Pulling to the right

[snapsule]

Hi, I recently purchased a 2005 Porsche Cayenne S (64,000 miles). I brought it in for a service and alignment as I noticed that it would pull to right. I've read a lot of message boards saying this could happen with larger vehicles, wide tires, etc. I drive the same road with a my Silverado Crew Cab with 20" wheels and wide tires and never feel it pull to the right.

The alignment service didn't seem to fix the problem. I was wondering if anyone else has experienced this type of behavior? If so, what fixed it. Maybe there are some other things that could cause it besides alignment???? I just don't know what it could be but I'd like to get it fixed. Other than the pull to the right I love the vehicle.

Although it's hardly noticeable I think the steering wheel is turned slightly to the right and might be the cause. Is it possible the steering wheel / mechanisms need to be re-centered / aligned? I'm not sure if my model has the servotronic system but I thought it might need calibrated as well. As you can see I'm searching every angle for a solution and desperately need some expert advice...

Thanks for any advice or tips to help me solve this problem.

[rizzo]

My 04S will "drift" to the right. I would not classify it as a pull. On a straight, flat freeway at speed the car will begin to move to the right if there is no input from me. Minimal input is required to keep it straight. Minimal being defined as touching the wheel with the slightest of left turning "pressure" applied.

This is how it's been since I got the car and after several alignments.

Hope that helps.

:cheers:

Hi, I recently purchased a 2005 Porsche Cayenne S (64,000 miles). I brought it in for a service and alignment as I noticed that it would pull to right. I've read a lot of message boards saying this could happen with larger vehicles, wide tires, etc. I drive the same road with a my Silverado Crew Cab with 20" wheels and wide tires and never feel it pull to the right.

The alignment service didn't seem to fix the problem. I was wondering if anyone else has experienced this type of behavior? If so, what fixed it. Maybe there are some other things that could cause it besides alignment???? I just don't know what it could be but I'd like to get it fixed. Other than the pull to the right I love the vehicle.

Although it's hardly noticeable I think the steering wheel is turned slightly to the right and might be the cause. Is it possible the steering wheel / mechanisms need to be re-centered / aligned? I'm not sure if my model has the servotronic system but I thought it might need calibrated as well. As you can see I'm searching every angle for a solution and desperately need some expert advice...

Thanks for any advice or tips to help me solve this problem.

[odix]

Hi -- Like Rizzo I have an '04 Cayenne S and I went through some alignment questions as well when I bought the vehicle (used/CPO) in early 2009 with 56k miles.

Not sure if your Silverado comparison is apple-to-apples. It's a very different vehicle from the Cayenne, even with large wheels. Cayenne's have a significantly shorter wheelbase which may make road/surface irregularities (crowns) more pronounced compared to a longer wheelbase vehicle. Also tire width is a big part of the puzzle.

Be sure to confirm your tires are OK, no sidewall weakness, etc. As to your steering-wheel centering issue I don't think that would impact physical driving dynamics but I'm not sure..

Welcome to Renntech and congratulations on your Cayenne purchase -- you'll love it! (And be sure to join Renntech as a contributing member -- you can read all the Cayenne Technical Service Bullitens as well as access a slew of other data.)

On a similar topic last December I noted the following in a post related to alignment:

>

"Sounds normal -- roads have more of a crown/camber than you may be aware. Also, Cayenne's have wide tires -- that width makes the crown more pronounced. I too thought I had an issue -- a friend suggested I find a long level and flat surface. I did (a large mall parking lot on Superbowl Sunday) and at speed (55 - 65mph) no pulling left or right or correcting steering required.

From what I've read Cayenne's (or any heavy vehicle) with wide sport wheels and tires are more prone to "drive down the crown" on roads with significant crowns, requiring corrective steering. I have the stock 275/45/19" wheels. Also I've noticed no problem on freeways -- they are not as crowned as rural or suburban two-lane roads"

>

[snapsule]

thank you rizzo and odix.

Rizzo - It's comforting to know that others have the same experience.

Odix - i found and read your earlier post about crown/camber in roads; the wide tires and driving it in a flat parking lot; that's something I plan to do very soon. I hope that the road along with the short wheel base and and wide tires is the reason for the drifting I notice. The Cayenne is different than any other vehicle I've owned. I'm just not used to the drifting I've felt and wanted to make sure there wasn't something that needs corrected.

[CTTinTO]

The Cayenne suspension geometry along with wider "performance" tires makes the Cayenne very sensitive to road crown.

If the vehicle drives straight on flat roads, then you are just experiencing road crown sensitivity and this is just normal.

If your steering wheel is not straight but the vehicle goes straight the you just need a toe adjustment.

I would look at a couple of things:

Tires:

This could be a tire conicity problem. Tires are coned shaped and tend to pull to one side by nature and in the tire industry, this is called conicity. At the factory, tires come in marked from the manufacturer as positive or negative conicity. At the factory they will then mount the tires so that the axle conicity cancels itself out. Sometimes the conicity is so high that it cannot be cancelled out.

The way to check this is to swap front tires left to right and see if the vehicle starts to pull the other way. If it does, then its an axle conicity issue. Unfortunately, the consumer is not provided conicity data so you have to make due with tires you got and essentially guess the best position for each tire through trial and error. Some of the newer hunter RFB machines do measure lateral force and can help pick tires. Sometimes, also inverting a tire on the same wheel (if they are not directional) will invert the tire conicity to make it easier to cancel out the conicity of the tire on the other side.

Alignment

Check your camber split. Ie: the difference between left and right. Camber split = FRcamber - FLcamber.

Example: FRcamber=-0.5deg & FLcamber=-0.2 so camber split is -0.7deg

Typically, since road crowns in north america slope right, you want to keep your camber split negative. For the Japanese OE, we targeted 0deg to -0.5deg camber split and typically ran about -0.35deg split on average for a comparible SUV.

On most alignment machines, they calculate camber split opposite of how I explained so be carefull when you look at the numbers and calculate it for yourself. My above calculation on a Hunter alignment machine would show +0.7deg and not negative. Either way, the key thing is to get the sum of the camber pointing towards the road crown to fight it.

don't go to negative or you will find the vehicle going the opposite way on flat roads.

Hope this helps

Mike