03-09-2021, 12:26 PM | #1 |
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Advice for tire sizes on staggered setup (328i xDrive)
So, I ordered a set of Forgestar F14's many weeks back, and finally got my hands on them. Being the noob that I am, I didn't know that a staggered set up could potentially be problematic for an AWD system. If I did, I would have gone with a square set up. I wish the dealer who helped me decide on the setup had mentioned this... but regardless, it's on me - I should have done my homework.
After going through the forums and calling around, I have learned about keeping the rolling diameter/revs per mile within 1% difference from the front to rear in order to avoid problems with the AWD system/transfer case. All of the shops that I've called have told me if I follow this rule, I will be alright. Should I believe them? I really don't want to cause long term problems with my car. I got the wheels test fitted yesterday, and they do clear the brakes/suspension. I am not sure about rubbing issues once the tires are mounted and the car is off the lift, though. Anyways, I would appreciate any input ya'll could offer here. Although I have some regrets about the setup I went with, I would really rather not try and go through the refund/exchange process with Forgestar (if it's possible). Will I be able to run these wheels on my car, considering fitment/xDrive? Even if it is possible, is it stupid to try and do so? Also, what tire sizes, if any, could work for me. I have called around and been given a few different recommendations that folks say could work for my situation. My car is a 2015 328i xDrive, and my wheel set up is as follows: Forgestar F14 Front: 19x9 ET33 Rear: 19x10 ET42 I know this is probably an unnecessarily aggressive setup for a 328. With what I know now, I would have certainly gone a different route. At the time, I trusted what the dealer I went through told me - that this is the most popular setup for my model (even with xDrive) and that the fitment was guaranteed. |
03-09-2021, 02:18 PM | #4 |
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aps F30, 437M with 245/35/19 & 285/30/19, +29 & +40, lowered B14 coilovers. your car would be 4mm & 2mm more tucked in front & rear and would fit without any rubbing issues.
https://f30.bimmerpost.com/forums/sh...&postcount=290 https://f30.bimmerpost.com/forums/sh...&postcount=321 bmw22915 F36, eibach pro-kit, 245/40/19 & 275/3019, +32 & +42. although h&r is lower, i think it'll fit, without rubbing but it'll be close because the diameter is 26.7" and 26.6". https://f30.bimmerpost.com/forums/sh...3&postcount=24 . Last edited by alohasurftoad; 03-09-2021 at 02:50 PM.. |
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03-09-2021, 02:45 PM | #5 |
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Man, thanks for being so helpful. I've been down a rabbit hole of tire sizes these last few days trying to figure this out. Tire rack also recommended me the same sizes as aps is running (245/35/19, 285/30/19).
The other most common recommendation I've gotten is 245/35/19 F, 275/30/19 R. Any thoughts there? Last edited by andrewk13; 03-09-2021 at 03:53 PM.. |
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03-09-2021, 02:59 PM | #6 |
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245/35/19(26.8") & 275/30/19(25.5") is right at 1%. it's reverse diameter stagger, rear sidewall is 0.2" smaller than the front, slightly reverse raked but may be difficult to notice unless pointed out. i've seen peeps with this size on x-drive without issue. try it out and let us know.
235/40/19 & 265/35/19 is also on option. i didn't list it because the fronts are stretched. you may consider it if you don't mind the stretched fronts and lightly stretched rear. slowF32, x-drive, H&R, 437M, 19x9 +29, 19x10 +40, 235/40/19 265/35/19. https://f30.bimmerpost.com/forums/sh...4&postcount=63 . Last edited by alohasurftoad; 03-09-2021 at 03:24 PM.. |
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03-09-2021, 03:42 PM | #7 |
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Yeah, with that 1% difference it may not be my best option. I would rather play it as safe as possible.
I would rather avoid having stretched tires as well. I'm thinking that one of the 2 suggestions in your first response may be my best bet. I'll be sure to keep the thread updated. |
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03-23-2021, 12:33 PM | #8 |
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Update - I ended up going with 245/35/19 Front, 285/30/19 Rear. All mounted up and they fit great with no rubbing at all. I have still not lowered it yet, however.
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03-23-2021, 01:13 PM | #9 |
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eibach pro-kit for x-drive(6-22) or rwd(5-22) if you want the front lower than the x-drive offering. additionally, changing out the damper to Koni SA or yellow sport would be better than just lowering springs alone. however, if you have the funds, a coilover such as KW V1 or street comfort would be even better.
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