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Difficult question for the rim/tire experts

4K views 33 replies 9 participants last post by  Nate D. Rector 
#1 · (Edited)
Let me say at the outset that I have read almost all posts in the wheels fitments sticky. They got me even more curious (or perhaps confused is the right word).

The facts:
1. My stock rim is 16 inches in diameter and 7.5 inches wide. Stock offset is 51 mm.
Stock tire size is 235/60/16.
2. My car was delivered to me with staggered AMGs in 18 inch. Fronts are 8", rears are 9" wide.
Offset is 30 mm front and 33 mm rear.
Tires sizes 245/40/18 and 265/35/18 -- very close to each other but undersized relative to the stock (equivalence is nearly perfect for 255/45/18)

My questions are:
1. In the back, the difference in the offset alone moves the rim 18 mm OUT towards the fender edge. To this we need to add another 18 mm from the 1.5 inch difference in the wheel width. This means that the AMG rim (18x9, ET33) should be almost flush, but it is NOT. Check the picture, I've got at least 20, possibly 30 mm to go.
I suspected that the camber could be way off, but that doesn't seem to be the case.

What is going on? Many in the sticky warn against rims with offset in the low 30s, but it looks like I can go in the 20s and still be fine, at least in the rear.


2. The tires are Vredestein and have very unique tread pattern.



There is a wall that has INSIDE embossed on each. All tires based on this appear to be mounted correctly.

I suppose these tires should be called directional, although there are no arrows indicating rotation.
They are not asymmetric (i.e., no left and right). Notice that the deep grove that runs along the circumference of the tire is always on the inside, but the "curved lines" in the tread patterns are obviously not rotating in the same way.

What am I missing? There is video on YouTube that glorifies this "aggressive" look, and offers some kind of explanation, but I am not ashamed to admit that don't get this schematics:



Opinions will vary, most likely, and I'd love to hear them all.

Best regards,
Steve
 

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#2 ·
opinion #1: you buy original wheels (ca $50 each), repaint them (ca $50 each) and buy new tyres (ca $150 each), and problem solved for $1,000. maybe you can get $500 for your wheels with tyres? i know you will not like this answer and it is not what you asked explicitly but sometimes a good solution is too close to our eyes to clearly see it.
 
#4 · (Edited)
i know you will not like this answer and it is not what you asked explicitly but sometimes a good solution is too close to our eyes to clearly see it.
Samo:
I started this thread with a purely academic idea in mind -- WE MUST KNOW.
Wheel fitment, after all, is not rocket science. It's adding and subtracting numbers and some basic geometry.

There are close to 800 posts in the sticky. The conventional wisdom seems to be "leave the low offsets for the r129 convertibles, lower than 20 mm offset for the w126). Makes sense looking at the factory specs.

Chris and Joe very recently have suggested that:
+35mm offset 8.5 inches wide front sits flush.
+35mm offset 9.5 inches wide rear sits flush.
and

it needs 35 side wall since it is lowered , the 40 sidewall touches the fenders arch on the bottom when weight is added .
Chris, I think, has LM1's I think and they have offset in the 40s

Based on what I've seen here and on other webpages, I thought I had understood the limiting parameters for the w/c140 wheel fitment. I actually wrote something in my FS thread that probably will have to be edited, verbatim:

"after reading and re-reading all fitment guides, I think I know why the PO has chosen undersized tires -- the offset on those rims is too low and a 285 mm wide tire will be pushed too far out and may interfere with the fender edge.

I will have to get another set of rims with offset in the 40-50 mm range. ET 30 /33 mm will not work for the c140 body"


Now, my newest experiment suggests that I was wrong (again, :-((( ). Not surprising at all, but my pictures also seem to contradict years worth of experience by many other members.

@glepore suggests that c140 and w140 may have different fenders, yet, I don't recall seeing different spec wheels for coupes vs sedans. Neither in stock form nor in the factory approved catalogs for AMG/Lorinser/Carlsson/Brabus upgrades.

