I want to put the rack on my Prius

you can easily go to Yakima: Car Racks, Bike Racks, Roof Racks for Skis, Cargo & Kayaks and enter your cars info. It will tell you what parts to buy. What are you trying to carry with it? Anything on the roof is going to kill mileage, im sure just having the bars on permanently will have a negative effect in mileage too. I had a yakima rack on my camry and mileage went from 27mpg down to 23mpg.

 

I've installed them before. For permanent installations, you'll need rivnuts or revitut nuts that work like "Pop" rivets, the installation tool and to "rustproof" the drilled holes with a good primer, before installing them. My favorite is to cover the bare metal with some cheap clear finger nail polish that I usually buy at the local Dollar Tree Store, before inserting the rivet nut. It's some really tough stuff. I use it all the time as a "rust resist" for bare metal.

If you don't rustproof it, years later, rust might cause them to come off. M6 rivenuts were that size I most often used.

Like BreitrthnU said, you'll be hit with wind resistance and a decrease in MPG.

 

I come from a Yakima roof rack user, i.e. round cross bar and Q-Towers. I was planning to transfer my old set-up from my old car (Acura RSX) to the 2012 Prius to haul two Trek mountain 3700 disc bikes, but after seeing Jimmy's pix of his Prius configured with Yakima's Whispbar Through System, I'm inclined to upgrade to the same system and eliminate the silly looking wind-noise eliminating 44" fairing:


(Jimmy's ride)

I like it because it looks very OEM'esque. Whispbar is suppose to be aerodynamic and reduces wind noise compared to round or square bars.

 

Where do the holes get drilled??

 

Right into the sheet metal of the roof.

 

nooooooooooooooo...LOL

 

Laugh out loud as much as you want to. Just look at this warning in the Family Handyman Magazine.


Car Accessories: Roof Rack Safety Warning | The Family Handyman
"Roof racks are great for moving lightweight cargo around town. Just secure the stuff to your roof rack and you're good to go. But if you're moving large, flat items like plywood or mattresses, you have to tie the load to the vehicle as well as the rack. A friend tied a mattress to his roof rack and took off for his cabin. As soon as he hit 40 mph, he heard “pop, pop, pop.” The “air lift” had ripped the rack mounting bolts right out of the roof (see photo). The body shop repairs cost more than the value of the mattress (and way more than a set of tie-down straps). You've been warned."

It also means that any roof rack can be removed and reinstalled to increase gas mileage. Just get matching stainless steel hex socket botton head screws and rubber sealing washers.

 

I'll just avoid the whole roof rack on my Prius - I have other cars for that stuff

 

If you are just carrying bikes with it, I would suggest getting a hitch bike rack. It doesn't hurt MPG as much and easier to load. If you are need the flexibility of a cargo carrier, you can get an attachment for the hitch also.

Just depends on what you are going to put up there.

Here is a post on the Thule AeroBlade.

Thule Roof Rack with Aeroblade | PriusChat