[nikbutsko]

Hey guys, so im currently running 19x8.5 +30 front and 19x9.5 +35 rear with 235/40/19 and 265/35/19 michelins sport 4s all season (xdrive btw). I’m thinking of putting on 255/40/19 front and 285/35/19 rear, would it be possible? Im trying to get the widest tires I can, with some meat to it so i get as much traction as i can.
If anyone would share their thoughts about it, would be much appreciated.

[xnick101]

You have to keep the tire sizes within 1% since its x-drive but yes 285 works fine on a 9.5" wheel.

[Geo_FF]

I posed the question to APEX and below is the response I received for a 19x9 and 19x10 setup. They suggested 255/35 and 285/30 as a wider alternative, xdrive compatible.

All of our BMW tire recomendations are calculated to be within a 3% threshold of the factory tire size overall rolling diameters. This ensures a reduced chance of rubbing under suspension compression, as well as avoiding any potential wheel speed issues that can cause problems with your DSC/ABS systems. With that said, 255/40-19 and 285/35-19 tires will be outside of that threshold and will be too tall for an ideal fit.

[mwinemil]

Originally Posted by Geo_FF

I posed the question to APEX and below is the response I received for a 19x9 and 19x10 setup. They suggested 255/35 and 285/30 as a wider alternative, xdrive compatible.

I was part of the Apex GB that just ended for VS-5RS wheels in 19x9 and 19x10. I have been struggling to select the right combo as well. The car is RWD so I don't have the same limitations as AWD in terms of issues around the diameter. I am mostly concerned with adding traction and not exacerbating understeer.

When looking at the combo of PS4S with 255/35/19 on the front and 285/30/19 on the rear I calculate a -.2" or -.775% change in diameter with the rear tire being smaller than the front. I'm sure this quarter-inch will be very difficult to notice with the naked eye but something about having a smaller height rear tire causes me to take pause.

If you move to 245/40/19 F and 285/35/19 R the rear tire is the same .2" different but this time it's larger as opposed to smaller. My concerns with this config are potential rubbing and also the potential introduction of understeer as the delta in widths becomes wider.

I have a spreadsheet where I'm tracking options (cause I'm a nerd) but I would love to hear what others have done. My decision will be driven by performance over aesthetics. Always.

So, I'm not sure this is helpful at all, but I am struggling with my tire choice as well.

[Geo_FF]

Originally Posted by mwinemil

I was part of the Apex GB that just ended for VS-5RS wheels in 19x9 and 19x10. I have been struggling to select the right combo as well. The car is RWD so I don't have the same limitations as AWD in terms of issues around the diameter. I am mostly concerned with adding traction and not exacerbating understeer.

When looking at the combo of PS4S with 255/35/19 on the front and 285/30/19 on the rear I calculate a -.2" or -.775% change in diameter with the rear tire being smaller than the front. I'm sure this quarter-inch will be very difficult to notice with the naked eye but something about having a smaller height rear tire causes me to take pause.

If you move to 245/40/19 F and 285/35/19 R the rear tire is the same .2" different but this time it's larger as opposed to smaller. My concerns with this config are potential rubbing and also the potential introduction of understeer as the delta in widths becomes wider.

I have a spreadsheet where I'm tracking options (cause I'm a nerd) but I would love to hear what others have done. My decision will be driven by performance over aesthetics. Always.

So, I'm not sure this is helpful at all, but I am struggling with my tire choice as well.

Same here - waiting for the 5RS shipment too, cheers. That was my only concern with the rear being smaller although the difference is very minor. Originally I was set on their recommended 245/40 and 275/35 setup, but there is a bit too much stretch on both tires for my liking.

Your 245/40 + 285/35 option looks promising and would be within the xdrive variance too. At least only the front would have stretch so that's a fair compromise for me. So the only remaining concern would be the rear being 3.5% larger than stock and if that will cause issues with DSC/ABS like Apex advises. Interested to hear other feedback as well.