So, I'm quite new to the C63 and I have a 2012 C63. I came from a C250. The steering on this car when at higher speeds (around 60-70 mph) feels a little "floaty". I know the car has speed sensitive steering but I would imagine it would tighten things up - right now the car feels a little loose at high speeds. Its still quite sharp, just seems to move a little but too much when under acceleration and doing things like changing lanes..




Any thoughts?

 

How are your tires?

 

Brand new, they have about 2k on them

 

is the trunk of your car loaded up? your car is too new to have suspension issues. maybe check your tire pressures.

 

Nothing in the truck, tires are reading according to TPMS that they are at 39 front and 42 rear.... It almost feels like when you unload the throttle in the middle of a turn, except I'm not doing that. Agreed on the car being too new - it has only 40k on it was just had its B2 service done.

 

What brand, model and size of tires are you running?

 

Bridgestone Potenza S-04
235/40 -18 Front
275/35 - 18 Rear
Also I do have spacers

 

SO4s are pretty stuff tires too. Strange. When was your last alignment?

 

Just had it and balance checked... Maybe I'm just crazy?? So based on what everyone is saying there is a good chance it's not a suspension issue?

 

you have 275s AND spacers?

Im not the guy whos gonna ***** about your spacers (someone will, but I have them too) but what size do you have in the back that you can possibly get in there with 275s also?

 

So TBH, I bought the car with them on. Based on what in seeing, there is no spacer in the rear and potentially a 10mm spacer in the front. I'm not sure what the C63s came with as far as rear tire (thought it was 255) so I assumed that there was a spacer in the rear as well, however looking at it closer now it doesn't look like it.

This is the font


This is the rear


This is how the car sits (ignore that it's dirty please!)

 

Gotcha. The 235 is oem fitment, so a lot guys run up to about a 12mm up there.
In the back 255 is OEM and in that case you can run a 10mm or so but I was pretty sure you wouldnt be able to have both, not with stock wheels anyways.

 

Gotcha. So what's the widest you can go in the rear with the stock wheels?

 

275. But not with spacers. And it takes the right 275. 265 is any brand.

 

Ok cool. Thanks for the info. Well now to figure out why the steering feels funny...

 

I had the same problem when I bought new tires recently. The steering feedback changed from firm and precise to floaty at speeds above 50 mph. I am just going to swallow the pill and switch to MPSS because I can't deal with the floaty anymore.
However, I must add that I was able to reduce the feeling a bit by deflating the tires just a little bit below the recommended pressure.

 

We now return you to your originally scheduled program. Good luck with that.

Stupid question perhaps, but Occam's Razor...... any chance tires are installed backwards? They're a directional tire. It can happen. My first thought was over inflation. Tire wise this is my next ....

 

Yup, checked direction - all are good. Yea maybe I'll drop the PSI a bit and see how it goes. Thanks Gents! So to change the subject one more time for fun, I keep reading that these cars eat tires almost as fast as gas. I read somewhere that if you increase toe in the rear +1 it drastically reduces tire wear... Any truth to this?

 

Alignment spec?

 

I don't have them unfortunately...

 

I would use a real tire press gauge to read the tire psi vs the onboard computer. Could be giving you false readings

 

assuming your tire pressures are correct...your rear isn't sitting lower than your front...

the front spacers shouldn't cause your far to be floaty...but it should feel darty when you turn. also your front end may follow cracks on the road much easier. maybe that is what you mean by floaty? your front end being floaty would feel like if you had 800 lbs in the back seat and your car was sitting 2-3 inches lower in front. floaty meaning when you turn your front with go but your rear will slowly follow and dangerously follow with lots of sway.

i'd remove the front spacers, match all tire pressures then drive your car around town. generally cars that have a wider stance in the rear or have staggered fitment were designed that way to aid with on and off throttle oversteer.

 

I've read 275s in the rear make this car feel 'floaty'. I can't confirm from personal experience, just from what others have said running that rear setup.

 

I'm betting on the alignment being off or the 275s being squishy and messing with the feel of the car. Rear tires have way more affect on steering and overall feel than people sometimes think. Ever run a snow tire on the back and summers on the front? No bueno. Try an alignment first and then maybe 265/35-18 SO4s out back if the alignment doesn't help. I ran SO4s in 235/40 and 265/35 F/R and loved them.

 

The difference between a 255 and a 275 is negligible at best. I noticed no difference when I changed to 275's