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I was browsing MT.net when I found a build thread that was talking about pinning the catches on the end of your safety harness. Apparently this is written into some of their rulesets over in Murica.

I have seen the little holes in the harness clips where they attach to the eyebolts, but never have I seen, nor heard of, a requirement to put a split pin or similar in there to prevent inadvertent movement of the catch and the risk that the clips come off the eyebolt.

Anyone do this, or know of it?



I get that it is possible for the catch to move (though it is spring loaded to stay shut), and presumably that hole was put there for this purpose.

But has anyone seen a need? I'd be interested to hear of anyone's experience of finding that catch open, or even partially open.

For me, it would be one more step installing/removing the race seat/harness each event. For someone whose harness is more of a fixture, it would be a non-issue I presume? Just need to have a supply of split pins in the workshop/garage.

I was aware of the intended purpose of the holes but, like those in the MT.net thread, I've never seen or heard of a scrutineer demanding it or a harness coming loose from not being pinned. If the belt is tightened correctly, the latch could swing wide open and it still wouldn't come off due to the shape of the latch and the tension in the belt. The odds seem very, very, very low that the latch would be forced open, the belt slackened, and the position of the latch moved in just the right way to pull it off the eye bolt, all at the same time.

I got asked why I didn't have a pin in my harness once about 10 years ago at a hillclimb in Canberra. Scrutineer was of the opinion that as the harness clips had a hole, while not a requirement, it was obviously intended to be pinned and why didn't I. I had never paid any attention to the holes before and had no idea what he was talking about so just smiled and nodded. Asked a couple of the older guys running that day once back in the pits who explained what the intent was, but they themselves had never done it before and most had never been questioned. Until reading this thread now, that was the only time I had ever heard of it.

PaulF wrote: ... If the belt is tightened correctly, the latch could swing wide open and it still wouldn't come off due to the shape of the latch and the tension in the belt. The odds seem very, very, very low that the latch would be forced open, the belt slackened, and the position of the latch moved in just the right way to pull it off the eye bolt, all at the same time.

Broadly, I am of the same opinion.

However, in a big shunt, the body will thrown around (even with the harness tightly fastened), the seat/mounts will flex somewhat (maybe the car too), and if the spring is broken it is conceivable circumstances may conspire in a way that the catch opens at the wrong time. Like you, I reckon that the chances of this are verging on zero, but not zero.

BTW thanks to electroCrunch on MT.net for the photo, a picture IS worth a thousand words!

I occasionally move my harness between cars, and given the difficulty of deliberately getting the damn thing off I can’t see any way it would come off accidentally, such as to require a secondary locking mechanism.

My thinking is that the hole for a split pin is only to cover the situation IF the spring were to lose its tension over time or break. You could then fit a split pin and still have confidence it wouldn’t come off.

So an either option rather than a both…

The very first harness I purchased about 30 years ago (a Willans) came with the split pins so I fitted then.

No harness I have fitted since has come with split pins, so I've never bothered putting any in and never been questioned about the lack of them.