Unbearable Arch Rub!

[bmwaddict]

Thanks for this...how do I get the offset changed?

You can't, offset is how close the mating face of the wheel is in relation to the front/back of the wheel. All alloys have an offset, usually stamped into the back of the spokes.

Not strictly true as a higher offset can be made lower with spacers , a lower offset however is far trickier to deal with although machining off the rear is not impossible , Machinemonkey has done this i believe :?

True Mr W, just explaining to the o.p. that in terms of immediate effect offset can't be changed, as in the wheels are that offset and they always will be, but as you say spacers have the effect of altering offset, as can machining the wheels.

 

[Dav the wheel nut]

What is the offset of your wheels? It could be the most significant point in all this and yet no one has mentioned it

Not sure what my offset is (or how to check it). From the sounds of things this could be the problem. Any ideas what they should be?

The offset, as someone has mentioned, is stamped on the inside of the wheel rim. It is shown as an et number. For example it will be stamped as et35 or et38. If you find this number and give the width of the wheels eg. 8 inch or 8.5 inch wide, it will be a starting point to try and sort it.
I run 8.5'' on the front, offset et35, lowered on eibachs without any issues.
I always say to people you are playing with very small margins when you change wheel sizes and one or two millimetres can make all the difference

 

[Raj_UK]

I machined wheels once upon a time to increase offset by a few mm. Was a major fail I didn't take into account after machining the part of the wheel mating to the hub would be wider and it was fouling against the brake caliper!!

 

[idej_z4]

What wheels have you got?

Riva DTMs

 

[idej_z4]

Offset explained

http://www.rimstyle.com/pages/alloy_wheels_explained.html

Thanks for this!!! Reading it sounds like my offset is too high as I'm getting arch rub. It also sounds like I can fix it with spacers. Just need to work out what size to get.

 

[idej_z4]

What is the offset of your wheels? It could be the most significant point in all this and yet no one has mentioned it

Not sure what my offset is (or how to check it). From the sounds of things this could be the problem. Any ideas what they should be?

The offset, as someone has mentioned, is stamped on the inside of the wheel rim. It is shown as an et number. For example it will be stamped as et35 or et38. If you find this number and give the width of the wheels eg. 8 inch or 8.5 inch wide, it will be a starting point to try and sort it.
I run 8.5'' on the front, offset et35, lowered on eibachs without any issues.
I always say to people you are playing with very small margins when you change wheel sizes and one or two millimetres can make all the difference

I'm running 8 inch at et34 on the front - as you've got 8.5 could the answer be to get some 5mm spacers??? Cheers.

 

[jamie_z4]

You won't fix it with spacers mate it will make the problem even worse It will make the wheels more prominent which will rub the Arches more. Only resolution is wheels with a higher offset or raising suspension

 

[idej_z4]

You won't fix it with spacers mate it will make the problem even worse It will make the wheels more prominent which will rub the Arches more. Only resolution is wheels with a higher offset or raising suspension

Gutting! The article that I just read said that if the offset was too high it could be fixed with spacers.

 

[jamie_z4]

The problem is your offset is too low. The lower the offset the further out from the hub the wheel is

 

[Ducklakeview]

Just a point..

You haven't got staggered wheels have you, ie different offsets front and rear? If so, is it possible you have a rear wheel on the front, or vice versa??

Mike

 

[Buckz]

What wheels have you got?

Riva DTMs

so 19x8 et34..

weird that you get rub!

I'm running 19x8.5 et38 with 235 rubber and I've got no issues.

I'd sell your set tbh and get a set of cmwheels csls.

http://www.cmwheels.com/index.php?route=product/product&product_id=1247

 

[mr wilks]

You won't fix it with spacers mate it will make the problem even worse It will make the wheels more prominent which will rub the Arches more. Only resolution is wheels with a higher offset or raising suspension

Gutting! The article that I just read said that if the offset was too high it could be fixed with spacers.

Simply put Dan if your offset was 50 you could make it lower by adding a spacer so for example adding 15mm spacer would make your et or offset 35
Now if your offset is already 35 & you added a 5mm spacer it would make it 30 , , & the basic rule is the lower the number the further from the hub sits the wheel face so therefore a higher offset number can be made lower but a lower cannot be made higher ( or at least not without serious machining facilities )

 

[idej_z4]

You won't fix it with spacers mate it will make the problem even worse It will make the wheels more prominent which will rub the Arches more. Only resolution is wheels with a higher offset or raising suspension

Gutting! The article that I just read said that if the offset was too high it could be fixed with spacers.

Simply put Dan if your offset was 50 you could make it lower by adding a spacer so for example adding 15mm spacer would make your et or offset 35
Now if your offset is already 35 & you added a 5mm spacer it would make it 30 , , & the basic rule is the lower the number the further from the hub sits the wheel face so therefore a higher offset number can be made lower but a lower cannot be made higher ( or at least not without serious machining facilities )

Back to the standard suspension then...

 

[idej_z4]

What wheels have you got?

Riva DTMs

so 19x8 et34..

weird that you get rub!

I'm running 19x8.5 et38 with 235 rubber and I've got no issues.

I'd sell your set tbh and get a set of cmwheels csls.

http://www.cmwheels.com/index.php?route=product/product&product_id=1247

That's a huge undertaking, as in, getting news ones, refurbishing the existing ones, selling the olds etc etc. Probably a job for summer.

 

[idej_z4]

Just a point..

You haven't got staggered wheels have you, ie different offsets front and rear? If so, is it possible you have a rear wheel on the front, or vice versa??

Mike

The rears are concave so unlikely.

 

[Dav the wheel nut]

Where exactly is the tyre catching? Is it definitely only on one side? I don't think there should be an issue with the wheel size and offset you have given.

 

[idej_z4]

Where exactly is the tyre catching? Is it definitely only on one side? I don't think there should be an issue with the wheel size and offset you have given.

It's just at the top front of the drivers side arch. My car sits slightly lower at that side, but when I went for my wheel alignment the guy told me all BMWs sit slightly lower to the drivers side. TBH though when the Mrs is in the car it also catches on the passenger side.

 

[Dav the wheel nut]

What is your tyre profile? 235/35/19 or 235/40/19?

 

[idej_z4]

What is your tyre profile? 235/35/19 or 235/40/19?

235/35/19 - I think I'll try some 225s and see if that helps.

 

[Dav the wheel nut]

All things considered it would seem your only option would be to try a thinner tyre, 225/35/19.
It still seems a little odd to me :?
Out of interest when you measure the distance from the top of the arch to the ground when the vehicle is unoccupied how much lower is the drivers side compared to the passenger if at all?