Wheel Offset....Doing my head in!!!!

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Boycie

New Member
Joined
Oct 27, 2004
Messages
23
Car
98 C180 Sport Estate 17" AMG alloys/04 CLK 200 Kompressor Cabriolet.
Hi Everybody,
2004 CLK 200 Kompressor Cabriolet fitted with 7J x 16 H2 ET 37. 205/55R16 Front
and 8J x 16 H2 ET 32. 225/50R16 Rear. If i change to the following set up would it work and would the wheels/tyres fill the arches properly?
7J x 17 H2 ET 37. 205/50R17 Front.
7J x 17 H2 ET 37. 225/45R17 Rear.
Will the rear need a 5mm spacer to bring the offset back to ET32?

Any Help would be good!

Thanks Boycie. :crazy:
 
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No spacer needed. Your 16s are staggered , i.e. wider at the rear, and the 17s are same width all round.

They will fit perfectly !

Sounds like the tyres on the fronts are too narrow tho' ... they should be 225/45/17, same as the rears.

S.
 
Boycie said:
Will the rear need a 5mm spacer to bring the offset back to ET32?

not if my maths is correct :)

the outside of the rear rim should be in just about the same place (give or take a cm) - the rim is an inch narrower so if they shared the same offset the outer edge would be half an inch nearer the centre of the car but by switching to an offset of 37 you move the rim out by 5mm so at the end of the day the outer edge of the rim will be approx 8mm inside the current set up.

Does that make sense?

Andy
 
Hello Boycie - had some fun with wheels/offsets in the past so here goes....

As far as replacing the wheels with the ones you have suggested would be possible but ......

a) As Sym pointed out the front tyre is too thin and should be 225 width - same as the rear as the wheel width is identical

b) As the latter combination has width of only 7" whereas your current rear wheel setup is 8" - this would mean that the outside edge of the wheel would actually retract toward the car by 18mm ( 3/4 of an inch )

Your question regarding if the wheels would fill up the arch - they won't - actually the opposite would happen with the rears and even with a 5mm spacer and 10 new bolts ( 5mm longer ) the wheel would still be sat 13mm more toward the body of car.

IMHO I would not do this change - even though 17" look visually better from the side looking toward the doors etc I would wait for a staggered 17" setup like 7.5 x 17 up front with 8.5 x17 at rear.

Hope this helps..
 
I'll come back in here and try to answer jasohal's points as well (to the best of my knowledge). Most of the points I'm making here are things I have learned/been told from a friend who is a very experienced tyre fitter

7J rims are designed for 195 or 205 tyres so 225 tyres are too wide and the cars handling could suffer - if you are going to stay with any tyre size then the 205s on the front are fine but should be your maximum width - there is however no reason why you can't run different tyre sizes front and rear - on my 8" rims I have 205s on the front and 225s on the back :).

Jasohal, I think your maths is more flawed than mine in your answer to part 2 - an 8" rim is only half an inch wider at the outside edge than a 7 inch rim so the outside edge would only move in the 8mm I suggested there will also be about 12mm additional clearance on the inside edge of the wheel so there should be no danger of fouling.

I agree that they won't fill the arches any more than your current setup and may not be worth the outlay.

Andy
 
Andy_K,

I hear you about the tyres - 225 is perhaps too wide for a 7" wheel.

However, from what you are saying - the wheel will retract 8mm from the outer edge and about 12 mm from the inner edge. That makes a total reduction in width of 20 mm. What about the missing 5.4 mm ??

If the offset remained the same - and the wheel decreased in width by an inch - surely you'd lose 12.52 mm from the outer edge and 12.52 mm from the inner edge.

But in this case there is also a difference in offset of 5mm - therefore the wheel will retract 12.54mm + 5mm = 17.54 mm ...
 
Fleagle said:
Offset calculator at http://toy4two.home.mindspring.com/offset.html

Your new wheel will have the following chracteristics:
The clearance from stut housing to the inside of the wheel will be 8mm MORE
The outside edge of the wheel will RETRACT in towards the body by 18mm

So, points all round to jasohal!

Also quite a handy tyre size calc at http://www.1010tires.com/TireSizeCalculator.asp

Regards, Dave

DOHH :crazy:

Great minds think alike!!
 
Cheers Boyz, just goes to show you cant trust a sales man! " Yea mate no prob they will bolt on and look the same as the merc wheels". So its a case of waiting for some ET30 and ET37's or maybe spacers on the back. Anybody got any input on spacers?
Cheers Boycie. :confused:
 
There is a range of acceptable ET for all Mercedes models. Even with the same width rim, oem Mercedes wheel offsets vary considerably.
17x7.5 all round or 17x7.5 front, 8.5 rear is standard for the CLK.
16x7 all round or 16x7 front, 8 rear is standard oem fitment for 16"
You can squeeze 19x11 under the rear arches on a CLK..
Which 17" wheels would you like?
 
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