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Wheel Offset, what you need to know


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One thing I get asked a lot is what VW wheel offsets are and how to work them out.

 

The first thing I'll add is a link to one of the easiest to read calculators I've found online:

http://www.1010tires.com/Tools/Wheel-Offset-Calculator

 

Wheel dimensions are funny things, partly in millimetres and partly inches, so are a truly international blend of confusion.

Obviously everyone is aware of wheel diameters and widths being in inches. The width of a passenger car wheel is often referred to as J (e.g. 8J X 19) which is an industry marking to do with bead profile and not something I'm here to bore you with.

Also on wheel markings/stampings you'll often see an H along with possibly another suffix too, this is quite simply for the hump in the wheel which is positioned to increase the strength of the wheel, e.g. H2. Google is your friend here if you're interested in specifics or this post will just get bogged down with pointless info.

 

Then we have the PCD, the Centre Bore and the Offset. These three things will determine whether your wheels will fit your hubs and the latter will be the deciding factor as to whether the wheel will physically fit in the wheel arch.

 

Offset

This is measured in millimetres and referred to as ET (einpresstiefe which is the German for insertion depth).

The Golf (& Scirocco) are based on FWD chassis despite the former's R models being 4WD.

FWD cars tend to have what's called positive offset (this helps with keeping the wheels pointing straight ahead when moving and aids stability).

If you have a look at the wheel diagram on the link I posted it shows how offset is calculated. There's an imaginary line running down the middle of the wheel profile and the offset is the distance between this and the rear of the hub mounting.

 

In very simple terms when dealing with modern passenger car VW's the lower number ET means the further the wheels will stick out, or in current fashion terms "stance" or "poke".

Lower ET = more poke. Or in English the wheel face will stick out more.

 

How much is too much? I can't really answer that as there are a lot of variables and whatever I state here someone will argue the case that they've done bigger and better.

In layman's terms if you want to fit bigger or wider wheels, or even just change the offset by fitting spacers there's a certain amount of room to manoeuvre before you have to resort to more drastic things like changing the suspension geometry and flaring the wheel arches themselves.

 

Factory wheels on a mk6 Golf R are 7.5 x 18 with an offset of 51 or 8 x 19 with an offset (ET) of 50

The mk7 Golf R gets much bigger wheel arches so the 7.5 x 18 wheels get a whole 2mm less offset at ET49 and the 8 x 19 wheels keep the same offset as the mk6 R at 50mm.

 

If the reason you're putting wider wheels or spacers on the car is purely to fill out the wheels arches (or 'stance' the car if you're down wiv da kidz) then how little offset is too much? I can't answer that as different people have different opinions and different uses for their cars. 

If it's an occasional driver or used for static show displays and MaccyD late night cruising then I guess your version of filling the arches will be different to someone who needs to drive in rutted lanes or potholed urban rat runs that are infested with speed humps. 

 

As a guide I'll say that an 8" wide wheel on a mk6 should be ideally around ET44 but I've personally got away with ET41 using 235 tyres on a non lowered car.

 

With a mk7 you have much more wheel arch space to play with. You can get away with ET40 on the front and probably ET35 on the back or possibly even slightly lower offset, again using an 8" wide wheel.

With an 8.5 inch wide wheel I'd say ET45 and maybe slightly less ET at the rear. BBS seem to prefer ET46 on a mk7. I've never tried 8.5 wheels on a mk6.

 

PCD & Centre Bore

As far as mk6 and mk7 Golfs are concerned (plus Sciroccos and Passats etc) then the magic numbers here we need to see are 5x112 for PCD (Pitch Circle Diameter) which refer to the bolt holes.

And our wheels require a 57.1mm centre bore. This is the hole that runs through the centre of the wheel and is needed to mount the wheel squarely on the hub so that you don't get vibrations and wheel bolts that undo themselves randomly (or even snap). Centre bore can be higher so long as you fit a spigot ring to reduce the hole to 57.1mm

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One thing I get asked a lot is what VW wheel offsets are and how to work them out.   The first thing I'll add is a link to one of the easiest to read calculators I've found online: http

If I’m ok to add a bit of extra info to this (after spending a fair bit of time playing around with different fitments on my mk6 R). This will probably appeal to those of us interested in achieving ae

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If I’m ok to add a bit of extra info to this (after spending a fair bit of time playing around with different fitments on my mk6 R). This will probably appeal to those of us interested in achieving aesthetic results. I know us mk6 guys are outnumbered, but we’re still out here!

 

19x8.5 et48 with 225 35 19 PS4S and 5mm spacers are pretty much bang on the limit of rub on H&R springs, assuming you do the arch screw delete and liner tuck. It’s what I’m currently running, the car sees some rough roads, and I avoid anything fouling. So effectively a final et of 43. 
 

It’s important to note that had I used 235 35 19 tyres I would not have had as much clearance, and likely would have rubbed. The 225 35 on an 8.5” rim creates a tiny bit of stretch, which goes a long way in avoiding rubbing. 
 

Also important to remember that not all tyres of the same dimensions have the exact same profile. A Toyo for example in 225 35 19 might have a much narrower tread width than a Michelin 225 35 19. This is something to consider, and it’s not an exact science. 


Couple of pics of the fitment:

 

60C2BDD6-FD5F-453D-BE6F-4B6B4400F7ED.thumb.jpeg.061bef1f2acc63634cf8cc286fbe00f7.jpeg
9AF75248-7B90-4DF8-A2CE-60D7891C44D4.thumb.jpeg.eb3bbf366428aa63a81e281cb7cddf68.jpegD788E566-AAAC-4192-8732-A9DE6B891460.thumb.jpeg.b5557be62b61f65fefb9908502858bca.jpeg
 

Oh, and something I see people messing up on a lot…

 

The 35 in 225 35 19, or for example the 40 in 225 40 18, is not a measurement per se, it’s a percentage of the tread width. So in my case 35% of 225mm. A 35 or a 40, 45, whatever, can be many different things, depending on the tread width. It’s crucial in understanding that if you’re trying to work out fitment. Just a bugbear of mine, that’s all 😬

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