My RX8 have stability problems. Every little hole or crack on the road make my car goes left or right (dangerously). I went 3 times at the dealer they try 3 alignment settings but I still have the problem. Anybody have experience the same problem?

 

IT'S NOT A PROBLEM. it' becasue of the size of the tires. there have been many reports on here about this. becasue of the size and type of tires they tend to pull in the grooves, especially at low speeds. fixing alignment settings wont make it go away.

some have said it has a name- tramlining. search for that.

 

but the tires on the 8 are only 225's. there are 225's on my moms 04 530i bmw and that car doesnt "tramline." On the other hand, my dads carrera 4s with 295's in the rear and 225's in the front tramlines like a biotch..... maybe its more the suspension setup, and not the tires. but then again, i dont know much about this or any suspension so im most likely really wrong.

 

Tread pattern is a big factor too. Suggestion: Assuming you have stock tires, test drive another RX-8 with the same tires/wheel size at your dealer and compare it to how yours handles on the same stretch of "bad" road to eliminate your car from having a unique problem. Do you have your tires inflated to 32psi cold?

 

Nice link, I was going to post about the difference between my summer tires and winter tires but that link dicsusses it.

 

It's a problem on my MP3 as well. Sometimes, driving on a rutted or sloped road causes the tire to follow in the rut, making you fight back at the wheel. A firm grip on the till is all that's needed to combat it. I think the wide and low tires we drive on today have a "tail wagging the dog" effect that we didn't have years ago. The hard and short sidewalls transmit everything right back to you.

 

I have never experienced this with either the Dunlop Winter Sport M3's or the Potenza RE040's. I've heard others on here who've changed to a different tire complain about it though.

 

that's cause virginia takes good care of their roads.

 

Over inflation of the tires could cause it to become squirrely. There was a great article in one of the auto rags (R+T, MT?)recently that showed what a huge difference 2 or 3 psi can make. It wouldn't be enough to trip your TPS light, but it could make the car more darty and succeptible to grooves in the road. Check that out.

 

Its not so much the size of the tire, but the aspect ratio. Low profile tires (wide with short sidewalls) like the 40 series stock tires on the 8 are prone to being sensitive to grooves, valleys, wear ruts in the the road. It is not unique to the 8.

 

Wide Low profile tires cause this (plus very tight steering with goos feedback make it worse).

I think the reason that low profile tires cause this is that they are very stiff due to the small sidewall, so there is little side to side flex to cushion road imperfections.

Add to that the very tight (excellent) steering that feedsback well to the driver (it is not a cruising car).

I was pretty surprised the first few times my car tried to pull to the side as I slowed for a stoplight.

 

From what I have found, there are several things that cause this.

Low profile tires
Tire diameter
Tight suspension
and how the steering arms are connected to the wheel. Mainly, the distance from center of the hub.

All of these items contribute to the transmission of road feel to the wheel. With the profile of the tires and wheel diameter being the most influential.

Wheel diameter tells how much wheel is going to be within 1/4 inch of the ground to contact rutts and cracks. Smaller wheels lift up higher faster and do not pull as much.

 

try minneapolis roads... After a winter here they all blow up the first day we have anything over 50 degrees. Ruts galore. I betcha the guys from them theres Canadian state things can tell some stories as well...

 

All cars do that. My mom's s500 does the same thing. My 8 does it my 7 did it. Who cares... my advice don't drive on the cracks

 

So, Marcus,

It's not a problem. Just be aware of it and enjoy the 8.

 

I agree with tire pattern. When i run snows I dont drift. Notice the drift w/original tires & especially at slow speed.

 

Tire size has an effect on tramlining, as does tread pattern.