Different Size Rear Tires (Straight from Factory)

J-sun · 07-17-2018, 10:06 PM

I discovered today that the rear tires on my M40i are different sizes. I was following my g/f (who was driving the M40i) and I noticed that something didn't look right. I checked the sidewalls and, sure enough, the left rear is 245/45 and the right rear is 275/40. So I have been driving on three 245/45's and one 275/40 for 3,400 miles.

A bit ridiculous IMO for a $65k vehicle to leave the factory (and Performance Center) with mismatched tires. I'm 2 hours from the dealer so I've been waiting for my first oil change to have them look into the annoying buzzing/rattle (possibly loose exhaust or heat shield) during acceleration. I guess I won't wait any longer. I expect two new tires for the rear.

Anyone else heard of this happening?

.

Sea-Tac · 07-17-2018, 10:38 PM

Totally strange! Let us know what the dealer says. I'll tell you this...it didn't come that way from the factory...dealer probably changed it out. Did you buy brand new?

J-sun · 07-17-2018, 11:51 PM

Quote:

Originally Posted by Sea-Tac

Totally strange! Let us know what the dealer says. I'll tell you this...it didn't come that way from the factory...dealer probably changed it out. Did you buy brand new?

I picked it up at the Performance Center back in May. It's never been to the dealer.

I've washed it several times and changed the oil after the break-in, yet never noticed the difference until I was following it in another car. Now it's completely obvious.

TxHornX3M40iGuy · 07-17-2018, 11:53 PM

Quote:

Originally Posted by J-sun

I picked it up at the Performance Center back in May. It's never been to the dealer.

I've washed it several times and changed the oil after the break-in, yet never noticed the difference until I was following it in another car. Now it's completely obvious.

That's pretty crazy.

verysideways · 07-18-2018, 01:47 AM

The front wheels and rear wheels are different widths - I suspect your car is fitted with 3 front wheels and only 1 rear wheel.
A 245 on a rear wheel would look stretched.

jbtco · 07-18-2018, 02:38 AM

Wheel damaged in transit and swapped for wrong one perhaps?

MarkyM · 07-18-2018, 02:43 AM

Quote:

Originally Posted by J-sun

Quote:

Originally Posted by Sea-Tac

Totally strange! Let us know what the dealer says. I'll tell you this...it didn't come that way from the factory...dealer probably changed it out. Did you buy brand new?

I picked it up at the Performance Center back in May. It's never been to the dealer.

I've washed it several times and changed the oil after the break-in, yet never noticed the difference until I was following it in another car. Now it's completely obvious.

That's just crazy, hope you get it sorted OK, I would ask them to replace tyre on other side as well so the tread depth is the same, sure it won't matter but no harm in trying

(I feel the need to go out and check mine now incase I have your missing wheel on my front)

Pretzel · 07-18-2018, 07:30 AM

Quote:

Originally Posted by verysideways

The front wheels and rear wheels are different widths - I suspect your car is fitted with 3 front wheels and only 1 rear wheel.
A 245 on a rear wheel would look stretched.

My set-up is square 245/50/R19 all around. For US?

I'll need to double check all wheels again to make certain

MarkyM · 07-18-2018, 08:19 AM

Quote:

Originally Posted by Pretzel

Quote:

Originally Posted by verysideways

The front wheels and rear wheels are different widths - I suspect your car is fitted with 3 front wheels and only 1 rear wheel.
A 245 on a rear wheel would look stretched.

My set-up is square 245/50/R19 all around. For US?

I'll need to double check all wheels again to make certain

The 20" wheels are staggered, 245 on front and 275 on rear

skier219 · 07-18-2018, 08:36 AM

That is a pretty embarrassing screwup for BMW. Amateur mistake right there.

Zembla · 07-18-2018, 08:43 AM

Quote:

Originally Posted by MarkyM

The 20" wheels are staggered, 245 on front and 275 on rear

Yup. The 19" don't seem to be (according to the brochure I've got in pdf). So, Pretzel, if yours are four identical ones, that's the way it should be

J-sun · 07-18-2018, 08:45 AM

Quote:

Originally Posted by J-sun

I discovered today that the rear tires on my M40i are different sizes. I was following my g/f (who was driving the M40i) and I noticed that something didn't look right. I checked the sidewalls and, sure enough, the left rear is 245/45 and the right rear is 275/40. So I have been driving on three 245/45's and one 275/40 for 3,400 miles.

