Which offset for the rear axle at 11x19?

[47Ronin]

Hello friends,

I am considering to order magnesium wheels from Litespeed Racing for my Z28. The problem is that Litespeed can only produce magnesium wheels up to a width of 19x11. So I thought I would go from 11.5x19 to 11x19 in the back.
Does anyone know which offset to choose to make it fit in the rear?
The offset from the 11.5x19 is +32, as you know all.

Thanks!

[j o n]

Offset and tire width are what matters... If you're using the same 305 width... Use the same offset

Offset is measured off a wheel's center, not an outer edge. So rim width is irrelevant

use this tool for visual
https://rimsntires.com/specspro.jsp

And if you're getting wheels made, get 4 with the same specs and use spacers in the front for the offset variance. So (4) 19x11 +31 wheels and then run a 20mm spacer upfront to get it to the +11 spec. Then you can rotate the wheels and tires

[47Ronin]

Originally Posted by j o n

Offset and tire width are what matters... If you're using the same 305 width... Use the same offset

Offset is measured off a wheel's center, not an outer edge. So rim width is irrelevant

use this tool for visual
https://rimsntires.com/specspro.jsp

And if you're getting wheels made, get 4 with the same specs and use spacers in the front for the offset variance. So (4) 19x11 +31 wheels and then run a 20mm spacer upfront to get it to the +11 spec. Then you can rotate the wheels and tires

Okay, thanks for the infos.

[pat_t]

Originally Posted by j o n

And if you're getting wheels made, get 4 with the same specs and use spacers in the front for the offset variance. So (4) 19x11 +31 wheels and then run a 20mm spacer upfront to get it to the +11 spec. Then you can rotate the wheels and tires

This is more or less what I've done with my second set of wheels to allow it to be rotatable.

I have (4x) 19x11 +25 wheels and running a 15mm rear spacer and a 20mm front spacer.

But also note you will need to fit extended wheel studs to the hubs in order to be able to run 15/20mm spacers.

[Mark_Z28]

Is there a reason the front 19x11s woudn't work in the rear? Is there a physical clearance issue I'm missing?

[Icedog]

I had a set made...

19x11 offset 32 - 120x5

[pat_t]

Originally Posted by Mark_Z28

Is there a reason the front 19x11s woudn't work in the rear? Is there a physical clearance issue I'm missing?

No reason. OE fronts work on the rear, but not vice-versa.

OE front on the rear will have about 10mm more poke out of the arches which isn't much. Looks quite good like that.

[Mark_Z28]

Awesome! Thanks Pat.

[j o n]

Originally Posted by Mark_Z28

Is there a reason the front 19x11s woudn't work in the rear? Is there a physical clearance issue I'm missing?

The fronts are an 11 offset, the rears are 32.25 offset. The fronts on the rears would be 21.25mm more towards to outside of the car. Depending on compression of suspension, contact with the qtr panel or flare is possible.

People have run 26 offset wheels, on the rears, with 305s on the track, no problem

[pat_t]

Originally Posted by j o n

The fronts are an 11 offset, the rears are 32.25 offset. The fronts on the rears would be 21.25mm more towards to outside of the car. Depending on compression of suspension, contact with the qtr panel or flare is possible.

People have run 26 offset wheels, on the rears, with 305s on the track, no problem

Your quoted offsets are correct, but your 21.25mm is wrong.
This is because the front is an 11J wide rim rather than 11.5J.

As I said, it's more like 10mm further out, and it works fine, even with 325s There is loads of room in the wheel arches on these cars.

[j o n]

Originally Posted by pat_t

Your quoted offsets are correct, but your 21.25mm is wrong.
This is because the front is an 11J wide rim rather than 11.5J.

As I said, it's more like 10mm further out, and it works fine, even with 325s There is loads of room in the wheel arches on these cars.

tire width is what matters, not the wheel width. If you're using 305's square, wheel width is irrelevant

offset is measured off the wheel's center line, which is constant, changing the wheel's width has no impact on measuring offset

For visual:
https://rimsntires.com/specspro.jsp

[pat_t]

Originally Posted by j o n

tire width is what matters, not the wheel width. If you're using 305's square, wheel width is irrelevant

offset is measured off the wheel's center line, which is constant, changing the wheel's width has no impact on measuring offset

For visual:
https://rimsntires.com/specspro.jsp

Yes. Your words are correct but don't tie up with your earlier assertion that the outer of the wheel would be 21.25mm further out.

I thought it was 10mm but it's actually 14.7mm to be exact:

[j o n]

Originally Posted by pat_t

Yes. Your words are correct but don't tie up with your earlier assertion that the outer of the wheel would be 21.25mm further out.

I thought it was 10mm but it's actually 14.7mm to be exact:

Use the tool i referenced
https://rimsntires.com/specspro.jsp

[pat_t]

Originally Posted by j o n

Use the tool i referenced
https://rimsntires.com/specspro.jsp

Yep, that ties up.. rounds it to 15mm. Close enough.

For ref the first one I used was www.willtheyfit.com