spyr0

been to get a puncture fixed in rear tyre on my 02.
guy says i have to replace all 4 tyres!!!!!!!
he says just putting 2 new rears on will sh*g the gearbox.
2.5 to 3mm left on the other 3 tyres - is he pulling my pi55er or what?
am i being taken for a ride here?
:O

Tez_H

wont **** gear box...
i think you need to make sure tyres on the same axle are very close so you may need 2 tyres...
and within 2mm front to back... not sure about this though, was told that figure by a mate who had a 4wd volvo

think the central diff will do too much work if there are large differences
am sure that someone else will comment too...

Scooby96

wont the suspension compensate for a few mm difference on each corner???

spyr0

"4 new tyres or he wont touch it"
he got a bill from someone else who had the exact situation as me (but just replaced the rears) and his gearbox went and blamed the tyre co.
eeeewww


[Edited by spyr0 - 12/3/2003 2:51:03 PM]

Tez_H

well there are some wiser people on here than me...

but i cant see how the gear box will be affected by the difference in circumference of the tyres...

the only effect will be to make the diffs do more work... as one wheel will have to rotate more when travelling in a straight line, so the diff will have to rotate... the bigger the difference the more rotation, hence more wear on bearings etc...

suggest a call to a dealer if you are that worried...
but i wouldnt get 4 new tyres from the bloke
personally i think he is trying to get business off you...
go somewhere else...

Tez

clintyboy12

I was in exactly the same position a few weeks ago - puncture to rear passenger. Tyres last changed as a set so 3 tyres with approx 3mm tread so he advised to change two - never mentioned about going for a full set.

Has he seen you coming (as the nun said to the vicar)?

Tone Loc

iTrader: (1)

I'd tell the stupid **** where to stick his tyres! Best to just change them by each axle.... i.e just change the back's or the rears as pairs.

Tony.

spyr0

difrent kettle'o'fish (carwise) i know but i had a freelander (i know!) and the rears turned slower than the fronts and 'castled' because the rears were 'dragging'.
rear diff and tyres were replaced by dealer FOC - maybe similar scenario with a scoob?.i am referring to the difference in diameters between new and old tyres btw

Tez_H

the rear diff only compensates for the difference in rotational speed on the rear axle, like cornering
for a 4wd you need a central diff as well for the difference in rotational speed between all 4 wheels when cornering....

so if 1 wheel is "bigger" on one axle then both that axle diff and the central diff will turn

... I think!

sounds to me that the problem with the free lander was a rear diff failure causing the rear wheels to scrub and nothing to do with the difference between front and rears... which would be handled by the central diff

the dealer serviced my 01wrx and the service report said tread deapth front to rear was different (3mm on front and 2mm on rear)
they ever said anything.
the fronts were replaced under warranty due to poor setup by the previous owner...


[Edited by Tez_H - 12/3/2003 3:45:50 PM]

spyr0

ok thanx peeps,
told him to replace just the 2 rears.....
cheeky get!!

andypugh2000

Think he is talking bollox if you ask me as my main dealer swapped my fronts for my rears with very significant tyre differences, that is why we have diffs on our cars to conpensate for DIFFerent wheel turning ability, ask the guy what happens when you are pulling out of your drive and your outer two wheels turn twice the speed than your inner two wheels, plus the centre diff is also viscous couples to allow for movement between the two axles, sorry but he is just after your hard earned mate

[Edited by andypugh2000 - 12/3/2003 4:08:36 PM]

RayC

you will get some "wind up" in the centre diff if the wheels are a different diameter, but i am very unaware of how it would blow the gearbox up!

for arguments sake a new tyre has 7mm of tread making 14mm per turn your 2mm tread tyres are about 10mm per rotation smaller so it could add up

i think the legal limit is 1.6mm anyway and i personally change all 4 tyres at once to ensure the car is balanced but thats my choice, just remember your tyres are the only thing conncecting you to the road irrelvant of how good your suspension, brakes 4WD is.