front/rear track & spacers make a real difference

[98c43amg]

Just thought I'd share with all, wheel offest, how that affects the front and rear track in relation to one another, and subsequent use of spacers really do make a =big= difference in handling.

The story.... The C43 comes with a staggered setup, rim widths 7.5" up front 8.5" rear, offsets 35mm & 30mm respectively. For the winter, I bought OZ superlegerra 8"wide rims for the Nokian RSI snow tires, 35mm offset, for both front & rear. Stock, the C43 (and all W202s?) already have a wider track in the front then the rear. With this wheel+offset combination above both for both front & rear:

- The front wheels now extended +6mm out from the axle, making the overall front track +12mm wider.
- The rear wheels retracted in towards the body by -11mm, reducing overall track by -22mm.

The result of all this was the car was basically squirrly, for lack ot a better way to put it, on turns with a very easy tendency to oversteer. That would kick in the ESP, that in turn causes the blood presure to rise (frigg'n overly anxious ESP/ASR ;) ). I thought it was the tires ... but also knew I'd screwed up the track, so thought I'd address that.

I had 10mm hub-centric spacers made for the OZ rims and had them put on the rear wheels yesterday (wish I did 15mm now) ... and low and behold, my car's handling is "fixed"! :p Whew.

The affect the 10mm spacers had on the handling of the car was so noticable and positive, I'd thought I'd let you all know how well it had worked for me in case anyone else is in the same situation.

[Pagz]

hey man thanks for the info...
im having spacers made to suit my milanos as we speak..
my current rear track is about 24mm in total less than the front!!...
i told them too make 5mm spacers.....but i can see it needs to be more like 10!!.......

Rgrds,
Paul

[jstrat85]

you see i lowered my car 1' in the back and i have 18's on and i wanted to do a spacer in the back but i feel like its going to rub? what do you guys think?

[98c43amg]

Originally posted by jstrat85
you see i lowered my car 1' in the back and i have 18's on and i wanted to do a spacer in the back but i feel like its going to rub? what do you guys think?

Gotta know the wheel width, wheel offset & tire size to have an idea.

[98c43amg]

Originally posted by 23K
my current rear track is about 24mm in total less than the front!!

Just wondering, rear is 24mm less when measured currently, or less then it was stock?

Stock, the C43 has a track of :

Front track 62.6 in/1,590 mm
Rear track 58.4 in/1,483 mm
(almost 100mm less in the rear)

Stock C280 has a track of:

Front track 59.5 in/1,505 mm
Rear track 57.8 in/1,469 mm
(about 35mm less in the rear)

So if I hold the front track constant to stock, do you mean your rear track is 1445mm or 1481mm?

Meaning, if you have a 230K and you're 24mm less in the rear as measured, it's actually 11mm wider now then it is when stock. So I was just wondering which you meant, 'cus if you meant as measured today, adding spacers in the rear might perhaps increase understeer if you go even wider with the rear.

(...just surmising that is... since as it reduced/removed oversteer for me when I went wider in the rear from when it was way too narrow ... I'm thus just assuming it could increase understeer if you went in the other direcction and went too wide in the rear in relation to the fronts ... it could very well be wrong of me to make that assumption.)

[Pagz]

Originally posted by 98c43amg
Just wondering, rear is 24mm less when measured currently, or less then it was stock?

Stock, the C43 has a track of :

Front track 62.6 in/1,590 mm
Rear track 58.4 in/1,483 mm
(almost 100mm less in the rear)

Stock C280 has a track of:

Front track 59.5 in/1,505 mm
Rear track 57.8 in/1,469 mm
(about 35mm less in the rear)

So if I hold the front track constant to stock, do you mean your rear track is 1445mm or 1481mm?

Meaning, if you have a 230K and you're 24mm less in the rear as measured, it's actually 11mm wider now then it is when stock. So I was just wondering which you meant, 'cus if you meant as measured today, adding spacers in the rear might perhaps increase understeer if you go even wider with the rear.

(...just surmising that is... since as it reduced/removed oversteer for me when I went wider in the rear from when it was way too narrow ... I'm thus just assuming it could increase understeer if you went in the other direcction and went too wide in the rear in relation to the fronts ... it could very well be wrong of me to make that assumption.)

hmmmmm....your probly right......
my setup is et35 front,et40 rear,i was adding 5mm spacers to make the rear et35 so the setup was stock....
so your saying going too wide or past the stock rear track could induce understeer??

Regards,
Paul

[98c43amg]

Originally posted by 23K
hmmmmm....your probly right......
my setup is et35 front,et40 rear,i was adding 5mm spacers to make the rear et35 so the setup was stock....
so your saying going too wide or past the stock rear track could induce understeer??
Regards,
Paul

I am saying that, using reasoning based on the observation I had with using my spacers ... but I'm not saying that's necessarily a trueth ... just surmising it might.

