355 Uneven tread wear

Independent suspensions, just like every other component on your car, need routine maintenace and adjustment. The suspension is a kinetic system, and settings do not remain static -- if you consider the amount of work your suspension does, you'll understand. Get you alignment checked, and have the toe adjusted; it's not incompetence, it's simply wear & tear.

 

Kinda normal for the 355.. Inner rears do tend to wear faster.

Rear camber is probably set somewhere about 2.0

Once you set your car to not wear tires, you loose some handling ability.

If anything get the alignment checked.

 

I am getting the same type of wear. I had the car aligned and replaced both tires after cupping of the previous set. I am still hearing tire noise similar to the cupped tire sound. The tires are Bridgestone Expedia s-01's. Any thoughts?

 

With the negative camber in the rear suspension 355 rear tires are going to wear on the inside, but both sides should be about the same. As stated above if you decamber the rear suspension you will change the handling but with the cost of most good 18 inch tires maybe that is a viable option.

 

That's a dagerous measurement, since the body of the car is unlikely to be exactly the same on both sides of the car anyway (makes it hard to "check by eye) and you can't be sure that the ground was perfectly level either. Why don't you take it to a professional? I find this a very strange thing for someone who appears not to know what they're doing to attempt. (using a ruler on top of it!)

 

Your symptoms sound like too much negative camber, more than too much toe, although the latter could accelerate the wear from the former.

Alignment can change with time, especially as the car is a monocoque and even a good pothole can cause a permanent change.

If you're willing to pop $70+K for the car, pop the $100-$200 for a proper 4-wheel alignment to check caster, camber and toe.

Pulling shims is like shooting in the dark if you are not measuring the effect.

Get the car aligned! Also check carefully for any play in the bushings and ball joints, as excessive wear in these areas will make alignment an exercise in futility, as the settings won't hold true due to excessive suspension free play.

 

You'll learn if you stand there with him and watch and ask questions. Most of the wheel alignment places I've been to are hopeless, so you'll be struggling to find a good one, so ask around. There's NO WAY you can start removing shims to change your camber without affecting toe as well...so unless you know what you're doing, know how to setup to check toe AND camber AND know for sure that your floor is flat (which is unlikely) take it somewhere good for the work to be done properly. Sounds like you have no idea what the toe is at the moment anyway.

 

Take it to the F-car dealership and have the tech that works on the 355 Challenge cars do your alignment. While you stand there and watch you will be able to answer all the questions the tech will have as to how you want the car set up. This will take some time, however. Don't rush it. It took 4 hours to set up my car the way I liked it and it was WORTH IT.
Heck, they are going to need a weight in the driver's seat, so it might as well be you!

Incidentally, I had the same wear pattern, driver's inside rear showing cords, other side showing rather normal, but negative camber, wear.

Let us know the remedy.

Pino

 

In my case, too much toe-out ruined the inside of the R/R tire. It also caused the car to veer to the right as it crested over hills. Weird sensation.

My car still had all of the factory "hash marks" on the shims and bolts indicating that it had never been touched since it left the factory. The bushings shift/wear as the car encounters road irregularities causing the alignment to go out of spec. (So I was told, anyway)
Yes, they can set it to factory tolerances, or move it around to reduce tire wear (to certain point, of course) while still maintaining some decent handling, or you can go balls to the walls (tire wear be damned!) for that slot car-like feeling.
I went with the former, and was still mightily impressed with the changes (for the better) the car received when all 4 wheels were going the right direction.

I hope that info helps,
Pino

 

Merdave,

I spent many hours adjusting the suspension of my 355. It started adjusting because of too much inside rear tireware. Then new tires made my car twitchy, then I almost killed myself driving to fast around curves. Mitch Alsup really help me in this thread:

http://ferrarichat.com/forum/showthread.php?t=13258&highlight=355+alignment

Basically I found a shop that had modern alignment equipment. The shop insisted I sit in the car with a half a tank of gas and then attached devices to all 4 wheels and did the alignment using a computer.
My current settings are:

Left Right
Front Camber -.6 -.6
Front Caster 7.1 7.0
Front Toe .01 .01
Rear Camber -2.3 -2.3
Rear Toe .01 -.01

Which are just perfect for my car.
--tony

 

If the excessive tire wear is smooth it is camber relatated. If it is featrhered it is a toe in/out issue ( or both could be out of whack).

The ride height must be set FIRST to get the car properly aligned. The ride height will affect the camber setting.

Camber is the inward/outward tilt of the wheel at the top. Caster is the forward/backward tilt of the wheel at the top (viewed from a side angle). SAI (Steering Axis Inclination) tells you if any of your compents are bent. The car will pull to the side with the most negative camber or positive caster.

Regretablly, there is no way to get the specs in tolerance without using an alignment rack.

Also, with an Independent Suspension, at rest (versus on turntables) the wheel will actually be more bowed in (positive camber) then when driving.

 

Interesting, why is this?

 

The rear end of an Independent rear suspension squats under toruqe. Remeber the old VW Bugs when viewed from the rear. The wheels were bowed less as the car accelearted.

The turntables on the aligment rack allow the tires to move outward on the contact patch as it is similar to your car moving down the road versus static at a stand still.