How much to mill off for front mount BBS RS?

[mx5roadster]

I am looking to front mount a set of bbs rs faces. I'd prefer to sandwich mount and not loose the .5", but I need to front mount to raise the offset and get them under the fender.

How much should be machined off the back for a safe setup? I was told 3mm is what you need to lathe off.

Thanks.

[mx5roadster]

Actually, it would be more important to know how much the face should overlap the rear barrel. Is 1.5-2mm enough?

[1badg35]

depends on the wheel halves you are using. you need to safely cover the thickness of the lip and barrel with the area being machined out.

I've done this before (with the consent of the person who wanted it as we remove any liability) and we wound up removing 2.5mm i think on an rs005 face

[mx5roadster]

Thanks for the help.

How much of the face was resting in the bore of the barrel? I noticed during my mock ups, the lip was slightly thicker than the barrel. If I milled off 3mm, I would get about 1.5-2mm of the face sitting in the barrel.

[1badg35]

That should suffice. As long as it's seated tightly inside of the barrel, that would do the trick. Obviously the more you remove the thinner the bolt shelf on the face becomes. So there is a fine line on how to do this right.

We actually may in the near future do a face mount set where we reinforce the front of the bolt shelf in order to compensate for the removal of the back of the bolt shelf on the face. And then will chamfer the edge of the front of the face once the reinforcement is welded to it

[mx5roadster]

Thanks for the help. Faces have been milled, I am not 100% sure I am comfortable with the amount of face that is seated in the barrel. A very bad picture of what I have going on.

[1badg35]

Wouldn't you want to show us the back side of the wheel so we see how the face is seated?

[mx5roadster]

That would only make too much sense, lol. I am getting about 1.6mm seated into the barrel.