[tobinaldo]

Hi all,

I need 2 new front tyres.

I’m currently running the genuine 437M wheels with 255/35/19 Pirelli’s on the front & 275/35/19 Michelin rears.

I’ve read on here that a lot of people are running 245/35/19 fronts with 265/35/19 rears.

My question is, can I change to 245/35 fronts and keep the 275/35 rears or will it cause any issue, as the rears don’t need replacing yet.

Thanks in advance

[danb1979]

Originally Posted by tobinaldo

Hi all,

I need 2 new front tyres.

I’m currently running the genuine 437M wheels with 255/35/19 Pirelli’s on the front & 275/35/19 Michelin rears.

I’ve read on here that a lot of people are running 245/35/19 fronts with 265/35/19 rears.

My question is, can I change to 245/35 fronts and keep the 275/35 rears or will it cause any issue, as the rears don’t need replacing yet.

Thanks in advance

Rule of thumb for 437Ms:

xDrive - 235/40/19 & 265/35/19
RWD - 245/35/19 & 265/35/19

So if yours is RWD then yes, 275s on the rear will be fine and personally what I'd run as 265s are a touch stretched from what I've seen (but that can also be that brand of tyre)

[tobinaldo]

Yea should of said it’s rwd not xdrive.

[rossm]

Worth considering that the 20mm difference between front and rear axles maintains a level of over/understeer.

Increasing front tyre width and keeping the same (as factory fit) or narrower rear tyre width (eg square setup) will promote oversteer

Increasing rear tyre width and keeping the same (as factory fit) or narrower front tyre width will promote understeer

Another trade off is weight, wider tyres are heavier leading to increase in unsprung mass and will hurt acceleration

Another trade off is resistance to aquaplaning. Wider tyres will have lower resistance to aquaplaning because there is a greater surface area to try and displace water from

And lastly the final trade off is steering feedback. Wider front tyres will increase lateral grip but the wider you go, the less steering feedback you get through the steering wheel for given inputs in terms of change in direction.

[tobinaldo]

Thanks both.

Ended up replacing the fronts with 245/35/19 Goodyear Eagle F1 Asy 6.

They look good and steering feels lighter.

Problem is, it’s emphasised the already large arch gap compared to the rear 🤦🏼*♂️ which I sort of half expected, might have to invest in some lowering springs next.

[danb1979]

Originally Posted by tobinaldo

Thanks both.

Ended up replacing the fronts with 245/35/19 Goodyear Eagle F1 Asy 6.

They look good and steering feels lighter.

Problem is, it’s emphasised the already large arch gap compared to the rear 🤦🏼*♂️ which I sort of half expected, might have to invest in some lowering springs next.

Cough... Bilstein B14s... Cough