The amount of black showing in my second pic is actually a solid 1.5". Measured it with a ruler. Something's not adding up.

In "DFSMopars" comment and photos above, he is claiming to have used a 15x7 ring with a 15 x 8 rim and there is no gap. So I'm anxious to hear what backspacing he's running. I think that must be the difference. Has to be. Unless those trim rings are extra deep. But then, what do I know?

And yes the 14x6 road wheels are black underneath the ring, but little, if any of it shows when the trim ring is on. That's what I'm looking for. Stock look, but bigger wheel.

It's simple math you either ordered the wrong back space or they built the wrong rim for you.
Ron

The backspace is 4-1/2", just like I ordered. That's the only backspace they offer for a 15x8 road wheel. Trim ring is seated all the way.
Measured the gap with a ruler. it's a solid 1.5"

Put your trim ring on a flat surface upside down and measure up, what's the measurement?
Ron

2-3/4"

The trim rings are the correct width @ 2 3/4 just like a factory 15x7 trim ring so let's do the math.
If you have 4.5 backspace and 2 3/4 trim ring your at 7 1/4.
You say there is an additional 1.5 gap right? 7 1/4 + 1.5 =8 3/4???

How is that possible? I think the backspace on the wheel is wrong or the trim ring isn't going all the way on.

Like I said earlier in this post a factory 15x7 has 4 1/4 backspace, trim ring is 2 3/4 4 1/4 + 2 3/4= 7"

Your rim has to have 3 3/4 backspace no???? 8"- 2 3/4 = 5 1/4 - 3/4" ( the 3/4" is the gap you should have been left with)=4.5" backspace.

8" wheel with 3 3/4 backspace leaves 4 1/4 to front so then minus 2 3/4 ring which = 1.5" left for the gap.

Someone please correct me if I'm wrong in my thinking.
Ron

I know it may seem very perplexing but I can assure you that you are not in the twilight zone. I think I can help explain.

An 8 inch rim is only 8" wide at the beads.

The rim is really/actually just about 9" wide (from lip to lip)

Backspace is measured from the mounting surface to the inner lip, not the bead seat.

The trim ring is 2-3/4" deep, yes. But should be measured from underneath the lip because the lip of the trim ring sits on top of the rim lip, which remember is 9" wide. About 1/8" of that trim ring is sitting completely outside of the rim.

The rest should spell itself out.

And doing all that math you were doing, with adding everything together to try to get a total of 8" may not be accurate either because who's to say that the spokes (or inner part of the rim we are measuring the gap from) sits exactly where the backspace is measured from, so don't rack your brain on all these fractions and math.

I have it sitting in front of me on my work bench. The trim ring is seated fully. The backspace is 4-1/2". The trim ring is 2-3/4" deep. And there is still a 1-1/2" gap. So I just need to figure out what to do.
Considering trying my hand at making a trim ring out of some stainless, if for nothing else, just for fun. Does anyone know if these things are pressed into shape from a die? Or cut from flat sheet metal and rolled into shape, then welded? Hey if I'm successful I can go into business : P

Width from lip to lip

Backspace

I know an 8" rim is measured bead to bead not edge to edge.

I thought I was trying to help you with your question not the other way around.

I have no clue why your stuff isn't working and no one else has taken the time to try and help you also.

My calculations of a stock 7" Ralley Wheel and factory trim ring work perfectly so I'm at a loss.

(Like I said earlier in this post a factory 15x7 has 4 1/4 backspace, trim ring is 2 3/4. 4 1/4 + 2 3/4= 7")

Ron, By all means, thank you for trying to help me figure this out. That's why I posted. Was hoping that by talking this through with some people it might make some sense. This gap is unusually large and it's a big disappointment.

I'm hoping DFSMopars chimes in. From looking at his pictures and statements above about using a 15x7 ring on a 15x8 wheel, I had hope. Even though his are Rallye's and mine are road wheels, should that make a difference? I don't know.

I may return the rims and get the Magnums, which are chrome under the trim ring. Maybe the gap wouldn't be so noticeable then. But I also read on here that a chrome rim doesn't hold a trim ring so well. Can anyone attest to this?

I've also read on here that some people just put some chrome tape on the rim to help hide that black gap. I was hoping to not have to do that though. Spending about $700 on rims and then put $8 chrome tape on it? I dunno.

Maybe I should give up and just get 15x7's. Do they make them with a 4" backspace?

Sorry, I think you are fighting a loosing battle, If you want 15x8 Rallye wheels to have a trim ring that fits I suggest you have them made with 1 inch more backspace than the 15x7 Rallye's then the 15x7 trim ring will look right on a 15x8 rim. I don't think it will work with the offset you are looking for on the front