CDI Tire Wear Question
 

When I bought my CDI, the PO had fairly new rear tires and good condition but older front tires. I had snows on for the winter, so when I installed the summer tires I rotated the ones in the rear to the front. The newer tires have 9/32 tread depth and the older ones 6/32. My assumption was that the fronts would wear faster and thus I'd be able to even out the wear.

Out of curiosity I asked the PO about buying two tires instead of four, and he said it was because of the rear tires wearing out faster (I guess he hadn't rotated as much as he might have).

I realize that the drive goes to the rear wheels...but it still surprises me that the fronts wouldn't wear out more quickly. Any of you CDI owners notice anything by way of wear patterns?

Someone's enjoying the torque :)

Sixto
83 300SD

Just so you know, you're always supposed to have the tires with greater tread on the rear axle.

Under normal driving, the fronts should usually wear out quicker than the rears.

Either rear suspension components are worn out or as suggested, PO was enjoying the torque in the CDI. Are the rear tires cupped by any chance?

True....but I'd also like to even out the wear.

On my 05 E class wagon I typically will put a new set of tires on the back and move the ones that have worn down approximately 1/2 way to the front. Then when the front ones are worn move the rear forward and repeat. I am of the opinion that tires are cheaper and last longer on the 98 E300.

W211 eats tires for a living, especially if alignment is bad or ball joint is worn. Doubly more so for the CDI, since it has so much torque.

I have put 10K miles on the tires which were fairly new and found no strange wear pattern at all. They are wearing evenly and slowly.

I am of the opposite opinion- you want the tires which do the primary braking and steering to be the best you have- so the worse tires go on the rear. You can always speed up slower- but when you need to brake more quickly you want the best tires.

Well, that sounds like you have excellent alignment then.

Rear wear out is usually due to negative camber, or incorrect toe. In extreme case, can be affected by a shock like hitting a pothole or curb, in which case can affect the alignment.

Furthermore, if your car has airmatic (not sure CDI came with airmatic as standard), putting it in Sport II mode will wear out the tires faster.

On rear drive cars I've had, the front and rears generally wore at about the same pace unless I was driving like a jackass.

The rears wear out faster, and the right rear faster than the left rear.

It's annoying running directional tires, which means I'm throwing out a tire with tread left in the name of replacing in pairs, cause I can't rotate them side-to-side.

Looks like I should probably put the good tires back in the rear, rotating left to right.

I almost always wear out the rear tires faster. :D Whats the point in having 200+ hp if you're not using them all! :D

The tires with the best tread go in the back. The front wheels have the engine pressing down on them, and they are able to steer. Tread creates inherent "wiggle" in handling, and it's undesirable. The lower the tread, the lesser the wiggle. If you are on the edge of hydroplaning, you'll be able to steer the front wheels info the skid. If the rears lose grip, you're along for the ride.

I understand your reasoning, but test after test have shown that the best tread in the rear has provided the best handling and safety. Hope that explanation helps.