It is possible that the current 265 mm rear tire is making the gap between the tire and the fender edge to appear wider than it is, but I doubt that going to 285 mm (mounted on a 9" rim) will cause the wheel to sit flush.

To sum this long narrative up. With the current wheel (18x9, ET33), the front surface is pushed OUT more than 37 mm relative to the stock (16x7.5, ET51) and there is a gap of about 20 mm.
Unless I am making some crazy mistake and my thinking is completely messed up, this should mean that the stock wheel/tire will be BURIED in the rear fender by more than 55 mm (two fingers).
Is that possible?

Thanks for the replies so far,
Steve
 
#3 ·
As to the offset, I think you may be reading info based on sedans. My coupe appears to have greater room in the rear than a sedan, and the fender appears to be rolled a bit from the factory. Also, if you went to 285's in the back, you'd be much closer to the lip. 285's plus a lower offset plus worn springs and no sls, and you might have an issue. Hence the warnings.

The tread pattern? No clue.
 
#9 · (Edited)
The "standard" AMG staggered set is 18x9 and and 18x9.5 44 and 46.
Yes, yes, yes. And those should bring the wheel out to sit very close with the fender edge.

Do the math, please

9.5" is the AMG rear option
Stock is 7.5".
The difference is 2" or 50 mm, split it in half, the AMG rim would be 25 mm out relative to the stock IF both were with the same offset.

However, the AMG rim has even lower offset, 46 mm, which means that the net effect is the edge of the rim sits 30 mm out relative to the stock.

On my AMG rim (must have come from E55), as I discussed below, the math is the following:
9"-7.5" = 1.5" difference, split in two -- about 18 mm gain. ET33 vs ET51 ads another 18 mm, meaning that lip of the rim is pushed OUT 36-37 mm relative to the stock.

This is 6 mm more (1/4") compared to the AMG option for the w140, yet, on my car, there is still a gap of about 20 mm.

Did I make myself clear this time?

Best regards,
Steve
 
#7 · (Edited)
For what it is worth, here are the recommendations from Discounttire.com for a '93 600SEC

Optional Tire Sizes

Stock 155/90-16 Plus One 225/55-17 Plus Two 225/50-18 Plus Three 225/45-19 or 245/40-19 Plus Four 245/35-20

Anziani
And this one more reason not to rely blindly on recommendations, particularly from sources like the one in the quoted paragraph.

FYI Neil, the stock tire for the 600SEC is 235/60/16.

But what size is not the reason this thread exists.
Again, my question concerned the wheel with 33 mm offset, as pictured in post #1 and the fact that this configuration is far from being flush.
May be those that have pictures should post them please. We should be able to figure this one out.
I'd very interested to see a stock rim on a coupe -- is there that big of a gap indeed?

Many thanks,
Steve
 
#11 ·
http://www.benzworld.org/forums/w140-s-class/1904425-w140-wheel-spacing.html

I think part of the problem with the math (and I'll admit to math ignorance) is that the wheel width then references a new center from which the offset is measured, therefore you can't just add the differences.

I looked at my 9.5 46's and wouldn't want much wider. Moving them inboard might cause issues on the other side, don't know.
 
#12 · (Edited)
steve-found your answer-use the calculator here: Wheel Offset Calculator | Tiwing.com

Enter 9 x 33 in the first field and 9.5 and 9x44 in the second-the outer edge RETRACTS by 14mm.

Enter 7.5x51 and compare to 9x 33 and you get it moved out by 37mm, while a 46 only extends by 24.

You're doing offset backwards, common error, as a lower positive offset moves the face of the wheel OUT towards the fender lip http://tiwing.com/tiwing_site/wp-content/uploads/offsetdiagram11.jpg or http://www.autoanything.com/wheels-rims/wheel-offset-vs-wheel-backspacing . Confused me for a minute.

