Wheel offset help urgently required

[JulianG]

Hello Guys,

Yesterday I managed to hit a huge lump of metal laying in the outside lane of the motorway... it burst my tyre and buckled my alloy

Anyway the wheel is beyond repair so I got online and ordered a replacement from Rochford Tyres. They then rung me back today to check I really wanted to order just one as it may not match. I asked why it wouldn't match and they said that the only RS4 V2 replica alloy they sell has an offset of 42 and that they couldn't say whether that was the same as my remaining 3 alloys...
Can anyone tell me if this is correct ?
Not knowing anything about wheels offsets, I always thought that only one size would fit a car ?
If this isn't the case, is there any reason why having a different offset would cause me an issue ?

I guess I should say that my car is a 56reg 2.0 FR TDi and the wheels are 18inch RS4 V2 replica's, running on 225/40/18 tyres.

Obviously I need to get this sorted asap as I can't drive around too much on the wheelbarrow wheel Seat supply as a spare

Cheers guys !

 

[Fl@pper]

measure the old wheel ?

or see if it's marked up in any way ?

 

[Liammc01]

I have Rs4 replicas and they have an offset of 45 and fit fine on my leon 2.0TDI on 06 plate, the bbs standard ones i took off were more of an offset if i remember rightly.

 

[JulianG]

Thanks Fl@pper
At least I know what offset is now ! lol

I'll have a measure up in the morning and see what it is.

Liammc01, now you say that I seem to remember mine being 45 too
If only I could find the invoice I got with them !

 

[Fl@pper]

i always find a small bit of wooden baton that drops just inside the rim will help as most are measured where the tyre beads rather than the actual edge as in the pic

if it was standard rims it would be listed but sadly once you get into replica's and aftermarket wheels it could be open to any size really

 

[leon263]

Have a look at the back of the damaged wheel if you still have it. The off-set will be marked somewhere on the back of the rim. It will begin with the letters ET............ e.g.ET45. If you do not have the damaged one then have a look at the back of an undamaged one. The figure 45 is a measurement in millimeters so if your are offered an ET42 rim then it will sit 3mm further out than the ET45s (unnoticable I would have thought). Be sure that the rim you have been offered is the same width as your current rims. Again you will find that information on the rear of the rim e.g. 18x8J. The width will have the letter J after it.

 

[JulianG]

Have a look at the back of the damaged wheel if you still have it. The off-set will be marked somewhere on the back of the rim. It will begin with the letters ET............ e.g.ET45. If you do not have the damaged one then have a look at the back of an undamaged one. The figure 45 is a measurement in millimeters so if your are offered an ET42 rim then it will sit 3mm further out than the ET45s (unnoticable I would have thought). Be sure that the rim you have been offered is the same width as your current rims. Again you will find that information on the rear of the rim e.g. 18x8J. The width will have the letter J after it.

Right checked the damaged wheel as you suggested... it says ET then blank
I then checked the others still on the car and all of them just say ET and no numbers after it !
They do say 18x8J though !

The more I think about it, the more I seem to remember the paperwork saying ET45, however I can't find the bl**dy paperwork now so I can't check.

But as you say, the difference of 3mm is nothing, so I really can't see that being an issue... although Rochford Tyres said it would be an MOT failure

 

[JulianG]

measure the old wheel ?

or see if it's marked up in any way ?

Right.... I've had a good measure up and I get the following figures :

Rim Width = 235mm
Back Space (B) = 160mm
Therefore half rim width (A) = 117.5mm
so I hope I'm right in saying Offset (C) = B - A
so (B) 160 - (A) 117.5 = (C) 42.5
and therefore my offset is 42 ?

 

[leon263]

Well done , you are correct. Surprised it's not stamped on the rim though. If the width of the new rim is correct I'd be going fot it.

 

[JulianG]

Well done , you are correct. Surprised it's not stamped on the rim though. If the width of the new rim is correct I'd be going fot it.

It looks like it should be stamped but they didn't bother !

Some codes are stamped (D, C and SFI Load)
but others are just blank (ET, PCD, and M)

Anyway good news is that I managed to get a replacement ordered (ET42) and it should be with me by Tuesday. Not impressed with having to pay £25 and not getting next day delivery though !