[Sportstick]

Hits some key points we've discussed, and surprisingly, debated.
-AWD does not add traction
-Stopping and turning are priorities


https://www.autoweek.com/news/techno...0Non%20Openers

[4Hockey4]

[Gilles79]

interesting, but if AWD is not adding traction, then I'm not sure what it's adding. Having moved over the years from a rear drive care with snow tires to a front wheel drive car with snow tires and currently an AWD with snow tires, I can say traction in the snow is hugely better.

[Sportstick]

Originally Posted by Gilles79

interesting, but if AWD is not adding traction, then I'm not sure what it's adding. Having moved over the years from a rear drive care with snow tires to a front wheel drive car with snow tires and currently an AWD with snow tires, I can say traction in the snow is hugely better.

As the article explains, AWD optimizes the traction the tires can generate. Traction can only occur at the contact patch. Tires have traction; vehicles do not. If zero traction at the contact patches, irrelevant if spinning two or four wheels. If good traction at the contact patches, AWD allows four of them to be powered versus two to more effectively propel the car. Thus, the greater criticality of the tires.

[Gilles79]

Originally Posted by Sportstick

As the article explains, AWD optimizes the traction the tires can generate. Traction can only occur at the contact patch. Tires have traction; vehicles do not. If zero traction at the contact patches, irrelevant if spinning two or four wheels. If good traction at the contact patches, AWD allows four of them to be powered versus two to more effectively propel the car. Thus, the greater criticality of the tires.

Thanks, your explanation is much better than that of the article.

[Rick.Null]

So, in essence, if you live in colder climates, get an AWD with solid winter tires for the most optimized winter driving.

If you'd like to take on risk, and have less than optimal driving experience, make do with the same winter tires on a RWD setup.

Ergo, AWD is awesome-er in the snow (given similar winter tires)!

[PeteTheMailman]

This will be my first rear wheel drive car since I started driving, around 25 years. Been using snow tires on my cars for roughly past 15. Assuming will be a slight relearning curve but streets that I use regularly are well plowed so not that worried

[Sportstick]

Originally Posted by Rick.Null

So, in essence, if you live in colder climates, get an AWD with solid winter tires for the most optimized winter driving.

If you'd like to take on risk, and have less than optimal driving experience, make do with the same winter tires on a RWD setup.

Ergo, AWD is awesome-er in the snow (given similar winter tires)!

"Awesome-er" isn't a measurement I know, but, yes, AWD with winter tires is the most capable solution.

The fallacy that perpetuates this discussion each year is having AWD on all seasons as the next fallback versus the superior RWD with winters, as you correctly point out. So, the "Null Hypothesis" wins!

Originally Posted by PeteTheMailman

This will be my first rear wheel drive car since I started driving, around 25 years. Been using snow tires on my cars for roughly past 15. Assuming will be a slight relearning curve but streets that I use regularly are well plowed so not that worried

Had RWD for many years with Blizzak WS tires in Michigan winters and never needed anything else. Perhaps stating the obvious, but put dedicated winters on all four corners...I've seem some folks try just the drive wheels.

[PeteTheMailman]

Originally Posted by Sportstick

Had RWD for many years with Blizzak WS tires in Michigan winters and never needed anything else. Perhaps stating the obvious, but put dedicated winters on all four corners...I've seem some folks try just the drive wheels.

Always! Wife used to give me crap, but once I started putting them on hers she is a believer. Was amused when I put my order in and salesmen was almost confused I WANTED summer tires, like yes will get dedicated winters. Most vehicles stocked are xdrive with all seasons, and I agree with all your points about this being a false senesce of security and a waste for most people.

[E46ZHP2]

From a performance standpoint, AWD is better than 2WD. Wet, dry, snow, whatever. That is why most of the highest performing cars have AWD. It's just better.

[leftoverture]

Well in my experience with our 228i x-drive, winter tires are much more about stopping than going. With the AWD, I had very little trouble getting going with summer rubber, but couldn't stop worth a darn.

[jv92red]

Originally Posted by E46ZHP2

That is why most of the highest performing cars have AWD. It's just better.

Hmmm. High-level performance cars trace their lineage from racing. But as we see in racing at the highest level (paved roads) like Formula 1, these are rear-wheel drive. Why? Essentially the gain in traction wouldn't be enough to justify the big gain in weight. And then of course some would say it's because they are mandated by the rules to NOT be AWD. Now in the future, this may change and they might figure out how to implement drive for the front wheels with less of a weight gain via technology with the added weight being mitigated by the additional traction.

It has been done a few times in the past:
https://en.m.wikipedia.org/wiki/Four...in_Formula_One

[TajoMan]

[Sportstick]

Originally Posted by E46ZHP2

From a performance standpoint, AWD is better than 2WD. Wet, dry, snow, whatever. That is why most of the highest performing cars have AWD. It's just better.

This prompts a few comments:

First, we need to disabuse ourselves of the concept of "better". "Better" or "worse" are purely human subjective constructs. Thing A may be different than Thing B, but whether any one thing is "better" than another is a subjective evaluation by a particular person, depending on their personal priorities, and not an objective reality that applies to all. There is no inherent "better" of anything in regard to anything.

