[OneTwo3]

Stock g87 wheel sizes are

Front 9.5 x 19” ET20mm
Rear 10.5 x 20” ET20mm

a staggered Edelweiss LT3 set is

Front 10.5 x 19" ET14mm
Rear 11 x 20" ET12mm

Compared to stock, the edelweiss fitment would be the equivalent of having around an 18mm spacer in front and 15mm in rear for the stock wheels.

Is this correct?

[aerobod]

Originally Posted by OneTwo3

Stock g87 wheel sizes are

Front 9.5 x 19” ET20mm
Rear 10.5 x 20” ET20mm

a staggered Edelweiss LT3 set is

Front 10.5 x 19" ET14mm
Rear 11 x 20" ET12mm

Compared to stock, the edelweiss fitment would be the equivalent of having around an 18mm spacer in front and 15mm in rear for the stock wheels.

Is this correct?

No, ET is based on wheel centerline, not wheel width. It is the equivalent of 6mm front and 8mm rear spacers.

From a tyre clearance perspective, assuming some increase in tyre width to match the wheel width increase, the sidewall will be about 8mm closer to the strut and 19mm closer to the fender at the front, at the rear about 2mm further from the inner wheel well and 14mm closer to the fender. If you use the same tyres they will look more stretched and will not be as close to the strut or fender than the appropriately wider tyres.

[OneTwo3]

Originally Posted by aerobod

No, ET is based on wheel centerline, not wheel width. It is the equivalent of 6mm front and 8mm rear spacers.

From a tyre clearance perspective, assuming some increase in tyre width to match the wheel width increase, the sidewall will be about 8mm closer to the strut and 19mm closer to the fender at the front, at the rear about 2mm further from the inner wheel well and 14mm closer to the fender. If you use the same tyres they will look more stretched and will not be as close to the strut or fender than the appropriately wider tyres.

Hmmm, this seems off.

The front wheel’s offset difference is 6mm(negative direction), meaning the new wheel sits 6mm further out compared to stock based on offset alone. Since it’s also 1 inch (about 25mm) wider overall, that adds roughly 12mm to each side.

So in total, the wheel should sit about 18mm further out.

Does that sound right, or am I misunderstanding how offset works?

[aerobod]

Originally Posted by OneTwo3

Hmmm, this seems off.

The front wheel’s offset difference is 6mm(negative direction), meaning the new wheel sits 6mm further out compared to stock based on offset alone. Since it’s also 1 inch (about 25mm) wider overall, that adds roughly 12mm to each side.

So in total, the wheel should sit about 18mm further out.

Does that sound right, or am I misunderstanding how offset works?

That is correct if the tyre size increases by the width of the wheel, but the tyre sidewall should be the widest part of the wheel/tyre assembly unless a ridiculous stretch beyond tyre spec is done. If you use the stock tyres on a wider rim, the sidewall won't move out as much as the rim width increase as the tread is still the same width, the tyre will just become more stretched

Putting 295 or 305 wide tyres on all 4 wheels wider wheels would bring the tyres out to a point close to where the stock wheels and tyres with 18/15mm spacers would be. The 285/30-20 rear tyres are only recommended on rims up to 10.5" wide anyway.

[OneTwo3]

Originally Posted by aerobod

That is correct if the tyre size increases by the width of the wheel, but the tyre sidewall should be the widest part of the wheel/tyre assembly unless a ridiculous stretch beyond tyre spec is done. If you use the stock tyres on a wider rim, the sidewall won't move out as much as the rim width increase as the tread is still the same width, the tyre will just become more stretched

Putting 295 or 305 wide tyres on all 4 wheels wider wheels would bring the tyres out to a point close to where the stock wheels and tyres with 18/15mm spacers would be. The 285/30-20 rear tyres are only recommended on rims up to 10.5" wide anyway.

I see. I want taking the tire into account at all. Thanks!

[Vojta89]

Originally Posted by OneTwo3

Stock g87 wheel sizes are

Front 9.5 x 19” ET20mm
Rear 10.5 x 20” ET20mm

a staggered Edelweiss LT3 set is

Front 10.5 x 19" ET14mm
Rear 11 x 20" ET12mm

Compared to stock, the edelweiss fitment would be the equivalent of having around an 18mm spacer in front and 15mm in rear for the stock wheels.

Is this correct?

Next time you can just use willtheyfit.com

[OneTwo3]

Originally Posted by Vojta89

Next time you can just use willtheyfit.com

Nice! Thanks for sharing. It looks my math was pretty close.

[aerobod]

Originally Posted by Vojta89

Next time you can just use willtheyfit.com

Although that site shows rim position, it doesn't show the tyre clearance, which is generally the issue for rubbing and getting a flush looking fit.

A 275/35-19 MPS4S has a nominal width of 275mm, but the quoted measured value on a 9.5" wide rim is 277mm with a 249mm tread width. On a 10.5" rim it isn't going to have a measured width that increases by 25mm, it is going to be more like about 290mm and the tread width is still 249mm. The tread position is only going to move by the ET change in the wheel - 6mm in this case.

A 295/30-19 MPS4S has a nominal width of 295mm, with a quoted measured value of 302mm on a 10.5" wide rim and a 279mm wide tread. It's sidewall will move out equivalent to a 23mm spacer on the stock wheel and tread will move out equivalent to a 21mm spacer on the stock wheel, but the position of the tread edge will be 8mm closer to the wheel centre. The 285/35-19 MPS4S has a tread width of 254mm, so it will be equivalent to using an 11mm spacer on the stock wheel when looking at the edge of the tread, which will also be 4mm further away from the wheel centre.