09-17-2024, 06:47 AM | #1 |
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Increasing the sidewall on 2018 330i x drive
I have a 2018 330i xDrive with 33,000 miles on the clock. The car still has 5/32nd tread depth on the Bridgestone Potenza S001 RFTs. This is not my daily driver. For winter I have a dedicated set of winter tire/wheel combo.
The setup is stock on 19-inch 403M wheels. Front: 225/40ZR19 (8JX19 ET36) Rear: 255/35ZR19 (8.5JX19 ET47) I want to transition to non-RFTs once these tires hit the 4/32nd tread depth with a revised setup as follows: Front: 225/45R19 (+3.4% OD) Rear: 255/40R19 (+3.8% OD) The overall rolling diameter difference between the front & rear with the increased profile remains zero. Now, I realize that the increase in overall rolling diameter from the OE tires should be within 3% however I don't see any other way to increase the sidewall thickness. I want to stick to stock wheels. Please advise. Thanks. |
09-17-2024, 11:19 AM | #3 |
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The vehicle height will rise 13mm. Also, the 3.8% "heightened" gearing and increased tire weight moment will slow tip in acceleration on paper, although I'm not sure your butt dyno will notice.
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09-17-2024, 07:26 PM | #4 |
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That is a serious increase in diameter (27"). For context, here is 245/45/18 which is 26.7"
https://f30.bimmerpost.com/forums/sh...0&postcount=10 |
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alohasurftoad3387.00 Gypsyking30.00 |
09-18-2024, 03:28 PM | #5 |
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The speedo will likely to be 1-2mph under reading at 70mph and you'll possibly get some rub on the front. I run 245/45/18 winters and it's paper sliver clearance at full lock on the front, and the speedo went from an actual 68.5mph at 70mph to absolutely bang on.
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hooligan_G016526.00 Gypsyking30.00 |
09-19-2024, 07:08 AM | #6 | |
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Quote:
Stock height? 245/45/18 is 26.7", 225/45/19 is 27" - if you're driving a stock height xDrive car and the clearance is that tight with your tire size, the OP is definitely going to have some clearance issues. Last edited by hooligan_G01; 09-19-2024 at 07:38 AM.. |
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Gypsyking30.00 |
09-19-2024, 11:15 PM | #7 |
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Gents,
Thank you all very much for chiming in with your valuable insight/suggestions. For the winter tire/wheel combo I have invested in an aftermarket 18X8J ET 35 alloy wheelset. I run Continental Viking Contact 7 225/45R18 tires and am very happy with the setup. I have decided to stick to the stock size for the summer and will order the non-RFTs in May next year. I'm gravitating towards the Continental ExtremeContact DWS06 PLUS however the heart says Michelin Pilot Sport 4 S. Please note that we have a long winter from November to April with peak temperatures touching -31F therefore there is a shoulder season (October & May) where the temperatures can drop to 30F or even lower. Considering all of that it makes sense to have a good All Season UHP tire (DWS 06 Plus) rather than out and out UUHP tire (Michelin). Thoughts? |
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hooligan_G016526.00 alohasurftoad3387.00 |
09-20-2024, 06:33 PM | #8 |
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The Continentals are a solid choice and they ride great too, if that's what you wanted with bigger sidewalls. I have them and no complaints.
Can't go wrong with Michelins either, but you'll have to keep the winters on during the shoulder months. |
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