This thread started in relation to winter tires. AWD with winter tires has the greatest capability. RWD with winter tires follows for winter conditions. AWD is only effective if and when the four wheels it powers can deliver the power to the ground, which is a function of traction, which solely comes from tires. All seasons are far less capable, so AWD with all seasons is a lower capability combination.

Lastly, high performance cars use AWD to divide the torque that would otherwise exceed the traction capability of fewer than all four tires. That is the benefit and purpose...to most efficiently translate engine power via more powered tires with traction to acceleration of the vehicle. Have a M5, or even an M2 or other high performance vehicle? Then, it may be more efficient at WOT conditions. For most typical 2 Series vehicles in the vast majority of use cases, which do not include WOT takeoffs, this benefit will never be realized.

[dradernh]

Re: AWD, I think this statement on page 34 of the current issue of Car and Driver is accurate:

"The bulk of new-car buyers these days want a tall perch, plastic body cladding, and the false sense of security all-wheel drive provides..."

[harma24]

Originally Posted by TajoMan

Interesting result. While the handling and braking results are as I would have expected, I would have guessed RWD w/ snow's would have accelerated at least as well (if not better) than AWD with all-seasons.

I have AWD, and I'll still stick with my summer/winter setup over all-seasons (although apparently more for the summer performance than winter performance).

[4Hockey4]

Originally Posted by dradernh

Re: AWD, I think this statement on page 34 of the current issue of Car and Driver is accurate:

"The bulk of new-car buyers these days want a tall perch, plastic body cladding, and the false sense of security all-wheel drive provides..."

Non F1 AWD (yes they are still RWD) does not create a "better" driving car. Winter tires are about grip, traction..and some stopping.

For folks that want that .02 advantage with AWD/Auto, sure, for everyone else, we buy the manual RWD 911..EVEN with all the HP. Cant imagine dumping $125K+ on a 911 4S auto...(of course 4S no longer available in manual..that explains alot.) Using Porsche since thats a upper perf. car, and not a 40K BMW. But its the reason I sold my AWD Audi and got the 235

Couple years old, even with the RWD less HP. Start at 4:00 mark. "Sucks the fun out of the 911", it keeps you safe. Its like driving an Audi lol - guy owes a 4S..I'm sure he's just a purist..

https://www.thedrive.com/porsche/946...-from-awd-911s

[aerobod]

If you look at the manufacturer with the purest range of sports cars at the moment, that would likely be McLaren. All of their non-hybrid cars (the bulk of them) are RWD and will still manage 2.9 0-100km/h in the case of the 720S or 600LT (2.8s 0-60mph), or 0.1 seconds faster again for the Senna.

[TrboMike]

Originally Posted by Sportstick

As the article explains, AWD optimizes the traction the tires can generate. Traction can only occur at the contact patch. Tires have traction; vehicles do not. If zero traction at the contact patches, irrelevant if spinning two or four wheels. If good traction at the contact patches, AWD allows four of them to be powered versus two to more effectively propel the car. Thus, the greater criticality of the tires.

So the assumption is if there is a possibility that two tire have no traction that all four will definitely have no traction? I guess rock crawling guys are stupid for having 4WD. They only need two.

[230iZTR]

AWD gets you better traction to get you going from a stop. Season-apporopriate tires and good driving technique give you traction to keep you going once you're rolling, regardless of drivetrain configuration. The article appears to back that. A physics textbook would back that. Driving in Tahoe seems to anecdotally back that.

[Sportstick]

Originally Posted by TrboMike

So the assumption is if there is a possibility that two tire have no traction that all four will definitely have no traction? I guess rock crawling guys are stupid for having 4WD. They only need two.

What an odd inference to draw when that has been neither implied nor stated. That conclusion does not at all follow from the logic of the prior discussion.

[dradernh]

Originally Posted by 230iZTR

AWD gets you better traction to get you going from a stop. Season-appropriate tires and good driving technique give you traction to keep you going once you're rolling, regardless of drivetrain configuration. The article appears to back that. A physics textbook would back that. Driving in Tahoe seems to anecdotally back that.

I think yours is an excellent summary. It reflects my experience driving AWD, 4WD, RWD, and FWD during 20 Northern New England winters – always with winter tires for 5-6 months of the year.

Getting going from a stop on a slippery surface was the principal benefit I experienced with AWD and 4WD. If I'd been in a similar circumstance with FWD or RWD, I might have had to have done better planning so that I didn't end up sitting while spinning my wheels.

The second greatest benefit came when transitioning from a high-grip surface to a low or very-low grip surface, whether that was ice, gravel sitting on top of a hard surface, or a steep incline like my driveway. This was most noticeable when switching from 2WD to 4WD in a pickup.

With a half-cord of hardwood placed over the rear axle, my pickups were by far the most fun in the winter. That was true just driving around in my rural region as well as at winter car control clinics where using both 2WD and 4WD was the fastest way around the road course sections.