[JXVOB]

Hey everyone, I have a '16 F36 435i xDrive Gran Coupe. I've been searching for a set of BBS RT88's for quite some time now and I've finally found a set. Before I pull the trigger I'd like to ask if my wheel/tire fitment will work for my xDrive system. I know I'm suppose to stay within a 1% diameter difference but I'm not sure if I'm calculating and ensuring that everything will fit correctly. Here are the specs with the possible tire size that I'll be buying for them. Thanks for the help and any recommendations on better tire sizes to help with the xDrive system is appreciated! Thanks again!
Front: 19x9 ET 36.5
Rear: 19x10 ET 38.5
Front tire: 235/35/19
Rear tire: 265/30/19
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[cfm56d7b]

Did you have a chance to visit https://www.willtheyfit.com/?

[alohasurftoad]

OEM diameter is 26".

235/35/19(25.5") is stretched on 9" and 265/30/19(25.3") lightly stretched on 10". diameter difference is 0.86%. those sizes will work however if you're not lowered it increases wheel well gap and also speedo/odometer error. increasing the rear to 275/30/19(25.5") will make front and rear diameter equal.

i'd go with one of these combos below

235/40/19(26.4") and 265/35/19(26.3") is 0.37% difference, will have a better ride and reduce fenderwell gap.

245/35/19(25.8") and 285/30/19(25.7") is 0.1% difference. good tire width/rim width fitment however the rear tire shoulder will poke slightly due to the slightly low offset.

255/35/19(26") and 265/35/19(26.3") diameter difference is 1.0%. good tire wheel fitment and best handling with least understeer. i have seen x-drives with this combo, without transfer case issue.

regarding the offsets, imo the front offset is a bit high and the rear a bit low. are there any other offset options? if not, a 5mm or 7.5mm spacer up front may be considered.

[Tommi_Mav]

Originally Posted by alohasurftoad

255/35/19(26") and 265/35/19(26.3") diameter difference is 1.0%. good tire wheel fitment and best handling with least understeer. i have seen x-drives with this combo, without transfer case issue.

regarding the offsets, imo the front offset is a bit high and the rear a bit low. are there any other offset options? if not, a 5mm or 7.5mm spacer up front may be considered.

I have an F32 x-drive. I put the OEM M437 wheels and I went with MPSS in this combination. No stretching at all and plenty of sidewall too.

Regarding the offset, mine with ET 29 front and ET40 rear are just poking a little bit. Your rears will poke even more.

[JXVOB]

Originally Posted by alohasurftoad

OEM diameter is 26".

235/35/19(25.5") is stretched on 9" and 265/30/19(25.3") lightly stretched on 10". diameter difference is 0.86%. those sizes will work however if you're not lowered it increases wheel well gap and also speedo/odometer error. increasing the rear to 275/30/19(25.5") will make front and rear diameter equal.

i'd go with one of these combos below

235/40/19(26.4") and 265/35/19(26.3") is 0.37% difference, will have a better ride and reduce fenderwell gap.

245/35/19(25.8") and 285/30/19(25.7") is 0.1% difference. good tire width/rim width fitment however the rear tire shoulder will poke slightly due to the slightly low offset.

255/35/19(26") and 265/35/19(26.3") diameter difference is 1.0%. good tire wheel fitment and best handling with least understeer. i have seen x-drives with this combo, without transfer case issue.

regarding the offsets, imo the front offset is a bit high and the rear a bit low. are there any other offset options? if not, a 5mm or 7.5mm spacer up front may be considered.

Thank you so much for the information! It's really appreciated. I'm going to end up going 235/40/19 front and 265/35/19 rear, I'm glad to hear that this tire setup will reduce the wheel gap as it's already horrendous as is right now. I made the mistake of purchasing wheels before suspension so I'm going to have to live with the poor wheel well gap for awhile. Unfortunately, they don't make the RT88's anymore so I'm stuck with these offsets. Thanks for the information on the spacers, going to be purchasing those before they come now! Thanks!

[alohasurftoad]

A 5mm spacer up front will put you at +31.5, plenty safe.

7.5mm will put you at +29, lowest I'd go as I've read just two people had 235/40/19 graze the fenderwell liner at full lock at this offset. however since you will be lowering, which adds slight negative camber, it should be fine and have a tighter gap.

of course you'll need to get appropriate length extended lug bolts for the spacer thickness. turner has hub extenders for spacers without extended hub flange but i've never had problems if using the typical star method to torque. i have a stud kit, though, not sure if that makes a difference.
.

[JXVOB]

Originally Posted by alohasurftoad

A 5mm spacer up front will put you at +31.5, plenty safe.

7.5mm will put you at +29, lowest I'd go as I've read just two people had 235/40/19 graze the fenderwell liner at full lock at this offset. however since you will be lowering, which adds slight negative camber, it should be fine and have a tighter gap.

of course you'll need to get appropriate length extended lug bolts for the spacer thickness. turner has hub extenders for spacers without extended hub flange but i've never had problems if using the typical star method to torque. i have a stud kit, though, not sure if that makes a difference.
.

I think I'll stick with the 5mm spacer until I'll actually be lowered. Do you have a link to for your stud kit conversion? I'd love to switch to studs then get extend lug bolts. Once again, appreciate your help!

[alohasurftoad]

Originally Posted by JXVOB

I think I'll stick with the 5mm spacer until I'll actually be lowered. Do you have a link to for your stud kit conversion? I'd love to switch to studs then get extend lug bolts. Once again, appreciate your help!

although they have bullet nose studs, i went with motorsporthardware, non bullet-nose because i prefer not having the stud sticking out too far if a thin(or no spacer) is used. https://motorsporthardware.com/produ...d-kit-14x1-25/

you may also consider apexraceparts...https://www.apexraceparts.com/store/...-stud-kit.html

or Bimmerworld... https://www.bimmerworld.com/BimmerWo...d-Package.html

of if money is no object and you're feelin' baller...https://www.vividracing.com/mrg-tita...151578732.html

forget about the hex tips and use double nut method for install. all of these are open end lug nuts. if you want closed end lug nuts, you'll have to get a 14x1.25 to 14.1.5 75mm stud conversion kit.

you really only need a stud kit up front for the spacers but i'd probably convert everything to studs for consistency. it sure makes wheels swaps so much easier.

[JXVOB]

Originally Posted by alohasurftoad

although they have bullet nose studs, i went with motorsporthardware, non bullet-nose because i prefer not having the stud sticking out too far if a thin(or no spacer) is used. https://motorsporthardware.com/produ...d-kit-14x1-25/

you may also consider apexraceparts...https://www.apexraceparts.com/store/...-stud-kit.html

or Bimmerworld... https://www.bimmerworld.com/BimmerWo...d-Package.html

of if money is no object and you're feelin' baller...https://www.vividracing.com/mrg-tita...151578732.html

forget about the hex tips and use double nut method for install. all of these are open end lug nuts. if you want closed end lug nuts, you'll have to get a 14x1.25 to 14.1.5 75mm stud conversion kit.

you really only need a stud kit up front for the spacers but i'd probably convert everything to studs for consistency. it sure makes wheels swaps so much easier.

Thank you so much for everything haha! I'll probably end up doing studs for both the front and rear.