Different thread pattern tyres on vehicle

[LesseW]

I recently replace the tyres on my Cruiser, i choose Michelin LTX force. The tyres have like 7000km on them.

I got two nails in a tyres, one nail went into the side wall and it cannot be fixed safely…

Guess what???? Fkn Michelin decided to discontinue these tyres and I cannot get hold of a new one. Michelin say the have the LTX trail available but the thread pattern is different to the LTX force.

What should I do? Put only one LTX trail on the vehicle or replace the opposite tyre also the with LTX trail to ensure the same tyre pattern on the axle but that means buying 2 tyres?

[Bugjuic]

Had the same issue with my father-in-laws Fortuner. Tires had 15 000km on them, slit a sidewall. Stock discontinued. Phoned around everywhere, no stock. Replaced all 5.

1. Always make sure you buy 5 new tires when purchasing new tires (Yes I know they are expensive, but in this case you could just have used the spare then)
2. I would never run one different tire (Even same brand and model if the other were worn beforehand over +-30k km) The diameters differ too much and you are effectively running one tire larger than all the others, and have personally seen a BMW diff giving in because of this.
3. Running only a set of 'NEW' rear tires on an AWD vehicle, also will create problems(Many will argue this fact, I would never do this to my vehicle), you might get away with a vehicle that has selectable 4wd.

Hence your best bet in my opinion is to keep on searching and phoning around for other shops that may still have stock of this model, even if you have to have it couriered, it is still worth it! Otherwise replace 5 new tires $$$ eina.

Good luck

[jakeslouw]

Peet, there are a lot of untruths and urban legends in your rules.

- You don't need 5, you only need 2. Please explain your rationale. See my last comment.

- Yes, you MIGHT see issues on different radius tyres on one axle, but please bear in mind that the average tread depth for AT tyres is 8mm. The average diameter of a 265/65-17 AT tyre is 776mm. I really REALLY doubt that a 1% radius difference will have any real effect. Online sites all say between 2% and 3% is perfectly fine. So even if one tyre was COMPLETELY worn to the TWI and one was new, I really doubt any vehicle with a decent differential will have issues. Not even your ABS or TC can detect 1% deviation: the software makes allowance for 3% +. I do agree however that more than 5% deviation MIGHT cause a diff to get hot on a 1000km trip. MAYBE.

- Running 1pair of new tyres on an AWD will cause issues: rubbish. Again, you obviously haven't got any scientific basis for this.

[Bugjuic]

Jakes

Ok so thus you agree that there is a difference in circumference on the wheels - thus whether it be a 2wd or 4wd system your distance covered by a wheel when losing 8mm of tread(16mm in diameter): 265/65R17 - 776mm as indicated by you
3.14*0.776m=2.438m
3.14*(0.776-0.016)=2.388m
2.438/2.438=1.021 which is 2.1% smaller in diameter

Thus for each revolution you are losing/compensating 50mm of length. Your electronics may definitely start seeing slip and try and transfer power. Thus if you have a specialized vehicle your onboard computer might possibly see it as slip and activate 4wheel lock. Even on conventional power transfer modes you cannot wholeheartedly tell me there will not be any minor compensation needed and premature wear on drivetrain components?

In saying all of this, the circumference of the Michelin LTX force and LTX Trail even when 'new' SHOULD theoretically be the same, but as most of us know, this is not the case, and there might be a few millimeters added or subtracted again. Also the LTX trail weight will differ from the LTX Force, which will result in your un-damped mass to differ. Your tire composition of the two will also differ greatly and be of a different compound as well as your contact surface to the road(tread pattern). Thus when braking hard or accelerating your slip will differ, again sending signals for the drivetrain to try and correct, adding onto the existing problem of premature wear. This can also create a safety issue where the front/rear compensation is accounted for in the traction control substituting for the slip difference and reducing braking effectiveness.

In short, you should replace 2 tires anyway, would be stupid to replace only 1. Thus replace 4 and have piece of mind. 5 would still be ideal as you don't then have to factor in Size/contact surface/grip/composition for future problems as this.

On your last point, out of interest, Subaru actually states that 2/32nd of an inch could damage the transfer case, as the transfer case does not operate hundred percent of the time and is only active when one of the wheels is spinning at a different rate than the rest...

Maybe I am paranoid and think too much about these things, but I know 4 tires are cheaper than a drivetrain .

[jakeslouw]

So Subaru's transmission cannot tolerate a 1.6mm deviation? Maybe then never fit any tyres made in ZA, because I can guarantee that deviation between 4 tyres of the same brand, type, and size. Also, the traction control system CANNOT register such a tiny deviation and lock up that accurately anyway.

Like I said: you read too much on the Interwebs.

[Bugjuic]

There good sir you are 100% correct. If I worry less, and read less then I will definitely do more! I am the kind of person who buys a battery charger more expensive than the battery itself, so when I get the battery I can look after it. Consequence thereof is sitting at home with a charger and no battery

[jakeslouw]

To answer Wessel: replace 2 tyres on the one axle. Keep the usable Force as a spare.

[LesseW]

Thanks all, appreciate the feedback.

[Mad Manny]

I see the Thread gave you roughly the same advice I gave you a few days ago:
As long as the tyres are the same size and spec, it won't really matter.

I have never & will never own a vehicle that doesn't have 5 wheels and tyres that are tge same, I will always replace all 5 tyres together unless, as in this case, something happens to one tyre, if I can get tge same I'll go for same size and spec.

If the tyres are worn then I'd put the new one on the Left Rear.
Why the Left Rear?
Left because our roads are generally lower on the left for water run off (not always, but generally) why Rear, because the rear are less important and less influential.
The new tyre will be rotated until it 'catches up' with the other four as they get spare wheel breaks.

My2cw

[Disco Nic]

New tires always on the rear, and ideally always replaced as a pair (unless it’s a puncture or what have you).

I don’t agree that the rears are less influential or less important… The rears actually contributes to stability of a vehicle, hence you always want the best tires on the rear axle.

[Mad Manny]

Rear Tyres:
Keep arse off the ground.
Aid stability.
Do less than 40% of the Braking.

Front Tyres:
Stability
60+% of the braking.
Steering.

But I always put the best two at the back as, on a RWD/AWD they wear the most...

[LesseW]

Thanks again for all the advice. I will replace the rear tyres and move the almost new LTX Force to the spare