# Driving term "fading" - What makes people do this? **URL:** \ **Category:** Factual Questions\ **Created:** [August 31, 2015, 6:20pm UTC](https://boards.straightdope.com/t/driving-term-fading-what-makes-people-do-this/729519 "2015-08-31T18:20:28Z")\ **Posts on this page:** 5\ **Page:** 3
**Author:** ![Kenm](https://avatars.discourse-cdn.com/v4/letter/k/bc79bd/32.png) [@Kenm](https://boards.straightdope.com/u/Kenm)\ **Post date:** [September 2, 2015, 2:34pm UTC](https://boards.straightdope.com/t/driving-term-fading-what-makes-people-do-this/729519/41 "2015-09-02T14:34:27Z")
> [@usedtobe](#): > > In driver’s ed, we were taught to hold the wheel at ‘10 and 2’ - people will not move their hands from that position and you can pull/push the wheel only so far before you either move hands or ‘cramp’ an arm. Because of airbags in steering wheels, that’s been modified to [**9 o’clock and 3 o’clock**](http://at.progressive.com/everything-insurance/9-and-3-drive-safe-today). > [@](#): > > NHTSA now recommends moving the hands down the wheel to the “9 o’clock and 3 o’clock” position. Here’s why. > When your airbag is triggered, super-hot nitrogen gas fills the bag, forcing open the plastic cover on your steering wheel. The bag then expands toward you at 150-250 mph. _The higher your hands are on the wheel, the more likely they are to be over that plastic cover—and the more likely they are to be injured when it blows open._ > > A driver otherwise protected by the airbag can suffer a broken nose or concussion caused by the hand being blasted into the face, finger or hand amputation, fracture, or a rather gruesome and very graphically-named injury called “de-gloving.” ---
**Author:** ![JcWoman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jcwoman/32/2889_2.png) [@JcWoman](https://boards.straightdope.com/u/JcWoman)\ **Post date:** [September 2, 2015, 2:40pm UTC](https://boards.straightdope.com/t/driving-term-fading-what-makes-people-do-this/729519/42 "2015-09-02T14:40:15Z")
> [@LSLGuy](#): > > Immediately before arriving at the intersection the driver will swerve abruptly in the opposite direction, then immediately turn in the correct direction. Typically they’ll only move laterally a few inches, but occasionally they’ll cross into the adjacent lane. If the former, it’s startling to folks driving alongside who may themselves swerve defensively. If the latter, there’s likely to be a sideswipe collision. It’s very rare for the swerver to pay any attention to any cars alongside them; their focus is around the turn they’re about to make. I suspect many of them have no awareness that they swerve at all. In my experience people who drive like this also tend to drive 5 under the speed limit, especially a block or two before the spot where they intend to turn. So when they start to swerve, the people behind them have lost patience and, thinking they’re turning, start to pass, only to have to slam on the brakes to avoid a collision. I witnessed a really bad one once, on a 50-mph road, one lane each direction. I was the second car behind Mr. Clueless. The car in front of me was about as impatient as me, but Clueless had been driving so slowly for about 3 miles that I was suspicious of his actions so held back. When Clueless veered toward the right shoulder, the guy in front of me started to pass him on the left, in the other lane. And then had to slam on his brakes when Clueless suddenly dove left into a side street while simultaneously (and last second) turning on his left turn signal. ---
**Author:** ![JustinC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/justinc/32/8083_2.png) [@JustinC](https://boards.straightdope.com/u/JustinC)\ **Post date:** [September 3, 2015, 4:26pm UTC](https://boards.straightdope.com/t/driving-term-fading-what-makes-people-do-this/729519/43 "2015-09-03T16:26:50Z")
> [@Machine\_Elf](#): > > Untrue. Start with this basic fact of singletrack vehicles: **at any speed,** if you are traveling on a curved path, you (meaning the combined center of mass of you plus the vehicle) are leaning into the turn. Therefore, **at any speed,** to initiate the turn, you have to move the wheels out from under you by countersteering. Many riders don’t notice it at very low speeds because at very low speeds the countersteer force/magnitude