Help :) Can I fit thicker tire on stock 2015 228i Sport line?

Nitrof23MT · 09-30-2019, 08:05 AM

I am currently running 225/40F28 -92w Bridgestone driveguard runflats. They are terrible with potholes on my 228i xdrive convertible sport line. I am going to switch to non runflats. I figure increasing my tire size to 225/45 would help with potholes. Does anyone know if i can do this with my stock 18" tires? Everything is set up stock.

Thank you for your help

sethwas · 10-10-2019, 08:35 AM

you mean thicker sidewall? as in go from 18" to 17"? That would for sure help with potholes.

Believe it or not going to a non-RFT may help as well because the sidewalls flex more - but you lose the ability to drive on an airless tire.

Seth

MassNerd · 10-10-2019, 01:37 PM

I think Nitro means increasing the sidewall height by increasing the profile of the tire from 40 to 45 while keeping the wheel diameter the same.

This would mean the overall diameter would be increasing from the stock 25.1" to 26". This would cause a 4.5% decrease in the speedometer reading for a given speed. Also of concern would be rubbing, that I can't answer.

I actually came here looking for a similar question on going from 245/35-18 to 245/40-18. 245/35-18 is very uncommon for snow tires. 245/40 or 235/40 are all much more common.

Maynard · 10-13-2019, 06:50 PM

Better off to go to a 17 inch wheel, unless you have the biggest of the big brake options - TireRack can probably verify off your vin. Lighter, more sidewall, and more options for snow tires.

Nitrof23MT · 10-16-2019, 10:13 AM

Yes I was looking to increase size to 45 vs 40. I ended up just putting runflats on even though I hate them. I wasn't ready to spend the money on new rims and unfortunately do not think I'll have the car long enough to justify spending the money (need bigger car). Tire rack also couldn't give me a good answer if they would fit.

bimmerboy71195 · 03-26-2021, 11:05 PM

Quote:

Originally Posted by Nitrof23MT

Yes I was looking to increase size to 45 vs 40. I ended up just putting runflats on even though I hate them. I wasn't ready to spend the money on new rims and unfortunately do not think I'll have the car long enough to justify spending the money (need bigger car). Tire rack also couldn't give me a good answer if they would fit.

I'm looking to do the same was this ever figured out?

09-30-2019, 08:05 AM	#1
Nitrof23MT New Member 0 Rep 14 Posts Drives: 228ix convert, 528i, x3 35i Join Date: Sep 2018 Location: midwest iTrader: (0)	Help :) Can I fit thicker tire on stock 2015 228i Sport line? I am currently running 225/40F28 -92w Bridgestone driveguard runflats. They are terrible with potholes on my 228i xdrive convertible sport line. I am going to switch to non runflats. I figure increasing my tire size to 225/45 would help with potholes. Does anyone know if i can do this with my stock 18" tires? Everything is set up stock. Thank you for your help
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10-10-2019, 08:35 AM	#2
sethwas Second Lieutenant 135 Rep 242 Posts Drives: 228i Join Date: Jan 2019 Location: South Florida iTrader: (0)	you mean thicker sidewall? as in go from 18" to 17"? That would for sure help with potholes. Believe it or not going to a non-RFT may help as well because the sidewalls flex more - but you lose the ability to drive on an airless tire. Seth
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10-10-2019, 01:37 PM	#3
MassNerd Second Lieutenant 171 Rep 294 Posts Drives: 2019 M240i Coupe RWD Join Date: Feb 2019 Location: New England iTrader: (0) Garage List 2019 BMW M240i coup ... [0.00]	I think Nitro means increasing the sidewall height by increasing the profile of the tire from 40 to 45 while keeping the wheel diameter the same. This would mean the overall diameter would be increasing from the stock 25.1" to 26". This would cause a 4.5% decrease in the speedometer reading for a given speed. Also of concern would be rubbing, that I can't answer. I actually came here looking for a similar question on going from 245/35-18 to 245/40-18. 245/35-18 is very uncommon for snow tires. 245/40 or 235/40 are all much more common.
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10-13-2019, 06:50 PM	#4
Maynard Colonel 3830 Rep 2,866 Posts Drives: 228iX & M2C Join Date: Mar 2016 Location: Upstate NY iTrader: (1)	Better off to go to a 17 inch wheel, unless you have the biggest of the big brake options - TireRack can probably verify off your vin. Lighter, more sidewall, and more options for snow tires.
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10-16-2019, 10:13 AM	#5
Nitrof23MT New Member 0 Rep 14 Posts Drives: 228ix convert, 528i, x3 35i Join Date: Sep 2018 Location: midwest iTrader: (0)	Yes I was looking to increase size to 45 vs 40. I ended up just putting runflats on even though I hate them. I wasn't ready to spend the money on new rims and unfortunately do not think I'll have the car long enough to justify spending the money (need bigger car). Tire rack also couldn't give me a good answer if they would fit.
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