Spacers. Confused..

[JensenM3]

Bought 2 sets of spacers.

Bought them from ECS. They said there are two specific sizes, one for the front and one for the rear. The fronts fit fine, the rear spacers were too small to fit on the hub. Not just a little bit, either.

Called and ordered another set for the rears. Asked for the same size as the front. The 10MM front spacers fit on the rear. So, naturally I asked for front spacers specs (ordered 15MM). They're the same size spacers as the rear. Don't fit.

They seem confused - their part numbers aren't working, or I'm getting the wrong information from the ECS help on the phone when placing these orders. Asked them to verify the size difference and they said they weren't allowed to go into the warehouse to check it. Weren't able to help me at all. Didn't share anything in relation to size.

Can someone tell me if the hub sizes are in fact different, front to rear? If so, what are the sizes? I need to break it down to the exact size and help these folks sell me spacers.

I've installed the front. I'm not anywhere near my X5 (traveling). I need to call them tomorrow.

Thanks!