is very low and the lean-in happens very fast. But you can initiate snap-turns at parking-lot speeds by executing a very deliberate twitch of countersteer. Beginners who aren’t consciously aware of countersteering will simply wait until their bike happens to be teetering in the correct direction, and then go with the flow; these are the people who appear very unsteady/uncertain at parking lot speeds. > > Watch [this video of low-speed countersteering](https://www.youtube.com/watch?v=OLzB5oriblk) at 1:29, and you’ll see it. Good video, thanks. I never noticed counter-steering at such low speeds; I always saw the ‘wobbling’ as the wheels having too little centrifugal force to stay upright and the small adjustments - turning into the lean - as countering the effects of gravity and stopping you toppling over. I’ve seen plenty of very experienced riders (including my instructor, 20+ years ago) at low speeds - usually in stop start traffic, but also professionals like Dougie Lampkin - have some wobbling at very low speeds. Sure, some slow turns will occur as your front wheel wobbles that way, if you make enough slow turns ;). > [@Machine\_Elf](#): > > Also untrue. If you’re on a motorcycle or bicycle with a fairly ordinary amount of rake/trail in the steering geometry and you are in the midst of a turn, the handlebars will be pointed in the direction of the turn (this assumes we’re not talking about [speedway racing,](https://en.wikipedia.org/wiki/Motorcycle_speedway) in which the rear wheel is power-sliding). The reason you push forward on the inside handlebar (i.e. the one closest to the center of the turn) during the turn is because if you don’t, the road forces will make the handlebars turn even tighter, getting the wheels back under the rider, bringing everything back up to vertical and ending the turn. Such is the nature of stable steering geometry. I certainly wasn’t talking about speedway, only riding on the road (at speed) or a circuit. You (maybe not ‘you’) push forward on the inside handlebar to tilt the bike over, as centrifugal forces ‘lean’ the bike in the direction of the turn because your front wheel is facing in the opposite direction. Once you’re exiting the turn you do the opposite to the handlebars to straighten up. You’re going to have to clarify “the road forces will make the handlebars turn even tighter”, as I’m afraid none of your second paragraph makes any sense, especially that, particular sentence. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [September 3, 2015, 6:28pm UTC](https://boards.straightdope.com/t/driving-term-fading-what-makes-people-do-this/729519/44 "2015-09-03T18:28:25Z")
> [@JustinC](#): > > I never noticed counter-steering at such low speeds; I always saw the ‘wobbling’ as the wheels having too little centrifugal force to stay upright and the small adjustments - turning into the lean - as countering the effects of gravity and stopping you toppling over. You say [“centrifugal force,”](https://en.wikipedia.org/wiki/Centrifugal_force) but I suspect you mean gyroscopic stabilization (or lack thereof) related to the spinning of heavy wheels. And yes, that’s part of what makes the bike unsteady at low speeds; but the bigger part is that at low speeds, it takes larger steering displacements (you have to turn the bars farther into the turn) to get the front wheel to move back under you before you fall over. So you’re used to tiny, brief steering corrections at highway speed, but now that you’re moving at 3MPH, you have to make big, rapid steering movements to get out of wobbles. > [@JustinC](#): > > I certainly wasn’t talking about speedway, only riding on the road (at speed) or a circuit. You (maybe not ‘you’) push forward on the inside handlebar to tilt the bike over, as centrifugal forces ‘lean’ the bike in the direction of the turn because your front wheel is facing in the opposite direction. Once you’re exiting the turn you do the opposite to the handlebars to straighten up. > > You’re going to have to clarify “the road forces will make the handlebars turn even tighter”, as I’m afraid none of your second paragraph makes any sense, especially that, particular sentence. Gyroscopic forces matter, yes, but not as much as you might think. [On a motorcycle](https://en.wikipedia.org/wiki/Countersteering#Gyroscopic_effects) with