Tire stopping distance ratings - why such differences and are they accurate?

[NYCaviator]

I'm shopping for new tires and am scratching my head about the stopping distance measurements. The Hankook Ion Evo tires are highly rated for EVs, and reviews indicate that they are very quiet and very comfortable. But, when you compare the stopping distances on Discount Tire/Tire Rack to something like the Michelin Pilot Sport All Season, it takes 22' longer to stop on a dry road, 37' more on a wet road with new tires, and 55' more on worn tires.

On paper, that seems like a huge difference.

How useful or accurate are these measurements? Are they assuming you're driving fast and slamming on the brakes suddenly?

Assuming they are accurate, why would anyone buy the Hankook when it's objectively much less safe? 37 to 55 feet in an emergency braking situation could be the difference between being involved in a crash or not.

I was about to order the Hankooks until I saw that data.

[finite_difference]

What’s the price difference? That might be your answer.

I do think it’s worth spending every penny you can on quality tires. I am personally a huge fan of Michelin tires.

[beardsicles]

https://newsroom.aaa.com/wp-content/upl ... Report.pdf

Some more data here. The differences AAA found for new tires are there but don't look as dramatic. Worn tires though, yikes. Replace your tires, people.

[Swansea]

I'm shopping for new tires and am scratching my head about the stopping distance measurements. The Hankook Ion Evo tires are highly rated for EVs, and reviews indicate that they are very quiet and very comfortable. But, when you compare the stopping distances on Discount Tire/Tire Rack to something like the Michelin Pilot Sport All Season, it takes 22' longer to stop on a dry road, 37' more on a wet road with new tires, and 55' more on worn tires.

On paper, that seems like a huge difference.

How useful or accurate are these measurements? Are they assuming you're driving fast and slamming on the brakes suddenly?

Assuming they are accurate, why would anyone buy the Hankook when it's objectively much less safe? 37 to 55 feet in an emergency braking situation could be the difference between being involved in a crash or not.

I was about to order the Hankooks until I saw that data.

I have these Michelins...perform great. Tire Rack may have data on stopping distances.

[finite_difference]

https://newsroom.aaa.com/wp-content/upl ... Report.pdf

Some more data here. The differences AAA found for new tires are there but don't look as dramatic. Worn tires though, yikes. Replace your tires, people.

Yeah, from reading that report with ~40% worse braking performance at 4/32", I am thinking it’s better to replace at 5/32". The Michelin tires hold up well though.

[Scorpion Stare]

But, when you compare the stopping distances on Discount Tire/Tire Rack to something like the Michelin Pilot Sport All Season, it takes 22' longer to stop on a dry road, 37' more on a wet road with new tires, and 55' more on worn tires.

Are you sure you’re looking at comparable numbers for both tires? In this Tire Rack test using a Tesla Model 3, the dry track stopping distances were:

• 83.7 feet (Michelin Pilot Sport All Season 4)
• 88.7 feet (Hankoon iON evo AS)

and the wet track stopping distances were:

• 92.3 feet (Michelin Pilot Sport All Season 4)
• 104.6 feet (Hankoon iON evo AS)

That’s only 5' difference on a dry track, and 12' difference on a wet track. These are from a single test using the same methodology, same test vehicle, same road surface, same weather conditions, etc. Results from different test sessions might not be comparable because of these and other variables.

Are they assuming you're driving fast and slamming on the brakes suddenly?

Tire Rack tests stopping distance for panic braking from 50mph to zero. At freeway speeds, the differences might be even greater. At 25 mph, vastly smaller.

[Jack FFR1846]

There are a lot of things that go into tire performance. But you said the magic words for "poor performance". Rated for EVs. These tires focus on low rolling resistance and universally use harder compound rubber to get both this and reasonable tire life with the dump truck weights of an EV. So any tire made for an EV will perform worse than virtually any tire that isn't an offroad mud tire. If you have an EV and want to focus on tire life, pay particular attention to what car the tires were tested on. If it was a Mustang Mach e, then they'll show similar life on your EV. If they're tested on a Camry, expect tire life to be half what was found on the Camry.

So back to tire compound, the softer compounds are key for grip and that goes directly to stopping distance. Coming from a roadracing background, I can tell you that on a dry track, tires with no tread will outperform brand new tires with lots of tread. In the rain, that's not the case and us roadracers would have a set of wheels/tires dedicated for rain. In the rain, tread depth and design are far more important than in the dry.

Are the stopping distances tested accurate? If they were tested on the same car, then yes. And this would mainly transfer to other cars, although the actual number would be different. For example, if a Camry stopped in 100 feet from a certain MPH, a much heavier Hyundai Ionic 5 would stop in a much longer number of feet. It's a simple physics governed fact. Driving a vehicle that's twice as heavy will take longer to stop. Sure, I know that traction is increased with weight but it doesn't overcome the weight moving at speed. If you want to stop faster, buy a Camry instead of a Kia EV6.

