That was the best explanation for me, who's absolutely zero in these affairs. 1 question: why rock crawling is where you will run into limitations imposed by the 50% torque limit on the rear drive wheels, not on icy roads. (Not that I want to do rock crawling... but explanation would help understand better)
Does CX-5 always start in AWD?
- Thread starter wbw
- Start date
Because weight transfers to the rear the steeper the incline and rock crawling often involves angles so steep the vehicle is in danger of rolling over backwards. In these instances the front wheels are barely planted and you need 90% of the torque to the rear wheels. Ice is too slippery to even contemplate a hill that steep so 50% torque transfer is typically more than necessary. Slippery surfaces require delicate power application to all wheels more evenly, rock crawling requires brute force on the wheels that are most heavily loaded.
I hope that makes sense.
Gotcha!! Awesome. You guys were talking in strange language all this while - slip differentials, locked gears, meshed what-not. Now in simple terms: I got it. No offence to anyone, though.
BTW: Hang me upside down, just started a thread on X3 (BMW) and CX-5. Just wondering.......
_russiankid
Member
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- 2016 CX-5 Sport AWD
As long as AWD will allow me to get'er sideways and have fun, the rest is whatever (whistle).
I think in any situation, the driver is the one who should be in control and not the car controlling the situation. If you've never experienced sliding in the snow, I suggested finding an empty parking lot and experimenting with how the car reacts to you slamming the brakes or doing your normal braking distance. That is the way I taught myself and has served me well.
I think in any situation, the driver is the one who should be in control and not the car controlling the situation. If you've never experienced sliding in the snow, I suggested finding an empty parking lot and experimenting with how the car reacts to you slamming the brakes or doing your normal braking distance. That is the way I taught myself and has served me well.
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- RDX Aspec Adv.
Shouldn't be zero problem on ice. Just turn tc/dsc off. Every vehicle I've ever owned would allow it except maybe my FWD g20 before I swapped transmissions tk one with lsd.
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- RDX Aspec Adv.
Anything will. I've yet to find a vehicle thay won't do that in low traction environs.
russiankid
Member
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- 2016 CX-5 Sport AWD
Hopefully it'll allow it in the snow as well.
State your source please? The lockup clutch in the transmission transmits all the torque all the time. The clutch in a LSD doesn't have any trouble either. How do you know the rear clutch will slip and overheat of the front wheels have little or no traction?
BTW One of my pet peeves is the 4WD versus AWD nonsense. If your vehicle has 4 wheels than 4wd and AWD are the same thing. All wheels equals 4 wheels. It used to be called part time and full time 4 wheel drive. Then Audi's marketing geniuses started calling their full time system "All Wheel Drive" to make it sound special. Now the whole automotive community is going on about AWD and some many nincompoops think the the AWD name means all wheels driven at all times under all conditions when practically no ones system does. There are enough different versions of full time 4 wheel drive or "on demand" 4 wheel drive (like my Element) to make covering them all with the name AWD meaningless.
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- RDX Aspec Adv.
It's common sense/physics. If the CX-5 is only transmitting 50% of its torque to the rear tires...unless the driveline is locked up solid with worm-gears...SLIPPING IS OCCURRING. Period. Slipping generates heat.
Second, yes, this is why every company has a special name for their system. My Jeep did drive all of the tires, all of the time that they had traction though, only pulling power from one tire to dist. to others when it lost traction. It had 2 drive-shafts, and ELSD's with clutch packs front and rear to accomplish this.
I don't mean to be hard on you but you post incorrect info almost every day, most often multiple times a day. You still haven't explained the video clearly showing all 4 CX-5 wheels slowing spinning in a controlled manner while trying to ascend the wet sheet of polyethylene (even though it's video proof that all wheels are driven). Why do you say the CX-5 doesn't have "real" AWD when this video proof exists?
Your new comment above shows you don't understand how a common automotive open differential works. An open differential can only transmit a maximum of 50% torque to either wheel (or front/back in the case of an AWD differential). Yet nothing is slipping in an open differential, it's made of solid gears, all meshed together (using ring, pinion and side gears). The secret is there are two output shafts (either to left/right wheels or front/back wheels depending upon which differential you are speaking of). While gears have friction that generate heat, there is no slippage possible in the differential, including the f/r differential that is responsible for the 50% torque limitation (ignoring any heat generated at the tire/road surface interface where any heat generated is dissipated well away from any mechanical components). In summary, it's not slippage of the AWD clutch that is responsible for the 50% torque limitation, it's the mechanical fact that an open differential can only transmit a maximum of 50% torque in either direction (by design).
