Wheel spacers

Good evening one and all. New member here with the first of my technical questions. I’m thinking of getting some 15" wheels on my mk1 to improve my tyre choice and they have some nice ones at MX5 Parts. I asked them about spacers and they couldn’t help me. So, what spacers can I fit on the car without getting into trouble with the wheel arch?

 

Thanks. 

Probably better off buying wheels with a low offset, if you are merely looking for a cosmetic improvements. 5mm wheel spacers is about as thick as you can go and retain the existing studs.

The aftermarket wheels sold by MX5parts appear to be the “correct pcd” for a MX5, which is slight odd, considering the correct offset on a 15" wheel for a Mk1 is 45mm, and on the Mk2, 40mm. So which is it? You can get a 35mm offset wheel, and that will “stick out” as much as fitting these wheels with a 10mm thick spacer, and none of the faff trusting aftermarket wheel studs.

35mm offset wheels with 5mm shims, so effectively 30mm offset.


Wheels are Maxilite 15" wheels from https://shop-eu.maxilite.ch/index.php?k=136&lang=eng

I think the existing wheels are et40 - it’s a 1.6. I’ll try MX-5 Parts again tomorrow and see what they can tell me. Am I the only duffer who needs some facts and data??!!

 

Something I wrote elsewhere.

 

Lets start with wheels.

If you don’t understand what offset is, use Google. However, what size wheels fit an MX-5? 

Tyre width and “Lows” make a difference. Assuming you are going to fit proper size tyres then for a MK1, from the hub face of the car, the bit the wheel actually bolts to, the original 14" MK1 wheel’s outer face was about 35mm further out. So if you want wider wheels, you need to work out your width and offset. 

So if you have a 15 x 7J wheel with a 30 offset, will it fit?

Width in inches so 7" x 25.4 to give the wheel width (they are wider than this, but this is good enough) 177.8 (you can round it up to 178. 

Divide that by 2 to give you half the width and then take away the offset 178/2 - 30 = 59mm. 

So here are the important figures. 

For MK1 cars, if that final figure is below 66, for normal tyres and suspension you will require no body mods to fit the wheels. 
For MK2 cars the figure is 78


If you go above these figures you are likely to need to roll your arches. Spastic camber is not a solution and it will cost you more in tyres that the cost of rolling.


If you fit big tyres the situation will be different, so 225 50 15 tyres would require the arches rolling and pulling if you are at the 78 figure for instance. 

Thanks Nick - very helpful!