Author Topic: Zero offset steering on W116 - and what about wheel offset?  (Read 8118 times)

s class

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Hi guys,

I have a 1980 W116 280SE.  It has the standard 14" Bundt alloys with Bridgestone Turanza GR50 in 205/70HR14.  The handling is really excellent.  In fact, it is my favourite car and is responsible for turning me into a total W116 fanatic.

For the sake of appearance I would really like to fit my nice set ot 15" Bundts that I have been searching for for years.  But they have an ET23 offset.  THis seems to make the centre of the tyre stand outside of where it is with the original wheels.  I am currently refurbishing the 15" wheels, but before I started I tried them on the front with some old tyres and the handling wasn't very good.  The car kind of wasn't sure which side it wanted to pull to first.  I'm sure the wheel alignment was not bad at all.

I assume zero offset steering is only zero offset if the wheels have the correct offset?

What offset should I have on W116?  I presume it is greater than ET23.

Any comments appreciated,

Thanks, Ryan in South Africa

'76 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '82 500SEL euro full hydro, '83 500SEL euro full hydro , '81 500SL

John Hubertz

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Re: Zero offset steering on W116 - and what about wheel offset?
« Reply #1 on: 24 March 2006, 06:57 AM »
Ryan - pop over to the m-100 forum and post this question.  Those guys know their 15" bundts like no other group. 
John Hubertz
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1977 450SEL (Max Headroom)

Mforcer

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Re: Zero offset steering on W116 - and what about wheel offset?
« Reply #2 on: 24 March 2006, 12:25 PM »
I did a lot of research into rims when I was looking at replacing my original steel rims. Here is the thread with some of my thoughts at the time.

The correct offset for a W116 is around ET25 or lower. I have heard that rims with offset as high as ET30 can fit but I can confirm that offset as low as ET11 will certainly fit. Remember that offset is measured in mm so even a change from ET25 to ET11 is only 14mm.

The way I looked at changing offset was that I trusted that AMG did their research when changing the offset of the rims sold for use on these cars. I would be very surprised if AMG changed the offset that had a negative impact on handling. They would have changed the handling characteristics to a slightly more sporty nature but you will be getting that with a larger rim anyway.

I also think that tyre performance will make a bigger difference to the cars handling than the slight variations in rim offset. I bought the best tyres I could find and the handling in wet and dry is excellent, much better than with the 14" rims and tyres.

As for zero-offset steering, I will need to check with my MB brochure on the subject but I thought the zero offset also referred to the north-south position of the point at which the tyre met the road, and not just the east-west position affected by the offset of the rim. A change in tyre size or even pressure will probably have just as big an impact in zero-offset steering than changing the offset of the rim.
Michael
1977 450SE [Brilliant Red]
2006 B200

The Warden

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Re: Zero offset steering on W116 - and what about wheel offset?
« Reply #3 on: 24 March 2006, 05:34 PM »
15" bundts exist?!? :o

Any pictures out there? Be interesting to see what they look like...I think I've only ever seen 14"...
1979 300SD (W116.120), miles unknown, daily driver, keeping her on the road
1984 Ford F-250 6.9l IH diesel

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Re: Zero offset steering on W116 - and what about wheel offset?
« Reply #4 on: 24 March 2006, 06:50 PM »
15" bundts exist?!? :o

Any pictures out there? Be interesting to see what they look like...I think I've only ever seen 14"...

They do exist but were not original MB equipment. They look identical to the 14" bundts but have a wider outer edge and are a perfect fit for older MB's like our W116. There were a few different manufacturers for these rims (MB outsource their rims).

Styria recently had a set that he sold too cheaply in my opinion.
Michael
1977 450SE [Brilliant Red]
2006 B200

oscar

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Re: Zero offset steering on W116 - and what about wheel offset?
« Reply #5 on: 25 March 2006, 02:43 AM »
Mr Hubertz re: your comments about The Warden's 300sd's non-merc wheels, (well spotted and handy info BTW), is offset all that s class should be concerned with.  ie if offset is within range yet new wheels weren't made with mercedes in mind, how would I know for instance if they would fit regarding the "dynamic stress compression fit" you speak of? 

I know lots of members have changed to non original wheels >14" without probs, but what should we look for apart from offset? Cheers
1973 350SE, my first & fave

John Hubertz

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Re: Zero offset steering on W116 - and what about wheel offset?
« Reply #6 on: 25 March 2006, 04:13 AM »
Hmmmm.  Hadn't considered the alloy/replacement wheel question.  Perhaps the old German who taught me the issues with wheels had an axe to grind against modifications?   

I do know the 15" bundts and the ever-popular Ronal and other AMG fitments were all designed with MB in mind.  I also noticed that my AMG/Ronals from a 107 (SL) I owned had the same "look" around the bolt holes and especially the back of the wheel where it fitted to the hub...  and that the backs of wheels fit to American cars don't look similar - at least the steel wheels don't.

Out of curiosity, I wonder if when these 15s were test fit to the aforementioned car if the tires were the correct size, in good condition, properly inflated etc....  and if all four were test fit or just two.

Here's a link you guys will love - http://www.1010tire.com/TireSizeCalculator.asp?submit=yes&vehicle=yes

You can punch in any OEM tire size and it will +1 or +2 and give you the correct tire to retain perfect fit within the wheelwell.

