I know this is a constant stupid question. And i could probably find the anwser if i look hard enough but. Im lazy. So... here it is.

I want some wheels that are 15x7 for an 85 gs. Im not sure which ones yet so. What would the correct offset be? Is it 40mm?


Sorry,
Im new

 

I know the '84-'85 GSL-SE has a 40mm offset. Not sure about the 110mm pattern though.

 

I run 15x7 with a 3" backspacing on my 85, you can do the math to convert to offset

 

3" backspacing is a 12mm NEGATIVE offset.

You really need to space it out that much? My 13x7s have 0 offset and they have a bit of clearance with the strut, so I'd imagine 15" wheels would have even more clearance and could use a little more backspacing (positive offset) Or am I missing something?

 

OOPS! I think i meant to type 4" backspace, so that would be 12.5mm positive offset

thanks for the correction.

 

So since I dont really know what all the inches to millimeters and crap like that...What is the "right" amount of offset for 15" wheels for an RX-7? 12.5mm positive offset as opposed to what? Whats the stock offset? Cause if this were a GSL-SE and it needed 12.5mm offset, wouldnt that be added to the stock offset of 40mm to make a total of 52.5mm offset? I know thats probably a horrible example, but basically, what offset is it for the 4x110?

~T.J.

 

40mm offset is always 40mm offset no matter what stock is.

 

25.4mm = 1"

offset = distance between mounting surface and centerline of rim

centerline of rim = (rim width) / 2

this thread shouldn't even exist. there are only a few companies making wheels for the 4x110 bolt pattern. Most of them will fit without issue on a 1st gen. Now if you are looking to buy expensive/custom wheels and you need to supply dimensions, well you better figure them out for yourself since you're not going to be happy when somebody mistypes 3 instead of 4.

Offset is an over rated measurement since it means absolutely nothing without rim width. Backspacing on the other hand tells you many things. One, it is the exact measurement from the inside lip to the mounting surface of the rim, and two it tells you that the rim width is at least 1 inch wider than the offset (in most cases, for cars).

So any rim with an offset of +12mm or 4" backspacing or less will work on a 1st gen.

 

well the stock offset is +23 (or maybe 22 i think) with a 5.5" wide wheel. you can do the math from there.

doesnt matter about height of wheel when it comes to backspacing

 

it does, though... the main point of interference is the strut.

 

im talkin about having the wheel being far enough out to look correct, not height.
i assume 15x7 with the proper offset and tires would be fine considering ajc13b has 17's.....

 

Ive decied i dont give a damn about the 4x110 wheels anymore. Im just going to do the rear gslse swap. 4x110 wheel are too far and inbetween. Plus, disc brakes are better.

But just so i can say i learned something here. So, if the stock offset was 40mm. And the stock wheels where 5.5in. And i got 7". Would the offset change?

 

So you're going to run different bolt patterns between front and rear?

Whatever you do, I suggest you keep the same pattern on all four corners for $$$ sake.

 

Well, i was going to try to swich the front to hubs with the gslse hubs. Do you know if that can be done?

 

What the hell did i just type? Let me try that again.

I was going to swap the rear end, and try to switch out the front GS hubs, with the SE hubs.

There we go, mcuh better.

It seem possible. Do you think it will work?

 

yeah se hub should bolt right up since yours is an 85