Does a drum to disc conversion increase or decrease wheel offset?

[beefy]

Beefy, since you seem so 'knowledgeable', I share with you my idea, and you tell me if I'm completely off base.

1) If I knew that the hat thickness was the only dimension that would change on my rearend track width, I could measure the thickness of my drum at the mounting surface, and I could get a measurement of the hat thickness of the disc hat that I intend to use. If there is a significant difference, greater than +/- .125", than I would use a spacer and/or decide if it was feasible.

2) If I knew that a disc spindle vs a drum spindle was the cause, I would consider whether to machine my drum spindles, or use a kit that required disc spindles

3) If I knew the hub was a cause, I would also consider whether or not to go with a kit that I can machine down my hub's outer diameter and reuse, or a kit with a disc hub.

Make sense?

1) yes... if you KNOW that the only change you are making is replacing a drum with a disc... then YES... the only change in the offset is the difference in thicknesses of those two components.



2) IF you must replace the spindle to swap from drums to discs (not always the case) then you would have to account SOMEHOW for the difference if there is one. Remember, it could be that the new spindle causes a negative (or inward) change in offset requiring you to actually use a SPACER rather than cuting down the hub.


3) IF you are changing the hub (which is NOT always required in a disc conversion) then you would have to account for the difference there as well.

The bottom line is this: First off, you didn't provide ANY of this information in your original post and frankly, even this information is STILL very vague.

We still have no idea what kind of car you are referring to OR what type of conversion you are attempting... So I'm not sure why you seem to be so confrontational about this.

It's clear that people here WANT to help you figure it out, but you're not helping us to help you.

[6'9"Witha69]

1) yes... if you KNOW that the only change you are making is replacing a drum with a disc... then YES... the only change in the offset is the difference in thicknesses of those two components.

2) IF you must replace the spindle to swap from drums to discs (not always the case) then you would have to account SOMEHOW for the difference if there is one. Remember, it could be that the new spindle causes a negative (or inward) change in offset requiring you to actually use a SPACER rather than cuting down the hub.


3) IF you are changing the hub (which is NOT always required in a disc conversion) then you would have to account for the difference there as well.

The bottom line is this: First off, you didn't provide ANY of this information in your original post and frankly, even this information is STILL very vague.

We still have no idea what kind of car you are referring to OR what type of conversion you are attempting... So I'm not sure why you seem to be so confrontational about this.

It's clear that people here WANT to help you figure it out, but you're not helping us to help you.

I am working off the assumtion it is for his 69 Firebird.