(Purchase) Two tires or four?

[Sandtrap]

i would eagerly shop for 4 new tires

j

[talzara]

The telltale sign for me is that they make a point of showing the tires being mounted on the white car when they switch from the blue, as if doing a careful comparison but then show both cars together at the end. They are not being compared with the same tires at that time. And in that final scene where they want to show the cars going the same speed, it seems obvious to me that the blue car made a deliberate hard left turn, rather than experiencing a fishtail skid on a curve-- they weren't even on a curve at that time.

It is clearly on a curve. Look at the road markings.

What you interpret as "ma[king] a deliberate hard left turn" is the driver losing control.

[Northern Flicker]

You are certainly welcome to cling to your own opinion. I'll go with what the tire manufacturer's recommend.

Actually, I'm not clinging to an opinion. I clearly stated that the claim may be correct, but I found the video unconvincing. If the tires with less wear go on the back, then one should not rotate except when purchasing a new pair to replace the worn front pair. That follows logically from the claim in the video, but is not also being recommended.

[billaster]

You are certainly welcome to cling to your own opinion. I'll go with what the tire manufacturer's recommend.

Actually, I'm not clinging to an opinion. I clearly stated that the claim may be correct, but I found the video unconvincing. If the tires with less wear go on the back, then one should not rotate except when purchasing a new pair to replace the worn front pair. That follows logically from the claim in the video, but is not also being recommended.

You keep using that word "logically" but I do not think it means what you think it means.

[Northern Flicker]

LOL.

Once you replace two tires and put the new ones on the rear of a FWD car, you will be replacing two tires at a time moving forward because the fronts will wear faster, in addition to starting from a more worn state. You will never get back to a normal 4-tire rotation, and will always have tires with lighter tread wear on the rear. The 2nd pair purchased will be when the rears were new not very long before, and thus with light wear. At that point, you could put the new tires on the front and get back to a 4-tire rotation if that were preferred. But they do not say that in the video. They say that whenever replacing a pair of tires only, always put the new pair on the rear.

So if precisely following the recommendation in the video leads to a safer configuration, then you never should rotate tires. The claim is that if one has the opportunity to avoid half-worn tires on the rear, one should do so. This would mean not rotating tires, and whenever the fronts become too worn, move the rears to the front and put new tires on the rear.

If rotating tires instead, then once all 4 are at half-wear, for the remaining tire life, the rears will be in a state they claim is less safe than if using the strategy described in the previous paragraph (not rotating except when replacing the front pair). With the 4-tire rotation, about half of one's tire ownership period would be with rear tires in a state the video claims is less safe.

Once you believe the existing tires being retained are less safe on the rear when needing to replace a pair, while they claim the driver can compensate for them in the front, and knowing the existing tires will wear rapidly on the front, needing replacement soon anyway, you may as well just replace all 4 tires now. That was the OP's conclusion, and I think the video will lead many to the same conclusion.

At best, the argument is more nuanced than the recommendation. For instance, if it sometimes snows where you live, you want the deeper tread on the front drive wheels. That will be safer in snow when you have not chained up (or installed snow tires), regardless of the status of the claim in the video.

The recommendation can be backed up with results of a scientific study if it is correct. It should not need the visual PR to sell it to the viewer.

[billaster]

You are completely inventing "claims" that the video does not make.

So if precisely following the recommendation in the video leads to a safer configuration, then you never should rotate tires. The claim is that if one has the opportunity to avoid half-worn tires on the rear, one should do so.

The video does not make this "claim".

If rotating tires instead, then once all 4 are at half-wear, for the remaining tire life, the rears will be in a state they claim is less safe than if using the strategy described in the previous paragraph (not rotating except when replacing the front pair).

The video does not make this "claim".

Once you believe the existing tires being retained are less safe on the rear when needing to replace a pair, while they claim the driver can compensate for them in the front, and knowing the existing tires will wear rapidly on the front, needing replacement soon anyway, you may as well just replace all 4 tires now.

That might be the case for someone who has money to burn, but for many it would be foolish to just throw away tires that have half their life left -- tens of thousands of miles.

The recommendation can be backed up with results of a scientific study if it is correct. It should not need the visual PR to sell it to the viewer.

You seem to be the only one who somehow believes that this is PR to sell four tires when it specifically tells you that you only need two. Every major tire manufacturer says the same thing -- if you replace two tires, put them on the rear -- e.g. Michelin, Goodyear, Firestone, etc. Many people aren't going to read a scientific report but a visual demonstration is quite useful. You can see why with your own eyes.

[Northern Flicker]

I'll address one of your points. The others are similar.

You are completely inventing "claims" that the video does not make.

So if precisely following the recommendation in the video leads to a safer configuration, then you never should rotate tires. The claim is that if one has the opportunity to avoid half-worn tires on the rear, one should do so.

The video does not make this "claim".

It most certainly does. It claims that the existing tires if left on the rear will render the car less safe due to the risk of fishtail skids. It shows treads up close and says that the new tires address that by channeling the water. Unless you are trying to claim that such an issue only materializes when there are new tires on the front (which would be pretty far-fetched) then they most certainly are claiming that a protocol which keeps minimally worn tires on the rear is safer. Once you put new tires on the rear, the used fronts will wear out and the cycle continues, keeping less worn tires on the rear.

Many people aren't going to read a scientific report but a visual demonstration is quite useful. You can see why with your own eyes.

Don't have to read a scientific report-- they can present the findings and a recommendation. Visuals are highly subject to PR strategies.

At best, the issue is nuanced. There is no way you would want the newer tires on the rear of a FWD car for driving in snow, as it is nice when you turn the steering wheel that the car actually heads in the prescribed direction.

[billaster]

I'll address one of your points. The others are similar.

