Do I need to get an alignment after changed wheel sizes?
 

going from 15 to 18s... not sure why I would, but I just wanted to make sure...

On the C230 I went from 15's to 17's and back to 15's without an alignment. Seems to be fine...

Just to be on the safe side, I would align the car after upgrading to 18"s.

Although, are you really shure you want to do that??? The ride will suffer inmensely.

A. Rosich
S320, 1998
E320T, 1995

The alignment should be the same, though those low-profile tires will be far less forgiving if your alignment is a bit off, or any related steering/suspension components are worn.

alright, well here is the deal, I just put on lowering springs and bilstein sports, so my car needs an alignment. Im not driving much, so I guess ill just wait untill the new wheels arrive.

I understand about the ride quality, but im young, and a stiff ride doesn't bother me at all...

The wheels won't change the alignment but they will change what the specs should be. In the end the guy doing the alignment better have a good idea.

In the long run alignment specs will have to be developed to deal with what you have done. I would suggest a few extra millimeters of toe based upon the direction everything moves under the extra loading. Those can be applied now or later.

Alignment specs are designed to allow stationary measurements that result in the proper position during loading. By altering the suspension factory specs no longer apply; but won't be changed when the tires og on.

thanks everyone. Right now im looking at 3 different alignment places. There is the dealership and two independant places. Both the independent places have another entity do the alignment. One shop is Ben's Workshop, a higly reputed establishment that has been around for years, and my mechanic, a mercedes fiend who has been working on my car since I got it and who I trust a lot. So I don't really know where to go... is there something in particular I should be looking for (i.e. some type of machine etc.) I would think the dealership would be the best, but I don't know how they would handle the new specs for the alignment and the price would obviosly be higher...

Yeah, go to a shop that uses the Hunter GSP9700:

http://www.gsp9700.com/

All of the dealers use them, and many independent tire shops do, too.

Click on the link for 'locate a GSP9700', enter in you city, state, zip code, the distance to search from your location, and you should get a nice list of shops.

I also recommend calling several shops for quotes. The pricing i got was all over the place, from $12 / wheel to $40 / wheel.

FWIW, my local MB dealer charged me $14/ wheel.

thanks a bunch!

My local dealer charges me only $90 for a full 4-wheel alignment. If it's not right, I get to take it back for FREE.

Also, get it aligned with the stock wheels & tires if possible (assuming your wheels are true, and your tires aren't badly or unevenly worn).

Make sure they get their BEST person to do your alighnment- remember it's not the equipment, but the operator. An excellent tech with string and chalk will do better than most who just "set the toe and go".

Also, make sure they give you a printout of the specs before and after. Also, if there are SportLine alignment specs for your chassis, get those, since you lowered and stiffened your suspension and are going to extrememly low-profile tires. They should also use the proper spreader-bar for proper toe set.

I've tried two alignment shops who have received glowing testimonals, but when it comes to Mercedes, they just don't do enough and have the experience.

My dealer does THE BEST PERIOD.

:-) neil
1988 360TE AMG
1993 500E

Neil, why should I have the alignment done with the stock wheels? Because the proper numbers are available for the stock wheels? Thanks.

Yes, the alignment numbers are setup for the stock wheels and tires. Try to get as close as to the factory setup as possible.

I have a set of 215/55R16 tires & wheels for the wagon that I use for SportLine alignment and when I go to my 225/45R17 tires & wheels the setup is perfect.

It just doesn't work the other way around.

:-) neil
1988 360TE AMG
1993 500E

right... see, I didn't know how the alignment business works, so I was assuming they "tuned" the car to the proper adjustment by "feel" rather than by numbers. But now I know better! So I will schedule an appointment with the dealer (also a highly reputed place with great service...and the proper machine) and ask them to set it up to sportline 300E specs. One last question... would the dealership have the sportline specs handy? Is there a place where I could print them out for their use? Thanks!

What should I say?

All I can say is if I read this thread and knew nothing about what was being said, I would be full of the wrong impressions.

Neil, had it right about the tech doing the alignment not a machine. But he has it wrong about how specs matter and what to do with them. if you want your car to drive right there IS NO spec to accomplish this. This is where the tech comes in. It is his responsibility to read the handling and the numbers and figure what to do. IFFFF he does this within someones factory specs.... great for him.

The actual readings will not change with your wheels. What changes is how your car reacts. The car NEEDS to be aligned with the tires that ones wishes to drive with. If the settings happen to work for driveablity with different tires , they should. BUT, tires make the car. The ones you are going to use are going to make the car ride like crap. They will have so much influence over the handling that the only hope for correction rests with an experienced MB/alignment tech. One whose shop is situated where he can do at least a 60mph road test before and after.

This goes for any alignment shop. If they are tight,in a city situation,that prevents proper road testing, they will not do the road test. One doesn't become good at aligning cars unless road tests before and after form the basis for your experience.

If I were chosing I would place the Alignment first in the term MB/Alignment tech. An experienced alignment tech will do better with whatever he aligns than a less experienced tech. Having ones experience be with MB finishes the deal, but given a choice between either factor I take the alignment experience to be more important than the MB experience.

Steve- is correct in his clarification. The "number" the factory gives is a range. Just setting it to any value in the range, doesn't mean the car will react the way you want it to.

My local MB dealer alignment tech (he does 99% of all MB alignments at the dealer), does at least 2-test drives (freeway on-ramp right next to dealer) and hence two-setups to "tweak" the alignment just right. He even calls me for a final test drive including a freeway jaunt upto 75 MPH, to make sure I'm satisfied.

$90 for 2.5 hrs work, I'm very happy.

:-) neil

Steve,
Back to the original question for a moment...
I am indeed confused.
I can see why the lower springs could influence the desired settings, such as the toe or perhaps the camber, but why would the wheels/tires themselves be a factor at all?

As I will now state for the third time, wheels and/or tires DO NOT affect the numbers on the machine. If it was at 3mm toe with one tire it will be the same with another.

The point is that changing tires changes the loading during driving. The specs that are given are a compromise designed to apply settings in a motionless state that will place things correct when driven. that is why the toe spec will have one set the front toed in. As the car drives down the road the rearward force deflects all the suspension pieces rearward. This makes the car pull itself relatively straight even though it were set toed in. Placing larger more agressive tread changes the relationship between motionless and loaded. This requires new specs. They aren't in a book they are the result of experience and observation. Its the reason all these huge tires wind up with inside tire wear. They were set to specs but in actual driving the real alignment winds up toed out under the heavier load.

Thanks Steve.
I actually get it!
That clarification was very helpful.

yes, thanks a bunch steve! This is all making sense now...