Different studless winter tyres per axle

[pikey]

I'm in Japan, and approaching winter means one has to get winter tyres (will get in to trouble with Police and insurance company)

My car (BMW 5 series X drive) has 245/40r19 98 on front and 275/35/r19 100 on rear.

I can't find a manufacturer that sells winter tyres (specifically 'studless' as I'll be taking into snow resorts) in both these sizes. So someone who sells 245/40 doesn't do 275/35 and someone who does 275/35 doesn't do 245/40.. (or rather my googling hasn't found one)

I figure my options are :

a) buy some for the front with some and for the back and not be concerned about the mix

b) buy new 19" 'winter' wheels with tyres that are the same. However my issue with this option is I'll only be staying for about 12 months before taking the car back to Australia with me.. that doesn't have a too much need for winter wheels and tyres.

Any tips / thoughts / advice on going with option a of two manufacturers?

Thanks



Edited to Add : Turns out in Japan there's not much in the way of choice for this car.. I had one Pirelli option to go for: https://www.pirelli.com/tyres/en-ww/car/catalogue/... .This was available in the same size, load rating, run-flat.. and approved by BMW. Bought online and got a local place to fit on the existing wheels. I could have changed the wheels to go for other tyres but then the car doesn't look the same, and probably doesn't perform the same and I'm a fan of keeping things OEM standard so..

Edited by on Thursday 7th December 02:29

[fttm]

Doesn't seem right , check the tires sizes fitted from new . Also sounds a stupidly low profiles for an SUV/off road vehicle

[pikey]

fttm said:

Doesn't seem right , check the tires sizes fitted from new . Also sounds a stupidly low profiles for an SUV/off road vehicle

Yep. It's what's on there at the moment, and having a quick look, the sales brochure says

1UX
M Light Alloy Wheel Y Spoke Styling 845M Bicolor (Jet Black)
(Front) 8J x 19 wheels + 245/40R19 tires 
(Rear) 9J x 19 wheels + 275/35R19 tires

Not an SUV or off road vehicle, is a 5 series

[fttm]

Yup sorry my mistake , skip read it as an X5 .

[mmm-five]

Just use a square set-up of 245/40r19 on all wheels.

[pikey]

mmm-five said:

Just use a square set-up of 245/40r19 on all wheels.

As a person who doesn’t know.. I have questions

Does 245 fit on a 275 rim ?

Would the 40 profile fit in the arch of where it currently has 35 ?

Thanks

[mmm-five]

said:

As a person who doesn’t know.. I have questions

Does 245 fit on a 275 rim ?

Would the 40 profile fit in the arch of where it currently has 35 ?

Thanks

The 40 is a percentage of the width, so as you go wider the percentage needs to go down to keep the sidewall the same height.

So 40% of 245 more or less equals 35% of 275 - that's why the common option for winter tyres is a square set-up.

This matching of overall circumference/diameter is especially important on XDrive models.

A 9J rim will work fine with a 245 width tyre.

Edited by mmm-five on Wednesday 22 November 09:21

[pikey]

mmm-five said:

A 9J rim will work fine with a 245 width tyre.

Maybe, but here in Japan it seems not. I asked three tyre places and they told me they wouldn't do it. I'm not that surprised.. they won't even consider touching the car unless there's a physical copy of the MOT- equivalent 'Shaken-sho' in the car for them to inspect!

In the end I found out BMW's approved winter tyre recommendation and went for that (same size & load). Other options seems to require extra wheels.