That Florida 6.9 (and indeed lots of cars with 15s and 16s I've seen, obviously has tires that are substantially larger then stock - not just the rim size but height....  maybe this is what you ran into when you fit those rims).



btw:  that car sold last night for $5100....someone got a good deal despite the incorrect upholstery cloth.
John Hubertz
"When the going gets weird, the weird turn pro."
(Hunter S. Thompson) 

1977 450SEL (Max Headroom)

s class

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Re: Zero offset steering on W116 - and what about wheel offset?
« Reply #7 on: 26 March 2006, 09:30 PM »
Thanks for your comments guys,

Yes 15" Bundts definately exist although even many mercedes specialists don't know this.  True, they were never OEM fitment.  Mine are 15"x7.5J ET23 made by Centra.  They make the W116 look very business like indeed.  When I test fitted the wheels they had old Yokohama A539 in 225/60 VR15.  I will soon get Bridgestone Potenza G3 for them.  And no, I'm not considering any non-bridgestone product. 

THanks, I will check out that M100 link.

'76 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '82 500SEL euro full hydro, '83 500SEL euro full hydro , '81 500SL

John Hubertz

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Re: Zero offset steering on W116 - and what about wheel offset?
« Reply #8 on: 27 March 2006, 09:30 AM »
Here's a post from one of the m-100 guys with experience in 15" bundts....  I posted your original post over there as they have a tire/wheel forum:

The off set of the wheels will not affect the car like that,it sounds as though the height of the front has been affected by the taller tires,this would tend to reverse the castor,making the steering feel as you describe.
I would fit correct tire to the 15" rims ,then get the alignment checked for castor .Are the body mounts OK?.The crossmember could be leaning back or forwards and the the different wheels could accentuate a problem you didn't realise was there.
If nothing works I'll give you $100 for them ...

...There are old cars,and then there are Classics..(Mercedes Benz Ad. 1999)
John Hubertz
"When the going gets weird, the weird turn pro."
(Hunter S. Thompson) 

1977 450SEL (Max Headroom)

s class

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Re: Zero offset steering on W116 - and what about wheel offset?
« Reply #9 on: 27 March 2006, 10:23 PM »
John,

Thanks for your efforts in gathering that information.  I appreciate that wider tyres will accentuate any existing bushing/alignment/suspension wear problems.  About 30 000km ago I replaced all the front end bushes : lower wishbones, uppper control arms bal joints, subchassis bushes, steering damper, steering idler bushing. 

According to my calculations, the 225/60R15 size has a rolling diameter very close to that of the original 205/70R14.  Certainly I can have the cambers and castors rechecked.  I generally have alignment done fairly regularly.

If nothing else works, I'm afraid the 15"s still won't be for sale - I think I will display them.  But no, I'm sure they can be made to work. 

Thanks again, Ryan
« Last Edit: 28 March 2006, 04:41 AM by s class »

'76 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '82 500SEL euro full hydro, '83 500SEL euro full hydro , '81 500SL

s class

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Re: Zero offset steering on W116 - and what about wheel offset?
« Reply #10 on: 27 March 2006, 10:28 PM »
As an aside, on alignment of my W116 in particular :

Here in South Africa we drive on the left hand side of the road.  Roads are generally cambered to slope towards the edge of the roads.  Most alignment shops here insist on wanting to set the left front castor higher than the right front castor by about 0.5 degree.  Apparently this is to counteract the tendency of cars to drift left following the camber of the road.  To me this sounds unnecessary.  I would rather have equal settings on both sides of the car.  I was even told once by a shop that they refused to do that for me because the car would be undriveable!?!

Has anyone had experiences of this type?

'76 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '82 500SEL euro full hydro, '83 500SEL euro full hydro , '81 500SL

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Re: Zero offset steering on W116 - and what about wheel offset?
« Reply #11 on: 28 March 2006, 01:11 AM »
According to my calculations, the 225/60R16 size has a rolling diameter very close to that of the original 205/70R14.

I have 225/55-16 tyres on my 16x7.5 ET17 rims. Great ride and handling! The AMG suggested size is 225/50-16 but I couldn't find this size with suitable load rating.
Michael
1977 450SE [Brilliant Red]
2006 B200

s class

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Re: Zero offset steering on W116 - and what about wheel offset?
« Reply #12 on: 28 March 2006, 04:44 AM »
Michael, sorry - in my previous post I said 225/60R16, but I meant 225/60R15 - I have now edited and corrected my previous post. 

Yes on 16" I agree that 225/55R16 or 225/50R16 would be suitable.  I use 225/55R16 on my 450SL.

You say you have great handling with these 16" wheels on your W116 - what is the offset of the rims?

Thanks, Ryan

'76 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '82 500SEL euro full hydro, '83 500SEL euro full hydro , '81 500SL

oscar

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Re: Zero offset steering on W116 - and what about wheel offset?
« Reply #13 on: 28 March 2006, 06:16 AM »
As an aside, on alignment of my W116 in particular :

.....  Most alignment shops here insist on wanting to set the left front castor higher than the right front castor by about 0.5 degree....... I would rather have equal settings on both sides of the car.  I was even told once by a shop that they refused to do that for me because the car would be undriveable!?!

Has anyone had experiences of this type?

Before 450se answers your last post, I'll just butt in and say I can't believe they'd do this and not ask.  In other words it pays to know what standard practice is, especially when you expect a pro to tend to something and may not know they've done something against instruction.  Thanks for that info, a question I'll be asking when I get bushes replaced.
1973 350SE, my first & fave

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Re: Zero offset steering on W116 - and what about wheel offset?
« Reply #14 on: 28 March 2006, 04:27 PM »
Yes on 16" I agree that 225/55R16 or 225/50R16 would be suitable.  I use 225/55R16 on my 450SL.

You say you have great handling with these 16" wheels on your W116 - what is the offset of the rims?

The offset of my rims are ET17. They are genuine AMG rims made for the W126, W123 or W107 which share the same steering geometry and offset as our W116. For that matter, any 126, 123 or 107 rims will be a perfect fit for our W116 and being later models had larger rims available as standard on most models.
Michael
1977 450SE [Brilliant Red]
2006 B200