Need Thule Replacement Carriage Bolt with Larger Square Shank for Rooftop Cargo Box

Question:

Hi. I bought a set of 8 of these to replace the rusted ones from my Thule roof pod. The are the right length and proper thread, but the square part of the bold end is too narrow and doesnt lock into and keep the bolt from spinning freely when you try to tighten it down. What would you suggest?

asked by: Ian R

Expert Reply:

The Thule Replacement M6 x 60 mm Carriage Bolt # 915-0660-31 that you referenced is intended for use with a specific kayak carrier, the Stacker # TH830. It also works with their roof-mount bike wheel carrier # TH98BV.

Thule offers a range of other similar replacement carriage bolts for other applications, such as # TH915-0675-11 which is a 75mm long bolt with a square shank that measures 0.238-inches. Their part # TH10403 is a fully-threaded 75mm bolt designed for their Adventurer Cargo Box. The square shank of this bolt measures 0.3-inches.

If neither of these items is the correct fit for your Thule product please let me know the size of the square opening for which you need the bolt.

expert reply by: Adam R

Joe F.

11/17/2021

Sadly, I also bought the M6 75mm bolts Code: TH915-0675-11 to use with the Thule roof box and had the same problem, the square part of the shank is too small and the bolts just spin so they cannot be used. The square dimension needs to be 0.313 inches (more accurately, 8mm) to fit into the square hole in the plastic bracket of the roof box. Do you sell a M6 75mm bolt with a 8mm square shank?

Les D.

11/24/2021

@JoeF It seems like the Thule # 915-0660-31 would work if you can get by with 60 mm length. The square section behind the bolt head seems more pronounced. What model of roof top box is it and what model cross bars are you using. If we can identify those we could just go directly to Thule to see exactly what screw they originally provided.

Joe F.

11/30/2021

@LesD The roof box is a Thule Adventurer. I've had it for a long time (20+ years) so I doubt that they still make this model. The mounting hardware that came with the box has plastic and metal pieces to capture the factory luggage racks on a 2016 Honda Pilot. The bolts need to be long enough to give enough slack in the bracket to engage/disengage the bolt head from the plastic piece without fully unscrewing from the plastic nut. I doubt that a 60 mm length will be long enough to allow this. If there was a bolt longer than 75 mm that had the correct 8mm square portion, then I could cut them to the correct length.

Les D.

11/30/2021

I found on the Thule website that there was only one model of "Adventurer" rooftop cargo box. The only bolts in that product has are the # 1500056148 Carriage Bolt sized M6-1 x 75, which attached to # 1500056083, Knob 3-Wing M6x1, and a lock washer. These should work for you.