How can you tell which wheel goes on which corner?

[Rolfe]

Just a quick question. Suppose you took the wheels off the car and shuffled them randomly. Where would you look to find out which one should be replaced where?

Because that seems to be exactly what my garage did when they fitted the new tyres.

I didn't say anything to them beforehand because I thought these coded tyre pressure sensors were common on new cars and they'd know all about it. I wouldn't have noticed except that they also gave me the car back with the pressures uneven. According to the dashboard the front right was too high, and within a few days the rear right had thrown a low pressure warning.

However, when I went out to sort this out I discovered that it was the front right that was underinflated and the rear right that was too hard. This did my head in.

The car is booked in to the garage next week to have this put right. However, given the degree of competence on display I may actually have to tell them where to look to find out which wheel goes where.

This garage has looked after first Ariel then Prospero since 2007. They've never done anything this daft before. It can't be anything to do with Caliban being an EV. Standards must be dropping.

 

[Robf]

I think only way for you to check is to deflate one down to just below recommended pressure and drive for a bit to update pressures in app. Then check readings in app and see which one reads as low, then repeat for other wheels .

 

[Rolfe]

For me, sure. But there must be a way for the garage to know which is which once the wheels are off. I mean, come on! And they're going to have to take them off to put them back on the right way round.

 

[Ian Key]

Or under-inflate one and over-inflate another leaving the other 2 at the correct pressure then as Robf says drive for a bit and see if the pressures match the readings.

The garage probably took them all off at once then replaced the tyres so have no idea which wheel came from which corner without realising the TPS wouldn't correct themselves.

 

[Rolfe]

Oh, read what I said. I want to know what to tell the garage so they can find out which wheel is which once they're off.

This is not my problem to fix. It's down to the garage to rectify their mistake. And I do not believe for one moment that MG has not provided the wheels with some indication of which one goes on which corner. Even if the garage is entirely aware that they need to go back on the axles they came off, anyone can lose track of which is which while they're in the middle of the job.

Dammit, I could tell them which was which when I took the car in, and they could still get them mixed up by accident. There has to be a way to tell.

I simply want to be able to spoon-feed the garage with the information if necessary.

 

[Captain]

Oh, read what I said. I want to know what to tell the garage so they can find out which wheel is which once they're off.

This is not my problem to fix. It's down to the garage to rectify their mistake. And I do not believe for one moment that MG has not provided the wheels with some indication of which one goes on which corner. Even if the garage is entirely aware that they need to go back on the axles they came off, anyone can lose track of which is which while they're in the middle of the job.

Dammit, I could tell them which was which when I took the car in, and they could still get them mixed up by accident. There has to be a way to tell.

I simply want to be able to spoon-feed the garage with the information if necessary.

I think they will have to troubleshoot the problem themselves by trial and error...?
I'm getting winter tyres fitted soon and will reccomend they invest in 4 pieces of tape to write the positions on (in Italian in my case)

 

[PaulD]

Oh, read what I said. I want to know what to tell the garage so they can find out which wheel is which once they're off.

This is not my problem to fix. It's down to the garage to rectify their mistake. And I do not believe for one moment that MG has not provided the wheels with some indication of which one goes on which corner. Even if the garage is entirely aware that they need to go back on the axles they came off, anyone can lose track of which is which while they're in the middle of the job.

Dammit, I could tell them which was which when I took the car in, and they could still get them mixed up by accident. There has to be a way to tell.

I simply want to be able to spoon-feed the garage with the information if necessary.

You almost certainly can't tell with the wheel off. There will be no indication anywhere.

I imagine they didn't care because on most modern cars you do a TPMS reset and the car will re-learn where each wheel is. Otherwise nobody would be able to do tyre rotation anymore without a load of hassle.

The MG4 user manual isn't very helpful on this point though:
"TPMS Self-learning: When replacing a TPMS sensor and receiver, or performing tyre rotation, the TPMS self-learning is required, please consult a local MG Authorised Repairer for details". If it's "self-learn" why does it need a dealer?

 

[Rolfe]

If that's the case, it's nuts. Imagine any local tyre dealer. Oops boss, I can't remember which of these wheels I took off the front and which off the back. Oh dear, the car will have to go back to the dealer for a reset.

 

[Robf]

They should have marked them when taking off, schoolboy errors that shouldnt happen at a garage.

 

[Rolfe]

Well, I can certainly tell them that the right hand side ones have been switched front and back. So that gives them a 50/50 chance on the left. Their problem.

It's crazy if they're not marked. It's classic Murphy's Law. Anything that can go wrong, will go wrong.

