Help with wheel offset

JAMES VTI S

I bought a set of wheels/tyres for my van but the rear wheels are scrubbing the inner arch lines and I've to take the new wheels/tyres off until I can sort it out. The information I've found so far is.

My van

Volkswagen Caddy 2007, 1.9TDi 105HP
6Jx16 ET50

The wheels I bought are off an

Audi A3 2004, 1.9TDi 105HP
6.5Jx16 ET50

Do I need spacers as I notice the rims sit more inside the arch than the last set, the last set were 16' also with 205/55/16r tyres.

Neilw

JAMES VTI S wrote: »

I bought a set of wheels/tyres for my van but the rear wheels are scrubbing the inner arch lines and I've to take the new wheels/tyres off until I can sort it out. The information I've found so far is.

My van

Volkswagen Caddy 2007, 1.9TDi 105HP
6Jx16 ET50

The wheels I bought are off an

Audi A3 2004, 1.9TDi 105HP
6.5Jx16 ET50

Do I need spacers as I notice the rims sit more inside the arch than the last set, the last set were 16' also with 205/55/16r tyres.

Are those widths and offsets taken from your wheels or off the web?

JAMES VTI S

Neilw wrote: »

Are those widths and offsets taken from your wheels or off the web?

Off the Web I'm taking the wheels of in a minute.

JAMES VTI S

This is what I found.

Bottom is the wheel that rubs the rear arch liners.

Neilw

Ok, so the offsets are different.

Your new wheels (bottom) are an inch narrower and sit 8mm closer to the inside of the arch compared to your old ones.

Strange that a narrower wheel with only 8mm offset difference rubs.

JAMES VTI S

What size do I need

Neilw

Are tyres the same size on both wheels?

JAMES VTI S

Yes. 205/55/16R

DakarVert

Can't see how they rub,

Taking off a 7J ET42 and fitting a 6J ET50 will "Compared to your existing wheel, this new wheel will have an inner rim which is 4.7mm further away from the suspension strut. The outer rim will poke out 20.7mm less than before"

Where on the liner does it rub?

DakarVert

Neilw wrote: »

Ok, so the offsets are different.

Your new wheels (bottom) are an inch narrower and sit 8mm closer to the inside of the arch compared to your old ones.

Strange that a narrower wheel with only 8mm offset difference rubs.

It won't be 8mm only if wheels are the same width.

The offset is basically the distance the mounting face is in relation to the center line of the alloy.

So an inch difference being 25.4mm, half that (You take a 1/2" of each side of the wheel, As the offset is measured from the Center)

Means the alloys is 12.7mm narrower on each side, The subtract the 8mm difference (Higher offset will sit the wheel further in) Which will make the new wheel sit 4.7mm further away from the strut.

JAMES VTI S

New wheels on the bottom

JAMES VTI S

Looking at the marks on the arch liners I'd say I might need 8 or 10 mm spacers. Wild guess

colm_mcm

You need 8mm spacers, simple as that.

Lower offset = wheels stick out, higher offset = wheels go inboard.

Tyres are the same and sit symmetrically on the wheel, so width of wheel is irrelevant.

To get the tyre sitting where it was, you need 8mm spacer.

Hub surface vs middle of tyre was 42mm (going towards the middle of the van), now it's 50mm.

JAMES VTI S

It's only rubbing at the rear, will I get away with doing this to just the rear.

colm_mcm

Personally I would do all 4 anyway as the geometry would be out.

FWIW I preferred your old wheels.

Neilw

DakarVert wrote: »

It won't be 8mm only if wheels are the same width.

The offset is basically the distance the mounting face is in relation to the center line of the alloy.

So an inch difference being 25.4mm, half that (You take a 1/2" of each side of the wheel, As the offset is measured from the Center)

Means the alloys is 12.7mm narrower on each side, The subtract the 8mm difference (Higher offset will sit the wheel further in) Which will make the new wheel sit 4.7mm further away from the strut.

Yes, I was going on the original post where the widths were the same. Forgot to edit my post

Neilw

OP has the van been lowered? Looks lower in the bottom pic.

JAMES VTI S

Yes the van have a V_maxx suspension kit fitted.

