AWD Tyre Wear Misconception?
Discussion
Was talking about my next car with my Father the other day, discussing AWD vs RWD cars on offer in my pricepoint. He swore up and down that AWD cars wear through tyres basically twice as fast.
I've never heard this before, and can't find anyone discussing this online at all.
His logic is that all wheels are driven, (x2 the number), therefore tyres are worn more? I said wouldn't that mean that the tyres won't actually wear any more as the acceleration force is distributed across twice the amount of contact patch, but he said no.
So; has anyone else ever heard of this before? Is it true? I've only ever driven FF and RR cars so have no experience with this, and it may impact my decision to go for something like an Evo over and FR/RR.
Cheers
I've never heard this before, and can't find anyone discussing this online at all.
His logic is that all wheels are driven, (x2 the number), therefore tyres are worn more? I said wouldn't that mean that the tyres won't actually wear any more as the acceleration force is distributed across twice the amount of contact patch, but he said no.
So; has anyone else ever heard of this before? Is it true? I've only ever driven FF and RR cars so have no experience with this, and it may impact my decision to go for something like an Evo over and FR/RR.
Cheers
People are very dim about 4wd, I think the 80’s marketing is to blame.
A 4wd will sometimeswear the fronts harder on the edges due to a heavier set up.
But the 2 tyres are rolling on the tarmac regardless of being driven or not. Lots of power may wear the tyres if they are slipping etc.
I have had people argue that a 4wd car will go round a corner faster on a tarmac racetrack (leave aside torque vectoring) when it’s the same contact patch as a non driven tyre.
A 4wd will sometimeswear the fronts harder on the edges due to a heavier set up.
But the 2 tyres are rolling on the tarmac regardless of being driven or not. Lots of power may wear the tyres if they are slipping etc.
I have had people argue that a 4wd car will go round a corner faster on a tarmac racetrack (leave aside torque vectoring) when it’s the same contact patch as a non driven tyre.
There's lots of different types of 4wd system which behave very different than each other, but none of them is going to generate double the tyre wear unless perhaps you're running with a differential fully locked (or lacking one of the differentials entirely) and you're spending very little time in a straight line.
Most modern 4WD cars are 2WD in 99% of road driving anyway, only engaging the secondary axle when the primary slips.
Most modern 4WD cars are 2WD in 99% of road driving anyway, only engaging the secondary axle when the primary slips.
the tyres on my Audis have always worn the backs first, think thats because in "normal" drive mode it's split 70/30 to the back, thats on a Torsen set up, Haldex might be different. The driving experience with Haldex is not as good in my experience, my son had an RS3, and it never felt as planted as my Torsen cars, and it (RS3) was very fussy about not changing tyres on all 4 wheels, whereas the Torsen system happily copes with new tyres on just front or back, might help if you tell us what cars your thinking about?
Super Sonic said:
I had a friend who swore blind that a car could stop quicker using engine and brakes to slow down than it could with brakes alone.
RIP Dan!
My father is the same. Shouts at me every time I drive him anywhere since I don't use the engine brake, because he thinks i'll won't stop as fast. I tried explaining to him that if your brakes can lock up the tyres then it doesn't matter where the braking force comes from but he just doesn't understand it RIP Dan!
ninepoint2 said:
the tyres on my Audis have always worn the backs first, think thats because in "normal" drive mode it's split 70/30 to the back, thats on a Torsen set up, Haldex might be different. The driving experience with Haldex is not as good in my experience, my son had an RS3, and it never felt as planted as my Torsen cars, and it (RS3) was very fussy about not changing tyres on all 4 wheels, whereas the Torsen system happily copes with new tyres on just front or back, might help if you tell us what cars your thinking about?
Was looking at WRX STis (2006) and some of the older Evos (IV) since both can be picked up for not much money around the 17k mark or lower for the WRX STIs (10k starting). Some of the 911 models come with AWD too, depending on the model.I'm familiar with the older Haldex systems and the constant maintenance required for them on something like an A3/S3, but haven't looked into what sort of AWD systems are on other cars as I took his word and thought that I would eat through tyres if I were to track the car :')
When I owned fwd vehicles, the driven axle wore tyres out much faster than the non-driven rear axle, I would guess rwd is similar.
Now with AWD torsen 50:50 all the tyres wear evenly in my experience.
As for the argument you are both correct to an extent, fwd/rwd change tyres in pairs but AWD is change 4 tyres.
Now with AWD torsen 50:50 all the tyres wear evenly in my experience.
As for the argument you are both correct to an extent, fwd/rwd change tyres in pairs but AWD is change 4 tyres.
Gress said:
Well, i'm very glad to be vindicated. I felt like I was going insane, since it seems so obvious but he was so adamant.
As mentioned above, he also thinks that using engine braking slows cars down faster too. There isn't much in the way of convincing him
What's the bet he is also absolutely certain that his car gives its best fuel economy at 80 mph.As mentioned above, he also thinks that using engine braking slows cars down faster too. There isn't much in the way of convincing him
You should ask him to sign up to PH and post his bizarre claims for 'feedback'.
Gress said:
Super Sonic said:
I had a friend who swore blind that a car could stop quicker using engine and brakes to slow down than it could with brakes alone.
RIP Dan!
My father is the same. Shouts at me every time I drive him anywhere since I don't use the engine brake, because he thinks i'll won't stop as fast. I tried explaining to him that if your brakes can lock up the tyres then it doesn't matter where the braking force comes from but he just doesn't understand it RIP Dan!
There may also have been more truth to it when most cars were RWD and had drums on the back? Drums brakes are pretty good these days, but there was a time when they were pretty awful.
Edited by kambites on Friday 12th July 07:36
kambites said:
I think this myth has roots in the fact that using the engine to provide some of the braking force keeps the brake temperatures lower and hence makes brake fade less likely; and means that if the brakes fail, the car will continue to slow, at least to an extent.
There may also have been more truth to it when most cars were RWD and had drums on the back? Drums brakes are pretty good these days, but there was a time when they were pretty awful.
He's quite old, so back when he was young he was probably right, when everything was small drum brakes, being able to use the engine to break kept temps lower so helped stopping distances on longer drives, or just outright made cars of that era stop faster since cars back then sometimes had undersized breaks.There may also have been more truth to it when most cars were RWD and had drums on the back? Drums brakes are pretty good these days, but there was a time when they were pretty awful.
Edited by kambites on Friday 12th July 07:36
LeoSayer said:
True, but in my experience the engine braking you get from permanent 4WD does help to slow a car down much better in icy conditions than 2WD.
Unless the differentials get involved in some way the effect of engine braking in a 4WD vehicle will be to apply the same amount of retardation to each wheel. i.e. the same rate of rpm reduction. When you press the brake pedal the amount of retardation at each wheel depends on the performance of its calliper/pad/disc. i.e. although the fluid pressure will be the same each side of the car the actual brake may perform differently. There may also be pressure differences front/rear or diagonally in a dual circuit system. This may make little difference under grippy conditions but can become significant on ice/snow, causing an individual wheel to spin or lock lock up.
All of the above will change if an ABS system chooses to intervene.
Gress said:
I wish.
I've had the same conversation with him twice over the years and both times he has been absolutely convinced that he is right.
Even had a bit of an argument over it
So buy two identical cars, one 2wd and one awd and prove him wrong.I've had the same conversation with him twice over the years and both times he has been absolutely convinced that he is right.
Even had a bit of an argument over it
It's easier and cheaper just to tell him he's wrong, but might be more fun to buy the cars and prove it.
Gassing Station | Suspension, Brakes & Tyres | Top of Page | What's New | My Stuff