[enad]

I'm shopping for new tires and am scratching my head about the stopping distance measurements. The Hankook Ion Evo tires are highly rated for EVs, and reviews indicate that they are very quiet and very comfortable. But, when you compare the stopping distances on Discount Tire/Tire Rack to something like the Michelin Pilot Sport All Season, it takes 22' longer to stop on a dry road, 37' more on a wet road with new tires, and 55' more on worn tires.

On paper, that seems like a huge difference.

How useful or accurate are these measurements? Are they assuming you're driving fast and slamming on the brakes suddenly?

Assuming they are accurate, why would anyone buy the Hankook when it's objectively much less safe? 37 to 55 feet in an emergency braking situation could be the difference between being involved in a crash or not.

I was about to order the Hankooks until I saw that data.

Are you shopping on their website for tires for your vehicle or by the general tire category?

[bombcar]

Car tires are tradeoffs. As the poster above mentioned, if you wanted absolutely shortest stopping distance on dry pavement, you’d be using racing slicks.

But those wear out really fast. If you want long lasting, you’d use steel rail wheels. But those don’t stop too fast.

And wet makes it all different and worse.

Snow makes it even different - can you run snow tires all year? Sure. But they get eaten up fast on dry pavement.

Are you going to change your tires when it’s raining? Probably not.

So you get one that balances everything as best it can.

[Doctor Rhythm]

I'd guess they are accurate but only under the specific test conditions. Wouldn't make sense to compare stopping distance of Tire X on a full-size SUV against that of Tire Y on a mid-sized sedan. You'd need to make sure all other variables are controlled before making an apples-to-apples comparison.

For what it's worth, I usually buy the second highest rated tire in its category.

[random_walker_77]

... with the dump truck weights of an EV.

Agree with just about everything you said, except the hyperbole about EV weights. Yes, they're heavier, but that Kia EV6 weighs a little less than a Jeep Grand Cherokee, similar to a Toyota Highlander, and substantially less than a Tahoe or Ford Expedition.

[Epsilon Delta]

For example, if a Camry stopped in 100 feet from a certain MPH, a much heavier Hyundai Ionic 5 would stop in a much longer number of feet. It's a simple physics governed fact. Driving a vehicle that's twice as heavy will take longer to stop. Sure, I know that traction is increased with weight but it doesn't overcome the weight moving at speed. If you want to stop faster, buy a Camry instead of a Kia EV6.

Stopping distances are engineering, not physics,

If you do the physics the increase in traction exactly overcomes the increase in momentum. Both are proportional to mass. The reason heavier vehicles take longer to stop is because they cheap out on brakes. Tires would only limit stopping for a heavier vehicle if the tire is literally come apart.

[bombcar]

No, because any brake can lock up the wheel. The question is how much braking force can be applied before the wheel loses traction e.g., locks up. Stickier/slicker tires will go further.

[onourway]

But, when you compare the stopping distances on Discount Tire/Tire Rack to something like the Michelin Pilot Sport All Season, it takes 22' longer to stop on a dry road, 37' more on a wet road with new tires, and 55' more on worn tires.

Are you sure you’re looking at comparable numbers for both tires? In this Tire Rack test using a Tesla Model 3, the dry track stopping distances were:

• 83.7 feet (Michelin Pilot Sport All Season 4)
• 88.7 feet (Hankoon iON evo AS)

and the wet track stopping distances were:

• 92.3 feet (Michelin Pilot Sport All Season 4)
• 104.6 feet (Hankoon iON evo AS)

That’s only 5' difference on a dry track, and 12' difference on a wet track. These are from a single test using the same methodology, same test vehicle, same road surface, same weather conditions, etc. Results from different test sessions might not be comparable because of these and other variables.

Are they assuming you're driving fast and slamming on the brakes suddenly?

Tire Rack tests stopping distance for panic braking from 50mph to zero. At freeway speeds, the differences might be even greater. At 25 mph, vastly smaller.

This is the only post that matters here and it's interesting that the OP has not responded to it. These tests are only meaningful when comparing the same cars on the same track on the same day in the same conditions. The numbers above are more in line with what I'd expect. The Pilot Sports are an all-season based around performance. The Hanook iON evo is designed around efficiency. Every single tire ever developed has certain design trade offs. You should choose the tire based on what characteristics you value most.

I used to be all about the most performance in a tire, but I've come around to realizing that accessing that performance on public roads is dangerous and a car that has a better balance and a bit less traction is actually more fun when I'm not on the track. And it's nice to have tires that last longer, are less expensive, and more efficient to boot.