Are my tires still usable?

[mazdamazda]

docsuv...

parang iba yata ang fortera hl (usa) & fortera (local)

fortera HL:



fortera (local):

[mazdamazda]

tread comparison pics:

fortera HL:



fortera (local):



btw... the more comfy ride can be attributed also to the thicker sidewall of the 215/70 tires.

[Doc Diesel]

take the penny test by tire rack....

http://www.tirerack.com/tires/tirete....jsp?techid=51

other tech stuff can be found there...

[chris_d]

Taken from tirerack website/link posted above

Where to Install new pairs of tires?

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 that the "proving grounds" name for the facility was correct. The ability to sense and control predictable understeer with the new tires on the rear, 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.

[mazdamazda]

is that applicable to the Full-Time 4WD Rav4?

AFAIK, the open differential (one for each axle) will intervene if one wheel loses traction. if both wheels of the rear/front axle loses traction, then the center differential will intervene.

[chris_d]

I am not sure if it would apply to all cars especially those will certain electronics and other mechanical innards that would assist during situations wherein the car would lose traction. I wasnt able to gather any info regarding that.

[hagiber]

Another reason why new tires go to the rear is that you generally want your "best" tires to be at the back because if you get a tire blowout at the front, you can still slightly compensate by steering... while if you get a tire blowout at the back, there's no easy way to compensate... Also, try to watch the fifth gear (or maybe topgear) video where Tiff demonstrated what happens when you get a tire blowout (sa front or back). Mas grabe yung spin niya when the rear tire had a problem.

[mazdamazda]

as I've said... that maybe applicable to 4x2 (fwd or rwd) vehicles only... since the rav4 is equipped with full-time 4wd (w/ 3 differentials) that may not be the case.

I've already switched the front & rear tires... and I haven't experienced any "sliding" when travelling the NLEX during a heavy downpour at 80-100kph (though to note, the sliding that I've mentioned is very subtle... but enough to alarm me already).

as I see it... if you are travelling in a straight line... wouldn't it be preferable to have your better tires in front to cut through the water?

[empy]

tagal na ng thread mo m2, baka kailangan nang magpost ng updated pics for us to evaluate :D

[j_avonni]

Mas pudpod pa ang gulong ng isang car ko kaysa dyan. But I'm still using them though very seldom and not on long drives. Kapos pa sa budget eh.