Tyre rotation - unused spare

[Samblers]

2010 defender 110 - my factory-fitted General Grabber AT tyres have got 60,000km on them and i'd say 40% life left. The spare has never been fitted. Car is quite new to me.

Given that i'd probably fit different replacement tyres, shall i introduce the spare into use now via a tyre rotation, or are my existing tyres too worn and therefore i just leave as-is and accept that the spare will get binned un-used?

If i do fit it, best to put it on the rear? Seems a waste not to use it?

Cheers, Sam

[numpty]

Seems a waste to me too. Just send it over to me and I'll utilise it for you.:D Why not just buy 4 tyres of your choice and keep it as a spare. Either way, introducing it on to the car should present no difficulties or problems.

[DEFENDERZOOK]

The spare can be rotated in......the two fronts will go to the back......

The back left will go to spare.........

The back right will go to the front.......

And the spare will go to front left.......





If you want......you can cross over the front tyres as you move them to the back...




The front left tyre will always wear fastest on the outer edge due to the camber of our roads and U-turns........hence why the spare is rotated in mainly on the left hand side........



Also.....tyres should be rotated every ten thousand kms........

You should get between 80 and 100 thousand kms on the grabbers......I replaced mine at 80 but only because I scored another set........

And that was without rotating in the fifth tyre........




Pressures are also important to tyre wear.......

[Samblers]

Cool, i'll rotate it in.

Just thought it might affect the ride (steering?) less if I rotated it in on the back?

Still, i guess its always going to have more meat on than the rest...

Sam

[gusthedog]

Nah rotate it in! You'll be fine. I've been doing similar on all my rovers for years with no dramas :). As Defenderzook said, chuck it on the front left.

[AndrewGJones]

i wouldn't rotate it in now, too much disparity between the 40% worn and new tread of the spare. the tires will be rotating at different speeds across the axle all the time instead of just when cornering.

You need to rotate them all from new, or at least buy a single new tyre to go opposite the spare you have now on the same axle.

though in theory that just moves the problem to the centre diff.

Maybe not a big deal, but that's what I was taught.

[AndrewGJones]

also, your braking and steering will be adversely affected.

i've never tested it out though, perhaps it's all in theory.

FAIK full time 4WD needs same / same all round. Tyre type, pressure, and wear should all be the same otherwise the driveline is working harder than it should and could behave strangely when you need to stop in a hurry.

[AndrewGJones]

actually, doesn't the LR handbook say not to rotate them at all? Or it gives instructions on how to?

rings a bell, but i don't have a handbook anymore.

[Samblers]

I think from memory the handbook gives instructions on how to rotate (i.e. the order)... but then i guess most people just do what they want anyway.

My worn tyres still have plenty of meat left on them, so its not like i'm putting a new tyre opposite a slick tyre on the same axle.

Road wheels rotating at different rpm ... isnt that what the diff is designed to do? Just playing devils advocate - would be interesting to hear from those who have done this (and have had issues, if any)

Cheers, Sam

[Yorkie]

i cannot see how it would matter when all diffs are open and cdl not locked, rotate it in. :)

the only issue you would have if like me you have a detroit in the rear, always careful to keep both sides simalar to avoid issues.

[AndrewGJones]

going in a straight line, in theory, all wheels should be rotating at the same speed. the diffs then are not spinning internally, only as a whole. therefore they are generating less heat, wearing out slower, and spreading the power evenly between the wheels.

it wouldn't be much, possibly negligible really, but to me it's not really a hassle to avoid; don't rotate in the spare/ do rotate from new.


The other thing that comes to mind is wet weather driving with one 'grippy' tyre and 3 with less traction. Again, theoretically.


If you are playing the devil, do I get to be god? :angel:

possibly more theory than reality, but it's up to you.

[Samblers]

Some measurements, for the sake of curiosity...

Tread depth on new (spare) tyre: 13mm
Tread depth, worn tyres: 8mm

I calculate difference in tyre diameter new vs. worn equates to 5 extra revolutions per road kilometer (397 vs 402).

Hardly a lot of extra work for the diff i woulda thought? (compared to going round a corner)

[gavinwibrow]

I got this from here some time ago!


5 tyre rotation - Spare to Rear Left, Rear Left to Front Left, Front Left to Rear Right, Rear Right to Front Right, Front Right to Spare.
6 tyre rotation - Spares to same side, Fronts crossover to Rears, Rears to same side Spare. DON'T crossover or change sides if the tyres are directional.

[AndrewGJones]

Some measurements, for the sake of curiosity...

Tread depth on new (spare) tyre: 13mm
Tread depth, worn tyres: 8mm

I calculate difference in tyre diameter new vs. worn equates to 5 extra revolutions per road kilometer (397 vs 402).
Hardly a lot of extra work for the diff i woulda thought? (compared to going round a corner)

good work, I like crunched numbers, especially with honey.

It is then the equivalent of turning one very big corner for the next 10K kms.

It may be more salient to consider the traction issue when braking in the equation too. Uneven braking, especially in the wet, in a car that likes to roll over but is especially unsuited to keeping you alive while doing it.

[AndrewGJones]

Also, a new tyre is stiffer than an old tyre at any given pressure. so at 45psi the diameter is not just the difference in the treads but also in the compression difference.

Still perhaps the diff issue is a non-issue overall and it has always been the braking/steering etc of concern to those who make the 'rules'?

[Samblers]

Time to put the theory into practice ...

[gusthedog]

And our roads slope down to the left, thus putting more pressure on the left wheel. And you turn right more than left which would also put more pressure into the diffs/centre diff. In my experience, rotating in a new tyre has little effect on any of this. ;) Like someone else said, it's really like turning a really shallow corner for a while. If you're concerned, swap it around every wheel every few thousand kms to get the wear even :D.

And in my experience, road camber and condition would have more effect than grip depth (within limits of course :)) on emergency braking and steering.

[DEFENDERZOOK]

just rotate it in and dont worry about all the perfect world theories.......

it will not harm anything and you will get less tyre wear.......


they are all the same size....type....brand....etc...you wont have any problems....

the hand book wouldnt tell you to run different pressures if the diffs couldnt compensate for it......

are you shoes worn identically left and right......?
can you still walk in a straight line......?

[Westie]

I've always rotated the tyres every 10,000km with tyres staying on the same side of the vehicle - but I've just learned that's old hat! Here's what Bridgestone has to say about it:

Tyre rotation (http://www.bridgestone.com.au/tyres/passenger/care/rotation.aspx)

I can't see anything in my L/R owners manual about rotating tyres.

Also - the placard on the fuse box cover says that 'a single axle roller rig may be used for speeds up to 5km/h..' I've always thought this means that the centre diff is happy with a difference in speed of up to 5km/h between the front & rear axles so haven't worried too much about introducing new tyres into the rotation.

[noogie]

Mine are due for rotation.
I'm gonna buy another new km2 and then I'll have 6 of the same and rotate in two's.
This way I'll have 2 new km2 s on the rear.
I know it's a bit more but having 6 is the way to go and you've got that second spare for touring.