So-my question *does* have a bit-more to do (potentially) with a parts supplier, but I don't know of anybody here that objects to FCP Euro, so I'll proceed:

My issue is that I need to replace my front brakes (after a trip a few miles west of Denver-ON some major mountains-when I got the wonderfully-premature: "brake failure" warning, which scared T-S-outta me...)

FCP lists packages for front brakes for 16" 17", and 17.5" brakes...

Except my rotors are ~13.5"

My fiancee-quickly suggested that perhaps those numbers pertain to WHEEL size... except I have not heard of *stock* 17.5" rims on anything.

I have an '08 XC90, 3.2L, AWD, with 17" rims... Again, the rotors appear to be 13.5" in diameter.

-Anybody out there know--what corresponds-to-what with those specified brake sizes?

 

Here's a good read on how to get some clues:

https://www.matthewsvolvosite.com/fo...ic.php?t=93783

Sounds like you may need to do some additional checking of the calipers to be exactly sure or do a more exact measurement since you're looking to see if you have 316mm (12.44 inches) 328mm (12.91 inches) or 336mm (13.23 inches).

Also, if you check out Tasca parts (a dealer store), they show VIN serial numbers along with the wheel sizing to find the right part. You could probably give them a call or email and provide your VIN to get the correct part number for the rotor and go from there.

https://www.tascaparts.com/v-2008-vo...--front-brakes

 

FCP Euro will guide you on the correct rotor and pad size if you provide them with a vin. I have an 08 xc90 3.2 AWD with 17" rims and my rotors and pads were for 336mm fitment.