Discussion
The Surveyor said:
My God, are you stalking me... first you take my user name and now your buying a V60, please don't tell me it's black 
Sorry, forgot about this thread as i bought a FWD one, yes in black and guess what, a Surveyor owned it before me...What do Architects drive these days!
Dave Hedgehog said:
Max_Torque said:
Like all 4wd cars, you should avoid running with vastly different levels of wear front and rear, and tyres should be the same size as well!
that is utter crapit is totally dependant on the 4wd system, many modern ones are far more tolerant than older systems, haldex does not care
the RS3 comes with different rolling radius and width front to back 255 F/225 R
As I understand it, the answer, as ever with these sorts of questions, is "it depends". A system like Haldex in a front engined car is FWD most of the time; obviously while it's FWD the relative tread levels makes no difference.
Haldex sends drive to the rear drive by engaging a clutch on the prop shaft; if the front and rear rolling radii are not as intended, once that clutch is engaged it will be fighting against its shafts attempting to rotate at slightly different speeds so one of two things will happen - either the clutch will slip slightly or one set of wheels will rotate at a fractionally different speed than the vehicle is travelling. This will either result in the clutch heating up and/or wearing slightly faster than would usually be the case or two of the tyres (probably the rears) wearing slightly more quickly as they scrub over the road surface.
However, it's worth noting that the same problem exists when the car is going around a corner as the rear proscribes a tighter arc than the front and Haldex systems aren't blowing up left, right and centre because their drivers go around corners. Realistically you're only going to have the rear drive engaged for a tiny proportion of the time so any extra wear is only going to be occurring a very small proportion of the time you're driving.
ETA: On a car with the same sized wheels and tyres front and rear it's always better to rotate the wheels to maintain even wear anyway. Why wouldn't you?
Haldex sends drive to the rear drive by engaging a clutch on the prop shaft; if the front and rear rolling radii are not as intended, once that clutch is engaged it will be fighting against its shafts attempting to rotate at slightly different speeds so one of two things will happen - either the clutch will slip slightly or one set of wheels will rotate at a fractionally different speed than the vehicle is travelling. This will either result in the clutch heating up and/or wearing slightly faster than would usually be the case or two of the tyres (probably the rears) wearing slightly more quickly as they scrub over the road surface.
However, it's worth noting that the same problem exists when the car is going around a corner as the rear proscribes a tighter arc than the front and Haldex systems aren't blowing up left, right and centre because their drivers go around corners. Realistically you're only going to have the rear drive engaged for a tiny proportion of the time so any extra wear is only going to be occurring a very small proportion of the time you're driving.
ETA: On a car with the same sized wheels and tyres front and rear it's always better to rotate the wheels to maintain even wear anyway. Why wouldn't you?
Edited by kambites on Wednesday 29th August 16:38
I read this thread earlier and despite being a Volvo man, wasn't aware V60 AWD's existed so that was that. Just been to Tesco to wash her car and a V60 AWD pulled up beside me at the lights. Black, grey arches... looked kind of raised slightly in XC fashion but wasn't badged as such, just V60 AWD. Quite liked it. Also an odd coincidence...
Davie said:
I read this thread earlier and despite being a Volvo man, wasn't aware V60 AWD's existed so that was that. Just been to Tesco to wash her car and a V60 AWD pulled up beside me at the lights. Black, grey arches... looked kind of raised slightly in XC fashion but wasn't badged as such, just V60 AWD. Quite liked it. Also an odd coincidence...
Not a coincidence, science!https://science.howstuffworks.com/life/inside-the-...
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