Do You Really Need AWD? Settling The Winter Tire Debate

hello everyone and welcome in this video sponsored by hancook we are covering one of the common debates surrounding one of my favorite subjects tires beside me I have three tires a summer an allseason and a winter tire with these three tires we're going to answer three main questions first do you really need winter tires second do you really need all-wheel drive and finally since these are all specifically designed for electric vehicles what is an electric winter tire starting from the beginning do you really need winter tires the answer feels pretty obvious if you live in a mild warm climate probably don't need them if you live in a cold climate with frequent snow almost positively you'll really benefit from winter tires to understand why we really need to understand how these different tires perform in Winter conditions so it's a simple question how much grip do summer all season and winter tires have while driving on snow well this is difficult to answer precisely because there's basically infinite scenarios where the results would differ things like ambient temperature Road temperature how much snow what vehicle are you in what tires are you on of the thousands and thousands of options out there there's a ton of variables but that's not at all satisfying so to get a solid answer I looked at all kinds of different test data where summer Tires allseason Tires and winter tires were all tested against each other on snow a bunch of different tests so from third party Tire testing facilities I looked at academic papers pulled data from tire manufacturers and so on now if you have a tire stopping distance from a certain speed you can calculate that Tire's frictional coefficient in other words how much grip it has so I did this for a bunch of different tires all performing braking tests on snow which gave me an average grip level for each different tire type for summer Tires the frictional coefficient was about .14 for all season tires about .25 and for winter tires about 32 to provide context a summer Tire on dry asphalt could have a frictional coefficient around 1.2 that's over eight times as much grip as the same Tire driving in the snow now to really understand what these numbers mean as it relates to driving in the snow we need to talk about stopping distances this perfectly illustrates why winter tires are so important slamming the brakes from just 30 mph the winter tires need about 93 ft to come to a complete stop in the snow the all seasons do pretty well but still need 122 ft to come to a stop nearly two car lengths longer than the winter tires for an emergency situation that's huge finally the summer tire needs nearly 213 ft to come to a stop again from just 30 mph that's more than double the distance versus the winter tire okay so this very clearly answers the question do you need winter tires if you're frequently driving on snow absolutely it dramatically improves grip meaning shorter stopping distances in emergency situations and better handling in all snow driving scenarios the way I like to think about it if I want to be as safe as possible I want equal or better tires than everyone around me for the conditions that I'm driving in if I'm driving on snow and have a great set of winter tires on I can react better and stop shorter than those around me maximizing my chances of avoiding a crash if I'm driving around on those same winter tires but now in the summer when it's dry well then I have less grip than everyone around me which isn't ideal you want a good Summer Set again meaning you have the maximum buffer of grip for whatever situation arises okay so for stopping distances whether you have two wheel drive or all-wheel drive doesn't matter what matters is what tires you have with winter tires being the obvious choice for driving in the snow this leads us to our second main topic do you really need all-wheel drive this is a really interesting question that depends on a couple factors including how you like to drive and what the terrain is like around where you drive under normal circumstances driving like a normal person on a sunny day with dry roads you probably won't even notice if your car is front-wheel drive rear wheeel drive or all-wheel drive there's so much grip available that it doesn't matter at all most cars sold today are power limited meaning they could be faster if they had more power rather than track limited meaning they could be faster if they had better tires but this changes when you drive in the snow where two distinct advantages of all-wheel drive become apparent acceleration and driving up inclines okay so first let's look at acceleration using the grip numbers we calculated earlier for summer allseason and winter tires we can see what the best theoretical 0 to 60 time is based on our car having all-wheel drive front wheeel drive and rear wheeel drive when driving in the snow for example a rear wheeel drive vehicle on summer Tires would take 37.6 seconds to accelerate from 0 to 60 on a flat snowy surface that's an eternity though switching over to winter tires on that same car would result in a 0 to 60 in 15.8 seconds certainly reasonable for snowy conditions a front-wheel drive vehicle with a bit more weight over the front axle and thus more weight on the driven Wheels can slightly improve these times with a 0 to 60 of 15 seconds when on winter tires but with all-wheel drive the potential 0 to 60 times are dramatically better with all-wheel drive and winter tires capable of providing an 8.4 second 0 to 60 that means while casually driving you likely won't notice any loss of acceleration on snow winter tires combined with all-wheel drive means you can accelerate with a very normal Pace but there's some really interesting things we can learn from these numbers as well a front-wheel drive vehicle on winter tire TI can accelerate significantly quicker than an all-wheel drive vehicle running summer Tires this once again illustrates how tires are the most critical factor for winter driving all-wheel drive if the driver prefers can allow for better acceleration it's nice to have but not exactly necessary the necessity of all-wheel drive becomes apparent however when you start driving in mountainous regions and tackling inclines this is just a matter of physics all-wheel drive can climb a steeper slope than two- wheel drive because all of the vehicle's weight rests over the driven wheels on a rear wheeel drive pickup for example most of the weight is usually over the front tires and any weight on the front tires can't be used for acceleration so it's all wasted this is why you may see folks adding sandbags to the back of a pickup truck that's rear wheeel drive now let's be very clear adding weight to a vehicle does not improve its traction but in the case of a rear wheeel drive pickup truck if you're adding weight to the back of the car you're Shifting the weight distribution back so the percentage of the overall weight that rests on the rear wheels versus the front wheel increases and by increasing the percentage of the overall weight that's on those rear wheels you improve acceleration so weight distribution as well as what the driven wheels are become very important when driving up inclines all right so once again let's look at summer allseason and winter tires equipped on all-wheel drive front-wheel drive and