New member - DSC light after wheel change

[1FastCasper]

Originally Posted by ants_oz

Cheers mate.

I urge you to trust the advice I have given though - the core problem can be traced back to rotational circumference differences.

Research it further, get more advice. But don't risk your transfer case - it's working harder than it needs to at the moment.

Sent ya a PM.

[upallnight]

Originally Posted by 1FastCasper

90.04 front
92.02 rear

92.02/90.04 = 1.0219 or 2.2%

How did you arrive at your numbers?

Circumference of a circle = π x diameter.

π=3.14

Diameter of the tire = height of the side walls plus the diameter of the rim.

Height of the side wall is the width of the tire multiply by the aspect ratio or
the aspect ratio is the height of the side wall / width of the tire.

height of the side wall = 270 x .40 = 110

rims are 20

tire diameter 275/40/20 = height of the side walls x 2 + rim diameter

tire diameter = 110 x 2 +20

tire diameter = 240

tire diameter 295/40/20 = height of the side walls x 2 + rim diameter

height of the side wall = 295 x .40 = 118

tire diameter = 118 x 2 +20

tire diameter = 256

256/240 = 1.0666666666666

That a difference of 6% not 2%

[Helihover]

Here's some simple math.

Go to a tire shop and pay a man to put on some 315's in the back and watch your light problem go away

[basicm]

@upallnight
You messed with centimetres and inches, i'm not sure your calculation is correct.

Anyway, i think your tire size is causing the problem.


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[1FastCasper]

Swapped the rear tires for a set of 315 35 20 from a friends 2012 ( I WANT TURBOS!!!). Went for a drive....same problem. Having eliminated tire size as the culprit, again I am led to believe the cause is elsewhere. All is well until accelerating on a curve or whipping out to pass. Seems to be related to lean angle.

I get no codes, just the annoying yellow light.


John

[ants_oz]

DAMN YOU AND YOUR PROBLEM SOLVING LOGIC Mate, seriously though, I am quite happy to be proved wrong in this instance, as it shows that the different sized rubber is NOT the culprit. Now, where to from here. Do you know anyone with a BMW-specific code reader - like the fancy software plenty of people have, but which I have not gotten around to buying yet? The reason I ask is that there are (I believe) quite a number of codes/faults which will not display on generic code readers, but WILL display on the BMW type software.

Another option - albeit a long-shot. Go to the connector for each wheel-speed sensor. Unplug it and give it a spray with electrical contact cleaner, plug it in again. As I said - a long shot, but a cheap one.

Oh, and remember - damn your Project Rushmore goodness Saw another one yesterday. And as much as I love my FJR - which is a do-everything beast - those Touring Ultras = mmmm.

Cheers dude, hope to get some good news soon regarding progress on the annoying yellow light.

[1FastCasper]

Originally Posted by ants_oz

DAMN YOU AND YOUR PROBLEM SOLVING LOGIC Mate, seriously though, I am quite happy to be proved wrong in this instance, as it shows that the different sized rubber is NOT the culprit. Now, where to from here. Do you know anyone with a BMW-specific code reader - like the fancy software plenty of people have, but which I have not gotten around to buying yet? The reason I ask is that there are (I believe) quite a number of codes/faults which will not display on generic code readers, but WILL display on the BMW type software.

Another option - albeit a long-shot. Go to the connector for each wheel-speed sensor. Unplug it and give it a spray with electrical contact cleaner, plug it in again. As I said - a long shot, but a cheap one.

Oh, and remember - damn your Project Rushmore goodness Saw another one yesterday. And as much as I love my FJR - which is a do-everything beast - those Touring Ultras = mmmm.

Cheers dude, hope to get some good news soon regarding progress on the annoying yellow light.

Thanks,Mate! I WILL get to the bottom of this! I'll send ya a PM with pics of the 2 wheelers that live next to the X5.

[ants_oz]

Noooooooooo! Jealousy is a curse, and I might get jealous!

[upallnight]

Originally Posted by basicm

@upallnight
You messed with centimetres and inches, i'm not sure your calculation is correct.

Anyway, i think your tire size is causing the problem.


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I'm sure if you change the 20 inches rims diameter to centimeter diameter, the result will still be the same.

[1FastCasper]

Originally Posted by upallnight

I'm sure if you change the 20 inches rims diameter to centimeter diameter, the result will still be the same.

From Discount Tire web site;

275 40 20 is 90.04
295 40 20 is 92.02

92.02/90.04 is STILL 1.02199

Rounds to 2.2%