Hello all and thanks for this incredible resource. I have a 2004 cabriolet ~120K miles that is my daily driver here in KS. I am thinking about upgrading wheels as the brand new Conti's that came on the car are about done. I have looked through lots of threads and the opinions and information are overwhelming. I know the size and fitment of wheels. I have tons of info on tires and preferences. I, however cannot get a couple of basic questions I have answered and was hoping it could be boiled down easily.

1) Pros and cons of moving to a larger wheel on this car? I see all sorts of aesthetic reasons and that is highly motivating but practically I have to help convince my better half who controls the $$. I currently have stock 16's. Was thinking of moving up to 17" maybe 18. Performance improvements? Mileage improvements? Other germane info?

2) Why a staggered set up? I like the aggressive look but is the performance going to be noticeably different in daily driving if I went to a squared set up. I realize this is subjective and you don't know my driving style but think incredibly average driving with occasional "git 'er done" bouts of excitement on winding roads and straightaways.

3) New wheels and tires shouldn't affect the alignment I would think but many threads talk about the change in driving habit after tire/wheel changes. Especially tires. This car pulled to the right horribly, like straight into the ditch, when I bought it and I forced the stealership to align the car . I asked them about the camber and they said not an issue. Thanks to this forum I proved that wrong and go them to align the car straight as an arrow. They also included the new Conti's and told me that most of the problem was the General tires that were on the car. That remark has stayed with me. Will the tires or wheel changes force me to get an alignment? Not a bad thing and probably time to do this even though there is no uneven wear on the tires but still a relevant question for my own knowledge.

I continue to pour through the search function and read other threads, both here and benzworld and still have a lot of confusion. Maybe I'm just obtuse but I would appreciate any wisdom and information you can provide.

Much Thanks,

Chuck

 

Staggered wheels setups are designed to reduce over-steer in powerful RWD cars when driven in a "spirited" manner. Here's why:

The first thing to realize is that a wider tire does give you a larger contact patch with the road - it simply changes the shape of that patch. The size of the contact patch is a factor of the weight the tire is supporting and the stiffness of the tire. A skinnier tire will have a more narrow lateral but longer longitudinal contact patch, whereas on the same car, a wider tire will give a shorter longitudinal, but wider lateral patch.

A wider lateral contact patch means better side-to-side grip when cornering. With RWD, as you corner, if the rear tires slip even just slightly, you get over-steer, meaning the rear wheels will kick out and push the front more forcefully in the direction they are pointed. Wider rear tires can eliminate some of this so the car steers more accurately in high-speed turns.

So why not just put wider tires all around? It's because wider front tires are harder to turn and also would wear much more quickly. So, the ideal setup in a RWD car is for the front tires to be large enough to handle the car's weight and performance needs, but for the rear tires to be wider to offer better lateral grip.

I seriously doubt you'd notice any difference in a CLK320 in everyday driving if you switched to narrower rears to match the fronts.

 

+1 ^^^

 

Rodney,

That is the best explanation and clearly explained. THANK YOU! You explained that like I was 5 (ELI5) which is exactly what I needed.

One question down and a couple to go Thanks much!

Chuck

 

So glad I came across this thread! Once again, Rudeney to the rescue. I decided to do away with the staggered setup on my 2006 CLK350. The new wheels & tires (225/45/18) are due to arrive in 3 days and I was still doubting my sanity, until I read this thread. Thanks again!