Tyre wear question

[Buckman]

Checked my tyres for wear. Checked outside groove and then inner groove and results as follows;

Offside front outer 7mm Inner 6mm

Nearside front outer 9mm Inner 9mm

Offside rear Outer 5mm Inner 4mm

Nearside rear outer 4mm Inner 3mm

I understand that it is time to change the rear tyres as they are the original tyres and have seen in excess of 36,000 miles. They are dated week 24 2016. Front week 41 2021 and other front week16 2019. However possible both front tyres were fitted at the same time? The nearside front seems almost new and would have been fitted last year.

Would you change all four tyres or just the three? It is an AWD vehicle and a sensitive transfer box.

 

[otherclive]

I would start out afresh and change all four. Are yours a mixture of makes? Your owners manual should give info on tread variations that are acceptable. Mine is 1 mm variation as it’s permanent 4WD. Yours is an odd mix of depths, surprised previous owner allowed that. Even if fronts were fitted at same time there's a noticeable variation in tread depth. My Bridgestones Weather Control are all at 4 mm as near as damn it and all I do is interchange them front- back- front but being unidirectional don’t rotate them around the car.

 

[Buckman]

I would start out afresh and change all four. Are yours a mixture of makes? Your owners manual should give info on tread variations that are acceptable. Mine is 1 mm variation as it’s permanent 4WD. Yours is an odd mix of depths, surprised previous owner allowed that. Even if fronts were fitted at same time there's a noticeable variation in tread depth. My Bridgestones Weather Control are all at 4 mm as near as damn it and all I do is interchange them front- back- front but being unidirectional don’t rotate them around the car.

All Continentals. I was quite surprised that rear tyres had achieved over 36k and still had a few thousand left on them if you were brave enough to go below 3mm.

At each major service the tyres are supposed to be rotated, but seems very possible that this did not happen? Major service is every second service so its had 2 major services in 4 years.

 

[Buckman]

BTW Kwik fit are the cheapest and then Halfords which are about £84 more expensive. Kwikfit offer a free 4 WD alignment check. With Halfords it is an extra £49 to do the actual alignment. If we go ahead with KF I have a funny feeling that wheel alignment will be required. Inde are charging up to £100 more per tyre so they are out of the question.
I am very wary of KF fit as we used them shortly after arriving in the UK in 1993. At the time we had a Montego that needed tyres. However they told us that we also need other things done like brakes, wheel alignment etc and we ended up with a bill of over £600 however I believe they have tried to polish up their image!

 

[Kevin M]

I would change all 4 at the cheapest supplier, unless there is any concern that alignment is out then it would be a flat refusal.
We are lucky to have a good independant tyre place who is reasonable.

Wouldn't trust KF to be honest.

Kev

 

[Buckman]

Blackcircles and able to use an Inde just down the road from us.

 

[ProfJohnL]

I would be concerned to find out why the tyre wear is so uneven. It could certainly be due to poor tracking, but perhaps one tyre had to be replaced because of a puncture.

What does the car manufacturers say about replacing tyres? There is a logic to having the same type of tyre at both ends of an axle, and if the tyres have to be switched round the vehicle at service, it helps if all tyres are the same model and age, which should see tyre wear evenly spread around all the tyres.

If the manufacturer does not make any suggestion or stipulation about matching, then it should not matter too much. (but watch it if you go to France where there is a law is slightly different.

As for which retailer, I don't think there should be any technical difference between the fitting of a tyre, but the ancillary services such as balancing or tracking might make a difference, however whilst you might expect to receive the same level of service from national company regardless of where you are in the country, often its local personalities that can make a difference.

Ultimately only you can make a decision about which retailer to use

 

[otherclive]

Blackcircles and able to use an Inde just down the road from us.

I have four wheel alignment done by an independent tyre supplier and it’s £70 if realignment is required. Nothing if nothing required. But I do have the tyres supplied by Blackcircles to be fitted by them.

 

[Buckman]

I would be concerned to find out why the tyre wear is so uneven. It could certainly be due to poor tracking, but perhaps one tyre had to be replaced because of a puncture.

What does the car manufacturers say about replacing tyres? There is a logic to having the same type of tyre at both ends of an axle, and if the tyres have to be switched round the vehicle at service, it helps if all tyres are the same model and age, which should see tyre wear evenly spread around all the tyres.

If the manufacturer does not make any suggestion or stipulation about matching, then it should not matter too much. (but watch it if you go to France where there is a law is slightly different.

