Mazda RX8 - Tyre balancing - Claire1

Hi there! I had a rear tyre replaced as I was told it was out of shape, and this was marked on the report (that I received after paying) as 'needs replacing today'. The other rear tyre has also been replaced as I was led to believe that this was necessary over the phone when I spoke to the garage I used (a large chain).

However when I saw the report, the tyre was assessed as 'ok' and below this in pen 'balance' had been written. I'm assuming that this means the second tyre has been replaced to balance out the other new tyre, but I've never had this happen before with other cars and other garages as I've had one tyre replaced without another being needed for balance. I feel I may have been sold a tyre I didn't need, which has resulted in a hefty total bill – does this sound like the case to anyone else?

Please also note that the treads for both rear tyres were noted as being 62% worn with 4mm on the outers of the tyres and 5mm on the middle of the tyres.

Thanks very much for any help you can give!

Mazda RX8 - Tyre balancing - gordonbennet

I suspect balance means the tyres were balanced.

The worn tyre would have had a lower rolling radius than the new one, and as far as recall the RX8 is RWD, which would have meant the diff was working all the time to balance out the different sizes, which would not to it any good.

Be thankful you don't have one of the more fragile soft roaders with an all wheel drive system made of cheese because you could have been looking at changing all 4.

It can be good practice to change tyres at 3mm anyway, under the circs i would have got both changed but kept the good one as a spare just in case of a puncture that couldn't be repaired at some point in the near future when the tyres were approaching half worn.

This wouldn't have been a thread at all if the spare wheel had been full size, just swap over and keep the out of shape for emergencies.

Edited by gordonbennet on 07/06/2017 at 14:35

Mazda RX8 - Tyre balancing - bathtub tom
The worn tyre would have had a lower rolling radius than the new one, and as far as recall the RX8 is RWD, which would have meant the diff was working all the time to balance out the different sizes, which would not to it any good.

Sorry GB, have to disagree with you on this. As someone who's destroyed a diff on a trial I can state they take an awful lot of abuse before crying enough.

The point of a diff is to take different relative rotations into account and as long as they're properly lubricated, that's what they do.

Why don't we see lots of diff failures on the M25 otherwise?

I wonder if Claire1 went to a 'fit quick' type of place?

Edited by bathtub tom on 07/06/2017 at 18:21

Mazda RX8 - Tyre balancing - FP

I have always ensured I have the same make/type of tyre on both tyres per axle - I understand this isn't a legal requirement, but is best practice. However, when I once damaged one front tyre I simply replaced just that one.

So without knowing more it's difficult to judge whether you have been ripped off.

By the way, I assume the word "balance" doesn't refer to the new tyres being balanced, in the sense of weights attached to avoid vibrations, does it?

Edited by FP on 07/06/2017 at 14:36

Mazda RX8 - Tyre balancing - Claire1

Hi FP! I don't think it means using weights for balance as the garage didn't mention anything about that, just that they needed to replace the other tyre as well as the misshapen one.

Thank you and gordon bennett for your answers, they're very much appreciated!

Mazda RX8 - Tyre balancing - edlithgow

By the way, I assume the word "balance" doesn't refer to the new tyres being balanced, in the sense of weights attached to avoid vibrations, does it?

That would be my default assumption, unless the garage specifically told me different.

If they told me it was to reduce load on the diff (assuming not AWD) I probably wouldn't believe them.

I think its normal practice to balance a newly fitted tyre in the above sense.

Mazda RX8 - Tyre balancing - John F

I feel I may have been sold a tyre I didn't need, which has resulted in a hefty total bill – does this sound like the case to anyone else?

Yes.

Please also note that the treads for both rear tyres were noted as being 62% worn with 4mm on the outers of the tyres and 5mm on the middle of the tyres.

Loads of wear left. New tyres are around 8mm. Legal limit 1.6mm. While different sizes are not ideal I suspect for your type of driving it would be irrelevant. The tiny difference in diameter would put virtually no extra strain on the differential pinion which would just very very slowly rotate in a straight line. They probably sold your tyres to a back street second-hand tyre specialist ( I have known one for years who has occasionally provided me with excellent service). And to add insult to injury, I bet they charged for disposal!

Edited by John F on 08/06/2017 at 13:50

 

Ask Honest John

Value my car