tbeiler

I purchased a second set of rims for summer use for my 05 E320 CDI and had them refinished. They are the 5 double spoke rims.
Rim dimensions are 8.5J x 17 with offset ET38.
Am thinking to get either 245/45 R17 fronts and 265/45 R17 or 265/40 R17 rears.
Do these tire sizes make sense, or could I go even wider on the fronts and/or rears without any interference.
Any 05/06 CDI's out there with same rims and tire sizes/ brands that you guys are using.
Haven't decided yet on tire brand yet.
Thanks in advance for any input.

kajtek1

The start in changing tire size should be rpm comparison.
Go to tire manufacturer of your choice site and first find rpm for original tires, than compare rpm of tires you'd like. Looks like some of the tire sizing you like would be bigger than OEM what will bring odo/speedometer differences.
For staggered wheels you need to match rpm more precisely between the axles.
Rule of thumb says that 3% difference is acceptable. Once you go 5% the CC and ESP might not like it.

tbeiler

Thanks Krzysztof, never even thought about rpm comparison between front and rear if I go staggered.
I still haven't ruled out all 4 tires the same size, albeit 245 width instead of the stock 225.
I know what the ESP is, but what is the CC? And how exactly could staggered tire sizes affect the ESP and CC?

kajtek1

Cruise control.
When ESP is comparing speeds at all 4 wheels all the time, CC suppose have "free will" wchich sensor to choose as technically it needs only 1.
Have no idea how exactly program works, but this is called "60 mph syndrome" when with uneven tires CC will work at lower speeds, but will disengage at 60 mph.

tbeiler

Got it, will definitely search for same overall tire diameter / rpm if I decide to go staggered. Will try for the less than 3% and if not then all 4 will be the same.
Thanks Kajtek.

Strigoi

Stick with the same size all around unless you are going with staggered wheels.

S70Houston

^^^^^ THIS!

tbeiler

OK, looks like the same sizes all around will be the choice, thanks for the input.
Appreciate all the comments from those in the know.

Strigoi

You also can't rotate the wheels when you have a staggered setup.

tbeiler

Also found out that tire warranty is reduced when there is a staggered tire setup, goes down by approx 1/2.

This from Continental Tires
• On vehicles with staggered / split fitments (different size tires on front and rear axle), tires cannot be rotated between the front
and rear axle. Without rotation of tires between the front and rear axle, the expected mileage / kilometers before wearout is
significantly lower, especially on the rear axle. Therefore, the Mileage Warranty for tires on the rear axle of these vehicles will be
50% of the standard Mileage Warranty for the product line.