Car Roof Rack Extension

[electrosteam]

Hi,

I have a 4-Runner with extruded section roof racks about 60x30 section and 1190 wide.
I need to load two kayaks, the short plastic moulded type about 35 kg, each 800 wide.

A simple solution could be lengths of timber (accurate pine from Bunnings ?), say 100 x 60 x 1800, with a slot routed out along the length 60x30 and clamps made up from aluminium plates and stainless bolts.

The clamps would both hold the timber on the rack section and prevent sideways movement.
The kayaks would each have two ratchet straps engaging the rack section and supports.

Will pine be suitable and tolerate such a long slot ?
With an acceptable amount of distortion ?
With an acceptably low risk of failing ?

Any other suggestions welcomed.

John.

[rwbuild]

Pine is notorious for moving substantially when exposed to the elements
Use structural formwork joists which are laminated and usually colored red available in a variety of sizes x50 the most common. You can resin coat it after sizing and grooving as required, Mitre10 will source it for you, the green and blue sheds will not know what your talking about
Tasmanian oak is also a very good option probably easier for you to obtain