Tyres Safety In The Wet

setan_bsd

Safety In The Wet : Danger Of Hydroplaning New Tyres In Front Or At The Back?
Most vehicles are equipped with the same size tire at every wheel position.   Ideally all of these tires should also be of the same type and design, have   the same tread depth and be inflated to the pressures specified by the   vehicle placard or owner's manual. This combination best retains the   handling balance engineered into the vehicle by its manufacturer.
  
  However due to the front tires' responsibility for transmitting   acceleration, steering and most of the braking forces on front-wheel-drive   vehicles, it's normal for front tires to wear faster than rear tires. If
  the tires aren't rotated on a regular basis, it's also common for pairs of   tires to wear out rather than sets. And if the tires aren't rotated at all,   it's likely that the rear tires will still have about 1/2 of their original
  tread depth when the front tires are completely worn out.
  
  Intuition suggests that since the front tires wore out first and because   there is still about half-tread remaining on the rear tires, the new tires   should be installed on the front axle. This will provide more traction, and
  by the time the front tires have worn out for the second time, the rear   tires will be worn out too. However in this case, intuition isn't   right...and following it can be downright dangerous.
  
  When tires are replaced in pairs in situations like these, the new tires   should always be installed on the rear axle and the worn tires moved to the   front. The reason is because new tires on the rear axle help the driver
  more easily maintain control on wet roads because new, deeper treaded tires  are more capable of resisting hydroplaning.
  
  Hydroplaning occurs when the tire cannot process enough water through its   tread design to maintain effective contact with the road. In moderate to   heavy rain, water can pool up in road ruts, depressions and pockets   adjacent to pavement expansion joints. At higher speeds, the standing water  often found in these pools challenge a tire's ability to resist hydroplaning.
  
  Exactly when hydroplaning occurs is the result of a combination of elements   including water depth, vehicle weight and speed, as well as tire size, air   pressure, tread design and tread depth. A lightweight vehicle with wide,   worn, underinflated tires will hydroplane at lower speeds in a heavy   downpour than a heavyweight vehicle equipped with new, narrow, properly   inflated tires in drizzling rain.
  
  If the rear tires have more tread depth than the front tires, the front   tires will begin to hydroplane and lose traction on wet roads before the   rears. This will cause the vehicle to begin to understeer (the vehicle
  wants to continue driving straight ahead). Understeer is relatively easy to   control because releasing the gas pedal will slow the vehicle and help the   driver maintain control.
  
  However, if the front tires have more tread depth than the rear tires, the   rear tires will begin to hydroplane and lose traction on wet roads before   the fronts. This will cause the vehicle to begin to oversteer in which the   vehicle wants to spin. Oversteer is far more difficult to control, and in   addition to the initial distress felt when the rear of the car starts   sliding, quickly releasing the gas pedal in an attempt to slow down may
  actually make it more difficult for the driver to regain control, possibly   causing a complete spinout.
  
  Members of The Tire Rack team had the chance to experience this phenomenon   at Michelin's Laurens Proving Grounds. Participants were allowed to drive   around a large radius, wet curve in vehicles fitted with tires of different   tread depths - one vehicle with new tires on the rear and half-worn tires  on the front, and the other with the new tires in the front and half-worn   tires on the rear.
  
It didn't take long for this hands-on experience to confirm thatthe"proving grounds" name for the facility was correct. The ability tosense and control predictable understeer with the new tires on therear, and the
  helplessness in trying to control the surprising oversteer with the new   tires on the front was emphatically proven.
  
  And even though our drivers had the advantage of knowing we were going to   be challenged to maintain car control, spinouts became common during our   laps in the car with the new tires on the front. Michelin advises us that   almost everyone spins out at least once!
  
  Experiencing this phenomenon in the safe, controlled conditions of   Michelin's Laurens Proving Grounds rather than in traffic on an Interstate   ramp in a rainstorm is definitely preferred!
  
  In case there is any doubt, when tires are replaced in pairs, the new tires   should always be installed on the rear axle and the worn tires moved to the   front.

setan_bsd

fyi, sebelom ni aku tukar dua tayar belakang kete aku sbb pecah...pastu aku letak la tayar baru tu kt depan... tayar lama tukar keblakang... kesannye? everytime masuk corner.. walaupun speed rendah...3 kali aku oversteer n 3 kali complete spinout...  mmg gile ah   (tp besh )

so skrg aku dah tukar balik tayar baru tu ke belakang... n problem solved!
tp yg heran nye... xkan org kedai tayar tu taktau psl nih... ? nape diex advised aku psl mende ni eh? bahaye tul la... btw kedai tu kt jalangasing..kt depan kwsp..ape tah name kedai tu..

[ Last edited by  setan_bsd at 22-2-2008 09:03 AM ]

batu_bergolek

Originally posted by setan_bsd at 21-2-2008 11:56
fyi, sebelom ni aku tukar dua tayar belakang kete aku sbb pecah... pastu aku letak la tayar baru tu kt depan... tayar lama tukar ke blakang... kesannye? everytime masuk corner.. walaupun speed re ...

Aku personally tak suka rotate tayar, kalo  tayar kereta aku botak (samada botak爏ama rata atau botak sebelah) terus tukar je, keputusannya
aku tak pernah lagi kene stop tepi jalan sbb nak kene tukar tayar pecah.

sedondon

aku selalu buat tukar tayar lama ke belakang....oooo tak boleh ya??