaife claims it: that their ATB differential reduces torque steer; and a WikiPedia article also confirms this, see https://en.wikipedia.org/wiki/Limited-slip_differential#Geared_LSD (Quote) "As is the case with all geared LSD designs, the Truetrac does not have any negative impact on steering"