Author Topic: Tripod mount towing mirror mounting re-inforcement  (Read 1673 times)

Offline kcwis

  • Newbie
  • Posts: 65
  • Newbie
Tripod mount towing mirror mounting re-inforcement
« on: November 23, 2017, 12:27:58 PM »
 We are putting new doors on a 76 gmc 1/2 ton 2wd and want to put the tripod mount style (3 leg) rear view mirrors on,any recommendations for re-inforcement of mounting locations? I searched most posts and didn't find any help. Will plates with nuts welded on be enough? The new aftermarket doors didn't come with anything top or bottom,one old door had a  bracket under the vent window but I'm guessing they were for the small dumbo mirrors,should I use those to support the width of the door under the vent window? I only have one so will need to fabricate another.

Offline Jason S

  • Senior Member
  • ****
  • Posts: 1561
Re: Tripod mount towing mirror mounting re-inforcement
« Reply #1 on: November 23, 2017, 11:23:44 PM »
Any kind of reinforcement that spreads the load out from the single hole in the door sheet metal will help.

For the camper mirrors on my '73, the doors have 1/4" (or maybe 3/16") steel plate on the inside. The plate has a hole drilled for the mirror bolt and it sandwiches the door skin between itself and the mirror mount.  It could have a nut welded and fastened inside the door shell with epoxy or body glue, but in my case it's not. 
1973 GMC K2500, Super Custom, Camper Special, 350, TH350, NP203, 4.10's
1974 Chevrolet K10, Custom Deluxe, 350, SM465, NP203, 3.73's

"1) Peace through strength; 2) Trust but verify; 3) Beware of evil in the modern world"

Offline Henry

  • Frequent Member
  • **
  • Posts: 331
Re: Tripod mount towing mirror mounting re-inforcement
« Reply #2 on: November 28, 2017, 12:07:48 PM »
Hi kcwis:
Yeah, if you want to put on towing mirrors, this is the time to make mods to your doors and make sure you got the holes in the right places. If you are using aftermarket doors they are most likely of thinner gauge than the factory doors and fo sho need reinforcement. you can use welding or adhesive. If you use adhesive, best to use reinforcing material that is steel instead of aluminum so you dont have differential expansion...use a high quality structural adhesive such as 3M #2216. The doors are especially sensitive to vibration under the quarter window, so if you have a mirror attachment that is there, you should reinforce this area. You can make your reinforcement plates thin sheet steel if you want, the stiffening can be accomplished by having a bent lip on the reinforcement plate. I personally like the use riv-nuts as the permanent mounted nut inside the doors for ease of installation and removal of mirrors. You can make the riv-nuts attach to (or through) the reinforcement plates. I think McMaster-Carr has a selection of these and the tool required. Whatever you do for reinforcement, check and re-check your design to make sure it does not interfere with the window mechanisms and door lock!
Good Luck,
Henry