Hitchclimber pulley

[Customcuts]

I recently purchased a DMM hitchclimber pulley for my climbing rig. I noticed a small indention on both sides of the pulley roller. It looks like it has been slightly drilled . Not sure if this is normal or what. I'm not worried about it affecting the strength or it being unsafe, just View attachment 248296View attachment 248297wondering if that all have this.

 

[treemandan]

I was thinking they did it to balance the pulley but I don't know as I have wondered myself.

 

[treemandan]

That is interesting.

Mine doesn't have those drill marks. Just got it.

The sideplates are different on yours.

Edit: Actually I can't tell if its the sideplates that are different or the pulley bearing. Maybe there are drill marks on yours that you can't see.

 

[KenJax Tree]

I have the exact pulley and it has that drill mark in it for whatever reason.

 

[Customcuts]

The sideplates are different on yours.

Edit: Actually I can't tell if its the sideplates that are different or the pulley bearing. Maybe there are drill marks on yours that you can't see.

Looks like the bearing is bigger on that blue one..... Wierd

 

[imagineero]

The 2 pulleys shown are different. The OP's (red) is the standard hitchclimber pulley which doesn't have a bearing. It has a bushing instead. All the standard bushed hitchclimber pulleys have that mark, it's nothing to do with ballance, I'd imagine it has something to do with the manufacturing process.

The second pulley shown is the hitchclimber rapide, which has a bearing. Bearing pulleys are more efficient than bushed pulleys, and not many pulleys do have bearings.... It can take the efficiency right up from 65~70% to closer to 95%. Pulley efficiency is a minor issue in applications like the hitchclimber, but becomes important when stacking multiple pulleys for mechanical advantage. Pretty soon, the mecahnical advantage won is lost from the inefficiency of the pulleys. Sheave diameter is also important for efficiency, and it starts getting pretty good at 5x rope diameter, and is excellent at 10x rope diameter. The 38mm diameter of the sheave on the hitchclimber also negates some of the efficiency gained from the bearing. As a hitch tender, the pulley on the hitch climber really does very little.

Shaun

 

[BigUglySquirrel]

The 2 pulleys shown are different. The OP's (red) is the standard hitchclimber pulley which doesn't have a bearing. It has a bushing instead. All the standard bushed hitchclimber pulleys have that mark, it's nothing to do with ballance, I'd imagine it has something to do with the manufacturing process.

The second pulley shown is the hitchclimber rapide, which has a bearing. Bearing pulleys are more efficient than bushed pulleys, and not many pulleys do have bearings.... It can take the efficiency right up from 65~70% to closer to 95%. Pulley efficiency is a minor issue in applications like the hitchclimber, but becomes important when stacking multiple pulleys for mechanical advantage. Pretty soon, the mecahnical advantage won is lost from the inefficiency of the pulleys. Sheave diameter is also important for efficiency, and it starts getting pretty good at 5x rope diameter, and is excellent at 10x rope diameter. The 38mm diameter of the sheave on the hitchclimber also negates some of the efficiency gained from the bearing. As a hitch tender, the pulley on the hitch climber really does very little.

Shaun

Great post Shaun.
I would have to agree with everything you said. To the OP: I have the standard "red" hitchclimber and it also has the center-drill marks on the sheave. Your gear isn't defective in any way shape or form.