How/why does gear selection affect handling in turns?

Discussion in 'Tuning General' started by RickS95, Mar 7, 2011.

  1. RickS95

    RickS95 Licensed Racer

    It's possible I'm just weird, but hopefully others have noticed this as well and are as stumped as me. When driving a general car and I take a general turn, the car seems to handle better (ie hold the turn better, tighter) when in the lower numbered gear, while at the same speed.

    I'll use the Dunlop turn at Suzuka as an example. If I'm taking the turn at 95 MPH in whatever car (be it FWD, RWD or AWD, it doesn't seem to matter), if I'm in third gear, the car will hold better than if I'm in 4th gear. In 4th gear, there is a gentle push away from the apex.

    Can anyone explain this to me using terms that someone who doesn't watch racing might understand?
     
  2. the_saint8

    the_saint8 Licensed Racer

    Reaction Torque?
     
  3. larrys4227

    larrys4227 Licensed Racer

    I'm no gear head ... those that are, please step up. Heres my theory ..... 4th gear will be at a lower RPM than 3rd at the same speed, yet the engine is producing more torque (IE: more power to the wheels, so its pushing the the car.)

    I've actually had pretty good luck recently powering through corners with a gear that isnt near redline. A recent conversation with Clacks (I think) taught me to start thinking about that. It was a F1 discussion about spinning comeing out of corners .... my cornering has improved alot since I starting applying it
     
  4. clacksman

    clacksman Licensed Racer

    Okay, what's goin-

    :sCo_chinscratch::sCo_chinscratch::sCo_chinscratch:

    :sHa_biggrin:

    I haven't noticed that exactly as you put it, but then you may not know what you're talking about (this is especially funny if you've exchanged emails with Rick).

    Lower gear = closer to horsepower peak
    Higher gear = closer to torque peak
    So in the higher gear you're trying to apply more torque which is what straightens you out. Maybe.
     
  5. DaletonaDave

    DaletonaDave Licensed Racer

    I've noticed kind of the same thing happen on various tracks. Even at Daytona. If my gear is taller (lower RPM's), the car tends to push up towards the wall more. If I shorten the gear some (higher RPM's), then I can hold it down closer to the yellow line.
     
  6. RickS95

    RickS95 Licensed Racer

    What Daletona said.
     
  7. RickS95

    RickS95 Licensed Racer

    Unfortunately, I resemble this remark. However, on a variety of occasions, mostly back in Prologue (I suck at the new game so much I don't race a lot anymore), when running Q laps, I would take sweeping turns in a higher numbered gear (saying higher or lower just confuses me) because it usually put me in the heart of the torque band which I always thought would be good coming out of a turn. However, being in said gears with lower RPM the car always felt loose and I'd usually have to lift and eff up my lap.

    So, back to the drawing board, I'd run more laps and eventually take the car screaming through the turns (mondo RPMs). While I didn't always get the jump out of the turns because I was well beyond peak torque, the car held the line and I didn't have to lift.

    As I said, my racing isn't quite what it used to be, but I've noticed the same thing happening with Mo5----->Low RPMs offer an unwanted gentle push into the sand, while higher RPMs let me keep my line.
     
  8. the_saint8

    the_saint8 Licensed Racer

    I mentioned torque reaction, something very common in Helicopters. As your engine is producing higher amounts of torque, that produces a result of your drivetrain wanting to twist in the opposite direction (that's why helicopters always have two rotors as to offset the torque reaction). It would be a good guess that under higher torque loads one of your rear wheels (rear wheel drive cars) is contacting the surface with more pressure than the other. The torque reaction twists the car chassis as well and over time will weaken the car.

    aircraft mechanics 101
     
  9. timneyb

    timneyb Licensed Racer

    Higher gear = more torque out of the engine, but probably less torque between rubber and road, because in a higher gear the engine has to work through a shorter lever to turn the wheels. So, it depends on how much taller the longer gear is as to which has more useful rubber-road torque, which determines where we shift in general. As we all know, figuring out exactly when to shift is therefore best left to experiment.

    More torque between rubber and road either means more accelleration force in general, which will push you out of a corner, or more wheel slip in the powered wheels, meaning oversteer in RWD and understear in others. The former is what I think is happening in the dunop or Daytona example, but in tighther corners at slower speeds where wheel slippage is an issue, you'll start to see FF and FR behaving opposite to each other.
     
  10. RickS95

    RickS95 Licensed Racer

    For what it's worth, my question concerned sweeping turns where you can take them in a variety of gears and at speed, not anything resembling a 90 degree turn.

    As a matter of fact, in one of the Jeff Gordon challenge thingies at Indy, I remember drifting into the cones on the outside if I was in 4th, but keeping my inside line if I remained in 3rd.
     
  11. THE_KART96

    THE_KART96 TPRA Staff

    I have noticed this, but not sure why it happens. And I never really thought about it. But I do know it's there and will use it to help the car turn. If I need a slight push, 4th gear. 3rd if I need to keep tight. (The gear might be different depending on car, track and hp) It's one of those things that you don't need to know why, just know it's there and use it as needed.
     
  12. The_Revengel

    The_Revengel Licensed Racer

    I've experienced this as well recently with my testing at Tokyo Route 246.

    The looooooong right hand sweeper (too loose to be a hairpin, to tight to really be a sweeper IMHO) is a great example. Taken in a lower gear it's easier to hold the corner and with the engine speed I feel it's a better exit. You can shoot out of the turn then hop into the next gear in stride.

    The cause? I don't know for a fact but I believe it has to do with engine speed & the push of a gear. I suspect the LSD may be involved. Follow me on this for a second and feel free to tell me what I'm smoking when I'm wrong.

    With a lower gear you don't have as much torque but you do have more power. There's no push because the torque level is below the LSD sensitivity setting. In a higher gear you're accelerating but you have more torque...so there's a push from the LSD.

    Does that stand to reason?



    Just trying to assist,

    Revengel
     
  13. THE_KART96

    THE_KART96 TPRA Staff

    This makes good scence. I'm not 100% sure but this is very close.
     
  14. AlfaVeloce32

    AlfaVeloce32 Licensed Racer

    I found this thread interesting because i have noticed the same thing, i know its been awhile since anyones commented on it but i wanted to add my 2 cents. If your in 4th going around a corner your at a lower rpm and your car is essential "rolling through the corner" your wheels at this point are not so connected to the engine. Whereas if you were in 3rd your at a higher rpm you are more on the motor, the car is much more reactive to slow down if you get off the throttle or speed up when you get on the throttle. This is one reason why we downshift before the corner, if your not in the correct gear before the corner in real life the car will be very upset and can cause severe understeer or you could lose the rear-end. Sometimes you get away with this in the game. Sometimes... lol... You guys may have already explained this by mentioning torque early in the thread; however, this is how i understand it.
     

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