Tires and offset

[airborne spoon]

I for my winter tires i run 255/40/20 on some 9" rims that are 30 offset. i know the stock rims are 8.5" and 40 offset for the front which is all I'm talking about because the rear tires are just fine.

When i backup and turn the front wheels rub on the inner fender but ONLY in reverse. Obviously this is because i have a different size than stock.

What i need help on is understanding offsets,

You can see on the screenshot from WTF its only a minimal difference in overall size so the issue is clearly the offset that makes it rub while turning in reverse. the first is with the current specs of my stock vs what i currently have, the second is if the aftermarket rims had a 40 offset instead of a 30

What are wheel spacers and can i install one that is equal to the 10 difference in my offset?

I have been using these for the last several years and they work amazing but that noise of the rubbing in reverse is just awful and turns heads in the wrong way and i want to correct it. I have already used a heat gun to mold the plastic a bit further away but its not enough.

 

[Russell]

Adding spacers will make it worse.

The tires rub forward and reverse. You hear it in reverse because the tread blocks are catching on the lower edge of the slats.
Dremel the slats back to reduce the noise.

 

[misterkye]

your new wheels are sticking out by 10mm more than the stock tire. 40mm vs 30mm offset is your issue. 10mm shouldn't be an issue, interested to hear more, however the previous recommendation of dremmel'n your wheel well might solve your issue.

 

[KalJoMoS]

All the comments are accurate already, if you have only rubbing issue then either as suggested to cut or modify by heat gun might be your solution. That same website you mentioned does give you a sketch representing the wheel placement by you given data. I had this available for my ET37 9” rims, I use 5mm universal spacers only at front.

As your is only app. 4mm difference then it might not need any spacers.

 

[Russell]

your new wheels are sticking out by 10mm more than the stock tire. 40mm vs 30mm offset is your issue. 10mm shouldn't be an issue, interested to hear more, however the previous recommendation of dremmel'n your wheel well might solve your issue.

The edge of the rim sticks out 16.3mm more than stock. You have to account for the .5" increased rim width too.

Dremmeling worked for me and my setup is 255/40/20 8.5 ET24.

 

[Russell]

I for my winter tires i run 255/40/20 on some 9" rims that are 30 offset. i know the stock rims are 8.5" and 40 offset for the front which is all I'm talking about because the rear tires are just fine.

<snip>

Your winter setup almost identical to my setup.