CX-5 almost rear-biased

[gazelle]

'21 GTR and it was a snow storm yesterday.

Won't go into having to press rear defogger button (which in some other cars is more appropriately called defroster and is not combined with side mirror defroster) every 15 minutes (was driving for 3 hours) and constant icing of windshield wipers.

What's more interesting is that at one point when I tried to accelerate, what I believe happened was front wheel(s) skidded and the car instantly became rear-biased, sending itself straight into a barrier, which I fortunately managed to avoid.
In about 10 minutes I got tire pressure sensor warning, checked the tires and the front passenger one was leaking pretty bad, had to inflate it a couple of times just to make it to the tire shop where they pulled out a pretty big nail.

I'm not sure if the nail was in the tire at the time this happened or not, but regardless of the reason why the front wheel(s) started to skid, is it really the way an AWD car is expected to behave?
This is my first AWD car, my previous CX5 was FWD and weirdly I felt much more confident in this type of situations when pushing the gas had predictable effect, all my previous ones were RWD - they all were also predictable in a different way, but this AWD - it doesn't seem like you can expect it to do anything in particular, it just decides on its own. Am I missing something?

 

[skid00skid0]

You hit black ice. The CX-5 does not have a limited slip differential.

I had a Subaru Outback with LSD, and an Audi A4, they both would plow straight under slippery conditions. The LSD in the Outback eventually loosened up, and it steered fine.

 

[gazelle]

LSD works on a single axle, while my issue was that the power was transferred to the rear.
That would be center differential's job, which CX5 also lacks, but even if it had it - more power to the rear would do the same thing, probably?
I think what could've potentially fixed that situation would be Torque-vectoring AWD.
Or a dumb FWD.

 

[ADS-B]

Just curious, how fast were you driving? Also, just for context, what kind of tires do you have?

 

[gazelle]

Just curious, how fast were you driving? Also, just for context, what kind of tires do you have?

about 45, stock Toyo with 15k on them

 

[ADS-B]

Keep the Toyo tires for warmer days and go right away and buy some winter/snow tires. Judging from the footage, it seems to me you were driving a bit fast for the conditions. Combined with the stock tires, I believe that’s a recipe for disaster and no car features will save you from that.

 

[stickerbush]

I ditched my OEM Toyos when I had a similar experience to OP, not on slush but just on a wet roadway. AWD will not make up for crappy tires.

 

[youri]

Based on the video, this was not likely to be due to the AWD. At that speed you would have to mash the pedal to the floor to get enough power to make the rear lose traction from the AWD system like a rear wheel drive car does.

I agree with everyone else, the stock toyo are terrible all weather tire in cold conditions.

 

[Snorting2.5]

First off, you did an excellent job correcting that skid. Great job.

It is normal behavior for a "FWD" Chassis (Including if AWD has been tacked on) To transition into rear wheel skidding when the front tire(s) slip(s).

I agree that its likely not much to do with the drivetrain type. The tires on your car were simply not suitable for those conditions.

Be safe.

 

[Snorting2.5]

Couple more points, through your windshield reflection, I saw your TCS light flashing before the oversteer occured. How exactly did your front tires skid while you were driving in a straight line? And, what exactly do you feel happened at the rear wheels which you suspect made the situation worse?

Second, I noticed the RPM's went up while you were correcting the fishtailing. I assume that this was the AT downshifting, thinking engine braking is needed? Or did you apply enough throttle for that to happen?

 

[gazelle]

Thanks, all excellent questions that I'm still trying to answer myself.
I agree the speed was too fast, I merged into that hwy, saw lights approaching from the rear, and pushed the gas. After my maneuver the lights receded.

Sorry I'm not sure how exactly tires skid Everything happened in 5 seconds and it's all subjective.

All I know is that I pushed the gas (I admit pushing it harder than I would've on a RWD), and that I got the same response I would've expected from a RWD, and definitely not from FWD. You can see that the first left turn is less pronounced, but in reality it was way more scary because it was not caused by steering, my very subjective feeling is that it was caused by rear part of the car shifting to the right, just as RWD would (and I've been driving RWDs on icy roads for a very long time.) It's just what I felt, in reality it could've been anything, maybe it applied brake to the front wheel that it thought was skidding and that caused all that? No idea

Regarding the correction, I kept just as much *constant* pressure on the gas as I would to maintain the speed, and subjectively I didn't feel any interference from the car, I'm actually really happy with the way it behaved during the correction. It's only now I see that it shifted, I definitely didn't apply throttle to do that, not sure why it did.