As for which retailer, I don't think there should be any technical difference between the fitting of a tyre, but the ancillary services such as balancing or tracking might make a difference, however whilst you might expect to receive the same level of service from national company regardless of where you are in the country, often its local personalities that can make a difference.

Ultimately only you can make a decision about which retailer to use

I was waiting for your input and it is appreciated. Being an AWD matching tyres is critical and recommended by manufacturer that tyres are changed in pairs. All the tyres seem to be wearing fairly evenly across the tread. I think you are correct surmising that the offside was replaced before the nearside which is supposed to be a No No.

 

[RogerL]

There's alignment and then there's alignment - the basic check is just toe-in/out but a full check uses laser equipment on all 12 possible axes - Hunter is the most popular but there are others - some places will do a free alignment check and charge for EACH adjustment needed, others have a flat rate.

I use A Line in Dudley, most of their customers are boy racers getting cars ready for track days but they're fine with "ordinary" cars.

 

[Buckman]

I am not sure if this applies to my much later model Jeep, but it is a concern although the dealer says not to worry. I also queried why tyres had not been rotated as per the service schedule, but got no answer to that question.

View: https://youtu.be/A4npdbQaixU

 

[otherclive]

Are you querying why under its previous ownership tyres had not been rotated? Was it looked after by the dealership you bought it from? If the OM hasn’t git the information on wear specification do JEEP U.K. have a technical contact via email? From your previous experience with the old Jeep and recent experience with this one I am not impressed with the marque’s support.

 

[Buckman]

Are you querying why under its previous ownership tyres had not been rotated? Was it looked after by the dealership you bought it from? If the OM hasn’t git the information on wear specification do JEEP U.K. have a technical contact via email? From your previous experience with the old Jeep and recent experience with this one I am not impressed with the marque’s support.

Dealer from whom we bought it did the last two services. On my previous 2012 Jeep the tyres were not rotated and when I complained they admitted it has not been done although we had a service plan.
The dealer collected the Jeep from our home a round trip of 140 miles to rotate tyres and to change the part allowing you to select low ration 4WD.
Can't complain about support as when I had the query regarding the battery, I got all the correct information once I got past the useless chat system. I find that with most chat systems, most of the time they cannot give you a straight answer.
A number of other websites also state that all four tyres need to be changed to avoid damaging the transfer case. Jeep OM only refer to same axle and tread depth and not both axles.

 

[otherclive]

Dealer from whom we bought it did the last two services. On my previous 2012 Jeep the tyres were not rotated and when I complained they admitted it has not been done although we had a service plan.
The dealer collected the Jeep from our home a round trip of 140 miles to rotate tyres and to change the part allowing you to select low ration 4WD.
Can't complain about support as when I had the query regarding the battery, I got all the correct information once I got past the useless chat system. I find that with most chat systems, most of the time they cannot give you a straight answer.
A number of other websites also state that all four tyres need to be changed to avoid damaging the transfer case. Jeep OM only refer to same axle and tread depth and not both axles.

I know it’s not a Jeep but my Sorento and Pajero accepted tyres with slightly more tread depth but they had to be fitted to the rear. But I rotated mine to equalise wear.
On such an issue as yours I would ask JEEP UK as you may find conflicting information doesn’t give you the confidence you require.

 

[RogerL]

There are of course a wide variety of types of 4wd, which work very differently, some of which are sensitive to differences in tyre diameter, ie tread depth, and some which aren't - sadly many dealers' customer-facing staff are clueless about the variations and can trot out all sorts of nonsense - some manufacturers' UK staff are no better.

The majority of 4wd owners don't understand the inner workings of their vehicle, nor should they be expected to - it's sad there's no reliable source of information for them to rely on.

 

[otherclive]

My Forester OM had specific information wrt tyre tread depth variation. But there were numerous “ experts “ on the forums who advised differently. When I said goodbye to it yesterday they were 4mm all round and even across each tread. I also did a full four wheel alignment check once a year.

 

[RogerL]

My Forester OM had specific information wrt tyre tread depth variation. But there were numerous “ experts “ on the forums who advised differently. When I said goodbye to it yesterday they were 4mm all round and even across each tread. I also did a full four wheel alignment check once a year.

Subaru had 3 completely different types of 4wd systems, certainly the Legacy/Outback could have any 1 of the 3, depending on the engine/gearbox fitted.

At a slight tangent, even basic ABS systems on 2wd cars need all 4 tyres to be similar diameter / tread depth as they work by comparing the difference in rotational speeds.

