16 inch x 7.5JJ
 

In the process of ordering and mounting new summer tyres I checked my aftermarket set and they are evidently 17JX. What's the "7.5JJ" part of the wheel size? How does it affect things?

The wheels say "ExecutiveLine by Alustar" and it's evidently ATS wheels but that's just about that. There is nothing indicating the offset and I can't find any documentation on the wheels. Just measure the distance with a ruler? :)

Re: 16 inch x 7.5JJ
 

That's the width of the wheel, which is the same as stock. Disregard the JJ, it's just code for something or other that I can't remember right now. Offset is usually denoted by "ET##" (The ## is the offset in mm). It will be tricky to measure with a ruler, offset is set from the wheel center line (which in this case would be 3.75" (95.25mm) from the backside of the rim.

Re: 16 inch x 7.5JJ
 

knowing the thickness of the wheel you can figure out your offset by measuring from the lip of the wheel to the back of the bolt holes where it would contact the hub. then figure in how far that distance is off from the center of the wheel.

Re: 16 inch x 7.5JJ
 

Actually, there is an ET-code which I'm fairly sure was 44 or 54, I'll check tomorrow when the sun is up.

The ATS set is 7, not 7.5. What will be the effect?

Thanks!

Re: 16 inch x 7.5JJ
 

Turns out the alloys where 16x7 with an offset of 42mm.

Since I was in a rush the tireguy said he wouldn't even mount 225s and seeing the current 225s on the rim I had to agree, they were bloating. I opted for 205/55 on that set and at least it looks normal. I have yet to drive it without the other set of wheels in the car :)

So.. the offset is much smaller but so is the wheel and tire. Will I have problems with this? I planned to drive on this setup until I have restored my originals.

Re: 16 inch x 7.5JJ
 

They're only .09% different in diameter but narrower. With that offset you should be fine.

Re: 16 inch x 7.5JJ
 

Yes I thought so. Since I lost a half inch on the alu and 20mm on the wheel it theoretically shouldn't be a problem with 43mm offset. As a matter of fact, I would think the outer side would be exactly where a proper 225 on 7.5' would be.

But hey, cars are mainly practical things, theories don't always work :)