Help with Tyre sizes

[SBN]

Ok another question related but this time is based on the correct tyre sizes needed.

I want to fit michelin alpin all the way round... Found some almost brand new 265 alpin pa2 for the rear on eBay but as they no longer sell these, finding some matching 245 alpin pa2 is proving difficult.

Is it ok, to mix pa2 and pa3/4 if the axles are the same models eg pa2 rear and pa3 or 4 upfront?

Reason I say this is there is a lot of threads online about summer ps2 and PS3 mixing because the replacement to the ps2 was the pss. The PS3 was noted as having softer sidewalls and therefore not recommended to be mixed with a ps2 on another axle. So does the same apply to winters as it does to the summer models?

[kambites]

Mixing tyres front to back isn't going to throw you off the road, whatever they are - I suspect the majority of cars on the road have mixed tyres. Whether it'll handle properly with that particular mix mix is impossible to say without a lot of knowledge about the two particular tyres and even then it will be highly subjective.

[TA14]

SBN said:

TA14 said:

SBN said:

I'll have a look at the handbook later but I did speak to BMW and they would only specify the tyres I have on the car without another option being available.

Predictable - they didn't say that it wasn't OK though. You'll be running with the same radius that you run when the 245s are quite worn (but still legal) and a width which won't bother you unless you're at more than 9/10s of the handling capability. Unless there's some weird electronic sensor issue or something you should be OK - that's why you could just do with a BMW expert to confirm it. You need a good independent BMW specialist or a friendly tyre company engineer that knows the car to remove that 1% of doubt; I guess that most people would just try the tyre.

It's £300 against 1% doubt good odds but I'm not the expert. Love the help on here guys it's really useful but will instead look for the correct tyres and then I won't get any warranty issues or similar etc

Hmmm, well it's your car, your money and your call so fair enough.

kambites said:

Mixing tyres front to back isn't going to throw you off the road, whatever they are - I suspect the majority of cars on the road have mixed tyres. Whether it'll handle properly with that particular mix mix is impossible to say without a lot of knowledge about the two particular tyres and even then it will be highly subjective.

yep, re: different versions of the same tyre, it's usually just a case of adjusting one axle by a couple of PSI. I've run Alpins for a while now, they're good in wintery conditions and quite a good all rounder. For the OP's specific query I'd have a quick chat with the technical section at Michelin: http://www.michelin.co.uk/about/michelin-in-the-uk I've found them very helpful.

[SBN]

Ok so there appears to be 235 40 18 setup for the m3 but it's on a 8j alloy not the 8.5j alloy I have. The winter set up is square all the way round where as mine is staggered.

So reading all the above does the 8j provide a better rolling diameter than my 8.5j because BMW fit as standard the 235 40 18 to these, all be it on 8j wide rather than 8.5j

Thanks

[B'stard Child]

SBN said:

Ok so there appears to be 235 40 18 setup for the m3 but it's on a 8j alloy not the 8.5j alloy I have. The winter set up is square all the way round where as mine is staggered.

So reading all the above does the 8j provide a better rolling diameter than my 8.5j because BMW fit as standard the 235 40 18 to these, all be it on 8j wide rather than 8.5j

Thanks

Manufacturers normally have recommended rim widths for tyre sizes - you'd be unwise to stray out side of those fitments

http://www.tyresizecalculator.com/tyre-wheel-calcu...

^ the above is a good guide but only a guide - tyre manufacturers normally publish sizes and rim widths (I say normally because I can't find anything on Michelin - but I have info for Pirelli and Uniroyal on my bookshelf

Minimum tyre width 225
Ideal tyre width 235,245
Maximum tyre width 255

Edited by B'stard Child on Monday 22 December 19:35

[SBN]

Also if deviate away from BMW's recommendations will IT invalidate my warranty...? Would my insurance company care or use it against me if I wrote it off etc?

[TA14]

B'stard Child said:

tyre manufacturers normally publish sizes and rim widths (I say normally because I can't find anything on Michelin - but I have info for Pirelli and Uniroyal on my bookshelf)

Minimum tyre width 225
Ideal tyre width 235,245
Maximum tyre width 255

Note the above: both 235 and 245 are ideal widths for your wheels; here's another source: http://www.toyo.co.uk/tire/pattern/snowprox-s953 with the same result

I doubt that the insurance company will mind in this case but it's always safe to check, simply call them.

[B'stard Child]

Have you tried using the search facility?

https://www.abi.org.uk/Insurance-and-savings/Produ...

Just seems you want answers to a lot of questions that have been covered a lot before

[xRIEx]

Debaser said:

Wheel width will be a number followed by the letter J.

Unless it's followed by, for example, JJ or K.

[SBN]

B'stard Child said:

Have you tried using the search facility?

https://www.abi.org.uk/Insurance-and-savings/Produ...

Just seems you want answers to a lot of questions that have been covered a lot before

Thanks for that had a quick look and the key words is within the manufacturers specification so will check my handbooks to see if the 235/40 is an optional tyre fit in the guide?

[B'stard Child]

SBN said:

B'stard Child said:

Have you tried using the search facility?

https://www.abi.org.uk/Insurance-and-savings/Produ...

Just seems you want answers to a lot of questions that have been covered a lot before

Thanks for that had a quick look and the key words is within the manufacturers specification so will check my handbooks to see if the 235/40 is an optional tyre fit in the guide?

http://www.pistonheads.com/GASSING/topic.asp?h=0&f=181&t=936149&i=0&mid=0&nmt=Has+anybody+bought+the+OEM+winter+tyres+for+E92+M3

[lbc]

SBN said:

Also if deviate away from BMW's recommendations will IT invalidate my warranty...? Would my insurance company care or use it against me if I wrote it off etc?

Insurance company will need to be notified if you deviate from manufacturers default spec.

That includes if you fit different spec wheels/tyres from original. Speed rating does not apply.

[SBN]

Just looked in the manual and it specifies 235/40 but only on the winter set up with the same size all round. For the staggered set up like mine it specifies the 245/40

Will probably end up getting what the manual says and avoid all shadow of doubt

[TA14]

SBN said:

Just looked in the manual and it specifies 235/40 but only on the winter set up with the same size all round. For the staggered set up like mine it specifies the 245/40

Will probably end up getting what the manual says and avoid all shadow of doubt

That seems to agree with the thread that BC linked to: 235 all round or (245f 255r IIRC)