What kind of spacers are recommended and do I need new wheel bolts

DakarVert

colm_mcm wrote: »

You need 8mm spacers, simple as that.

Lower offset = wheels stick out, higher offset = wheels go inboard.

Tyres are the same and sit symmetrically on the wheel, so width of wheel is irrelevant.

To get the tyre sitting where it was, you need 8mm spacer.

Hub surface vs middle of tyre was 42mm (going towards the middle of the van), now it's 50mm.

But the new wheels sit 4.7mm further in from the suspension! See my earlier post with an explanation.

Hang on was the van lowered with the new wheels?

If so its the lowering that's the problem (Would be worse with the old wheels)

colm_mcm

Stick a bolt through the old wheels and measure how much thread at the back of the wheel, stick a bolt through the Audi wheels and compare.

JAMES VTI S

DakarVert wrote: »

Hang on was the van lowered with the new wheels?

Same ride height for both new and old wheels. Yes.

colm_mcm

DakarVert wrote: »

But the new wheels sit 4.7mm further in from the suspension! See my earlier post with an explanation.

Hang on was the van lowered with the new wheels?

I saw your post, but I don't think your calculations are correct.

DakarVert

colm_mcm wrote: »

I saw your post, but I don't think your calculations are correct.

willtheyfit.com will give you the results.

A 0 offset alloys means the mounting face is exactly on line with the Center of the alloy, Then the higher the number the further the alloy will sit from the arch.

Hard to explain, But a 7J ET50 and 7J ET42 is a simple difference of 8mm not when it's 6J and 7J though as the Center line is different.

For example a 7J ET40 and 6J ET40, The 6J will sit 12.7mm further away from suspension AND 12.7mm further away from the arch. (You lose. 1/2" each side) Not the same if that makes since.

DakarVert

JAMES VTI S wrote: »

Same ride height for both new and old wheels. Yes.

Same ride height both wheels?

I honestly can't figure it out then, The 'maths' says it should have more clearance if anything.

Maybe it's the difference in the tyres, Possibly XL tyres or something.

colm_mcm

If you take a 2 wheels with 0 offset, 1 6j and 1 7j both with 205mm tyres, the centre line of the wheels and tyres will be exactly the same, and the position of the tyres relative to the arches and suspension would be the same too.

The offset relates to the centre of the wheel (and thus the tyre) vs the position of the hub. The width of the wheel itself doesn't come into it.

DakarVert

colm_mcm wrote: »

If you take a 2 wheels with 0 offset, 1 6j and 1 7j both with 205mm tyres, the centre line of the wheels and tyres will be exactly the same, and the position of the tyres relative to the arches and suspension would be the same too.

The 6J wheel will sit 12.7mm away from suspension and 12.7mm away from the arch.... Your losing an 1" in width, So because the Center line is the same you lose 1/2" each side.

But yes the tyres should be the same give or take, Tyres arn't always 100% exact in measurement though, Varies from tyre to tyre.

JAMES VTI S

colm_mcm wrote: »

Stick a bolt through the old wheels and measure how much thread at the back of the wheel, stick a bolt through the Audi wheels and compare.

Good idea

colm_mcm

DakarVert wrote: »

The 6J wheel will sit 12.7mm away from suspension and 12.7mm away from the arch.... Your losing an 1" in width, So because the Center line is the same you lose 1/2" each side.

But yes the tyres should be the same give or take, Tyres arn't always 100% exact in measurement though, Varies from tyre to tyre.

yes, the wheel will be narrower, but the tyre will be the same as it sits equally on both sides of the wheel. (Ignoring minute differences in how the sidewall would be)

A 50 offset wheel with an 8mm spacer will line up the same as a 42 offset wheel.

Keep in mind the OPs new wheels are actually narrower, but tyres are still rubbing

Neilw

Is the arch liner being rubbed in front of the rear wheel or behind it?

JAMES VTI S

Neilw wrote: »

Is the arch liner being rubbed in front of the rear wheel or behind it?

Back

vectra

JAMES VTI S wrote: »

What kind of spacers are recommended and do I need new wheel bolts

Hub Centric.

JAMES VTI S

So it's 8mm I need?