 

[Buckman]

There are of course a wide variety of types of 4wd, which work very differently, some of which are sensitive to differences in tyre diameter, ie tread depth, and some which aren't - sadly many dealers' customer-facing staff are clueless about the variations and can trot out all sorts of nonsense - some manufacturers' UK staff are no better.

The majority of 4wd owners don't understand the inner workings of their vehicle, nor should they be expected to - it's sad there's no reliable source of information for them to rely on.

Rather than rely on dealer I think I will go along with the general opinion on the video plus some other websites. Anyway I will be changing all 4 tyres on the Jeep anyway to be on the safe side as the difference in tread between front and rear tyres is apparently significant on a Jeep as the transfer box is trying to compensate for something that is not there as it thinks for example you are on a muddy field or ice.

 

[otherclive]

Rather than rely on dealer I think I will go along with the general opinion on the video plus some other websites. Anyway I will be changing all 4 tyres on the Jeep anyway to be on the safe side as the difference in tread between front and rear tyres is apparently significant on a Jeep as the transfer box is trying to compensate for something that is not there as it thinks for example you are on a muddy field or ice.

Does it not give a drive selection for 2WD which would be rwd only. What’s your reluctance to contact Jeep UK?
Notwithstanding I would be putting four new tyres on anyway.

 

[Buckman]

Does it not give a drive selection for 2WD which would be rwd only. What’s your reluctance to contact Jeep UK?
Notwithstanding I would be putting four new tyres on anyway.

Jeep is permanernt 4WD, Hate using Chat system.

 

[JTQ]

Quite probably it has already cropped up in this thread, but surely if Jeep had any misgivings about their diffs not coping with trye wear, would not the user handbook have some note to that effect?

From an engineering viewpoint "working" a diff, given its various case hardened gears and rolling element bearing should be no bad thing, better doing so than not,
The cross axle diffs will always be working, not least going other than in a straight line.

 

[RogerL]

Quite probably it has already cropped up in this thread, but surely if Jeep had any misgivings about their diffs not coping with trye wear, would not the user handbook have some note to that effect?

From an engineering viewpoint "working" a diff, given its various case hardened gears and rolling element bearing should be no bad thing, better doing so than not,
The cross axle diffs will always be working, not least going other than in a straight line.

According to Wikipedia https://en.wikipedia.org/wiki/Jeep_four-wheel-drive_systems#Quadra-Trac the Quadra-Trac 4wd system used by the Jeep Cherokee doesn't have a central differential, it has a wet clutch pack to transfer power to the front as the rear is always driven - so similar to most soft-roaders except they always drive the front axle with part-time rear drive.

 

[ProfJohnL]

All two or more wheeled vehicles used on normal roads will experience different rotational speeds on their individual wheels when they negotiate any bend. It's a inevitable consequence caused by the radius of the turn at each wheel. This is why vehicles with two wheeled axles need a differential on each driven axle. The purpose of the differential is to allow each wheel on the axle to be able to turn at different speeds to prevent mechanical binding or 'wind up' of the transmission.

In some situations having a differential can mean if one wheel on an axle may have less grip than the other and it may spin and loses traction and the other loses torque and it won't actually drive.

This is not normally a problem on normal roads, but in situations where grip can be low for example on mud, snow, sand or ice, or due to load shifting when on steep slopes, some vehicles used in these situations may have "limited slip" or selectably lockable differentials, which are designed to reduce or prevent slippage. Under these conditions it is expected the wound up energy will be enough to overcome the tyre grip and relieve the transmissions tension, so its not a problem.

If a vehicles with locked differentials then moves onto a high grip surface, and the differentials are not unlocked, the tension in the transmission may not be relieved and it may continue to build until it can overstress components and cause a failure.

The car manufacturers instructions should be followed about when to use the locking system and more importantly when not to use it.

I would give much greater credence to manufacturers instructions about tyre management than to hearsay in forums. If nothing else it will help to preserve any manufacturers warranty if it has not expired.

 

[JTQ]

According to Wikipedia https://en.wikipedia.org/wiki/Jeep_four-wheel-drive_systems#Quadra-Trac the Quadra-Trac 4wd system used by the Jeep Cherokee doesn't have a central differential, it has a wet clutch pack to transfer power to the front as the rear is always driven - so similar to most soft-roaders except they always drive the front axle with part-time rear drive.

I can see then there will be great concern that the tyre wear states front to back will be a cause of real concern.
By opting to drive and compensate between powering the two axles with a friction clutch means 100% of the resulting slip is converting power to heat. Heat into the oil and metal masses involved in that clutch assembly.