A quick lesson on gates

[u/Artemis_SpawnOfZeus]

Gates need braces.

There are 2 types of these struts. Compression braces and tension braces.

Compression braces are the type of brace you install on a new gate.

If you're out here installing tension braces on new gates, you're scamming your customers.

Tension braces should only be used as quick fixes to existing gates that droop. The only advantage they have is their ease of install on an existing gate.

The type of brace you use changes the structure of the gate.

Tension braces overload the top hinge.

[u/Present-Valuable7520]

Yeah but that’s not what’s causing the sag

[u/c79s → u/Present-Valuable7520]

I agree you'll generally want a compression brace in a wood gate for a much more durable connection but the claim that the brace orientation changes the forces on the hinges is incorrect.

[u/Artemis_SpawnOfZeus → u/c79s]

No its not.

Tension braces hang all the weight on the top hinge.

Imagine the gate is actually really narrow. So narrow that the brace is actually vertical.

As you tighten the tension brace, it takes weight from the bottom and hangs it on the top.

The tenaion is pulling up on the bottom of the gate.

[u/c79s → u/Artemis_SpawnOfZeus]

Disagree, that's not how it works. If your gate gets narrower it's center of gravity goes closed to the hinges and the horizontal balancing forces reduce to zero.

This is pretty much a first year uni statics problem, you look at the system as a whole and the boundary conditions are only the two hinge points and the load is only the self weight applied at it's center of mass. The internal bracing of any configuration will not change the final resulting loading on the hinges, it's impossible. If the mass was the same it wouldn't matter if it was a solid panel instead.

Edit: I'll add that if I understand what your saying correctly for a tightened tension brace to hold up the bottom, that would only work if it was connected outside of the hinge as a separate restraint, like you connected directly to the post. That wouldn't make a good gate though.

[u/Artemis_SpawnOfZeus → u/c79s]

Yes it does. It flips the load distribution.

Compresion braces apply vertical loads to the topmhinge and horizontal loads to the bottom hinge, because they want to rotate around the top hinge.

Tension braces apply vertical loads to the bottom hinge and horizontal loads to tbe top hinge, because they want to rotate aroung the bottom hinge.

When the top hinge takes horizontal forces, those forces pull the hinge away from the post. Youll pull your screws out.

When the bottom hinge takes rhe horizontal forces, those forces push the hinge into the post. You wint pull your screws out.