 

[mg4mc]

Or... decent tyre fitters will have scan and reset tools for TPMS - so many cars have TPMS nowadays they really should know how to deal with it. A learning point I guess is to make sure you make them aware TPMS is fitted and ask if they reset/reprogram the system as part of the cost.

 

[Kithmo]

For future reference you could ask them to mark the inside of the tyres with the yellow crayon they use for marking puncture positions. E.g. "NSF" for near side front, "OSF", off side front, "NSR" near side rear and "OSR" off side rear. Near side being the passenger side and off side the driver's side.

 

[tsedge]

For future reference you could ask them to mark the inside of the tyres with the yellow crayon they use for marking puncture positions. E.g. "NSF" for near side front, "OSF", off side front, "NSR" near side rear and "OSR" off side rear. Near side being the passenger side and off side the driver's side.

That's exactly what a decent shop will do.

There's never any marking in my experience, since TPMS apart (which is independent of the wheel/tyre maker), wheels and tyres are generally interchangeable.

My guess is they assumed that with an MG4 it didn't matter which tyre went where and that they did them in pairs to not mix up front and rear and thought that would be fine.

 

[Jef]

And then there is the problem that most tyres are directional, usually marked on the side wall, but the problem comes from mixing the tyres up nearside to offside, they will not rotate in the correct direction.
Hope you get it sorted Rolfe but do check the refitted tyres are rotating in the correct direction.

 

[PaulD]

It's crazy if they're not marked. It's classic Murphy's Law. Anything that can go wrong, will go wrong.

I take it this is your first car with this type of system? It's perfectly normal for them not to be marked. In fact I have never seen any car with them marked.

Many people routine swap tyres front to rear (and sometimes left to right) so the markings would be wrong after the first tyre change anyway. Most garages will strongly advise that you fit the newer tyres to the rear of the car, which would mean swapping the front wheels to the back. (unless you wanted to pay to swap the actual tyres on all four wheels when just replacing two of them)

Also, as I said before, you certainly don't need to go to the dealer for every car when swapping wheels. If you do a TPMS reset (via the menu) on many cars they simply learn the new wheel location. My previous car didn't even need that, and would auto-detect if a wheel has changed location and re-learn after a set period of driving.

Unfortunately for you, I therefore imagine a lot of tyre fitters don't pay much attention unless specifically asked about it. Let's face it, so many cars have TPMS now, imagine if every car they did had the owner come back and complain. They'd soon have to adjust their process to stop it happening as it'd be a huge waste of their time.

I take it you had all four tyres changed at once? To be honest that's probably quite unusual in itself as normally the driven wheels wear at a faster rate.

 

[PaulD]

And then there is the problem that most tyres are directional, usually marked on the side wall, but the problem comes from mixing the tyres up nearside to offside, they will not rotate in the correct direction.
Hope you get it sorted Rolfe but do check the refitted tyres are rotating in the correct direction.

That's not often the case these days. A lot of tyres are asymmetric, in that they have in inside and outside but are not directional. Therefore any wheel can go in any location.

This is even true of some tyres which clearly look like they should be directional.

 

[Jef]

All of my previous cars which had TPMS did not identify specific tyre location, merely light the light if one was low presure in which case it would not have made any difference which wheel was fitted where.

 

[Rolfe]

For future reference you could ask them to mark the inside of the tyres with the yellow crayon they use for marking puncture positions. E.g. "NSF" for near side front, "OSF", off side front, "NSR" near side rear and "OSR" off side rear. Near side being the passenger side and off side the driver's side.

Well, you know, if I'd thought that (a) the garage were a bunch of morons, and (b) that the wheels weren't already marked by the manufacturer to mitigate against the garage being a bunch of morons, I'd have done that.

I think we're going to have the sort of words that will ensure I don't have to worry about future occasions.

 

[Rolfe]

And then there is the problem that most tyres are directional, usually marked on the side wall, but the problem comes from mixing the tyres up nearside to offside, they will not rotate in the correct direction.
Hope you get it sorted Rolfe but do check the refitted tyres are rotating in the correct direction.

I wouldn't have the foggiest idea how to check. But the garage are not normally a bunch of morons, so I think they will get it right this time.

 

[PaulD]

All of my previous cars which had TPMS did not identify specific tyre location, merely light the light if one was low presure in which case it would not have made any difference which wheel was fitted where.

They probably used the non-direct measurement system then, without actual sensors in the wheels. It's a much easier system if you're not bother about seeing the actual pressure.