275/70/16 to 265/70/16

[Walter Sobchak]

Would this be an acceptable size swap?, my car currently has 275/70/16s on but there is more choice on 265s, it’s been ages since I’ve had to put a different sized tyre on a car to the one that’s currently on there so embarrassingly have forgotten what the profile numbers mean!, I’d be putting a complete set of 4 on the car.

[paintman]

https://tiresize.com/tyre-size-calculator/

Use the 'Tyre Comparison' gizmo. Shows differences in dimensions & speedo readings.

[SystemOfAFrown]

A 10mm change is nothing on a relatively high profile 270mm tyre. It'll make the speedometer read a couple percent faster, that's about it.

[LeadFarmer]

Basically the 275 means the tyres are 275mm wide, the 70 equates to the tyre wall depth as a percentage of 275, so 70% of 275 gives a tyre wall measurement of 192mm. Take your wheel diameter of 16" and add 192mm (x2) for the overall wheel/tyre diameter.

So the 265 tyres will be an overall smaller diameter to the 275 tyres, as the tyre wall will be 70% of 265, so smaller tyres. This can be corrected by going with a tyre with a larger tyre wall measurement such as 265/55 or 265/60 (if they exist?) to increase the overall diameter of the tyre.

The width of the rims determines what the minimum and maximum tyre width can be.

I've just spent weeks researching buying a spare set of wheels for winter tyres for my Mercedes CLK, and the width of the actual wheel determines the minimum and maximum width of tyres that can fit them.

My wheels are 17" diameter and are 7.5J (7.5" wide) on the front and 8.5J (8.5" wide) on the rear. The range of winter tyres available for the rear 8J wheels is very limited, but dropping the wheels down in size to 16" really opened up the choice of tyres available, but the 8J width of the rear wheels still created restrictions. I have therefore bought a set of wheels that are all 7J which can be fitted front and rear, and gives quite a vast choice of winter tyres available.

If there is an owners forum for your specific car then you may find some advice on what width and diameter wheels can be fitted to your car (or use Google), and once you know your wheel size options you can then find what tyres will fit those rims.

I used this chart when deciding which wheels & tyres to get for my CLK. If your wheels are 10" wide (10J) then they will accept both 275 & 265 tyres. The wheel width is stamped on the inside of the wheel and will give the wheel offset as well, such as 7J ET37 etc. The photo below is of the inside of the standard wheels that were on my CLK and are 8.5" wide with offset of ET30

Edited by LeadFarmer on Saturday 3rd September 22:36

[Pica-Pica]

The speedo will read 1.45mph faster at 80mph

See:
http://www.wheelcalc.com/

Screen shot of your sizes.


The profile number means the unladen sidewall height is that%age of the tyre width.
So sidewall for 275/70 is 192.5mm and for 265/70 is 185.5 . So unsurprisingly it is 7mm shallower.


Being smaller, you won’t have clearance issues, I doubt there will be handling issues.
What does your tyre label on the car say (door pillar or inside fuel flap usually) ?
Your insurance may wish to know if it is away from standard. Always best not to give them an excuse for an ‘undeclared modification’.

[Walter Sobchak]

LeadFarmer said:

Basically the 275 means the tyres are 275mm wide, the 70 equates to the tyre wall depth as a percentage of 275, so 70% of 275 gives a tyre wall measurement of 192mm. Take your wheel diameter of 16" and add 192mm (x2) for the overall wheel/tyre diameter.

So the 265 tyres will be an overall smaller diameter to the 275 tyres, as the tyre wall will be 70% of 265, so smaller tyres. This can be corrected by going with a tyre with a larger tyre wall measurement such as 265/55 or 265/60 (if they exist?) to increase the overall diameter of the tyre.

The width of the rims determines what the minimum and maximum tyre width can be.

I've just spent weeks researching buying a spare set of wheels for winter tyres for my Mercedes CLK, and the width of the actual wheel determines the minimum and maximum width of tyres that can fit them.

My wheels are 17" diameter and are 7.5J (7.5" wide) on the front and 8.5J (8.5" wide) on the rear. The range of winter tyres available for the rear 8J wheels is very limited, but dropping the wheels down in size to 16" really opened up the choice of tyres available, but the 8J width of the rear wheels still created restrictions. I have therefore bought a set of wheels that are all 7J which can be fitted from and rear, and gives quite a vast choice of winter tyres available.

