Need NEW TYRES for my 2020 D-MAX LSM

travelyounger · Guru

RE: Need NEW TYRES for my 2020 D-MAX LSM

gold dandelion · Senior Member

Pirelli Scorpions.

-- Edited by gold dandelion on Monday 13th of February 2023 09:20:06 PM

Warren-Pat_01 · Guru

Bill B, rest
You raised the question about rotation. This should go to someone who has worked in the tyre industry.

After I bought our 2nd + hand GU Patrol & at the first change of tyres, I asked the the tyre dealer to consider incorporating the spare in the rotation plan. I was told it wouldn't work but instead of following it up, I chose to ignore the issue. I always battled to get the tyre cover off to check the pressure. Eventually at another purchase of a set of tyres I checked the spare. It was bigger than the rest by 20mm (possibly bigger tyres were fitted by an earlier owner - all round). That tyre was 10 years old, was in perfect condition with no cracks, bumps, etc. The dealer said the cover kept the UV rays from destroying the rubber. With that last set of tyres that I put on, I did ask that they all be rotated. We covered 200,000kms in 7 years of ownership in that car.

So going back, is it better to rotate 4 & throw an unused tyre away after 5-6 years? Or rotate all 5?

shakey55 · Senior Member

Greetings all,

When it comes to tyre rotation in any pattern other than front to rear, rear to front, and only on the same side, PLEASE do not reverse the rotation of the tyres after the first 500km of travel. And disregard any instructions on rotating the spare into service if it will mean the reversing the rotation of the tyre.

When new, the tyre sidewalls and cord plies are unstressed. After about 500 km of travel the tyres become stressed, which results in the cords and plies stretching, and the rubber/polymer/cords which hold the tyre together expand in one direction to their designed extent and size. These are what holds the tyre together in a radial manner - basically by the application of torque, a twisting force, which also places strain on the wire-and-rubber beads and the capping of the aramid or steel belts in the tread edge areas. It also places stress on the tread blocks and the sipes (the really thin 'cuts' in the tread area that basically suck the tyre down onto a wet surface).

Reversing the rolling direction of the tyre will cause the torque to be applied in the opposite direction, with potentially disastrous results including tyre delamination - the edges of the steel or aramid (soft woven form of Kevlar) belts can cut through the cords and plies and fly off. Note the occasional truck tyre coming apart on the highway at speed, as we've probably all seen. That is usually caused by either heat build-up due to low pressure, or a tyre has been rotated to the opposite side of a truck after being re-grooved or repaired.

This is why some tyres are marked with a rotation arrow from new (i.e. they are 'directional' tyres) - it's not just because the tread is shaped in a particular way, but because the design dynamics of the tyre require that the tyre assume a particular mode of deformation to ensure safety and stability.

What will happen if the tyre gets directionally reversed after its run-in period is that the cords binding the plies will stretch and weaken. Once this happens they will look like little bulges, typically about the size of a 50-cent coin and protruding up to several millimetres. The cords may snap completely and you will then have the traditional blowout - usually on the sidewall just below the tread/belt area. Not a comforting thought at 110 km/hr going down the freeway with two tons of LandRover and 3.6 tons of trailer into oncoming traffic.

Let me reiterate - PLEASE, for your own sake and that of every family on the road - PLEASE do not reverse the rotation of the tyres once they have been on the road from new for 500 kms or more. Ever. I've seen the aftermath and it ain't pretty. Writing reports for the insurance companies/police/coroner isn't fun either.

- Wayoutwest
Tyre and wheel specialist, 5 years at Bob Jane T-Marts, 2 years with Tyrepower, 2 years with Mullins Wheels, must have changed 50,000 tyres in that career.
Disco 2 auto trans with 2-in lift kit 1999, Disco 2 std 5-spd man trans 2001 - both 4.0 petrol V8. Part-time A/T driving instructor.

Roy E · Senior Member

re Yobarr's pic of bogged car & van.
Yes, without researching Yobarr's vehicles, I did believe it was his but, it doesn't matter to me that it's not his, I still love that photo.
It reminds me a bit of bogging my Pajero in a salt marsh in Oman (Middle East) back in 1991 when I was trying to get a close look at some flamingos.
Luckily, I had no trailer attached and used some discarded wooden planks other drivers had used to get un-bogged, to get myself un-bogged.
Cheers,
Roy.