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Just wanted to get some opinions here. I want to buy these Michelin Super Sport tires but the closest size they come in is 265/35/ZR19 98Y and 295/30/ZR19 100Y. Of course you guys already know the oem size is 255/40/19 and 285/35/19. Would it be okay for me to use these tire and what are the side effects. I've done some research and the overall diameter is a difference of 0.7 inches front and 0.9 inches rear. Thanks guys.
 

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I need to know this aswell...so come on guys, does somebody know?

Stock size is:

255/40-19 - Tire diameter is 686.6 mm
285/35-19 - Tire diameter is 682.1 mm

Difference is -4.5 mm, -0.7%


Michelin Pilot Super Sport:

265/35-19 - Tire diameter is 668.1 mm
295/30-19 - Tire diameter is 659.6 mm

Difference is -8.5 mm, -1.3 %

Max is 3.0 %

Will this effect the speedometer? If so...how?
 

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I'm interested in this too. Where are the Tire Guru's? :dunno:
 

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Here also ! Please let a tyre specialist tell us all about it please :dunno:

I found a calculation tool but I am unsure what the outcome means (usable tyre or not ? the difference of the rear wheel would be 3.3%

Here is the link and see image below for the calculation made Tire size calculator

 

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Here also ! Please let a tyre specialist tell us all about it please :dunno:

I found a calculation tool but I am unsure what the outcome means (usable tyre or not ? the difference of the rear wheel would be 3.3%

Here is the link and see image below for the calculation made Tire size calculator

That would be awesome...more accurat speedometer won´t hurt at all, very nice to have.
 

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Stock tires front: 255/40/19 = 27.03"
Alternative front: 265/35/19 = 26.30"

Stock tires rear : 285/35/19 = 26.85"
Alternative rear : 295/30/19 = 25.96"

Rolling diameters are shorter and much shorter for the rears which will not be as significant in relevence to affecting ABS and speedometer accuracy. With shorter rolling diameters your topend speed will be compromised a bit and low end picked up a bit. This can be considered a "poor man's" diff. ratio change.

Equation used to calculate rolling diameter: tread width x sidewall profile diveded by 25.4 x 2 + rim diameter = rolling diameter.
ex. 255 / 40 / 19
255 x .4= 102 then divide by 25.4(to convert mm to inches)= 4.01, then multiply by 2(upper & lower sidewalls)= 8.03, then add 19(rim diameter in inches) = 27.03 inch rolling diameter.

Hope this makes sense. :)

Ranger
 

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Thanks for your input Ranger! I actually have a Tire Comparer app on my phone that helps me with this one, so the numbers on my earlier post seem to be just fine, the app works as it should :)

It blows that they haven´t done´them in stock size, but going with 265 front/295 rear will give the car even more grip.
 

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Thanks for your input Ranger! I actually have a Tire Comparer app on my phone that helps me with this one, so the numbers on my earlier post seem to be just fine, the app works as it should :)

It blows that they haven´t done´them in stock size, but going with 265 front/295 rear will give the car even more grip.
And a little harsher ride :Thumbdown: but it will also look better
 

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Stock tires front: 255/40/19 = 27.03"
Alternative front: 265/35/19 = 26.30"

Stock tires rear : 285/35/19 = 26.85"
Alternative rear : 295/30/19 = 25.96"

Rolling diameters are shorter and much shorter for the rears which will not be as significant in relevence to affecting ABS and speedometer accuracy. With shorter rolling diameters your topend speed will be compromised a bit and low end picked up a bit. This can be considered a "poor man's" diff. ratio change.

Equation used to calculate rolling diameter: tread width x sidewall profile diveded by 25.4 x 2 + rim diameter = rolling diameter.
ex. 255 / 40 / 19
255 x .4= 102 then divide by 25.4(to convert mm to inches)= 4.01, then multiply by 2(upper & lower sidewalls)= 8.03, then add 19(rim diameter in inches) = 27.03 inch rolling diameter.

Hope this makes sense. :)

Ranger
Great information Ranger - thanks for that! So, if the car has been lowered (H&R Springs), would there be a chance of running into issues with these sizes? May not be able to answer that, but just wondering.
 
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The 295/30 19 is 799 r/mi +3.2 %

The Michelin PSS is also available in 305/30-19 792 r/mi +2.3%

The stock tire is 774 r/mi

No reason to go through all the calcs when the manufacturers provide r/mi data in their specs.
 

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Just and FYI for anyone who leased their car. I was interested in these tires as well, but just confirmed with BMW that per the lease contract the car must have a matching set of tires of the same size and speed rating as the OEM tires. They added that it is somewhat at the discretion of the dealer, so they MAY accept these since they are very close in size and obviously of similar quality. But if you leased and want to go with these I would suggest confirming with your dealer (in writing) they will accept these on a returned car.
 
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