If there is an owners forum for your specific car then you may find some advice on what width and diameter wheels can be fitted to your car (or use Google), and once you know your wheel size options you can then find what tyres will fit those rims.

I used this chart when deciding which wheels & tyres to get for my CLK. If your wheels are 10" wide (10J) then they will accept both 275 & 265 tyres. The wheel width is stamped on the inside of the wheel and will give the wheel offset as well, such as 7J ET37 etc. The photo below is of the inside of the standard wheels that were on my CLK and are 8.5" wide with offset of ET30

Edited by LeadFarmer on Saturday 3rd September 14:42

Thanks, that’s really informative and helpful, also really like CLKs, what have you got W208 or W209, both are lovely things to waft about in!.

[Walter Sobchak]

Pica-Pica said:

The speedo will read 1.45mph faster at 80mph

See:
http://www.wheelcalc.com/

Screen shot of your sizes.


The profile number means the unladen sidewall height is that%age of the tyre width.
So sidewall for 275/70 is 192.5mm and for 265/70 is 185.5 . So unsurprisingly it is 7mm shallower.


Being smaller, you won’t have clearance issues, I doubt there will be handling issues.
What does your tyre label on the car say (door pillar or inside fuel flap usually) ?
Your insurance may wish to know if it is away from standard. Always best not to give them an excuse for an ‘undeclared modification’.

It’s a early/mid 90s Toyota Landcruiser so doesn’t get up to 80 very often! .

Main reason I’m looking at changing them is it’s got road biased tyres on at the moment and I wanted a decent set of ATs on it, in the past I’ve used and liked General Grabber AT3s but I can’t find them in 270 only 265, although thinking on it further I might hold off until after I’ve done the 2/3 inch suspension lift I’m planning as I might want to look at other different profiles too, there is quite a lot of choice on them it seems from further reading.
Thanks for your help

[LeadFarmer]

Walter Sobchak said:

Thanks, that’s really informative and helpful, also really like CLKs, what have you got W208 or W209, both are lovely things to waft about in!.

2003 CLK 240 A209. It's a beautiful car, It has something like 60k miles and is in Immaculate condition. Previous owner was wealthy and had numerous cars, this one had been sat in their garage unmoved for 4 yrs and they wanted the garage space for their new car. They phoned their Merc Benz dealer and asked how much they would buy the car back for, they replied £1,500 so instead they sold it to us for that figure. A real bargain.

[Walter Sobchak]

LeadFarmer said:

2003 CLK 240 A209. It's a beautiful car, It has something like 60k miles and is in Immaculate condition. Previous owner was wealthy and had numerous cars, this one had been sat in their garage unmoved for 4 yrs and they wanted the garage space for their new car. They phoned their Merc Benz dealer and asked how much they would buy the car back for, they replied £1,500 so instead they sold it to us for that figure. A real bargain.

That looks lovely, and like you say a real bargain!.

I had a W208 320 cab until quite recently but unfortunately rust was starting to get to it.
The bodywork on your one looks fantastic for coming up to 20 years old!!.

[Stuart70]

LeadFarmer said:

Basically the 275 means the tyres are 275mm wide, the 70 equates to the tyre wall depth as a percentage of 275, so 70% of 275 gives a tyre wall measurement of 192mm. Take your wheel diameter of 16" and add 192mm (x2) for the overall wheel/tyre diameter.

So the 265 tyres will be an overall smaller diameter to the 275 tyres, as the tyre wall will be 70% of 265, so smaller tyres. This can be corrected by going with a tyre with a larger tyre wall measurement such as 265/55 or 265/60 (if they exist?) to increase the overall diameter of the tyre.

Surely going to a 55 or 50 would be an even smaller diameter to the tyres? Being 55% or 60% of the smaller 265?

Would need to go for a 75 to move towards matching the diameter. If such a thing were available these days!

Apologies if I have misinterpreted!!

[LeadFarmer]

Stuart70 said:

Surely going to a 55 or 50 would be an even smaller diameter to the tyres? Being 55% or 60% of the smaller 265?

Would need to go for a 75 to move towards matching the diameter. If such a thing were available these days!

Apologies if I have misinterpreted!!

Yes, you are right, I was thinking of my tyre sizes when I wrote that, not the OP's, my mistake. Increasing the tyre depth can make up for reducing the diameter of the wheel so the wheels dont look too small in the wheel arch, as well as correcting the speedo etc.