You are completely inventing "claims" that the video does not make.

So if precisely following the recommendation in the video leads to a safer configuration, then you never should rotate tires. The claim is that if one has the opportunity to avoid half-worn tires on the rear, one should do so.

The video does not make this "claim".

It most certainly does. It claims that the existing tires if left on the rear will render the car less safe due to the risk of fishtail skids. It shows treads up close and says that the new tires address that by channeling the water. Unless you are trying to claim that such an issue only materializes when there are new tires on the front (which would be pretty far-fetched) then they most certainly are claiming that a protocol which keeps minimally worn tires on the rear is safer. Once you put new tires on the rear, the used fronts will wear out and the cycle continues, keeping less worn tires on the rear.

You are just making stuff up.

Nowhere did they say "if one has the opportunity to avoid half-worn tires on the rear, one should do so." That is simply false. If you believe they said this, you should be able to provide a direct quote.

Nowhere do they say that the existing tires if left on the rear will render the car less safe due to the risk of fishtail skids." That is simply false. If you believe they said this, you should be able to provide a direct quote.

They do say that leaving the old tires on the rear and putting newer tires on the front will make the car more likely to fishtail. The newer tires should be put on the rear.

[Northern Flicker]

You are just making stuff up.

Nowhere do they say that the existing tires if left on the rear will render the car less safe due to the risk of fishtail skids."
...
They do say that leaving the old tires on the rear and putting newer tires on the front will make the car more likely to fishtail.

So you are actually claiming that putting new tires on the front is what makes the existing tires on the rear more likely to fishtail? I did say I thought that was far-fetched.

Unless you are trying to claim that such an issue only materializes when there are new tires on the front (which would be pretty far-fetched) then they most certainly are claiming that a protocol which keeps minimally worn tires on the rear is safer.

There is one sentence in the video about the rear tires hydroplaning first, which would be a possible explanation for that, though I'm somewhat skeptical that more worn tires on the front with less traction somehow save you when the rears are hydroplaning. The claim is that the driver is more likely to be aware of the front tires hydroplaning and can slow down.

[Northern Flicker]

Per a Car and Driver article front traction is most important for recovering from a hydroplaning event:

At the first sign of hydroplaning, let off the throttle and attempt to steer in the direction you want to travel—doing so very gently. Abrupt, herky-jerky steering movements can induce a skid, as can slamming on the brakes. Gentle brake application while steering is fine on cars equipped with anti-lock brakes (ABS), which nearly all cars made in the past 20 years are equipped with. Be smooth and consistent with the brake pedal. If gentle steering inputs have no effect, don't keep adding steering angle. Wait for the front tires to bite; trust us, you'll feel it.

To each their own, but I'd rather have front traction and the ability to try to steer out of a fishtail skid than to lose front traction and lose the ability to steer the car at all.

[LotsaGray]

With FWD all the acceleration traction is front wheels but this is the least reason to put better tires to front
Stopping is next up the ladder. Front tires provide vast majority of stopping
Controlling a slide or hyrdroplaning requires steering and rear tires don’t provide steering.
Then when you combine traction, stopping or accelerating, plus steering it is easier to make front end hydroplane. If putting better tires on the front reduces this that is a better situation.

What is obvious is the video shows with worse tires on front THOSE drivers realize they are hydroplaning sooner. Even if that was a good reason it only addresses one traction issue. You can avoid hydroplaning by slowing down. Hydroplaning is nearly a binary state. But stopping distance with worse tires on front is always greater regardless of speed.

As to telling you are in hydroplane of rear wheels, it is not hard to know. Fact is most drivers suck at foul weather driving. But that is not a good reason to make a car less safe.

[an_asker]

Update:

Got four Michelins installed last week. Was in and out of Discount Tire in less than 45 minutes. For good measure, got alignment done right after that.

[Rotarman]

I always only replace 2 if the others are fine. New tires go on the back (back to front if FWD, RWD is easy because new goes on the back then next time I do all 4). I never waste time getting tires rotated or throw useable tires in the landfill unnecessarily.

[MH2]

With FWD all the acceleration traction is front wheels but this is the least reason to put better tires to front
Stopping is next up the ladder. Front tires provide vast majority of stopping
Controlling a slide or hyrdroplaning requires steering and rear tires don’t provide steering.
Then when you combine traction, stopping or accelerating, plus steering it is easier to make front end hydroplane. If putting better tires on the front reduces this that is a better situation.

What is obvious is the video shows with worse tires on front THOSE drivers realize they are hydroplaning sooner. Even if that was a good reason it only addresses one traction issue. You can avoid hydroplaning by slowing down. Hydroplaning is nearly a binary state. But stopping distance with worse tires on front is always greater regardless of speed.

As to telling you are in hydroplane of rear wheels, it is not hard to know. Fact is most drivers suck at foul weather driving. But that is not a good reason to make a car less safe.

Too much thinking.

Buy quality tires. Replace those tires with other quality tires when the tread depth is 4mm for winter tires, 1.6m for summer tires, or the they hit the seven year mark.

[YeahBuddy]

Looks like the answer here is all 4. By the way, what year Corolla and how do you like it?

I owned one long ago, a 2004. My dad has a 2010 and I'm currently driving a 2022 or 2023 rental and I actually like it, besides this odd braking it does automatically in traffic. I can't tell if it's sensing traffic or it's heavy on regen braking. Other than that it's a nice little econobox!

[Luke Duke]

For a FWD vehicle. I replace two at a time and never rotate. Rear ones get moved up front and new ones go on the rear. Buy two more when the front tires need it. Repeat.

I don't waste two hours a year sitting at the tire shop and I spread out the cost of tires.

RWD vehicles get rotated and all 4 replaced at once.