However, the CX-5 can apply brakes individually to a wheel (or wheels) it detects are spinning. While this can't change the fact that a differential can only apply a maximum of 50% torque in either direction, it does mean the CX-5 can apply more than 50% torque to the tread of one tire (by increasing the torque required to spin the unloaded wheel). This works particularly well on slippery surfaces such as ice where total forces are low (and would be an inelegant solution for rock crawling because the forces are high causing the braked wheel(s) to consume an inordinate amount of available power).
Yes, every company has a unique name for their AWD systems. The reason is MARKETING. While it's true the Jeep system you are discussing is more complex, more expensive and can direct torque more efficiently in high torque situations, it is not true that it's better for driving on icy roads. That takes sensitivity so as to not upset the delicate balance of forces and this is where the lighter, simpler system used by Mazda (and most other CUV's) really shines. I don't know what else I can say to get this through your thick cranium except to suggest you move somewhere with a lot of snow and ice 6 months/year and actually learn how they work in the real world.
If you do, you will come to the same conclusion that ALL other experienced snow/ice drivers have come to: In regard to driving on snowy/icy roads, all AWD systems work, it's really all about the tires. I'm never going to get stuck regardless of which AWD system I have but I might spin out at 40-60 mph. Therefore I want the AWD system that's the least likely to spin out on ice. This is how people die on icy roads. And the systems that maintain a more delicate balance have the advantage here. That's why I didn't buy a Jeep as a ski vehicle.
This might sound weird, but I can understand MikeM explanation on the diff easily because I have a Redcat Sumo RC car, 4WD, with both front and rear diff. I had to open the diffs up, cleaning the pinions and gears, and even jam them with a piece of paper for drifting. You can also learn a lot about the diff behavior with an RC car, see how it behaves when one or more wheels locked up. It's a simplified model, but a good one to play with.
That is nonsense. A clutch can lock up and not be slipping. The statement was that the if the rear clutch was fully engaged and the fronts had no traction the clutch would slip, overheat or both. This is an assumption with no basis. It's not common sense physics without more information.
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- 2022 2.5GT
It's a hypothetical situation. We are talking about climbing rocks with a CX-5 for goodness sake. The clutch on the CX-5 rear axle is designed to take up to 50% of the drive and although it will have a margin of safety it will not be able to sustain driving 100% of the weight. It can and does overheat in certain extreme conditions which is why it will drop out until it cools. There is enough information in the pdf's above to confirm these comments.
The motor industry makes a distinction between AWD and 4WD - Google it.
4WD refers to a mechanical system with lockable diffs and axles. AWD refers to systems like the CX-5 that can take on all wheel drive when required, either by a multi plate clutch, viscous drive or other means.
Keep in mind that the fact the AWD clutch exists at all is to be able to modulate the power to the rear wheels without shock. The least likely time for it to overheat is when it's fully locked up. The design of the clutch is ingenious in that it uses a very small, low power solenoid to engage the rear drive. The small solenoid engages a small pilot clutch which begins to transmit torque to the rear wheels. This small transfer of torque on the small pilot clutch engages a special cam/ball mechanism that forces the larger main clutch plates together. This cam multiplies the force acting on the main clutch. The total torque applied to the rear wheels is modulated by pulsing the current (on/off) to the small solenoid and the cam mechanism therefore modulates more or less torque to the main AWD clutch plates depending upon the on/off duty cycle of the solenoid.
"4WD" refers to any mechanical system that direct coupled. The differentials do not need to be locking differentials to be considered "4WD". Most 4WD's have open differentials and sometimes limited slip differentials, locking differentials are quite rare. Most all 4WD's will have locking hubs. This is how the system is converted from 2WD to 4WD (along with engaging the transfer case). The locking hubs do not increase or decrease off-road ability, they simply allow the front wheel drive axles/front differential/front drive shaft to be disconnected when 4WD is not engaged to save fuel and wear on the driveline between the wheels and the transfer case.
The rear hubs on a AWD CX-5 are always locked and thus the rear axle/rear differential is always turning (when the vehicle is in motion). This explains most of the extra fuel burned by an AWD CX-5 vs FWD.
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Is that how it is on other cuvs? Maybe not and that's why the cx5 has a bigger difference in mpg between awd and fwd compared to other cuvs. Also, does this offer any extra advantages? Quicker response and handling?
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- RDX Aspec Adv.
I guess that diff overheating light has no purpose, then...
