That's what I did

 

I just replaced all four tires. I had been using Hankook Ventus V12s and got about 10k on 2 separate sets of 275s on the rear. Not great but still better than the 6K I got out of the OEM Pzeros. I don't drive it hard with only the occasional hard corner or launch but deinitely not melting them at every stoplight so I was kind of disappointed I was still only getting 10K out of thrm.....but since I was getting them for about $150 a pop installed (buddy runs a tire store ) I guess i can't complain too much. Unfortunately his shop is not a Michelling retailer so I couldn't get the sweetheart deal on the PSPs. Just installed them yesterday and considering whether I should adjust the alignment as described here. For those of you with PSPs, what is the mileage you're getting out of the rears? I guess it's a cost benefit thing. If I'm going to have to drop $200 for an alignment job to get 30% better treadwear I guess it's a wash.

 

I put less toe in and got amazingly great wear on my C63 ( OEM) sizes and I am lowered in H&R coilovers.

 

You guys who are reducing toe-in in the rears, are you also reducing fronts? Is it necessary?

Whats the best compromise for good tyre wear while retaining some of the current setups direct cornering?

 

I ended up keeping all stock settings except for rear toe in which is now zero. I don't push my snow tires too hard so I can't tell any difference so far. I'll give an update once I get a few miles on it...

 

I left the front at whatever the stock spec is.

 

I have got mine in for an alignment today. I asked for minimum toe (0.28) on rear only. I was advised the fronts should also be done if the car is to be set up correctly.

Also asked about Neutral Toe. Was advised that on acceleration the rear wheels will flex outwards thus resulting in positive toe, upsetting the cars direction of travel. I figure MB have gone to a lot of trouble with their car setups to get them right hence I will stick with their minimum settings to maximise tyre life and hopefully not dramatically ruin the cars cornering balance.

Will report back here after I have had a chance to see how it drives.

 

I have had a good week of driving and can report that the new set up is very good. The tyre tech did not touch the front toe at all. only the rears which were set to 0.28. The shop owner said the fronts would have to be adjusted as well however the guy who did the work said that was not correct.

The car now has different driving characteristics. Its a little more skitty over bumpy roads on very hard acceleration from a dig. It jumps around a little more than before but hardly a problem. On smooth surfaces there is no difference.

On the highway at speeds the car used to "walk" a little over bumps like it was hit by a cross wind. It does not do this any more.

On my favourite sweeping corner the car seems to be faster. Maybe its that its more predictable and I am confident pushing a bit harder. Its very progressive and has lost the "snap back" characteristics of the old set up on the limit.

In summary I'd say the new set up is better than the old and will obviously give much better tyre life. The only negative is the walking on uneven road surfaces on hard acceleration from a dig. Its nothing to really be concerned about but I think setting the toe a degree or two more (0.29 - 0.30) would probably fix this while still improving tyre mileage.

Cheers

 

I had my toe-in set to neutral (rear only, front is stock) and have had my summer tires on for about a week. So far, I see minimal difference from the stock setup. This morning I took the long way into work which has several twisty-curvy roads and places to accelerate hard and the car feels fine.

My gut tells me that the rear end may not be as planted as before but it is very difficult to quantify this due to all of the variables (temperature, moisture, road conditions, etc.). If I had it on a track all of the time I could see staying stock and sacrificing tire life. I would rather have a bit more oversteer (which is my goal half of the time anyway...) and feel less guilty about the occasional wheel spin since I know the tires will last longer.

Going forward I will advise of any issues but for now I say, sever the toe!

 

can anone confirm these factory alignment specs are accurate for non black series C63 (maybe p30/p31 too?):

Camber: -1 to -1.8
Toe: .08 to .25

REAR (PER SIDE):
Camber: -.9 to -.1.9
Toe: .28 to .52

based on this and the responses so far I'll prob leave front untouched and only set the rear toe to .28.

 

Wow this thread is still going? LOL. Glad I am hearing some positive things from you whom have reduced their rear toe!

Unfortunately I can't give much feedback about wear still, Car only has 3200 miles lol. Dang garage queen!

 

YES. That is exactly the factory specs according to Hunter.

The front is fine left untouched. It doesn't wear tires much. It really depends on your driving style.

The less rear TOE is what helps wear. I will tell you the less you go tho, the more oversteer you will have. I will not tell you guys what mine is set at because it is crazy sensitive to oversteer now and if you're not use it steering with the rear wheels, it's not a good thing!

I will tell you tho I am WAY out of factory specs with regards to rear toe

 

keep in mind the actual specs change depending on the ride height of the vehicle.

 

I have the Yokohama advan sport stock tires and have 12.2k miles on them and going strong. I don't drive like a Rhys Millen wannabe but I'm not babying them either.

