Hello everyone and welcome
in this video
I have teamed up with Michelin to talk about what happens to the performance of tires as they wear and some of the strategies
taken by tire manufacturers to design tires that still perform even when they're near the end of their life now something that's
Fascinating about tires, but perhaps not entirely intuitive is that as a tire wears its dry performance actually improves
Braking distances tend to get shorter and cornering grip tends to increase the opposite
However happens in the wet as the tire nears the where bars braking distances increase and cornering grip
Decreases, well, why is this and what can you do to prevent wear from ruining a tires performance first off?
We need to break down how a tire gets its grip which can be grouped into three categories
construction compound and tread pattern a tires overall grip is a
combination of all
three the construction of the tire provides the overall shape of the contact patch and how it interacts over bumps and
Imperfections the compound obviously plays the most critical role how well the compound sticks to the road
Determines how well the tire performs and what's cool about compound is that it doesn't change as the tire wears
So you want compound grip to be as high as possible for both wet and dry grip and finally we get to the tread
Tread patterns are great for wet
Grip, they improve traction in the wet by evacuating water away from the road contact to help prevent the tire from hydroplaning
So it's logical then that as the tread wears away what performance wears away with it in the dry?
however
that tread pattern reduces the amount of rubber contacting the road and
Decreases the rigidity of the contact patch
Allowing it to flex and squirm as the tire starts to wear away
That tread pattern wears away with it and the response and grip of the tire improve
This is why in racing when it's dry, you'll see tires without any tread pattern at all
Just a smooth sticky flat surface for the tire to clench the road
So how does this information change how tires are designed?
Well, according to Michelin you're four times more likely to get in an accident when roads are wet versus when they're dry
No surprise considering you'll have less grip and worse visibility
So then from a design standpoint
Wet grip is incredibly
Important for driver safety and while it's obviously important for a new tire to stop well in the rain
it also seems obvious that the performance of that tire should last the life of that tire whether it's 30,000 miles or
60,000 miles the tire ideally should keep a high level of grip in wet conditions even near the end of its life. Ok
So what can you do differently with the tire to make sure it still performs well in the rain as it wears down
Well, let's look at two different tires on the Left. We have Michelin's premier AAS tire and on the right. We have a hypothetical
competitors Grand Touring all season tire from a tread standpoint
You'll notice some interesting features on the premier is first off you can see the Center grooves expand as the tire wears
This is to ensure that water evacuation remains high as you lose tread depth versus the alternative
Of having groups that get narrow as the tire wears
The premier is also has emerging grooves which start off like sipes and emerge into grooves as the tire wears
Again to make sure the water has somewhere to go. There are also full depth zigzag sipes
These sipes act as high pressure biting edges
That cut through water to grip the road and they can also help clear water off the surface like a windshield wiper
Allowing the rest of the tire to contact the ground now sipes are common across
Manufacturers, but often they are not the full tread depth meaning that wet grip diminishes as the tire wears
So why would a competitor not have full depth sipes?
Well, if you think about it when people buy a new car
They're testing out that car on new tires. The impression they get of the car is partially based on the impression those new tires
Give that driver by only having partial depth sipes
The tire tread is more rigid which gives the driver better on center steering feel and improved steering response
Simply put it feels good. But as the tire wears wet performance is degraded
So what does michelin do to improve on center steering feel and steering responds?
Well by implementing three-dimensional zigzag sipes, it improves the rigidity of the tread blocks
You can also improve the tread stiffness by using thinner sipes
Super thin sipes result in less tread movement providing better feel but super thin sipes
Of course come at a additional cost if a sybiz only two tenths of a millimeter wide versus one millimeter wide
That means the molding tool has to have a piece of steel that's point two millimeters wide
This makes the tooling much more challenging and as a result much more expensive
It's easier and cheaper to use wider
Partial depth sipes that still allow for good grip in the wet when new and good steering feel and this hasn't even touched on
Compounding which is truthfully the most important part of wet grip
Michelin uses really high levels of silica a derivative of sand in their tires to improve wet performance
Silica can penetrate through a wet surface to contact the road and provide grip but silica can be difficult to work with
To effectively use silica with an entire the silica needs to be extremely pure and very fine
Silica alone doesn't want to bond with rubber compound
so it requires the right bonding agents and mixing process to get the silica to properly adhere within the compound as I've said before in
Many videos and I certainly don't mind repeating. There's really nothing as powerful that you can do to improve the braking and handling
performance of your car then getting a good set of tires that extra stopping distance can mean completely avoiding an accident or not and to
Demonstrate this I participated in some testing performed at Michelin's Lauren's proving grounds in, South Carolina
Which I'll have links to in the video description if you'd like to check them out
so a huge thanks to Michelin for partnering on the video and sharing some insider information on tires as
Always if you have any questions or comments, feel free to leave them below. Thanks for watching