QUOTE(vios2002 @ Jan 22 2014, 07:06 PM)
wah david you so pro... some time we cant avoid if wet road still manage to control but that also depend on what speed we taking but if oil on the road then just hope the worse will not happen.
dry road is easy to control if understeer as long as dont panic....
Many a times the understeer we experienced in our car(even if the's WET condition) is not irrecoverable because the tyre traction was designed way beyond what we experienced. I'm trying to simplify some technical thing here so you can understand it well.
When you turn your car into a corner, your front MacPherson strut will be slightly expand, coupled with chassis flex to induce a certain degree of body roll. For example, when you turn right at certain speed(basically rempit kinda speed), your left front wheel will start to squeel like a pig and you start to feel steering kick back. That is called
CAMBER THRUST. I know you wouldn't click on the link and read, so I make it simple for you to understand what is a CAMBER THRUST. When you roll a coil upright, the coin go straight because the radial force(upward) and lateral force(side way) are equal. If you roll your coin by slant to the left, the coin will roll in to the left, getting tighter and tighter until spin. Vice versa, if you roll the coin by slant to the right, the coin will roll to the right until it spin and fall. Now imagine, when you're taking the above right corner, your car body roll due to chassis flex and your suspension setup, the weight being transferred into your left wheel. Your wheel is pulling OUT to the left, whereas you're turning into right. You'll hear a lot of tyre screeching noise because of this nature of design. The car itself is designed to understeer(particularly our cars that uses Torsion Beam at the back). Reason for factory to setup such understeer is to alert you, the tyre is starting to reject your turning direction because it's started to stress. The faster you attack the corner, the harder CAMBER THRUST you get, the more tyre screeching noise you hear.
Why those cars gets an accident despite they're understeer to the RIGHT, but they crash their car on the LEFT?!
(Take note, more than 80% of my investigation of speeding accidents, it appears to be a long tyre marks indicates that victim is trying to negotiate a high speed right turn, whilst ended up crashed into the left side) Here's the reason, our country practice right side driving. Average Joe like you and me would be automatically have more confident in negotiating right turn better than left, on a high speed left turn, regardless of what our subconcious will tell our hands to go ease on the steering wheel trying not to push it too far as we can't see the longkang on the left hand side. Ask yourself, how often did you hear tyre screeching sound when you racing through a left corner? But it happens alot during a right turn! Now, set that confident level of driving theory aside. What happened is, when CAMBER THRUST beyond our EXPERIENCE, we think we're going to lose the head(too much understeer as if the car going to fly), we instinctively jump the gas pedal. Your transmission(known as GEAR BOX) sense the left wheel is on the ground, so the differential will absorb the torque from the wheel on the ground, and try to gain grip on the RIGHT. When that happened, originally your car was having heavy understeer unable to turn right, now your gearbox helped you to put more torque on the right wheel because you jump the gas pedal. Now you have an OVERSTEER to deal with
Again, an average Joe like you and me probably will immediately turn the steering wheel to the LEFT rapidly(triple facepalm). Don't forget our left wheels is currently having CAMBER THRUST to the left, our steering input got very little(probably none) effect to the tyre traction anymore. Still I have to mention this again, an average Joe like you and me found the steering is not helping, so INSTINCTIVELY we STAB on the brake pedal! The poor car now from oversteer to the right became extreme weight shifting from the back to the front. Let's reconstruct how we make a perfect recipe of counter clockwise DONUT.
1) Turning right corner, lateral weight pushing the left wheel out, as a result CAMBER THRUST to the left, understeer to the right
2) Tyre screech too loud, seeing cannot cope with the speed, jump the gas pedal
3) Transmission sense left wheel on the ground, right wheel need more torque, differential use the left wheel to spin up the right wheel. From understeer become oversteer
4) Driver seen the car suddenly oversteer, scared jump the cliff, hit the wall, car, dog, bike or anything on the right immediately countersteer to the left kao kao
5) Since the left tyre is currently on CAMBER THRUST, there's nothing the steering can do much about it, and driver become even panic because the tyre is not reacting, so KICK on the brake pedal
6) When brake kicks in, majority of the weight from the back of the car will be transfer to the front.
Conclusion: With a full left steering lock + weight being shifted from the back to the front + having camber thrust to the left. We've finally made up an irrecoverable OVERSTEER
Now, finally I can answer your question if you did grind through the above. In wet condition, you don't hear tyre screeching sound. You going over speed also don't know. Again, the tyre will still have decent wet traction, but it's even easier to make it spin if you jump the gas pedal and stab the brakes. Usually, if you're already heavily understeer, just continue negotiate your steering and GRADUALLY relief your gas pedal until suitable speed. Last but not least, you wouldn't wanna hear this, I was once below 25 year old, buy insurance also kena loading. Instead of adrenaline rush, I fuel up my blood with octane. Being a male, and below 25 that 2 factor is already troublesome, couple with a CAR will be a perfect combination of overspeed. Drive steadily my friend. I didn't ask you to hog on the main road at 40kph, just trying to enjoy the car.
Jan 8 2014, 06:04 PM, updated 12y ago
Quote
my fren last month jz bought an auto tranny year 09 with on the road price rm55k mileage 40k km..
stay safe
Are you kidding me?!
0.3175sec
0.37
6 queries
GZIP Disabled