My wife hit a pothole & bent a rim here in Potholuma, CA. Her Mercedes CLK 500 comes with staggered 17" rims, 7.5" in front & 8.5" in rear. We’d like to go with the same size all around. The owner’s manual says we can. The Mercedes dealership says it will cause all kinds of handling & mileage issues. Does anyone out there know the real answer?
I am not a Mercedes expert, so I have no business arguing with the dealer, but doesn’t a CLK ride on a standard C platform? If so, then surely you could put 7.5" wheels all the way around with no clearance problems and no adverse affects on your daily commute.
If, however, you are the kind of driver who clicks off the stability control and pushes the CLK hard through the curves, I fear that you may experience increased oversteer if you change the original layout. Without its electronic reigns holding it back, that engine is more than happy to break the rear end loose. The staggered tire widths keep those drifting turns balanced.
My wife’s BMW has staggered wheels, and I would have no concerns with putting same-width wheels all the way around on her car if I were replacing wheels.
@ntagnst I believe the ABS/stability control module “knows” what size tires and rims you have. Using the same size front and rear could cause havoc. You might be able to reprogram the control module so that it realizes you have the same size front and rear tire.
All the ABS/stability control cares about is tire diameter, not width, so as long as the replacement wheel/tire combination is the same as the tires on the 8.5" wheels you should be OK.
And I always give preference to the carefully-researched owners manual over the folks at the dealership. What, exactly, does it say?
@texases I believe the control module takes into account the overall diameter of your tire/wheel setup.
You could theoretically have a narrow and a wide setup with the same overall diameter.
You are right about giving preference to information in the owner’s manual.
But I think it’s usually best to stick with the same size tires and rims that the vehicle was originally equipped with.
The difference in width matters not to ABS and stability control. And I
I’m sure the difference in overall tire diameter for the staggered front and rear are not enough to confuse these functions.
The owner’s manual says it is Ok, it’s Ok. The dealership sells the cars and services them, but refer to shop manuals written by the same engineers that wrote your owners manual.
That handling and mileage line is used by nefarious tire shops to upsale high-performance tires on cars that never see speeds North of 75 mph.
My interpretation of what manoluto said was if you drive this vehicle to the limit of it’s capabilities, then it matters. To drive it at its limit, you have to turn off the stability control. If you’re a run of the mill sedate driver, driving it like you would a Malibu, then the same size tires can be used all around.
If you go with the same width all around, it won’t manifest itself as mechanical problems (assuming that you change the rims too), but it will affect handling and stability. The suspension is designed to make the most of the wider rear tires, which are used to accomodate the greater loads placed in the rear tires in acceleration, especially on a tightly curved on ramp. And the suspension’s anti-roll components are sized to keep the car stable with the wider rear tires. Change this characteristic and you’ll compromise the suspension design.
Whether you feel the difference or not depends on how you drive. If you only take it to the store, you’ll probably never notice. But if you do a lot of highway driving and drive aggressively, you may notice the difference on the on and off ramps.
The bottom line is that changing tire widths on any vehicle changes its handling. Whether you notice it or not depends on how you drive and your driving environment.
You have to be careful here. Some staggered fitments have different wheel offsets front to rear.
So while it might appear that you can use the same wheel all around, it might not be the case. careful research needs to be done.
I’m probably about to be forced to go to non-staggered wheels on my MR2 because it’s getting almost impossible to find high-performance tires in its size anymore. You don’t have that problem, so there’s really no reason to get rid of the staggered wheels. Why take the suspension hit?
@ntagnst you said your owner’s manual said you can use the same size tires front and rear.
Does you owner’s manual also cover the CLK320 or CLK350? Those cars use the same size tires front and rear.
What about using same size tires on staggered rims?
Here’s the thing. The car’s suspension is designed for a certain wheel and tire dimension. If you change those dimensions, then it is hard to say what will happen. But it probably won’t be something good.
For example, alignment. There’s two kinds of alignment. Static, which is the alignment an alignment shop does by adjusting scews and bolts on various suspension components. Then there’s dynamic alignment, which is the car’s alignment when it is driven down the road, the wheels turning, bouncing up and down over bumps, being turned left and right, etc. Static alignment can be adjusted. Dynamic alignment cannot. It is built into the car’s design.
Mercedes engineers designed the car so that if the static alignment is correct, then the dynamic alignment will be also. But that will only be the case if the wheel and tires dimensions remain the way the car was as it rolled off the Mercedes assembly line.
Me, I always stay with the same wheel and tire dimensions as the car was shipped from the factory.
This post it two months old. I don’t think th OP is following it anymore.