I did a search on your handle and found your specs in the "23k ... so far" post:
goodyear eagle 235/35/19 on 8.5x19 ET35 front
goodyear eagle 245/35/19 on 9.5x19 ET40 rear
(looks real great btw!)

your car came with 7" rims and had a 35mm difference in front/rear track (I'll assume the rims had a 35mm offset too) ... So now if I use the online offset calculator... (I'll ignore where the wheel ends on the inside since I don't think it factors in as much as how wide the track gets)

8.5x19 ET35 front :
The clearance from strut housing to the inside of the wheel will be 19mm LESS
The outside edge of the wheel will EXTEND an extra 19mm

9.5x19 ET40 rear :
The clearance from strut housing to the inside of the wheel will be 37mm LESS
The outside edge of the wheel will EXTEND an extra 27mm

So your front track is currently 38mm wider in the front then stock, and 54mm wider then stock in the rear, reducing the difference by 16mm. So ya, if you're adding spacers to the rear, you're moving even farther away from the rears being around 100mm narrower, the way the AMGs are set up.

But to be quite honest, I have no idea if that'll indeed induce understeer, or if it does, that it can't be "tuned-out" with an alignment. I'm only surmising it might, based on the observation I had with how big a difference in handling I had going from a 141mm difference to a 121mm difference in track (where a 107mm difference was stock)... and figuring AMG went with such a narrower track in the rear for a reason, as it noticably affects the balance of the car.

[jstrat85]

18 by 8.8 all the way around and 225/40/18 in thefront and 245/40/18 in the back.

[98c43amg]

Originally posted by jstrat85
18 by 8.8 all the way around and 225/40/18 in thefront and 245/40/18 in the back.

Did you mean 18 by 8.5? You didn't mention the all important offset, and the size of the spacer. But unless you're running rims with the offset in the 20's, I sure don't think you should have a problem with what I see everyone running here. The AMG comes with a 8.5"- 30mm offset rim stock in the rear, and it has room to widen the track with that. Plus, your rear tires aren't too wide either.

[SLAMMED_C]

hmmmmm....your probly right......
my setup is et35 front,et40 rear,i was adding 5mm spacers to make the rear et35 so the setup was stock....
so your saying going too wide or past the stock rear track could induce understeer??
Regards,
Paul

By the looks of your pics.. I dont know how much more you could go further out since the wheel is pretty flush with the fender as is.. maybe 5mm more.. but even still is there going to be enough clearance when you drop your ride?

[jstrat85]

i was thinking a 5mm spacer? i want it to be flush with my fender.

[Pagz]

Originally posted by SLAMMED_C
By the looks of your pics.. I dont know how much more you could go further out since the wheel is pretty flush with the fender as is.. maybe 5mm more.. but even still is there going to be enough clearance when you drop your ride?

Hey,
Yeah there is more room than it looks....at the moment the inner of the wheel rubs on the plastic lining when i take corners hard...
last time i check there was about 10mm gap between the face of the wheel and guard,so i will stick with the 5mm spacers to correct this,and hopfully it all handles well!!....

Rgrds,
Paul

[Pagz]

Originally posted by 98c43amg
I am saying that, using reasoning based on the observation I had with using my spacers ... but I'm not saying that's necessarily a trueth ... just surmising it might.

I did a search on your handle and found your specs in the "23k ... so far" post:
goodyear eagle 235/35/19 on 8.5x19 ET35 front
goodyear eagle 245/35/19 on 9.5x19 ET40 rear
(looks real great btw!)

your car came with 7" rims and had a 35mm difference in front/rear track (I'll assume the rims had a 35mm offset too) ... So now if I use the online offset calculator... (I'll ignore where the wheel ends on the inside since I don't think it factors in as much as how wide the track gets)

8.5x19 ET35 front :
The clearance from strut housing to the inside of the wheel will be 19mm LESS
The outside edge of the wheel will EXTEND an extra 19mm

9.5x19 ET40 rear :
The clearance from strut housing to the inside of the wheel will be 37mm LESS
The outside edge of the wheel will EXTEND an extra 27mm

So your front track is currently 38mm wider in the front then stock, and 54mm wider then stock in the rear, reducing the difference by 16mm. So ya, if you're adding spacers to the rear, you're moving even farther away from the rears being around 100mm narrower, the way the AMGs are set up.

But to be quite honest, I have no idea if that'll indeed induce understeer, or if it does, that it can't be "tuned-out" with an alignment. I'm only surmising it might, based on the observation I had with how big a difference in handling I had going from a 141mm difference to a 121mm difference in track (where a 107mm difference was stock)... and figuring AMG went with such a narrower track in the rear for a reason, as it noticably affects the balance of the car.

thanks!...
and thanks again for the info...
well i guess if the AMG's are set up this way there must be some good reason for it!!.....

also.....i read somewhere that having the rear track smaller than the front aids aero dynamics and therefore fuel economy??...

Rgrds,
Paul

[98c43amg]

Originally posted by 23K
also.....i read somewhere that having the rear track smaller than the front aids aero dynamics and therefore fuel economy??...


interesting. I hadn't heard that yet but I'll take your word for it.

-steve

[Pagz]

Originally posted by 98c43amg
interesting. I hadn't heard that yet but I'll take your word for it.

-steve

lol yeh im not sure weather its true or not either.....just remember picking it up somewhere.....

Rgrds,
Paul