PDA

View Full Version : Wheel Fitment Guide


Oversize
21st October 2011, 06:18 PM
Might be of some interest:

http://www.alloywheelsdirect.net/information/fitting_chart/mercedes-benz

At least this table lists the W116 (scroll down to the very bottom), although it gives no indication if other offsets will fit (ie anything above 30P). Or what's the widest wheel that won't foul on the guards, brakes, or suspension.

Michel & Styria do you know the offset of your wheels?? :rolleyes:

I know that with the correct offset wheels I can get 255mm tyres under the rear guards (as fitted to 6301)! BTW 255mm is 10"!! :p

Michel
21st October 2011, 06:30 PM
I know that with the correct offset wheels I can get 255mm tyres under the rear guards (as fitted to 6301)! BTW 255mm is 10"!! :p

on a 6.9? or a normal 116?

Michel
21st October 2011, 06:33 PM
on a 6.9? or a normal 116?

I just read on 6301 :p

Since it is yours, why don't you telll us the offset? :rolleyes:

Oversize
21st October 2011, 06:38 PM
When I get all the wheels off I'll have a look inside them and hopefully the answer will be there! Otherwise I'll have to do some measuring. Any idea on an easy way to work it out if it's not stamped on the wheel (with the tyre fitted)?

Michel
21st October 2011, 06:43 PM
When I get all the wheels off I'll have a look inside them and hopefully the answer will be there! Otherwise I'll have to do some measuring. Any idea on an easy way to work it out if it's not stamped on the wheel (with the tyre fitted)?

There must be a science to it, but I was always useless in Maths.:o

I prefer to check the wheel.:D
99% of them are stamped ;)

Styria
23rd October 2011, 06:45 AM
Hi Mark, unlike Michel, I am brilliant at Mathematics (like in 2 plus 2 equals 3.5), but I must admit to not being able to determine the wheel offsets. In other words, where the measuring points are etc. I can tell you that the wheels fitted to Gleaming Beauty required a spicer of about 12mm in thickness, but even so, I am not certain if they are required. They were supplied by the tyre retailer and I have never attempted to fit those rims without the spacers. I would dare say though that there is every chance that the rears could be fitted without the spacers. On the front, clearance is somewhat more of a critical nature - the suspension has got to be at the correct height to avoid for the tyre to touch the AMG spoiler/front guard when turning the wheels.

Oversize
23rd October 2011, 07:14 AM
Styria, small spacers are often required to ensure the centre hole in the wheel is a snug fit over the hub. Otherwise the wheel nuts bear the whole weight of the car and can fail as a result. Unfortunately they're illegal here in Victoria as it can upset front wheel alignment and handling characteristics, as well as cause a failure of bearings and even stub axles if the track is substantially increased and components are therefore overloaded.

Pehaps this info on wheel offset may help everyone (including me)??

http://en.wikipedia.org/wiki/Offset_(wheel)

Michel
23rd October 2011, 07:26 AM
Pehaps this info on wheel offset may help everyone (including me)??

http://en.wikipedia.org/wiki/Offset_(wheel)

That link goes nowhere Mark :o

Oversize
23rd October 2011, 07:29 AM
I really don't know why the link doesn't work. I re-tried attaching it several times with the same result! :mad: I just searched Wiki for wheel offset. Here's the text:

The offset of a vehicle's wheel is the distance between the centerline of the wheel and the plane of the hub-mounting surface of the wheel. It can thus be either positive or negative, and is typically measured in millimeters. Offset has a significant effect on many elements of a vehicle's suspension, including suspension geometry, clearance between the tire and suspension elements, the scrub radius of the steering system, and visually, the width of the wheel faces relative to the car's bodywork.

Zero Offset - The plane of the hub mounting surface is even with the centerline of the wheel.
Positive Offset - The plane of the hub mounting surface is shifted from the centerline toward the front or outside of the wheel. Positive offset wheels are generally found on front wheel drive cars and newer rear drive cars.
Negative Offset - The plane of the hub mounting surface is toward the back or brake side of the wheel's centerline.

"Deep dish" wheels typically have negative offset or a very low positive offset.

To maintain handling characteristics and avoid undue loads on bushings and ball joints, the car manufacturer's original offset should be maintained when choosing new wheels unless there are overriding clearance issues.