A bit ridiculous IMO for a $65k vehicle to leave the factory (and Performance Center) with mismatched tires. I'm 2 hours from the dealer so I've been waiting for my first oil change to have them look into the annoying buzzing/rattle (possibly loose exhaust or heat shield) during acceleration. I guess I won't wait any longer. I expect two new tires for the rear.

Anyone else heard of this happening?

I should have mentioned that my M40i has the 20" wheels. So the 245/45 on the left rear is the wrong tire.

Are the 20" rims different widths (front vs. back), or are the tires just different widths?

OJ MINI · 07-18-2018, 08:52 AM

I am curious if this will damage the diff or if everything will be OK !

verysideways · 07-18-2018, 09:01 AM

Quote:

Originally Posted by J-sun

I should have mentioned that my M40i has the 20" wheels. So the 245/45 on the left rear is the wrong tire.

Are the 20" rims different widths (front vs. back), or are the tires just different widths?

Wheels are different widths front to back (8" and 9.5" IIRC) hence my comment about a 245 being stretched if it was on a rear wheel rather than a front wheel.

Also knew it was the 20's from the tyre sizes - 19's would be 245/50 and 21's would be 245/40.

Aaaaaaaaa · 07-18-2018, 11:23 AM

Going to check my car right now lol

Kief · 07-18-2018, 12:12 PM

Quote:

Originally Posted by OJ MINI

I am curious if this will damage the diff or if everything will be OK !

^^^This

jdurhan · 07-18-2018, 03:56 PM

I suspect your Transmission / Differential is not liking two different size tires
on the main drive wheels. That could be your buzz or rattle right there.

J-sun · 07-18-2018, 04:25 PM

Quote:

Originally Posted by jdurhan

I suspect your Transmission / Differential is not liking two different size tires
on the main drive wheels. That could be your buzz or rattle right there.

The buzz/rattle occurs only under acceleration around 1,500 RPM, and it's at its worst in sport mode. It sounds like the noise others have attributed to a broken exhaust weld or loose heat shield - although I'm not sure anyone has actually confirmed that a dealer has successfully diagnosed and fixed the rattle.

Rik762 · 07-18-2018, 04:28 PM

I have the 20 inch staggered set up and because of the long journeys I undertake across Spain, carry a full size 'front' wheel / tyre spare. This was OK'd by BMW technical to be used as required on the front or back axle as both sizes have the same rolling radius and won't affect the transmission.

gongtowjai · 07-19-2018, 01:18 PM

They owe you a new car...the drivetrain/transmission will get mess up. Your alignment is already messed up. The more you drive, the parts get more mess up. I would record everything and use it to demand a new car with your specs.

verysideways · 07-19-2018, 01:23 PM

Quote:

Originally Posted by gongtowjai

They owe you a new car...the drivetrain/transmission will get mess up. Your alignment is already messed up. The more you drive, the parts get more mess up. I would record everything and use it to demand a new car with your specs.

Errr, no.
See the post directly before yours.

sor · 07-19-2018, 02:53 PM

Quote:

Originally Posted by verysideways

Quote:

Originally Posted by gongtowjai

They owe you a new car...the drivetrain/transmission will get mess up. Your alignment is already messed up. The more you drive, the parts get more mess up. I would record everything and use it to demand a new car with your specs.

Errr, no.
See the post directly before yours.

Now if they had a different radius or totally different wheel, THAT would be wild it wasn't caught. Still I wouldn't think it would damage the car if caught early.

