Offset range for 4 lug wheels?, What's the range that will work on a narrow body w/ 4 lug wheels? Options

[DC_neun_vierzehn]

As the title and description states ... I would like to understand the specs I need to be mindful of when shopping for wheel replacements on my '73 2.0 stock 914. I know my stock Fuchs (which I will keep) are 15x5.5 and have a 4x130 bolt pattern.

But what is the offset range I need to stay within or wheels?

And can I go wider than 5.5? Like 6 or 7?

Many thanks in advance. I did try to search the site for these answers, but I could not find a clear answer.

[chmillman]

Was just doing some similar calculations for myself. My 914/4 was converted to 5-bolt. I am currently running 7x15 Fuchs - ET 23.3 - and 195/65's. The rear lip has been rolled, but the fender has not been pulled. I can just get the first joint of my fingers in between the tire and fender lip in the rear, but due to the narrower width of the 195's and stiffer sidewalls due to the stretch (as opposed to 205's), plus the fact that the rear swing arms tilt slightly inwards on cornering, they do not rub.

I was looking at possibilities to going back to 6" rims and 185/70's for a couple of reasons, so I thought I this would be a good time to compile a list of sizes and offsets.

- The backset (distance from wheel hub mounting surface to inside rim) is approximately 110-112mm (4.3-4.4") for all -

4-bolt
5.5" width ET=40

All I have here are the original 4-bolt 5.5" Fuchs alloy wheels from before the conversion. With ET=40, that makes a backspace of 110mm, so close.

I don't have any specs on 4-bolt 5.5" steel wheels, I guess they are similar.
The Maxilite repros available here have an ET of 35.


5-bolt
5.5" width ET=42
6" width ET=36
7" width ET-23.3

What was interesting that I didn't really think about at first is that the inside of the rim is always at the same place. When the wheel gets wider it moves both the centerline and the outer edge outwards. We're always thinking about the rears rubbing, but also in the fronts, going from 5.5" to 7" pushes the wheel centerline outwards by 19mm (3/4") and I think that in addition to wider/lower section tires, that may also contribute to harder steering at low speeds.