Here is a 275 on a 9.5x46 (I"m running the 275 combo from my s420 which was fitted conservatively). Not much room, eh? A 33 with a 285 would be no bueno;

 
#18 · (Edited)
steve-found your answer-use the calculator here: Wheel Offset Calculator | Tiwing.com

Enter 9 x 33 in the first field and 9.5 and 9x44 in the second-the outer edge RETRACTS by 14mm.

Enter 7.5x51 and compare to 9x 33 and you get it moved out by 37mm, while a 46 only extends by 24.

You're doing offset backwards, common error, as a lower positive offset moves the face of the wheel OUT towards the fender lip http://tiwing.com/tiwing_site/wp-content/uploads/offsetdiagram11.jpg or Wheel Offset vs. Wheel Backspacing Explained . Confused me for a minute.
I slept on it because it didn't want to come across (again) as a troll, but have to disagree with you that I got it wrong. No, I didn't.

The calculations I provided earlier I did on a piece of paper. No need to over-complicate something this simple.

In post #9 wrote the following (verbatim):

"9"-7.5" = 1.5" difference, split in two -- about 18 mm gain. ET33 vs ET51 ads another 18 mm, meaning that lip of the rim is pushed OUT 36-37 mm relative to the stock.

This is 6 mm more (1/4") compared to the AMG option"

The web-based calculator you are using shows the same.
Current wheel: 7.5 ET51
Option 1: 9.5 ET46 (extends extra 30 mm and cuts 20 mm from the backspacing)
Option 2: 9 ET33 (extends extra 37 mm and cuts 1 mm from the backspacing)

Yes, my wheel is 6-7 mm further out than yours, but there is still room to go OUT. Will try to buy some spacers to determine exactly how many more mm till I can call it "flush"

Best regards,
Steve
 
#14 ·
wheels

Thank you; I love simple answers. Now, for another one: I've found some nice 16" wheels off an E class sedan which are 7"; I presume these would work on my '01 S500 (bolt length and other measurements)? I hope so, because my car has some less-than-attractive after market chrome wheels I'd like to get rid of in favor of a set of nice OE ones. Am I on the right tract with that?
James
 
#16 · (Edited)
Steve, I will stick by my numbers. What I didn't realize was the smaller tire was for a "zero" option. The stock tire is as you said 235/60/16 If it were my car I would pick the correct tire size and work backwards onto a wheel. I did that for my CL500 and my CL600. No problems at all.
Anziani
 
#19 · (Edited)
Steve, I will stick by my numbers. What I didn't realize was the smaller tire was for a "zero" option. The stock tire is as you said 235/60/16 If it were my car I would pick the correct tire size and work backwards onto a wheel. I did that for my CL500 and my CL600. No problems at all.
Anziani
OK, as you say Neil.

We should not be even discussing plus-sizing here, but since you insist:
Stock: 235/60/16
Size +1: 235/55/17
Size +2: 255/45/18

The archives have plentiful discussions on this subject.

Best regards,
Steve

PS I will challenge to find one person here that rides on 225/50/18 -- they are even skinnier than the stock, who in their right mind would go up in rim size by 2 inches and decrease the width of the tire...? Not to mention what a 225 tire will look like on a 9" or 9.5" wide rim.
 
#20 ·
If this helps you somehow Steve .These are my Lorinser LM1 , cant get it any flusher then this .
At the rear at one stage I had a smaller tyre and what happened is the speed sensor was giving wrong signals out resulting with the transmission going bananas , I almost had to stop on the road as the car was braking then not braking then accelerating all of it's own ,weird if you ask me ,at the time I installed them I didn't know about this sensor ,I found out the hard way ,infact the day after I took the rear wheels (booth ) of & took them with my ute to the tyre shop not to go thru that dangerous drive again .
Now she is Perfect with these sizes /tyres & rims combo .
Joe had Spacer under his I think ,W140's by what I heard don't like them , don't know why or if there is any correct info on this .:thumbsup:

Lorinser LM1
19 x 8.5" / 19" x 9.5"
Offset: Front 35 mm / Rear 38mm
Front Tyres 255/40/ZR19 - Rear Tyres 275/35/ZR19 ,no spacers used .

