437M tyre advice

[step_change]

Hi, I am after a set of genuine 437M and tyres for my 35is. My existing 326 runflats on the rear will be an MoT advisory and so I have to do something about it; they have another 500 miles or so on them, max. So if I am to swap them out for 437's then now is the time to do it rather than spend £500 of dead money on two new runflats for the 326's.

More often than not on eBay, 437s come from a M3/M4 and so have 255/35/R19 on the front and 275/35/R19 on the rear. I do not think these tyre sizes are quite right for the Z4 and make it a bit "over-tyred" and that the 255 on the front can scrape and the 275's are a bit wide on the rear.

If I were to buy such a set of wheels from the bay clad with such tyres, would it be possible to move those 255/35/R19 from the front and put them on the rear wheels? I'd then only be up for the cost of putting two new 235's on the front and then could sell the 275's (and the 326's) to part fund this project. Otherwise, buying a good set of 437 wheels off ebay only to have to replace all the tyres as well makes this expensive and as put me off doing it for the last two years!

Appreciate your thoughts and any guidance in layman's terms on this minefield subject please!
Steve

[B21]

Hello, I've looked at this too..

I do know of a 18i with those wheels and tyre sizes..the guy is a bit of a poodler but complains about the handling..but on a non MSport 18i his don't foul, but then again his max speed is about 60mph..

For DSC reasons the rolling circumference front and rear on an E89 should ideally be within 1% tolerance..1.5% tops otherwise when it all goes wrong the DSC unit may struggle..I gad that experience when I inadvertantly created a 2.4% difference..

So ideally you need something like 235/35 and 265/30 or 245/35 and 275/30

255/35 is a bit stretched for a 10J or is it 9.5J

[True-Blue]

The standard tire sizes you mention definitely don’t work on the E89, the rears will definitely rub. Even if it didn’t rub, which it will, it will look terrible and feel like an over-tyred tractor - been there and done that

255/35/19 will work on the rear, but don’t give a lot of rim protection on the 437’s despite technically be a ‘non-stretch’ fitment on the rear rim. If you’re good at staying away from kerbs it’s a good fit and gives decent ride quality - I had PS4S in this size.

[True-Blue]

You’ll find pics of my old VO in the standard tire sizes in this thread, and with replacements fitted including 255/35/19 rears

Page 5 before and 7 after

viewtopic.php?t=126944&hilit=Wheels+thread&start=75

[tiglon]

I've been looking at doing similar, but have settled on 788M's instead - exactly the same size and offset as the 437M though.

I currently have 265/30 and 235/35 on 276 wheels, which drive very well and will be carried over to the new wheels. I would suggest that a 35is may benefit more from wider tyres than a 20i or similar.

When you increase the tyre width you will get more grip, but also more aquaplaning - whether this is important to you depends on your driving style and when/where you do your driving.

[step_change]

Thanks guys. So other than buy rims only, which hardly ever come up as genuine forged 437's it looks like buying the sizes I mentioned before off of eBay (255/35/R19 on the front and 275/35/R19 from an M4) which go for about £1200 in unmarked condition and then having to swap the tyres and get some 235/35/19 and 265/30/19s = another £700 or so It makes this an expensive proposition, even when considering the sale of the 326's and the tyres from the bought 437's (which I assume I wouldn't get a lot for).

I will have to think about it. I didn't really want this project to be more than a net cost of £1000 or so after resale of the old wheels/tyres.

I am trying to convince myself that because the rear tyres are shot anyway and the fronts are down to 2mm I am up for a £900 bill anyway.

Convince me of what to do

[True-Blue]

If you can get a set with good tires the tires will sell easily enough to the M3/M4 crowd.

The set I bought had continentals on which I sold for at least £200 IIRC

Also, Michelin are doing £100 off four 19’s again at certain garages.

[tiglon]

There are a few 437M's without tyres, but they are generally not much cheaper than with tyres (around £1k in good condition). Realistically, if you're going to spend £900 on new tyres, you aren't going to be able to upgrade the wheels to something much more desirable for £100.

These ones look good in satin black and could probably be had for a little under £1k:

https://www.ebay.co.uk/itm/265344069867

I'm able to justify the spend to myself because I've got 788M's for £850, and the alternative was getting my current wheels powder coated for £360. If I can get £400 for my old wheels then it's only cost me a few quid more.

I reckon most people selling wheels on ebay are open to offers - you can probably haggle at least 10% off most of the listed prices.

[B21]

There are a few 437M's without tyres, but they are generally not much cheaper than with tyres (around £1k in good condition). Realistically, if you're going to spend £900 on new tyres, you aren't going to be able to upgrade the wheels to something much more desirable for £100.

These ones look good in satin black and could probably be had for a little under £1k:

https://www.ebay.co.uk/itm/265344069867

I'm able to justify the spend to myself because I've got 788M's for £850, and the alternative was getting my current wheels powder coated for £360. If I can get £400 for my old wheels then it's only cost me a few quid more.

I reckon most people selling wheels on ebay are open to offers - you can probably haggle at least 10% off most of the listed prices.

Well I’ve bought those babies, hopefully they will look ok against Atacama Yellow

[step_change]

Yes they'll look super against the Yellow. I saw them earlier but not quite what I am looking for on my Canberra red. I want the two-tone grey silver ones. I've got a few months before MoT so will keep looking.

Are you going 235/35/19 fronts and 265/30/19 rears? That seems to be a well proven combination.

[B21]

Yes they'll look super against the Yellow. I saw them earlier but not quite what I am looking for on my Canberra red. I want the two-tone grey silver ones. I've got a few months before MoT so will keep looking.

Are you going 235/35/19 fronts and 265/30/19 rears? That seems to be a well proven combination.

Based on crunching the numbers and desk research yes 235/35 19 and 275/30 19…that gives a front rear rolling ratio within 0.1%

245/35 19 which is the recommended size for a 9J front rim gives a 1% front rear speed differential

Also not sure whether it would foul..

I’m running 235/40 18 and 265/35 18 at the moment on 8.5j 9.5j rims and that seems to work well

Albeit with a little right hand rear wheeel rubbing which doesn’t occur on my 20i..crappy active suspension may be the cause.

Once the Ohlins are on it may be different

People suggest with 400 ish bhp I need 275 rears..again once the Quaife lsd is in that may effect things..

[tiglon]

They will look great on the yellow

[B21]

They will look great on the yellow

I wonder what SWMBO will say with the arrival of wheel set number 5?

[tiglon]

They will look great on the yellow

I wonder what SWMBO will say with the arrival of wheel set number 5?

If anything like mine, something including the words "is", "that" and "necessary"... followed by something about agapanthus and diamonds...

Luckily she just signed up to a £90 per month phone contract so she'll break a lot of glass if she starts throwing those stones

[Argyll Andy]

Luckily she just signed up to a £90 per month phone contract

Does someone come and tuck her up in bed and read her a story every night for £90 a month Will?