I purchased curt trailer hitch for my 2014 Audi Q7. I had to first remove the bumper impact bar which comes factory installed. In place of bumper impact bar, the trailer hitch is supposed to fit perfectly. It actually fit perfectly. However the bolts that came with curt trailer hitch were too long to fit in fully. So I ended reusing the bolts that came out of the bumper impact bar. My question is - are the bumper impact bar bolts safe enough to be used on trailer hitch. Will bumper impact bar bolts be able to withstand very heavy loads which curt trailer hitch can carry. Or should I replace these with bolts that can withstand load on trailer hitch. The bumper impact bar bolts color is silverish and the ones that came with curt trailer hitch had golden/yellow color on it

  • 1
    Check the markings on the heads of the bolts - that will give you the grade.. and therefore load capacity.
    – Solar Mike
    Mar 16 '18 at 6:55
  • Personally, I would contact the hitch manufacturer and have them provide the correct bolts.
    – CharlieRB
    Mar 16 '18 at 12:35

Yes, the bolts should work just fine.

The bolts were providing enough support for the bumper impact bar and would be expected to hold up to a collision/impact without failure ... there's no reason to believe they won't do the same for the hitch. As long as you've torqued them down, they should easily be able to hold the hitch.

  • This is not about just holding the hitch. This is about holding the hitch and then towing a trailer. Mar 16 '18 at 16:39
  • @msgboardpana - That was my meaning. This should not be an issue. If the hitch was made to haul the load, the bolts are more than capable of holding the tow hitch to the vehicle. Mar 16 '18 at 16:54
  • Hmm, the bumper impact bar is subject to an impact so the bolts are not put under a tension load, while with a tow hitch they will be under tension when the tow hitch is being used...
    – Solar Mike
    Mar 16 '18 at 21:19
  • @SolarMike - Yes, but they would be under tension if the bar was hit. The bolts have to survive this, which could be far worse than what having the trailer hitch on there would be while being used. BTW, all bolts when affixed and tightened are under tension. Mar 16 '18 at 21:32
  • They might be under shear if the bar bends, most bumper bars are held on by the bolts acting in tension as you point out and that is the direction of the force applied to the bumper bar which won't increase the tension on the bolt...
    – Solar Mike
    Mar 16 '18 at 21:35

enter image description here The impact bar has M12x1.5 bolt of 50mm length and Grade 8 (8.8) . The bolts that came with hitch receiver are grade 10 (10.9). So the conclusion is I cannot use the bolts from Impact bar because grade 8 is less strength than grade 10. Check this link for info on bolt grades . I ordered M12x10.5x50 bolts of grade 10 online.


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