 

[cz5gt]

ditch those Toyos, they are summer ones. Not good for anywhere north of the south belt.
If in the rust belt or in the northern states I would use proper winter tires

 

[ADS-B]

Your tires lost the grip (definition of skid) precisely because they are simply not made to be used in winter weather conditions. You somehow feel "betrayed" by the AWD but I think what almost cost you were two things: wrong tires and speed.

 

[Snorting2.5]

I definitely didn't apply throttle to do that, not sure why it did.

Vehicle must've detected you lose speed during that skid and downshifted to help you engine brake (Same way it would when braking going down a hill)

 

[ColtX-5]

LSD works on a single axle, while my issue was that the power was transferred to the rear.
That would be center differential's job, which CX5 also lacks, but even if it had it - more power to the rear would do the same thing, probably?
I think what could've potentially fixed that situation would be Torque-vectoring AWD.
Or a dumb FWD.

The electronically controlled clutch in the front of the rear differential *is* the center differential. It applies torque to the rear wheels all the time and increases it as programmed according to input from several sensors in the car. That and an open differential should apply the rear torque to the inside wheel, somewhat damping yaw motions, as long as you don't apply too much power for the road conditions.

 

[GTXT23]

You hit black ice. The CX-5 does not have a limited slip differential.

I had a Subaru Outback with LSD, and an Audi A4, they both would plow straight under slippery conditions. The LSD in the Outback eventually loosened up, and it steered fine.

I dont know about 2021- but 2023 CX5s are only AWD and have a CLSD - transmission - The Subies used to have a viscous LSD prior to the CVT debacle - now who knows --- But the 2023 CX5 NA with center LSD handles pretty damn good for a suv - Ive been thru all kinds of ice and snow patches in shaded steep fwy turns - no issues whatsoever -- other vehicles following usually drop way back in these conditions

 

[madar]

If you hit ice, and it looked like you did, all bets are off. You would've had better traction with winter tires but the only good things on ice are chains. The car tried to correct itself after the fact but it looks like it couldn't make the right decision fast enough due to the speed. I have dedicated snows on mine and although it makes the car nearly invincible in blizzard conditions, ice is not in the cars menu.

 

[gazelle]

Sure, I'd take a RWD on winter tires vs AWD on summer ones any winter day.
I'm just not so sure whether I'd take all season AWD vs FWD CX5 on a winter day I drove FWD CX5 for 4 years / 40k on Toyo A23 and never experienced this kind of behavior.
I think the nail must've played a role, it's the biggest nail I've ever had in a tire, and I suspect it still didn't fully penetrate when I was pushing the gas.
After reading A36 reviews I definitely think I'm a very lucky person, switched to Pirelli Scorpion AS 3, will see how it plays out.

 

[skid00skid0]

I dont know about 2021- but 2023 CX5s are only AWD and have a CLSD - transmission - The Subies used to have a viscous LSD prior to the CVT debacle - now who knows --- But the 2023 CX5 NA with center LSD handles pretty damn good for a suv - Ive been thru all kinds of ice and snow patches in shaded steep fwy turns - no issues whatsoever -- other vehicles following usually drop way back in these conditions

"LSD" forces both REAR wheels to rotate at the same speed. It has nothing to do with the center diff.

 

[GTXT23]

"LSD" forces both REAR wheels to rotate at the same speed. It has nothing to do with the center diff.

See last image , courtesy Mazda North America​

Mazda describes it as a Center Limited Slip Differential - on AWD systems for CX5 ( 2022-24)​

On-Demand Coupling​

Up to this point we’ve been talking about systems that drive all four wheels all the time through a center differential. On-demand systems operate differently in that they primarily drive only one axle until the coupling engages the opposite axle for assistance. Clutch packs are commonly used here, but so are toothed couplings called dog gears. Often the hardware sits just ahead of the secondary axle, though some systems decouple on both sides of the driveshaft to improve efficiency. Wherever the coupling is located, its mission is the same: Engage the assist axle progressively as needed.

A clutch-pack coupling increases the torque routed to the assist axle by increasing the clamping force on the friction discs, but these systems typically use lighter-duty hardware than full-time systems use because they only drive the second axle a small percentage of the time. Defaulting to two-wheel-drive operation also improves efficiency, which is why on-demand systems have become so popular in this age of strict fuel-economy regulations. Moreover, they offer most of the benefits of electronically controlled limited-slip differentials since they can be programmed to dispatch torque to the secondary axle before slip is detected.

[+] Improved efficiency relative to full-time all-wheel-drive systems
[-] Not full-time all-wheel drive
Found in: Mazda CX-5, Volkswagen Golf R

A superior system for awd with a fwd bias