(Quad exhaust is next on the list .)
 

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#22 · (Edited)
If this helps you somehow Steve .These are my Lorinser LM1 , cant get it any flusher then this .

19 x 8.5" / 19" x 9.5"
Offset: Front 35 mm / Rear 38mm
Front Tyres 255/40/ZR19 - Rear Tyres 275/35/ZR19 ,no spacers used .
Thanks Chris. 38 mm offset on a 9.5" rim will be 8 mm further out than the 46 mm offset on a 9.5" rim.
Problem is this does NOT help me. Your combo places the edge of the rim roughly in the same place as my 33 mm offset on a 9" rim (only 2 mm difference).

I am leaning towards a hypothesis that a PO has modified the fenders, I cannot think of any other explanation.
Must see another coupe and compare side-by-side.

Best regards,
Steve
 
#24 ·
What's the goal? To find out just how much tire you can stuff in there? I've done that with 107s, w108s, w114s, w126s, and even a w124. I've left my w140 alone though despite having a set of staggered brabus reps and a set of the AMG twin spokes like the OPs too. My w140 doesn't really go in reverse though. :-( @Red4evr bought a 1992 500sel to take the motor out of it, and his car goes in both directions. Neither of us have really thought much about how much tire you can stuff in there. Such a heavy car to jack up, and we don't know what we would do with those 8-hole w140 wheels and huge tires.

Oh... I do have a set of 25mm 14x1.5 adapter spacers. I have thought about reducing the rear offset by an inch on each side with those. I assume that would help the look a lot, but not the ride.

Are 1992 500sel air suspension cars? I'm pretty sure my 1993 300se is not.
 
#25 ·
The goal is to KNOW. It simply can't be.

25 years of w140 driving experience, thousands of posts -- they all point at issues with offset lower than +35.
This is NOT the case with the car we are discussing.



This car came to me with the ET 30/33 rims. Not my choice. I have been trying (unsuccessfully) to sell them and get factory-spec'ed ones.

This is/was yet another question/problem I encounter with this car that seems to have no (easy) answer....

Steve
 
#33 · (Edited)
The goal is to KNOW. It simply can't be.

25 years of w140 driving experience, thousands of posts -- they all point at issues with offset lower than +35.
This is NOT the case with the car we are discussing.

Over the weekend I did repair the tire with the nail in it.
While I had the car lifted up, I decided to pull the spare tire (full size, OEM 8-hole rim with ET51, Pirelli P600 235/60/16, never used) and tried it.
The AMG bolts I have are much shorter and could not be used, so I did not get the chance to lower the car and measure exactly where it sits.

But, from just having it there, it appears that the OEM wheel/tire is way DEEP inside the fender.

Not as bad as it was in the Moskvitch 412 my uncle had when I was a kid:



but still deep enough. I suppose if I had it on the ground with the suspension fully loaded, it would have looked like this:



Anyhow, to close this thread, it appears that on the coupes, the front can take 8-8.5" wide rims with offset 30 mm, while on the rear, at normal ride height, 9-10" wide rims with offset around 35 mm will be fine.

Here is a decent look at the 18x8 (ET30) and 18x9 (ET39) wheels that were discussed herein.
Notice that while someone might be inclined to say the word 'flush', but in the rear, there is clearly a lot of room for 'improvement'




Thanks to all that contributed.
Steve

PS While reading on this subject, I came across some pictures of another 600SEC, apparently sold in 2007. The car appears to have the correct AMG monoblocks and the rear looks very similar to mine:


 
#26 · (Edited)
To help a little.

