[Slipperyshoe]

Hi. Fully aware this has been done to death but despite searching, I still cannot find a definitive answer.

I’ve the 405m in 20”. The standard tyres are hideously expensive and lacking in availability at the high st tyre places. I’ve found that in the US they’re using 245/35/20 in front and 265/30 rear.

I’ve read in one post that I can use 245/35/20 front and 255/35/20 rear but they looks to be quite a big difference. I’ve no idea! Getting the tyres in these alternative sizes is around £500 cheaper for the same tyres, so huge difference in cost!

According to the poster .BMW. In a post from April 19, I can use these sizes. Can anyone else confirm please?

[robbiep]

It's usually recommended that you stick within 3% difference as an absolute maximum.

On that, the rears (3.8%) are considerably outside that margin

The fronts are within it, but there does seem to be a big difference in tyre width - I'd be concerned as BMW don't recommend any width over 225 for the fronts, no matter what the wheel size.

You want to run massive wheels, you end up with a limited choice of tyres, and high costs for them - it's either suck it up and live with it, or change to smaller less blingy wheels

[martin10chk]

What you can physically fit and what you should fit are very different things. Those tyres are a long way off factory spec. That’s a big no for me.

[SantaEugence]

Is the percentage difference only an issue for xDrive not RWD? Not sure which you have OP

[martin10chk]

Originally Posted by SantaEugence

Is the percentage difference only an issue for xDrive not RWD? Not sure which you have OP

For xDrive close matching front and rear is the issue. OP is proposing to go oversize all round - differentially front and rear. OP if you are xDrive this is a huge no. But i would say its a no in any case just because its a long way off the designed for size

[Slipperyshoe]

Thanks for comments, although not quite what I wanted . I’m not Xdrive. Appreciate transfer issues are a risk on those.

Regarding the fronts @245 this is what the majority of our American cousins seem to be using on the OEM 20’s. loads of threads here and on PH discussing reduced understeer etc. They usually pair with 265/30’s.

Not that I ignore BMW guidance, but their guides are often written with commercial pressures in mind. E’g after looking at * marked PS4S school non-star, I would PREFER to not have * marked tyres on this rubber.

So I have three no’s and a possibly. Guess it’s clear where the thoughts are.

[robbiep]

I'd just add that if you were going to go so far away from any manufacturer size, you should probably inform your insurance company - otherwise in a claim situation, you could find a world of grief. Yes, it's incredibly unlikely, but it's worth thinking about.

[HighlandPete]

Originally Posted by Slipperyshoe

Thanks for comments, although not quite what I wanted . I’m not Xdrive. Appreciate transfer issues are a risk on those.

Regarding the fronts @245 this is what the majority of our American cousins seem to be using on the OEM 20’s. loads of threads here and on PH discussing reduced understeer etc. They usually pair with 265/30’s.

Not that I ignore BMW guidance, but their guides are often written with commercial pressures in mind. E’g after looking at * marked PS4S school non-star, I would PREFER to not have * marked tyres on this rubber.

So I have three no’s and a possibly. Guess it’s clear where the thoughts are.

If not for your 335d, what model? That could influence opinion. Although you seem to be well outside OEM, plus a strange combination.

[Slipperyshoe]

Originally Posted by HighlandPete

If not for your 335d, what model? That could influence opinion. Although you seem to be well outside OEM, plus a strange combination.

It’s for a 340i f30.

Looking like a resounding no from the forum.

[JNW1]

Personally the way I'd approach it is to look at a site like Tyre Reviews and establish a short list of suitable candidates (and by suitable I mean tyres that have strengths and characteristics which are in tune with how you drive and what you want from a tyre). I'd then look to see what the price and availability is like for those tyres and make a choice from there; I wouldn't stray massively from the standard/recommended sizes but that's probably just me being cautious!

[HighlandPete]

Originally Posted by Slipperyshoe

It’s for a 340i f30.

Looking like a resounding no from the forum.

Also remember there can be insurance implications when we deviate from OE sizes.

[Slipperyshoe]

Thanks again for the strong guidance! I cancelled the order and stuck with stock sizes in the end.

[Londoner]

Originally Posted by Slipperyshoe

Thanks again for the strong guidance! I cancelled the order and stuck with stock sizes in the end.

I had the same conundrum. 340i - stuck with stock sizes in the end due to warranty but the slightly larger front sizes apparently make a real difference.