07-17-2018, 10:06 PM	#1
J-sun Enlisted Member 17 Rep 45 Posts Drives: 2018 X3 M40i Join Date: Dec 2017 Location: MO iTrader: (0)	Different Size Rear Tires (Straight from Factory) I discovered today that the rear tires on my M40i are different sizes. I was following my g/f (who was driving the M40i) and I noticed that something didn't look right. I checked the sidewalls and, sure enough, the left rear is 245/45 and the right rear is 275/40. So I have been driving on three 245/45's and one 275/40 for 3,400 miles. A bit ridiculous IMO for a $65k vehicle to leave the factory (and Performance Center) with mismatched tires. I'm 2 hours from the dealer so I've been waiting for my first oil change to have them look into the annoying buzzing/rattle (possibly loose exhaust or heat shield) during acceleration. I guess I won't wait any longer. I expect two new tires for the rear. Anyone else heard of this happening? . Attached Images __________________ X3 M40i \| Dark Graphite \| Mocha
	Appreciate 1 abcsoup184.50 Tweet Quote

07-17-2018, 10:38 PM	#2
Sea-Tac Major 1455 Rep 1,487 Posts Drives: 2108 X3 xDrive30i Join Date: Apr 2018 Location: Bellevue, Wa iTrader: (0) Garage List 2018 X3 xDrive30i [0.00] 2016 328i xDrive [0.00]	Totally strange! Let us know what the dealer says. I'll tell you this...it didn't come that way from the factory...dealer probably changed it out. Did you buy brand new?
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07-18-2018, 01:47 AM	#5
verysideways Lateral grip estimator 957 Rep 1,390 Posts Drives: i4, M2 Join Date: Jul 2011 Location: Cotswolds, UK iTrader: (0) Garage List 2023 BMW i4 Individual [7.83] 2010 Porsche 997.2 ... [0.00] 2002 Morgan Aero 8 [0.00]	The front wheels and rear wheels are different widths - I suspect your car is fitted with 3 front wheels and only 1 rear wheel. A 245 on a rear wheel would look stretched.
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07-18-2018, 02:38 AM	#6
jbtco Captain 163 Rep 641 Posts Drives: F80 M3 Join Date: Nov 2008 Location: Scotland iTrader: (0)	Wheel damaged in transit and swapped for wrong one perhaps? __________________ M2 competition, Alpine White Previously Owned : X3 M 40i, F80 M3 Comp Pack, DCT, Yas Marina Blue, F80 M3, DCT , E92 M3 Comp Pack, E92 M3, Z4MC, E46 M3 CS, E46 M3
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07-18-2018, 08:36 AM	#10
skier219 Captain 607 Rep 969 Posts Drives: X3 M40i, M2C, Ferrari 328 Join Date: Nov 2010 Location: USA iTrader: (0)	That is a pretty embarrassing screwup for BMW. Amateur mistake right there.
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07-18-2018, 08:52 AM	#13
OJ MINI Private 66 Rep 61 Posts Drives: M3 G80 X-Drive Join Date: Feb 2018 Location: Czech iTrader: (0)	I am curious if this will damage the diff or if everything will be OK !
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07-18-2018, 11:23 AM	#15
Aaaaaaaaa Banned 7559 Rep 5,056 Posts Drives: The other M3 Join Date: Oct 2014 Location: So Cal iTrader: (0)	Going to check my car right now lol
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07-18-2018, 03:56 PM	#17
jdurhan New Member 0 Rep 13 Posts Drives: 2018 X3 M40i White Join Date: May 2010 Location: Trafford, Pa. iTrader: (0)	I suspect your Transmission / Differential is not liking two different size tires on the main drive wheels. That could be your buzz or rattle right there.
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07-18-2018, 04:28 PM	#19
Rik762 Second Lieutenant 129 Rep 264 Posts Drives: 2022 X5 M50i Join Date: Mar 2013 Location: Sherwood Forest iTrader: (0)	I have the 20 inch staggered set up and because of the long journeys I undertake across Spain, carry a full size 'front' wheel / tyre spare. This was OK'd by BMW technical to be used as required on the front or back axle as both sizes have the same rolling radius and won't affect the transmission.
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07-19-2018, 01:18 PM	#20
gongtowjai I'll Kung Fu Panda your ass 106 Rep 2,100 Posts Drives: '16 F30 XDrive Join Date: Dec 2006 Location: Queens iTrader: (0)	They owe you a new car...the drivetrain/transmission will get mess up. Your alignment is already messed up. The more you drive, the parts get more mess up. I would record everything and use it to demand a new car with your specs. __________________ '16 F30 340 XDrive - AW-Lighting & Track Packages. The FIRST drive was awesome....
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