Those are asymmetric tires, non-directional. They rotate in either direction forward, but don't show the same tread pattern when rotated 180 degrees.

By looking at the valve stem it does not look like a usual TPMS one, night not have it.

EPC shows ET 39 on the rears.

You're trying to sell a tire combo with "small" tires that are "old", with non-mint wheels. Not sure how to help on that one... This means as they are they won't fit many applications that people might have to be looking for. If you dismount them, then you'd need to find someone interested in the tire size you have, but also again have to deal with the concern over their age. I am not concerned about age as much as others. If I were in your shoes I would use the tires until they are worn, then sell the wheels, or keep the wheels as you note you'd do without having the tires. The treadwear you note won't last a long time IIRC 280....
 
#29 · (Edited)
To help a little.
Thank you

Those are asymmetric tires, non-directional. They rotate in either direction forward, but don't show the same tread pattern when rotated 180 degrees.
I stand corrected. Have reversed the terminology.I always thought that the v-shaped tread blocks mean that the tire is designed to roll in only one direction and can be used on one side of the car -- can be rotated from the front axle to the rear axle.

If you look at the tread of those Vredesteins, the shape of the grooves seems to follow the direction of rotation on one side, but goes on "reverse" for the other. This is what puzzled (and still puzzles) me.

EPC shows ET 39 on the rears.
For what rim size? Offset value WITHOUT the width of the rim is useless.

You're trying to sell a tire combo with "small" tires that are "old", with non-mint wheels. Not sure how to help on that one...
How asked for help selling? BTW, the tires are small for the w140 but right for the e55 (or e500), which must have been the donor vehicle.

I am not concerned about age as much as others. If I were in your shoes I would use the tires until they are worn, then sell the wheels, or keep the wheels as you note you'd do without having the tires. The treadwear you note won't last a long time IIRC 280...
The wheels are back on the car. I will probably drive to the inspection line next week and have it finally registered. You're correct that there are no takers (it's been almost a year) and for the time being, I will have to live with the over 6% difference (the speedo will be way off) for a few weeks.

So far, the wheels were collected dust in my basement and fitment was not on my radar as the car was being worked on.
But now, with this much time spent wrenching and having depleted the saving account, it is driving time (I hope).

I had reservations that these rims do not fit (but apparently they do, for reason that are not understood yet) the c140 and I am hoping the discussion here will help me decide if I want to get new (and larger) tires for these rims, or write-off the loss and get different ones.

Best regards,
Steve
 
#27 ·
I'll bring my car down if you want. You can put one of my wheels on the rear and compare if you'd like. I thought you were challenging the common wisdom, not the particulars of your vehicle. I'm also wondering if the po messed with the wheels themselves-ie had the centers machined. Unless there was some crazy wheel setup on the car originally, I doubt there would be reason to modify the body (absent collision damage and a repair that changed the shape). The other option is to actually measure the tire, some tires measure above or below their branded width.
 
#28 · (Edited)
You are either not reading everything I wrote, or I cannot express it right. Probably the latter.

1. Yes, I thought that even on the subject of wheel/tire fitment I am destined to be the guinea pig. All fingers point at this as of now.
Is it going to be the common wisdom or the particulars of the car remains to be confirmed.

EDIT: If you search the archives trying to find out if low 30s offset will work on the w140, this is what you'll typically see:
No it will not be ok.
J8 and 245/45 is just perfect but again, you will rub because your offset is wrong
2. Wheels are not machined.
3. The car has not been repainted as far as I can tell.
4. The tire size in this case is not too critical. Where the lip of the rim is with the respect to the fender arch is the big question.

Adding more width to the tire could cause some rubbing, but when people say flush, they usually mean metal to metal flush.

Thanks for the offer to come down.

