I went to tyre fitters for 2 new ones on front of my Land Cruiser and was told they had to fit all 4 at once on a 4WD! The rears were very good . They said different tread depths would damage the dif. They fitted 2 when I said it was 2 or none.
I asked them to check the pads while the wheels were off as I new from my service garage that they only had a few thousand miles left. They said thy were metal on metal and needed new pads and discs straight away. I knew that was not true as there was no noise and the brakes were good.My garage checked next day and there was still life in the pads and the discs were fine.
In view of this I mistrust the stuff about the tyres. Has anyone else come accross this?
It's certainly true thatyou should always buy tyres in sets of four for a 4 x 4. In the olden days, when there were really only Land Rovers, they had no centre differential, and it was easy to break a half shaft - or worse. Of course, that was only if you used four wheel drive on the road. (Sometimes you had no option if you needed low range).
What happens is that all the wheels have to turn at the same speed and you get transmission wind up. Either a wheel has to slip, or something has to break. If you correctly use the four wheel drive on loose surfaces, it won't hurt anything. Also, these days, many 4 x 4s have the centre differential, which allows a bit of leeway. Still better to give that an easy life if you can.
As long as the existing tyres still have deep tread, it will be ok. Never mix sizes on a 4 x 4 though. All four tyres must be the same size. Same make if you can, but that's good practice for any car anyway.
ive dealt with transwind up on military vehicles and yes it is true about tyre sizes. but surely the normal wear on tyres doesnt warrant a whole new set.
theoreticaly u could say as soon as you turn one corner the front tyres have worn a bit and are now knackered as they are 0.005mm less diameter than the back tyres, lol
u shouldnt use 4x4 all the time anyway and specialy at high speed on normal roads. you,ll blow the gear box,
anyway enough waffling,
dont use that garage again or just get ya spanners out and do the work yourself if your ok with it,
Sounds like a load of tosh from the garage. I've towed with a Land Rover for 13 years and had individual and pairs of tyres replaced without any problems. One damaged tyre (for instance) does not warrant a whole set of four. The diffs' allow for the tiny differences in rolling circumferences due to wear. But size in this case does matter. Always use the correct size tyres and never mix them up as previous posts have said. If you do change your tyre size as I did from the standard 7.50x16 (because they are getting harder to find), you must expert advice and change all four.
some of the new all time 4x4 recommend that there is no larger difference than 3mm between any of the tyres fitted to the vehicle i havent seen or dont know any thing about yours so i can not comment but they do sound like you dont want tobe going there
I remember reading an article in one of the magazines in my dentists waiting room about the 4WD Volvo XC70.
The magazine "help me complain" section were challenging a dealer on behalf of the customer to get back £3000 worth of diff repairs after they had only changed 2 tyres on his car, despite the manual advising having all 4 changed.
I was surprised that the tolerance should be so small on a ruggedised vehicle.
What does it say in your Toyota handbook?
HTH
Paul
------------- "Whether you think you can, or think you can't... You're right"
If you only use the four wheel drive off road, or in snow - that is when the tyres can slip on the ground, you won't have problems.
On newer vehicles with a centre differential, the problem is not so severe, but you still don't want one side of the diff going faster than the other all the time.
The major damage I've seen has always been with the older Land Rover type, with no centre diff. Sometimes with a maximum weight trailer, you would need low range for hills, even on the road, and that's when the gearbox can be destroyed. Seen quite a few, but not recently.
Even the same nominal size of tyre, from a different manufacturer, can have a substantially different rolling radius. If in doubt, take a piece of string, and measure right round the circumference of the tyre. Then do the rest. That can be a bit fiddly, so you can just make a chalk mark on the tyre right at the bottom. Make a mark on the floor next to it, then move the vehicle forward until the mark on the tyre gets to the bottom again. Make another mark on the floor, and measure back to the first one. That is how far your tyre will travel for each revolution. You may be surprised how different they are, and that's why we don't want to make the situation worse.
Never had a 4X4, but are they like other vehicles - possibly have different pressures front and rear - in which case would that not have an effect on width, circumference, and all the more technical, esoteric wizardry, etc.....?
....not to mention the different demands of concrete surfaces versus tarmac surfaces versus loose chipping surfaces....
Gram
------------- What's the difference between a chicken?
I have a Discovery.Its permanent four wheel drive.I only ever replace a tyre when it needs it and never four at a time.I have had no problems and its just clocked up 121k.The handbook simply states a tyre must be replaced when its indicator band becomes visable or when its tread depth reaches the minimum permissable depth that legislation allows.
I should check your handbook but to me it sounds like they were trying it on.
Its good practice with a permanent 4x4 to change the tyres round front to rear every 3k to 4k. This will give even tyre wear alround. You will end up changing all 4 at the same time then. It costs me £10 to have my 4 changed round & all tyres balanced at the same time. Why take the chance.
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Topic: 4 WD Tyres scam or for real?