 

I just sold my 04 Cobra which had an independent rear suspension, "for a short time", but the tires just simply don't sit perpendicular to the road surface causing the inside of the rear tires to take a lot more abuse than the outers. After swapping to a build solid axle rear in the cobra the straight line traction, and the life of the rear tires went up considerably, same motor / trans, with lower gears in the carrier, compared to the original irs in this car I'm speaking of.

 

are you implying that the LSD can improve wear life? that would be interesting to know

 

No, I swapped out the entire Independent rear suspension for a built up solid axle. But if you were wearing one tire more than the other, I would say so about the LSD being able to help.

 

Is .28-.52 talking about fractions on an inch? Here in Oz we call camber the same at Degrees but toe is measured in mm(millimetre) Or better put what does .28-.25 equate to in mm for any Oz blokes that have aligned?

 

would like to know 2 getting an alignment next week thanks

 

Not to get too far off topic, but does the toe spec change for different wheel diameters? It seems like a 17" wheel would have a larger toe angle than a 20" wheel with the same number of inches of toe . . .

 

Toe is the angle by which the wheels deviate from the driving direction. All other things being equal, it is not going to change no matter what you do with your wheel size.

 

Diabolis - toe is NOT an angle - it's a distance, measured in mm or inches. You calculate it by running a string parallel to the centerline of the car, and then you measure - perpendicular to the string - from the string to the front of the wheel and from the string to the back of the wheel. The difference between these is the toe.
For two different size (diameter) wheels at the same toe angle, the larger diameter wheel seems like it should have a larger toe measurement. I've never looked closely at manufacturer's alignment specs - do they ever reflect this?

 

Guys I am new to the C63. In fact I haven't even gotten it yet. It's still at the shop getting ready for delivery. I ended up with a 2011 C63 with the P31 package. So I've been reading everywhere that it burns through tires very fast so naturally I am interested in prolonging their life as much as possible.

Someone mentioned toe settings to me and none of that stuff makes any sense to me at all. i guess all I would like to know is that what should I ask the people at the wheel alignment shop when I take it in? My goal is to prolong the tire life as much as possible. I have no idea what toe to ask for me. Someone mentioned ask for a 'neutral' toe, but I am not even sure what that means.

I would greatly appreciate some advise and help on this guys. Thanks a ton!

 

Toe is measured in degrees on every single alignment machine I've ever seen, however, what you are describing is also true. What you're not accounting for is that when you measure your toe in millimeters (or inches) you need to account for the radius of the wheel. The larger the wheel, the higher the difference between the string and the front and rear of the wheel respectively, but when you divide by the wheel size you'll always end up with the same angle. A larger wheel will only give you a more accurate measurement if you use your method, but you'll always end up with the same toe angle.

As an analogy, imagine an LP record on a turntable - if you put a dot at the outer edge of the disc and one close to the center label, the linear speed of the dot on the outer edge will be greater than the one on the inside, but both of them are turning at the same angular speed of 33.3 RPM.

While I know that the string method was used in the past, the relevant parameter is always the angle, not the actual distance (which would indeed vary based on the size of the wheel and is thus meaningless).

 

Unless you're a serious racer and need to modify the geometry of the car in order to suit the vehicle's dynamics and a particular race track or driving style, I would keep the toe angles at exactly what the engineers at MB determined is the best compromise between tire wear and safety, which is what it all comes down to at the end. Yes, zero toe will result in no tire scrub and thus less wear, but it will also affect the handling characteristics in a way that may be less than ideal for normal driveability.

There was a good article on camber/caster/toe and their effects on car dynamics in Grassroots Motorsports magazine some time ago, but I would have to go the basement and search through boxes of dusty magazines to find it, so Google is probably a better choice. Besides, I am sure there are lots of other excellent articles on the web that explain the concept.

As for my $0.02, unless you're prepared to assume the risk that your car may oversteer when you're not expecting it and that you know how to correct it (or you're going to spin), I would leave the toe at the factory settings. The engineers at Mercedes-Benz have spent a lot of time figuring out what are the correct toe values for optimum handling.

And, I have to ask here - if tire wear is an issue, why would you guys buy a C63 in the first place? I mean, I am running lots of negative camber on the P-car so that it corners better at the track, but that chews up the tires even more, which I am happily willing to accept. The way I see it, it's like complaining that the C63 is a gas guzzler. If gas consumption is an issue, you should probably be looking at a Prius, not how to make it use less gas by disconnecting two of the eight fuel injectors and running on six cylinders. Not trying to start a flame war or anything - I am just curious about the mentality. Getting more performance at a greater expense, sure - but getting less performance or a narrower safety margin as in this particular case to save a couple of bucks is not something I can understand.