Steve

PS On my wife's Audi A8, I have the standard 17x8" 5-spoke rims (ET48) and the S8 option in 18" (9-spoke ET43 fitted with 1/4" spacer so effective the total offset is around 35-36mm). I am a newbie to the MB world, but have some rudimentary knowledge on the subject of what it takes
 
#30 ·
Nothing like having wheels and tires that fit in there but aren't the correct size for the odometer on a depleted bank account. (I try to look at the positive side of things when things are really down.). Just pump them up to higher PSI/maybe maximum per the sidewall. The weight rating on a tire is at max pressure and so there is leeway regarding your safety if you increase higher....

I did not want to bash in your for sale thread so I thought I would comment here. (Not my intention to bash in the first place).

I don't get how the tires work the way they do. If it the car is not pulling to one side then I think the engineers that designed them so are correct, and we collectively just don't get it, yet....

I put one part number you gave into EPC, it spit out models that the wheel would fit, I selected the first model 211.xxx. It shows the two part numbers you gave. It also shows their specs. The rear you are selling are ET 39, per EPC.

The less offset you have, the more lever force the tire/wheel combo asserts on the suspension, as they are being moved outwards, like the handle of a wrench. After my weird tire size that one tire store convinced me to get for my AMG +1s on my W201 wore out, I went back to my standard size tires/wheels. I do not like to wear out my suspension. Let the tire do some of the "work".

As long as they fit you are going to survive. If the rear tires are smaller than the front you may eat the rear tires and brake pads quickly. I am not familiar with the traction control in the W140. This happened with the OE sport tires on my mom's W204, both before 30k miles....
 
#31 · (Edited)
Nothing like having wheels and tires that fit in there but aren't the correct size for the odometer on a depleted bank account. (I try to look at the positive side of things when things are really down.). Just pump them up to higher PSI/maybe maximum per the sidewall. The weight rating on a tire is at max pressure and so there is leeway regarding your safety if you increase higher....

I did not want to bash in your for sale thread so I thought I would comment here. (Not my intention to bash in the first place).

I don't get how the tires work the way they do. If it the car is not pulling to one side then I think the engineers that designed them so are correct, and we collectively just don't get it, yet....

I put one part number you gave into EPC, it spit out models that the wheel would fit, I selected the first model 211.xxx. It shows the two part numbers you gave. It also shows their specs. The rear you are selling are ET 39, per EPC.

The less offset you have, the more lever force the tire/wheel combo asserts on the suspension, as they are being moved outwards, like the handle of a wrench. After my weird tire size that one tire store convinced me to get for my AMG +1s on my W201 wore out, I went back to my standard size tires/wheels. I do not like to wear out my suspension. Let the tire do some of the "work".

As long as they fit you are going to survive. If the rear tires are smaller than the front you may eat the rear tires and brake pads quickly. I am not familiar with the traction control in the W140. This happened with the OE sport tires on my mom's W204, both before 30k miles....

I am not sure what to make of it. Probably should not bother to respond as bashing is not a word I wanted to see withing this thread.

1. Those wheels/tires were not my choice. They are not a good fit for the w140 and the reason have been offered to someone else with a different MB in the stable.

2. If you see what I've done so far to bring this car back to life, you'll probably understand why the accounts are depleted.

3. I might have mistaken ET33 for ET39 (will double check), but this will only change the whole picture by 6 mm in direction inwards. The entire discussion as to when the surface of the rim and the fender edge line up, will be affected to the point that instead of saying that the current set up is "6 mm further out compared to the AMG option", I should be saying that "they are equal".

4. You might be satisfied to know that since engineers designed it this way, it must be OK, but this doesn't work for me.
I see something that perplexes me -- I try to understand it.

5. I did not ask if I will survive, pay a toll in terms of suspension damage, or whether or not it is even safe to drive. The question what are the proper rims/tires for the w140 was also not intended for discussion here.

Now, 20+ posts after this thread was started, can we please return to the topic -- c140 with 18x8 front with ET30 and 18x9 with ET39 and absolutely NO rubbing. How come?

Best regards,
Steve
 
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