Had to change all four tyres

[Jimmac]

i recently had a sidewall puncture on a rear tyre and leasing company told me to go to Kwik Fit as they hold a contract to chnage tyres for them. manager there told me that as the other three tyres were all more than 3mm lower than the new tyre all four had to be changed - he showed me a Kwik Fit notice to depots regarding this stating it was a sefty issue - somehting to do with the 4 wheel drive.

KF spoke to leasing company who accepted this. i have now had a bill from the leaisng co for changing the other three tyres due to 'irregular wear', spoke to the chap there who knew nothing about changing four tyres on any issue.

anyone know if the KF instruction to change all four is correct ?

 

[elm70]

In a proper 4x4 car, it may be recommended to change all 4 tyres in case 1 of them need to be replaced and there is a noticeable difference in the tyre profile size

But, our PHEV is a "fake" or batter an electronic 4x4/AWD .. with front axis completely independent from rear axis

So, there was no need to change more then 2 tyres .. only the tyre on the same axis may need to be replaced for avoid to "over load" the differential on that axis

In additional to this, I don't see why you are responsible for this ... a profile 3mm lower then new can be compatible with the amount of km done by the car ...

PS: Possibly the cheapest solution would have been to mount a new tyre after an "aging" process which cause to reduce 3mm of the profile ... :mrgreen: ... this means only 1 tyre to be replaced and nothing else

 

[NightPHEVer]

As previously mentioned - because the front wheels aren't actually attached to the rear wheels via a transaxle - which is the case on a conventional 4X4 petrol or diesel design, then it's difficult to imagine that the front vs rear tyre tread depths have to be the same. Although there is another recent thread on Technical Discussions 'New tyres and EV warning light' highlighting potential difficulty with the S-AWC (Super All Wheel Control) 4wd system which might cause the EV warning light to come on (or not as the case may be) if tread depths are radically different front and rear.

I had to replace a beyond repair Toyo R37 recently, but fortunately for me I had a spare one year old part-worn (cost me £50 with 6mm of tread) which conveniently had the same tread depth as the other three (which had done around 14,000 miles). But the 'spare' (I live in the Scottish Highlands so I carry a well-secured spare wheel!) I now have is new (7mm tread depth) so in the event of any future un-reparable punctures the point will soon come when it's tread depth is not compatible with what's on the car. So at the very least I'd have to by one more Toyo to match the new 'spare' and then fit both to one end or the other.

When I got my part-worn Toyo swapped over and a new Toyo R37 'spare' put on my spare rim, the Hi-Q tyre shop also informed me that according to Mitsubishi all four tyres should be changed. Whether I would have to have signed some sort of disclaimer for Hi-Q's benefit had I wanted the new R37 fitted to the car and not just as a spare (ie. that I was fully aware of Mitsubishi's advice but was ignoring it) I'm not sure. But I own my PHEV so don't have to negotiate with a lease company.

 

[jaapv]

It appears to me that the problem here is not so much the mandatory swapping of all four tyres - it is at least arguable- but the lease company attempting to squeeze their customer.

 

[Woodman411]

For what it's worth, User Manual 9-17:

View attachment MitsubishiTires.png

 

[Harald]

For what it's worth, User Manual 9-17:

Hi Woodman,
could you pls. post a picture of the differential between the front and the rear axle?
The next point in the manual is also interesting:
Installing other wheels will lead to the result that the TPMS sensor cannot be mounted?
I've already forgotten the type of humor that is hidden in the manual...

 

[Woodman411]

For what it's worth, User Manual 9-17:

Hi Woodman,
could you pls. post a picture of the differential between the front and the rear axle?
The next point in the manual is also interesting:
Installing other wheels will lead to the result that the TPMS sensor cannot be mounted?
I've already forgotten the type of humor that is hidden in the manual...

