Diameters of fork dropouts?

So I picked up my new-on-closeout 2009 Jamis Satellite Femme yesterday (which is another story for another thread--I'll post up after I've actually had a chance to ride it some). I went to put it on my many-years-old (not even sure how old, picked up off of Craigslist) Thule roof rack with fork-secured bike carriers, and... it wouldn't fit. The opening in the dropouts is smaller than the diameter of "skewers" in my carriers!

Thank goodness my car was otherwise empty so I could fold down the rear seats and put the bike inside--after letting it teeter off the roof of my %$@$^# car while I was trying to figure out the issue. :mad: Fortunately, as far as I can tell, all that did was cause a couple scrapes and knock the rear wheel out of true (which I didn't realize until I got home). Getting those first few scratches and dents can be traumatic, I guess I just wanted to get them out of the way all at once. :rolleyes:

Anyway, my Trek hybrid fits just fine--I drove cross-country with it on there. I'm wondering if these bike trays I got were designed for mtb's--I suppose it makes sense that those might have bigger, sturdier axles and subsequently larger dropouts in the fork?

Do road bikes typically have smaller dropouts, or did I get something unusual, here? Am I going to have to buy a new bike tray to be able to carry this bike? That wouldn't be the end of the world, since I already have the mounts/crossbars/etc ~$150 or so on a new carrier would be worth it if that's what I need to do, but how can I know for sure that I'm getting one that will be compatible with my bike?