Wheels are usually stamped with their offset using the German prefix "ET", meaning "Einpresstiefe" or, literally, "press depth". An example would be "ET45" for a 45mm offset.

[edit] Calculating the offset of a wheel

First, measure the overall width of the wheel (remember, just because a wheel is 18x7.5, does not mean that the OVERALL width is 7.5”. It means that the measurement between the outboard flange and the inboard flange is 7.5”). Next, divide that width of the wheel by two; this will give you the centerline of the wheel.

Overall width/2 = Centerline

After determining the centerline, measure from the hub-mounting surface of the hub to the edge of the inboard flange (if the wheel were laying flat on the ground – face up – your measurement would be from the ground to the hub-mounting surface). This is your back spacing.

Back spacing - Centerline = Offset

Michel
23rd October 2011, 07:39 AM
Many thanks Mark.

Very fulfilling stuff.

I trust that now, Godfather would be able to find the true answer to 2+2 :p

Tony66_au
23rd October 2011, 09:18 AM
Wheel spacers are only illegal in Vic if they are aftermarket and their use is common enough out there with the big trick being use of the correct wheel studs AND wheel nuts.

Even mag wheels that fit without spacers but with a massive offset will shear studs if the correct studs are not used with length and tensile strength being the key area's to watch with the weight of the car being supported on the hub.

However Torque also plays a huge part with the friction between mating surfaces of the wheel and the hub being paramount and the actual shear strength of the Studs also playing a large part.

This is something I learned the hard way :-) and is also why most serious race cars use centre spin on locking hubs.

Im looking for a great US site I found a while ago that explains this all in detail.

Cheers,
Tony

motec 6.9
26th October 2011, 02:01 AM
Hi Mark good find but has been posted before by the late John S http://www.topklasse.net.au/forums/showthread.php?t=2502

SEL_69L
26th October 2011, 03:38 PM
The correct wheel offset is VERY important!

The w116 employed zero offset steering.

That is where the centre axis of the kingpin passes through the centre of the contact patch of the tyre on the road.

This explains why handling and steering sensitivity are affected when the above design condition is not met. It also helps to explain why the bushings in the suspension will have a shorter lifespan.

I have made the mistake of buying a 15" wheel with the wrong offset.
Check with MB for the correct offset for the wheel you may have in mind to buy.

For instance, the table listed in this thread only includes information for 14" and 15" wheels for the W116. The correct offset for for other than those wheel diameters listed needs to be found from MB.

Oversize
13th March 2012, 10:11 PM
SEL 69L what's the offset of your 15s?

BTW I need to correct a post made by me on 23rd October (8.14am) where I mentioned small spacers. I was actually referring to sleeves that fit inside the centre hole of a wheel to ensure there's a snug fit over the spigot of the hub. These aren't spacers and are therefore legal. Soory for the brain fade; I think I was confusing myself!!! :confused:

Oversize
6th April 2012, 08:33 PM
Ok I'm now proficient in measuring offset even if the wheels aren't marked...

Remove the wheel centre cap. Lay the wheel or wheel/tyre down on a flat surface with the front of the wheel facing upward. Place a spirit level across the top so it rests on the rim of the wheel, or outer sidewall of the tyre. Don't rest it on any raised sidewall letters, or numbers (unless they're on both sides), as it'll throw out the measurements.

Measure from the flat surface (the floor) to the bottom of the spirit level (a),
Measure from the back of the wheel centre (where the wheel sits flush against the hub) to the bottom of the spirit level (b).

The centreline of the wheel (c) = a / 2.

Subtract the greater value of b and c from the other, to find the offset.

If c is greater than b then the wheel has a positive offset (most modern wheels today),
If b is greater than c then the wheel has a negative offset (deep dished wheel),
If b is the same as c then the wheel has a zero offset.

After some practice it's quite easy. :)

Oversize
30th May 2016, 04:31 PM
I think the devices I was referring to are more a centre bore adapter rather than a spacer that caters for an incorrect offset. Thus I'd suggest they're legal...

c107
30th May 2016, 07:46 PM
I run 16x7.5 ET23 225/50 on my C107 and find them better than the original 14s.

They rub a bit on the front and so next time I will try 225/55. These wheels and tyres were originally on my C126 where they did not rub.