and rear wheel drive vehicles to see the maximum incline each combination could drive up we'll refer to Incline in units of percent grade similar to what you'd see on highway signs and remember percent grade is rise over run so if you have a 45° angle that's 1 over one which gives you a 100% grade for all-wheel drive the math is conveniently very easy it turns out whatever the frictional coefficient is tells you exactly the maximum theoretical grade you could climb so for winter tires with a coefficient of 324 they could climb a 32.4% grade for front-wheel drive and rear wheel drive this is significantly more complicated to calculate as it's dependent on the weight distribution as well as where the center of gravity is located regardless using realistic parameters you can get a good understanding of how steep of inclines you can handle so something really interesting happens here because the amount of grip you have is very low the incline you can go up is also very low so front-wheel drive tends to have the advantage here if you were to have a lot of grip the incline you would go up would be much steeper so you'd have more load transfer to the rear wheels and rear wheel drive would end up being advantageous but in snowy conditions you tend to see the opposite play out so the maximum incline a front-wheel drive and rear wheeel drive vehicle could Ascend on winter tires turns out to be about 18 and 177% respectively and yeah as you can see having only two wheel drive versus four-wheels driven means you're cutting the incline you can drive up nearly in half in fact on a snowy hill an all-wheel drive vehicle on summer Tires could potentially climb a steeper incline than a rear wheeel drive vehicle running all season tires this illustrates a really powerful Point all-wheel drive is very important when it comes to driving on any sort of snowy incline giving a pretty simple logic Matrix to determine if you need winter tires and all-wheel drive are you driving in the snow yes then winter tires are a good idea are you driving in a hilly region yes then all-wheel drive is a really good idea and again if you're only driving on flat ground you can still benefit from all-wheel drive in terms of acceleration it's just not necessary to get from A to B so finally let's dive a bit deeper into this tire right here Han Cook's winter tire designed specifically for electric cars generally speaking winter tires have some serious sacrifices they're louder they have more rolling resistance and they use softer compounds all of these aspects are problematic for electric cars you're going to have more noticeable tire noise you've got less range and because EES are really heavy and the compound is soft you're going to have more tire wear realistically you can't eliminate these challenges outright if you want good grip in the snow you have to make sacrifices but hancook did put a lot of effort into making this a quiet tire and if you've ever driven on winter tires you'll readily know that they are quite noisy there are very clear reasons why winter tires are loud first off they have deeper tread depths this is important for traction on snow but it means you have more air pumping through the tire as you drive on the road which is loud you also have gaps in the tread block edges again these are important for snow traction and also for water evacuation especially on tires where you don't have as many main grooves which aren't good for snow traction but really help in the rain hence their prevalence on on summer Tires but these big gaps in the tread blocks means more tread movement and more air pumping noise coming out from the tire an issue summer Tires don't suffer as much from so how do you make a winter tire quiet well tread pattern plays a big role here so you'll notice the V shape is staggered so it alternates from each side on where it's contacting the ground this spreads out where the air is pumping through the tire which reduces noise you also have differing length tread blocks which breaks up the pattern hitting the road further reducing noise so if you were to use a symmetrical vshape along with equal siiz blocks well it would create this high pressure point which along with the rhythmic nature hitting the ground would create more noise they also have knurling inside the grooves which cuts down on cavity resonance finally you'll notice acoustic foam inside the tire further reducing the noise that reaches the cabin ultimately it results in a tire that has an a rating in Europe's standardized noise no testing the highest rating available and in my own testing on my car it actually equaled the noise level of the allseason tire and it was even quieter than the summer Tire which was impressive to see this is a genuinely quiet Tire yet it can handle real winter conditions now in terms of rolling resistance yes it was a focus and the tire does have stiffer sidewalls to accommodate for the heavier weight of an EV but there weren't major sacrifices made in order to minimize rolling resistance so versus an allseason or summer Tire you can expect to take a small range penalty in order to gain that Traction in Winter conditions but they did do something really interesting aerodynamically in order to help with that range penalty standard winter tires tend to have bulky blocky tread blocks leading to the edge of the tire where it meets with the sidewall this tends to be less aerodynamic so for this tire hancook uses a much more rounded Edge in Wind Tunnel testing they found this reduced the drag coefficient of of the tire by 0.3 okay at first this doesn't really sound like that big of a deal and for combustion Vehicles it really isn't modern combustion cars tend to put less focus on aerodynamics than electric cars because you can make up for range easily with a slightly larger fuel tank EVS though tend to have really really aerodynamic shapes these shapes are super sensitive to small changes in Wind Tunnel testing on a very aerodynamic EV hanook found that the improved aerodynamics of the tire can reduce the overall drag coefficient of the car by 02 keep in mind a modern EV might have a drag coefficient as low as 0 2 so 0.02 is a huge percentage difference a combustion car without a big focus on aerodynamics won't see as big of a penalty based on Tire selection because there's already so much turbulence around the wheel well overall as this is Han Cook's latest winter tire offered they say it matches the snow performance of their previous winter tires but with better noise better dry handling better wet handling and better wet braking so it's a much more well-rounded tire without giving up snow grip and with that I hope you've enjoyed nering out on tires as much as I have a big thank you to hancook for sponsoring this video and letting me pick the brains of their Engineers if you enjoyed this I have two other videos Deep diving into each of these other two tires which are absolutely fascinating so I'll include the links to those if you have any questions or comments feel free to leave them below thanks for watching

Channel: Engineering Explained

Views: 643,846

Keywords: winter tires, summer tires, all season tires, winter vs summer vs all season tires, awd vs 4wd, awd vs tires, hankook, hankook ion, electric car, electric car tires, engineering explained

Id: 1KGiVzNNW8Y

Length: 14min 33sec (873 seconds)

Published: Fri Dec 15 2023