Sorry I don't know. Either it was an oversight to leave this verbiage in there from the non-phev to the phev, or could they be referring to the front trans-axle (aka "multi-mode eTransmission")? Ok so now that you've mentioned it, anyone install aftermarket rims successfully with tpms? I was curious about that too (whether the Outlander phev's tpms was more complicated for some reason).

 

[Harald]

In such cases, I simply try not to take the wording too seriously.

 

[Woodman411]

In such cases, I simply try not to take the wording too seriously.

And what if the manual is correct? I found out that the Outlander PHEV has two transaxles. Could it be that the manual is referring to the differentials within the transaxles?

Front Transaxle
The front transaxle is a compact and light weight design employing a configuration in which the differential drive gear takes up the motive power from either the front motor or the engine. It has an in-built clutch that, with the engine running in Series mode, automatically engages to transfer drive from the engine directly to the wheels when the Outlander PHEV switches to Parallel mode.The single-speed fixed ratio reduction gear layout for both motors and engine means that the vehicle is driven by the motors at slower speeds when they work most efficiently and by the engine at higher speeds when the engine provides the most efficient motive power.The result is high-efficiency motoring from low to high road speeds without the need for a complex bulky multi-gear transmission.

Rear Transaxle
Employed only to transmit power from the rear motor, the rear transaxle is of a simple construction using a single-speed fixed ratio reduction gear that makes the most of the inherent characteristic of the electric motor. Open axle ball bearings provide high-efficiency in the unit and the countershaft is located in the upper section of the transaxle to reduce oil agitation losses.

 

[Harald]

It seems that I need to write more directly:
I do of course respect such notes in the cases where they make sense.
But in case where I can detect clear nonsense, I dont bind myself to the text of the booklet.

Maybe this is an engineer's approach versus a lawyer's approach?

If you would buy a "Non-Mitsubishi" spare wheel, would you buy a wheel without TPMS sensor?
Or would you pay one cent for a wheel that is not airtight?

The product would be better if the handbook would be reduced to 100 pages ...

 

[Woodman411]

It seems that I need to write more directly:
I do of course respect such notes in the cases where they make sense.
But in case where I can detect clear nonsense, I dont bind myself to the text of the booklet.

Maybe this is an engineer's approach versus a lawyer's approach?

If you would buy a "Non-Mitsubishi" spare wheel, would you buy a wheel without TPMS sensor?
Or would you pay one cent for a wheel that is not airtight?

The product would be better if the handbook would be reduced to 100 pages ...

Even if the explanation doesn't make sense, I try to understand why. Why do they risk giving an explanation that people like yourself dismiss as "nonsense"? In this case, why are they discouraging non-OEM parts?

(My take, at least in the USA, there are many low-quality wheels flooding the aftermarket, combined with many roads in the USA with potholes that can knock out your teeth, and so plenty of cases of cracked wheels that leak air. Not to mention the unlimited combination of wheel and tire sizes that can compromise performance in various ways. If I was a manufacturer, I would discourage non-OEM wheels too, not many people are willing to pay up for aftermarket wheels that are truly high quality and ideal size)

Anyway, we're digressing from the OP, about whether the tire shop's advice (and manual) is legit. There are differentials in both transaxles. Can different tire sizes (due to wear) negatively affect these transaxles? I honestly don't know, would like to hear a logical explanation either way.

 

[Harald]

There are differentials in both transaxles. Can different tire sizes (due to wear) negatively affect these transaxles? I honestly don't know, would like to hear a logical explanation either way.

Design of the differential works with the assumption that driving on a straight line will not have difference in RPMs between the left side and the right side.

Having different tyre diameters will therefore lead to a certain load on the differentials and therefore "increase the differential oil temperature".

Having less than 5% diameter difference when badly worn tires are combined with one new one, I would not expect that this will lead to a failure on the differentials. If it would be a concern for me, I would simply drive for a few miles and measure the temperature by simple means.

Best regards, Harald

 

[jaapv]

Not to failure, but possibly to long-time wear.