18" alloys

[vinay.chapaneri]

Hi to anyone,

I have a W203 with factory fit 15" alloys i want to upgrade to 18" alloys can anyone tell me if this will effect the ride, brakes or give me any sort of advice before i part with my money

many thanks

 

[guydewdney]

ride will be considerably harder / hasher. make sure that you get the offset (ET figure) to match...

17s are a better compromise... but its up to you

 

[LAND-ROVER 90]

Going from 15 to 18 will make the car feel as if it is very hard.you will feel every bump on the road as you will need to fit very low profile tyres,and they will wear out quicker.
The only good side is they will look great.
Good luck watever you decide.

 

[vinay.chapaneri]

Guys

the wheels i have in mind are 18"AMG replica on 225/40/R18 tyres , the man in the shop told me that the rolling diameter is the same and it wont effect the ride as the height of the car is the same. is he right, i dont want to spend any money if it will comprise the ride or any other part of the car.

I looked onthe official merc web page and you can upgrade to 18" alloys with the same tyre. however it mentions that when you have 17" AMG the et on the back is 35 and et ont he front is 37 can you tell me what that mean?

also will aftermarket wheels take the ET into consideration?

 

[guydewdney]

et is the offset - ie how much the wheel is offset from the brake disc.

37 et means its 37mm from the disc / mounting point to the outside edge of the rim.

aftermarket ones are made in all sizes - you need to check this - a few mm either way is ok (like 5mm) - any more is going to negativly affect handling.

tyre diameter / rolling radius should be kept similar to the originals for the speedo to be accurate (amongst other things)

to work out tyre size:-

225/45/18 => 225mm x 45% = tyre wall height (in mm)

18" = diameter of wheel rim

total = 18/2 (9") + tyre wall height/25.4 (to make into inches)

do the same for both, make sure they are very similar.

 

[talbir]

Sorry, but offset is NOT the measurement from the mounting face to the edge of the rim. If it was, then an ET of 35mm would suggest that the wheel was only about 10cm wide !

The offset is the measurement from the hub face to the centre line of the rim, not the wheel edge. If the hub face extends beyond the centre of the rim towards the inner wheel arch, then it is a negative offset (as seen on some trucks and Widebody MB's such as W126 SEC widebody's which had 11" rear tyres with an ET of -12.7 !). But with standard MB's the offset is always positive as the hub face does not extend beyond the centre point of the rim.

Moreover offset means absolutely NOTHING without considering the WIDTH of the wheel. The two need to be considered together. If two wheels have the same ET number but one is 7.5" and the other 8" then you have a 1/2inch difference -which can be enough to cause plenty of damage. If the width of the wheel increases, then generally the ET should be decreasing.

If you have a wider wheel with a lower offset, it will stick out further than stock - this could have implications in respect of rubbing the arches etc, but putting that to one side, your car will have a wider track, which means IMPROVED handling. But of course this only works if the offset/width combination sit well with the dynamics of the car and suspension, i.e. if it's not aggresively lowered and there is room in the arch for a wider wheel etc.

ET and width are absolutely crucial - rolling diameter only needs to within 1% of stock. But if you are 1mm wrong with offset/width combo, it can be very damaging.

talbir

 

[SUE.]

Offset is the measurement in millimeters from the wheel centre line to the wheel mounting face. More often than not, offsets are positive(+) where wheel styles tend to be flush or convex. Negative (-) offsets tend to have concave styling

This might explain it better.

 

[sooper coop]

Sue.

your knowledge of rim-width knows no boundaries.

and you thought i should get out more.

 

[SUE.]

Sue.

your knowledge of rim-width knows no boundaries.

and you thought i should get out more.

Dont take it to heart,i was only jokeing.Sorry.

 

[guydewdney]

i wasd just trying to keep it simple - and yes - i was wrong - but the basis of what i said was still right... noone else seemed to respond, so i thoguth i'd lob in some info...

 

[SLinKyjoe]

15 inch to 18 inch

rim widths...no boundaries....wrong but yet still right!!!!!


is that an elephant over there?

 

[SUE.]

rim widths...no boundaries....wrong but yet still right!!!!!


is that an elephant over there?

SEE!. I told you i am not dumb,Blonde maybee.

 

[tom7035]

NEVER had any problems like this with the Austin Sixteen!

 

[liteuser]

i have 18" AMG reps on mine, fit well with no rubbing

 

[shadowninja]

The problem with 18s is that you'll tramline on dual carriageways/motorways. It can feel like you're driving a boat in choppy waters. On the upside, your car will look cool as you get flung off the road into a ditch.

 

[whitenemesis]

The problem with 18s is that you'll tramline on dual carriageways/motorways. It can feel like you're driving a boat in choppy waters. On the upside, your car will look cool as you get flung off the road into a ditch.

So true!! LOL

 

[andy66]

when i fitted 18's on my c class the difference in ride and comfort was very noticeable...(far worse than standard),i had problems with "tramlining" on many roads and found the ride very harsh so i sold them on...BUT THEY DID LOOK GOOD!!!

 

[liteuser]

i disagree, sorry, i drive from Cardiff to Cambridge, (210 miles) regularly and not one problem, but i am in the outside lane, lane 1 is for lorries only, he he.

 

[DR&SJL]

Does anybody know of a site or source of old Merc brochures? That way you can see if the 18 inch wheels that you are sourcing, probably from a scrap yard, are the correct ones for the car of that year. Web site with scanned copies would be ideal. I have a 1998 R129 face lift with 17 inch wheels but I am also thinking of going for 18 inch ones.