I think there was a thread about this a while ago but I can’t remember the outcome. I had to replace a rear tyre today and went to a recommended local garage. They insisted I would have to replace both of them, although the other one was virtually new. On the upside, their price was a lot less than I had expected and they replaced a scuffed wheel trim (don’t ask!) unasked and at no charge. Is it really a requirement to replace tyres in pairs?
Yes and no. You must have the same type of tyres on an axle. Which means that they must be tyres which do not differ in such essential respects as:
the brand
the dimension
the category of use (ex: road, snow, special use)
the structure (radial or diagonal)
the speed code
load capacity index
But that still leaves room for some variation - but good luck arguing it with a garagiste who wants to sell you an extra tyre.
Thanks, Jane. My new garagiste certainly isn’t the kind of guy you argue with.
What was wrong with the rear tyre… ???
There was some damage to the sidewall caused by a contretemps with a sharp, high kerb at the local carwash. It was a borderline safety issue but I decided it would be wise to avoid any risk. Thanks for reminding me of my incompetence.
Oh, most of us have done something like that in our time… 
don’t take it to heart. 
Very wise not to take the risk of keeping the tyre - 
Maybe keep the other as a spare if it is the right sort?
Good thought, Vero, but they kept the other tyre and knocked a little off the bill. I’m sure they came out ahead, though, and will have to keep a close eye on things when I use them again. Never had this issue with my trusty old garage in Scotland.
I suppose, in a sense the garagiste was right - in totally ideal circumstances you would want the same make/type of tyre on each end of one axle - but if the “good” one was genuinely very new and I was being told to throw it away and buy another new one simply to match a replacement on the other end of the axle I think I would politely walk away - especially if the issue with the “bad” one was some marginal sidewall damage which did not need to be addressed urgently.
Even if you want to stick to the same manufacturer/series these days it should just be a question of buying online.
As to radial/crossply - certainly don’t mix them on the same axle and the normal advice is that it is OK to have to mixed constructions on separate axles if you have crossply on the front and radial on the rear.
Of course if you don’t mind, or even relish, heart-stopping amounts of oversteer you can do it the other way around.
The law is the CT person. How would they ever know the tyres were not changed at the same time? Yes they have to match on the same axle as Jane explained but otherwise know one is likely to know if only the bad one was changed especially if the other is nearly new.
If you happen to be a certain Lewis Hamilton it would make a difference but Al, doubt it unless it’s a hypercar.
Just wondering where folk stand with using a spare wheel. surely the tyre on that is meant to be safe to use ???
I suspect the garagiste didn’t have a close enough match in stock. If I’d thought about it a little more, I would have asked him to order a suitable tyre, or get one myself over the internet. You learn some interesting and expensive lessons during your first few months in France. I’m sure there will be lots more to come!
It is usually just a galette: not a permanent replacement and not for driving over 90km/h, it is just supposed to get you to the garage who will change both tyres.
This is the french law…
Our 2012 Peugeot has a “normal” spare wheel. I forgot that things have moved on…
If so I can see the logic up to a point as it saves arguing about whether the tyres “close enough” but a licence to print money in this sort of situation.
You’re lucky to even get a temporary spare these days, usually just a tyre temporary-“repair” inflater - which ruins the tyre for a definitive patch even if the damage would have been fixable.
Ah, but this is progress… 
Seriously, it does beggar belief that the spare wheel was done away with… Was it simply to save space or money or what… ??? 
Weight - for the small increase in fuel economy in standard consumption tests and money for the small reduction in headline retail price (or extra profit depending on how you look at it).
Talking of fuel economy… this summer I came across a couple of British families. They insist on driving with windows open rather than use the air-con, for the sake of fuel efficiency.
I did trips with each family and found they had the same mindset. As I sweltered and boiled, each driver finally shut the windows against the 35+C temp and reluctantly switched on the Aircon for about 15 mins… after which it was firmly switched off and the windows reopened.
Now one person, possibly … but two different drivers… both in the age range mid-30’s and with modern cars (maybe 5 years old).
What is your take on this…
IIRC opening the windows increases wind resistance and up fuel consumption by a similar amount to A/C