There was a post a while ago about using different patterns on the same axle on a 4x4 and whether that would upset the 4x4 system.

End result was that the important thing is not to mix tread depths on each axle if I remember correctly. Something to do with wheels turning at different rates, etc...

What sort of damage would it cause ?

Reason I ask is that I have a nasty vibration at around 80mph in my 4x4 and have been running a spare for a couple of weeks, now back on repaired wheels and the vibration is still there, kinda feels like front wheels but the view from the rear view mirror is blurry ?:.

Have had tracking and balance checked last night, all spot on.

PS: I am pretty sure the vibration was slight before I had the puncture, so may not be related.

 

 

the ford 4x4 system can compensate for differant wear rates on tyres and will not cause any damage

however - the vauxhall one will shit itself and fall in bits

 

I am told that about 3% difference in wheel speed is what it takes to cook viscose coupler. Also it is not very healthy for centre differential that statelites are rotating at massive speeds so generally I would argue for using the same kind of tires at the same wear state. Probably changing rears with fronts form time to time is good idea.

 

Jakub, that seems to be the "common" idea, XR4x4's apparently suffer badly from if tyres are uneven and the cossie 4x4 system is similar if not identical.

What would a "cooked" viscous coupler result in, in terms of driveability, etc... ? How would you know it's knackered ?

 

Depending on how you drive, you probably won't until it goes on a Rolling road.

 

xr4x4 and cossie 4x4 MT75 is identical apart from the gear ratio's.

one easy way to tell if the center diff is cooked, drive like a fruit on a wet carpark and see if you can get it donutting


seriously tho, off the top of my head, you jack up the front wheel (either side but just one), leave the car in nutral, use a torque wrench to measure the resistance when you turn the wheel using the hubnut - off the top of my head, it should be about 75nm resistance for a good center diff

 

The system itself is identical.



Depends if it welds itself solid or just realeses it's viscouse fluid through the overheated sealings. The latteer one I know frome experience and it just starts to behave mostly like RWD car. Generally there would be no torque to the front when rear slips. Also viscouse fluid will contaminate transfer oil.


If the VC would lock itself (which is less commn I think, I've seen it on a Scoobie once) you would have trouble turning the car, tires would make funny noises when turning especially when turing tight like parking. Also car would understeer terribly at higher speeds and ccould make lots of nosies from transmission

 

When my tyres were all-akimbo the only time I noticed it was when flooring it at the lights in the wet, the car would kinda accelerate diagonally if you get my drift (pun not intended honest).

 

If you see it on rolling road cuh kind rolling road is good place to fry it :-(

 

You can get it donutting both witha nd without good VC unit


I know that the diff itself schould give much less. I mean 50Nm setting is tarmac Grp. N car. But if you turn the wheel then there are gears between hmmm :-/

 

i did say off the top of my head - i'll have to dig the techy book out with all the info in

 

mmm, I wonder now, cos I've had a lot of vibration (not noise) on a long right hander (dual carriage way, fairly smooth) and 90 odd mph, so much so that I had to slow down as it was really uncomfortable

 

I might try that tonight

 

Vibration on long righthander can be downnpie catching on the fron prop-shaft.