a nice heavy front wheel at highway speed, the gyroscopic roll moment is only about 12% of the total roll moment, with the remaining 88% coming from the front tire tread as it tracks to the outside of the turn. Imagine instead that you’re riding a pedal-bicycle down a mountain pass; a bicycle wheel has very little gyroscopic effect compared to a motorcycle wheel, so the rolling moment (when initiating a turn) is derived almost entirely from the front tire tread as it out-tracks. There are even singletrack vehicles with _zero_ gyroscopic stabilization: [ice bike](https://www.youtube.com/watch?v=Nc4GnkHWE0I) [downhill ski bike](https://www.youtube.com/watch?v=Z29Mw5fdaaY) The ice bike never develops much speed, which may explain why it seemed so wobbly. But the ski bike zooms right along; steering is just fine, even in the absence of any gyroscopic effects. When I spoke of road forces making the handlebars want to turn even tighter while in a turn, I was describing a property of stable steering geometry. This is a consequence of [trail,](https://en.wikipedia.org/wiki/Bicycle_and_motorcycle_geometry#Trail) and the idea is that if the bike is leaned over, the road pushing upward on the front tire’s contact patch creates a torque around the steering axis that makes the handlebars want to turn into the turn. This steering torque is separate from any torque that the rider may be applying with his hands to the bars. You can see its effect in [this series of plots.](https://en.wikipedia.org/wiki/Countersteering#/media/File:Countersteer_response.JPG) The rider applies a constant torque to the handlebars; the handlebars at first rotate as you would expect with his applied steering torque (away from the turn), but as the bike begins to lean into the turn, the self-stabilizing countertorque is produced by the steering geometry and the road force on the contact patch, forcing the bars to turn in the same direction as the turn. By the end of the plot (12 seconds), the rider is still pushing forward on the inside handlebar, but now the bars are turned in the same direction as the turn, and the bike is leaned into the turn. If the rider removes his hands from the bars, the self-stabilizing countertorque will turn the steering even more tightly into the turn, bring the wheels back under the bike to make it upright and restoring straight-line travel. ---
**Author:** ![JustinC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/justinc/32/8083_2.png) [@JustinC](https://boards.straightdope.com/u/JustinC)\ **Post date:** [September 3, 2015, 7:14pm UTC](https://boards.straightdope.com/t/driving-term-fading-what-makes-people-do-this/729519/45 "2015-09-03T19:14:03Z")
You say po-tah-toe, but to me it’s the centrifugal forces of the spinning wheels which stabilise a top-heavy, unstable vehicle and allow me to ride - for fun - and understand, at speed, how my tyres are gripping and how if I move my weight around the bike I’ll make it more stable and reduce the likelihood that I’ll put it down and slide into something that doesn’t move. I did understand, as soon as I had posted that I didn’t, your ‘tightening’ sentence but it didn’t make sense at first. To me, I push away and I lean over, then I push the other handlebar and I straighten up. But I never pushed enough, either way, to significantly differ from the direction I was travelling in, even though the magazine told me I’d be pointing my front wheel away from where I was going, even though I was ‘looking’ in the direction I wanted to go. The magazine also stipulated that racers would be using opposite lock all through the corners when racing on tarmac, and my gentle push opposite to the turn I was making confirmed that, to me. I’ve not watched the videos yet, but I can imagine them through your descriptions and I will refer back to this thread in the future. I’ll probably learn something once I re-read it. Out of interest, what do/did you ride? I’ve only ridden small bikes, so this isn’t a ‘mine is bigger than yours’ question. I still would like to ride good bikes, some of my family have a lot of them, I’d like to ride fast and survive in the future. [Previous page](https://boards.straightdope.com/t/driving-term-fading-what-makes-people-do-this/729519.md?page=2)