Deactivating the Spring in a Grigri 3 for Lead Rope Solo

(updated 3/13/23)

This post will share how I disabled the spring on a GG 3 so that it is functionally similar to a Petzl Grillon (a version of Grigri without a spring that is used as an adjustable lanyard). When using a GG with a deactivated spring for lead rope solo with the proper HUB configuration, it can prevent high-clip failure; contribute to more positive lock-ups in general; feed super-smooth; won’t flip-flop around during lock-up; is more convenient to pull slack, and can shorten the distance of a fall depending upon how it is rigged. Even with the mod, it can still be used for TR belaying; lead belaying (you’ll have to hold cam arm down with your thumb when pulling slack); and as an adjustable lanyard like the Grillon. Back in the day I also used one for route setting in a small gym because it allowed me to go up (had to pull slack) and down and instantly locked-up so I could hang and work.

This post will detail my modification, NOT how it can be used for lead rope solo. For more information on that see my blog post on the GG3 HUB (held upside-down and backwards) System for LRS:

Read this!

• I would encourage you NOT to do this modification. I am only documenting this because people wanted to know how I did it. This should only be done with the proper tools and skills. It’s easy to fuck it up and you’ll likely ruin your GG and/or make it dangerous to use, so don’t try if you aren’t confident and skillful in tool use and making modifications. 
• Modifying the GG is using it WAY beyond the manufacturer’s design parameters and intended use. LRS is dangerous and can kill you if you don’t know what you’re doing. 
• Once this modification is made you will not be able to use it in the inverted position for LRS any longer. It can only be used with the HUB system for LRS. Each system has benefits and drawbacks (see my post on the HUB System for LRS.)
• Alternatives to making this modification that give similar function are: 1) Using a GG+ in the Tope Rope mode (weak spring setting) and get most of the functionality of this modification. The downside is you have to put up with the anti-panic handle which is a PITA IMO and the lock-up is not as immediate.

If you could disassemble the GG (you can't without destroying the axle), this is what you'd see. The photo is for informational purposes only so that you can see the construction of the GG. To deactivate the spring, the GG and axle do not need to be disassembled. This shows the spring inside that provides tension to the cam arm. My goal was to grind off the end of the spring that's sticking up (blurry in photo) so that the spring tension is released. The following steps tell how I did it without destroying the GG or having to remove the axle.

Steps for deactivating the spring on a GG3 (others models are different and these steps do not apply to them)

1. Take out tiny screw from corner of plastic cover. Insert a super thin piece of plastic (cottage cheese or yogurt carton lid) underneath it till it is stopped by the axle (this is to protect the finish on the Grigri). I inserted a large flat blade screw driver between the black plastic cover and credit card toward axle as far as possible. Twist the screw driver blade so that it will eventually pop off the black cover over the lip of axle. It will take a fair bit of force.

2. Once cover is off, it will expose the end of the spring sticking up through the side plate. Use a cotton swap, toothpick, or wooden match  to get out as much grease as possible

3.  Second warning: this is a very delicate operation and it’s easy to ruin your GG. I used an 1/8” carbide ball bit in a Dremel tool. Insert bit through opening and try to gradually grind the end of the spring below the level of the side plate. This is a slow process and takes precision, patience and a steady hand. Make sure to wear eye protection - bits of grindings will be flying everywhere. Also when you’re almost through the spring, the small end piece sticking up will snap off and go flying because it’s under significant pressure.

5.  Once the end is ground off, the tension of the spring will be released inside of GG. Note: If you don’t grind the end of the spring below the level of the side plate, it may still rub on the underside of the plate and the cam arm will not be as free to move as it should be. So make sure you grind the end of the spring as low as possible (tricky). Use a cotton swab to clean out as much grease and grinding bits as you can. There could be some fine grindings that you can’t get out but they don’t interfere with the action of the GG. The spring remains inside the housing but it doesn’t affect the use of it because it’s not attached to anything. At this point the cam arm should be free to rotate in both directions fairly

6.  Grind or sand half the thin, narrow lip off of plastic cover as shown in red below so that it’s easy to insert back over the end of axle flange.

7.   After putting the plastic cover on over axle flange, slide into place so hole in cover lines up with the hole in the side plate making sure the remaining lip of the plastic cover slides underneath the axle flange. Put the screw back in and carefully tighten. Be careful not to over-tighten because the screw’s threads are only going into the plastic spacer below the metal side plate. 

It should look and function like before except is no spring pressure to overcome. The cam arm should be free to swing open and closed with little or no resistance so that, in combo with the HUB cord and ropes of 9.5 or less should feed fairly freely. If there is too much friction you can play with the HUB cord so that it hangs at around a 45 deg angle. Should there still be too much friction there is one last mod that is possible that’s detailed in my next blog post.

8.   The unsprung GG can still be used for TR belay and bringing up a second as before. However for lead belaying you will need to hold cam arm down with your right thumb while pulling slack for the leader. For how to rig the GG3 for lead rope soloing, see this blog post.