HOW TO MEASURE
Decide where the rack would sit, then measure the width of your roof (drip rail to drip rail) where both the front rack and back rack would sit. Also the width of the flat area of the roof at that point. This will decide on the width of the racks. Also, check your roof curvature for clearance in the middle of the rack when deciding on the width. There is a little wiggle room but not much.
Next I need measurements for the fastener system. Measure up 2 1/2" upward from the point you have determined you would set the rack of the roof (see attached picture), then measure down to the corner (tangent of the curve) of where the roof starts to slope downward...that will be measurement B (length of turnbuckle). Then from that point, measure down to the underside of the rain gutter...that will be measurement C (length of turnbuckle fastener). I need measurements B & C to determine the length of turnbuckle and fastener, so I don't give you one that is too long and won't tighten the rack down to the car, or one too short that won’t even attach it onto the car. If you'll notice in the picture, the fastener and underside of the turnbuckle won't damage your car, as the fastener has a rubber grommet on it and a dense foam pad on the back side that will protect your rain gutter and roof.
Summery of measurements needed:
1. Width of the roof drip rail to drip rail at the front and at the back of where the rack would sit.
2. Width of the flat area at that point - at the front and at the back of where the rack would sit.
3. Measurements B (see picture)
4. Measurements C (see picture)
If you need help with the measurements or have any other questions, please, email or call.