PaoChe

I was just told by my "BMW guy" (family friend and private bmw mechanic) that changing wheel sizes is not advised for the E60 because the size of the wheels is stored in ROM in the car's computer when its at the factory and that its impossible to override. He warned me that my speedometer and odometer could be seriously effected and that the computer could start throwing out tons of error codes and that its not worth it. He said that the E39 didn't have this problem (he's partial to the E39 still).

I've searched the forums and came up empty handed soooo...

I've noticed that all of the members here who's cars didn't come stock with style 166's magically have them on their cars and don't complain about errors. Is it just a simple trip to the dealer to reset it? Or is the fact my car is old, from 03/2004 with 16" wheels, the problem?

acuteperformance

what size do you want to go to? as long as the outside diameter is close it'll be fine.

michael
acute performance

PaoChe

I was going from stock 16's to most likely the 166's at 19". Given tire dimensions it looks like the 166's are still about 6cm larger in diameter than my 134's. Thats pretty big.

acuteperformance

The proper tire sizes for 19" are

Front: 245/35/19
Rear: 275/30/19

As long as you get those sizes, your outside diameter will be nearly the same as the 16s. In other words, you'll have zero issues.

Michael
Acute Performance

mymonkey562

What would be the ideal size for 20s?

PaoChe

What about other things that depend on tire rotation, like FTM? The wheels I'm interested in come with tires already on them, so if they have the set up listed in the info section 255/40R-19 (front) 285/35R-19 (rear) then I would imagine it'll cause problems. I'm not sure about the tires that are on the wheels, i'll have to look into it.

So just to be completely clear, even if the diameter it just 1-2cm off, it will notcause my car's computers to freak out at all? No errors? No noticeable differences in speedometer, odometer, or even the car's calculation of things like MPG?

Masterspy

I have OEM M166 coming from 17". I have no problem at all. Of'course you need to stay within 3% total outside circumference from your original specs. Regarding FTM. If it trigger fault, you can always reset it from your idrive.

v_therussian

In all the time this forum has been online and E60's production ran, people slapped 19s, 20s and even 21s on their E60's. And we are yet to hear ONE story that would prove your friend/mechanic right. But what do we know, right?

PaoChe

Yeah, he's a die hard e39 guy. He knows his shit, he's been doing it for 30 years. I'm sure he'll come over to the dark side someday.

acuteperformance

245/30/20 275/25/20

You will have NO problems. No problems with FTM, no problems with rotation MPH whatever, no computer issues, no errors, no odometer being a problem, no incorrect MPG calculation.