SL350 2009 - Wheel offset / tyre wear. Looking for advice.

[sausage]

19 inch wheels on a 2009 SL350.

A trip to my local indy raised the suspicion that my wheels have an incorrect offset. The wheels do not seem to be "SL" wheels according to the indy.

I have had a look through my manual, and the long exhaustive website that lists possible offsets here: https://www.alloywheelsdirect.net/information/fitting_chart/mercedes-benz.

During MOT last week it came up that my rear tyres are wearing unevenly, mainly the extreme inner edges. I saw extreme, because my 911 used to do this regardless of whether the full 4-wheel geo had been set up a day, a week, a month or a year earlier. It just did that and always did it. I assumed heavy engine over rear tyres and heavy right foot - the rear of a 911 squats down under acceleartion - and so presumably affects camber and causes a slight "in" at the top of the camber causing more wear on the inner sides.

However the SL is wearing the inners out far more than the 911 did, in fact 98% of the width looks to be 5-7mm whereas the extreme inner is severely worn. Yes they are the cheap tyres the dealer sold the car with.

Having seen an identical 'looking' set of wheels on ebay I suspect I might have these:

Manufacturer Part Numbers as I can tell: A2184011602 & A2184011702
I think they are CLS AMG 19'' for W218 & X218 Models

Front 8.5J x 19 ET 34.5
Rear 9.5J x 19 ET 48


The SL owners manual states the offset should be:

"Mixed dimensions" - which I do have, specifically 285 rear and 255 front.
Front ET35
Rear ET40

Or "AMG equipment" 285 & 255
Front ET30
Rear ET31

My thoughts:
1) Does it matter? How do I find out for sure.
2) No point in having a 4 wheel alignment if the wheels need to be changed.

Any comments or advice please?

Thanks
Mark

 

[JBell]

The offsets on your wheels are not that far off to affect the tracking that much.

I wouldn't worry about it but I would have Hunter alignment done

 

[sausage]

Thanks for the vote of confidence I will look into Hunter alignment and who can do it locally.

This morning I joined a SL350 group on facebook and already I have found someone there has an earlier 350 with the same wheels. They used 25mm spacers on the rear. I have never used spacers before, but am now considering them.

 

[JBell]

Thanks for the vote of confidence I will look into Hunter alignment and who can do it locally.

This morning I joined a SL350 group on facebook and already I have found someone there has an earlier 350 with the same wheels. They used 25mm spacers on the rear. I have never used spacers before, but am now considering them.

Would go for a DRA fitment (bolt on) will be a 50mm kit, Use H&R, I will look for the part No later

 

[NJS5]

Don't forget to advise your insurers if you have non-standard wheels and/or spacers.

NJSS

 

[KennyN]

Thinking out loud , how will pushing the wheels outward with spacers have any impact on inner tyre wear ?

With the severe inner wear you describe does that not point to more of a negative camber issue , something that wont change by moving the wheels outward as the camber will still be the same.

K

 

[LostKiwi]

My SL500 uses 19s and has no issues with inner tyre wear.

My rims are these:

19" AMG IV 2pc wheels in 9709 Sterling Silver - Alloy Wheels Direct (58289)

Buy 19" AMG IV 2pc wheels in 9709 Sterling Silver for your Mercedes SL Class R230 Roadster. Worldwide Shipping from Alloy Wheels Direct (Part No. B66031092 & B66031093)

www.alloywheelsdirect.net

I would suggest you have an alignment or bush issue thats causing excessive wear.

 

[sausage]

Thinking out loud , how will pushing the wheels outward with spacers have any impact on inner tyre wear ?

With the severe inner wear you describe does that not point to more of a negative camber issue , something that wont change by moving the wheels outward as the camber will still be the same.

K

I might be wrong, but I believed the advice for spacers was to correct the offset, not remove the wear.

 

[JBell]

I might be wrong, but I believed the advice for spacers was to correct the offset, not remove the wear.

The H&R part no is 50556651, this is for a 50mm DRA Kit (2 x 25mm) for 14mm Bolts, Hubcentric

 

[sausage]

My SL500 uses 19s and has no issues with inner tyre wear.

My rims are these:

19" AMG IV 2pc wheels in 9709 Sterling Silver - Alloy Wheels Direct (58289)

Buy 19" AMG IV 2pc wheels in 9709 Sterling Silver for your Mercedes SL Class R230 Roadster. Worldwide Shipping from Alloy Wheels Direct (Part No. B66031092 & B66031093)

www.alloywheelsdirect.net

I would suggest you have an alignment or bush issue thats causing excessive wear.

Thanks. My concern was solely on the mis-matched offset. I am not sure if your wheels match the approved offsets - I imagine they probably do knowing you they are very nice wheels.

As advised by Jbell - I will be looking for a Hunter 4 wheel alignment. It is having a re-test MOT as I write, then a service and at that time I will talk to MBAutomotive, Loughborough about the alignment and offset. Hopefully it is just a case of doing the alignment.

As a word of caution.
Porsche 4 wheel alignment requires a certain brand of alignment machine. They are not cheap. My car had just been done at main dealer. A month later I took it to the Centre Gravity clinic - they run a day in January where you can have a free health check of all running gear/suspension etc. It is a good day, coffee, bacon rolls and lots of people from the Porsche forums that one has probably met before. They checked my car, told me I had a "fast road setup" and showed me all the data. I was surprised as I had just paid Porsche £140 to do it. Centre Gravity are THE UK outfit for having one's 911 set up properly and the community swears by them with people coming from all over the country to pay lots of money for a Centre Gravity set up.

I ended up in a row with the dealer principle where my geo had recently been done. Eventually he acquiesced that Centre Gravity were not some back-street chop-shop and yes they did have the correct tools and machines to do a proper check. He agreed to double check my car.

My car was EXACTLY set to factory specifications.

The rear tyres still wore unevenly. BUT, the main moral of the story is that two "expert businesses" with years of experience did not agree on the setup of my car. I will never know the answers to this and there is no point to-ing and fro-ing over the ins and outs of it, it happened, it was years ago. But absolutely 100% two experts with identical machines completely disagreed, FOR MONTHS about the car. Typical that the customer gets caught in the middle of a situation like this.

Regardless, I will be getting my 4 wheel alignment checked and adjusted. If anyone knows of a Hunter service near the Leicestershire Rockies (Charnwood), that would be appreciated.
Cheers
Mark

 

[LostKiwi]

Thanks. My concern was solely on the mis-matched offset. I am not sure if your wheels match the approved offsets - I imagine they probably do knowing you they are very nice wheels.

I believe they are the SL65 19" setup - they were fitted by our greatly missed Television (aka Malcolm) as it was his car.