At what point to change a tyre...

AdrianC

Lovely, but it doesn't grow a third pair of wheels to become 6wd.

James2k

Mercdriver wrote: »

If you like wasting money. AWD is different to permanent 4WD. For example my CX5 has a bias towards FWD and will use rear wheels on demand. If the rear tyres don't need changing, then I wouldn't change them unless they were at similar wear to the front.

depends on the system, jeep specifies a very tight tolerance between front and rear axle (on my grand cherokee). because slip is detected by dissimilar rotation speeds. and mismatched tyres give exactly that. Thus wearing the clutches in the transfer case.

Similarly with my Audi which has a Torsen centre diff, Audi recommend the same depth on all tyres, for the same reason.

Will the car explode as soon as you drive away? no, but its best practice.


@AdrianC
4WD is generally used when the car/truck has a low range setting. awd, when its automatic thru the use of clutches etc

https://www.subaru.com.au/car-advice/awd-vs-4wd

AdrianC

James2k wrote: »

@AdrianC
4WD is generally used when the car/truck has a low range setting. awd, when its automatic thru the use of clutches etc

https://www.subaru.com.au/car-advice/awd-vs-4wd

Lovely, but complete marketing-driven !!!!!!!! to try to spin THEIR system as better than others.

AWD simply means all wheels are driven.
4wd means four are, without any comment on how many there are in total.
It is that simple.

James2k

No it isnt,

https://www.consumerreports.org/cro/2012/12/2wd-awd-or-4wd-how-much-traction-do-you-need/index.htm

https://www.digitaltrends.com/cars/fwd-vs-awd-vs-rwd/

https://www.autotrader.com/car-shopping/2wd-4wd-or-awd-which-best-you-215919

ach forget it, try this

http://lmgtfy.com/?q=awd+vs+4wd+differences

Whether you like it or not, they are different systems

AdrianC

AWD = 4x4, 6x6, 8x8
4wd = 4x4, 6x4, 8x4

That simple.

James2k

There's only one thing around here that's simple i'm afraid.

Mercdriver

James2k wrote: »

There's only one thing around here that's simple i'm afraid.

That last comment James is unnecessary. You can be a professor and still be mistaken.

My car is AWD but the rear wheels only drive when the car thinks the front ones aren't getting sufficient traction. This is the same with all AWD systems, whereas 4x4 is where all four wheels are being driven all the time, hence permanent 4WD. AWD doesn't mean all wheels are being driven all the time at the same time.

AndyMc.....

Mercdriver wrote: »

That last comment James is unnecessary. You can be a professor and still be mistaken.

My car is AWD but the rear wheels only drive when the car thinks the front ones aren't getting sufficient traction. This is the same with all AWD systems, whereas 4x4 is where all four wheels are being driven all the time, hence permanent 4WD. AWD doesn't mean all wheels are being driven all the time at the same time.

So what were the early Land Rovers?

AdrianC

AndyMc..... wrote: »

So what were the early Land Rovers?

Part-time 4wd. Permanent didn't come in until the s3 Stage 1 v8, then the Ninety/One-Ten, then Defender. But that was basically just the permanent system from the Range Rover. No fancy torque-splittery there, just a lockable centre diff.

There's part-time systems, there's permanent systems, and - increasingly - variable torque-split systems, using a variety of controls.

AndyMc.....

AdrianC wrote: »

Part-time 4wd. Permanent didn't come in until the s3 Stage 1 v8, then the Ninety/One-Ten, then Defender. But that was basically just the permanent system from the Range Rover. No fancy torque-splittery there, just a lockable centre diff.

There's part-time systems, there's permanent systems, and - increasingly - variable torque-split systems, using a variety of controls.

Non of which fit into Mercdrivers description.