str8ridin

So, if I am getting middle wear on my CLK in the rear (Bridgestone Potenza S03's 255/35/18) at 32psi, then that is a sign of under inflation??

ctemkin

I drive a 2003 E500. I had the same problem with SO3s, way too much wear in the middle, which I noticed when I was removing them and putting on winter tires. I have assumed that this was due to overinflation rather than underinflation, perhaps because I inflated them to the factory recommendation for hard driving. Even though I don't drive that hard, I figured it would help handling, and the ride of the E500 is so good that I don't think the additional pressure made the ride noticeably harsher. Recently I saw a thread on the 211 forum that indicated that wear in the middle has been a common problem. It bothers me that the factory recommended pressure would result in premature wear, and I guess that when I switch back to summer tires I will set them much closer to the "normal driving" pressures.

Luke, what would you suggest? I saw what you suggested for the E55, but don't know if that would apply to me.

Ronin007

No over inflation.

I think you answered your own question. If you don't drive hard why would inflate your tires to the hard driving settings? Use the normal driving pressures as your starting point as that is how you drive by your own admission. Not trying to flame you, more of trying to point out that just because you use performance settings or performance parts does not mean your vehicle is going to respond or handle better. You want to setup your vehicle for how "you" use it and that is a moving target depending on several factors as Luke pointed out in a previous post. When I use to road race cars I use to see people put the stiffest sway bars on their vehicle and could not figure out why it didn't improve the car's handling. Sure it would work for some tracks, but not for others. It is all a matter of balance.

ctemkin

Darren,

You raise an excellent point in your post. I inflated the tires to the higher amounts because I understood that this would improve handling. I did this not because I push the car hard as a general matter, but because I wanted the car to have the maximum ability to avoid accidents. In the DC area it is common for people to drive aggressively or, even worse, inattentively--just the other day some school bus driver lost control and ran the bus into the woods because she was talking on a handheld cell phone. On a regular basis people cut you off, stop dead without signalling while they decide whether to take a turn or go straight, etc., etc. So I opted for the higher pressure on the theory it would help avoidance maneuvers. This is also more or less why I got SO3s in the first place--because of handling and braking performance. And the car has been great to drive, which is something I am willing to pay for (presumably why we have Mercedes in the first place) in terms of increased tire wear if that is what it takes. However, if I am in fact not getting much benefit from higher inflation, and it has a severe impact on tire wear, well then I would be crazy to continue to do it.

The reason I posed the question to Luke was that I would like to benefit from his judgment and experience. I don't see myself as experimenting with different tire pressures the way he has, and I would certainly appreciate benefiting from his efforts--or yours for that matter.

Ronin007

ctemkin - Like I said it is all a matter of balance. I have seen people setup their cars like race cars but never go to the track and then complain that the car handles like crap on the road and ask why? Low profile tires, a lowered suspension with stiff springs and sway bars, with track rated shocks will make your car handle like a go kart but it will beat you up on each and ever expansion joint and ripple in the road. Sure some people will think it is cool, but is it pratical? I don't think so. It is all a matter of finding the balance of how you use your vehicle, how much money are you willing to spend, and how much are you willing to compromise.

As to safety on the road, you already seem to be observate so that is a huge start. I would recommend attending a defensive driving course sponsored by a car club or driving school. Even a club track day would be helpful. Learning car control in a controlled and well instructed environment will help you tremendously. I am not saying for you to go out and become a race car driver. Just attend one event will teach you tons of stuff to work on for years.

Cheers!!