Upgrades 20. Crutch (Crotch) Straps

The standard seats come with a 4 point harness, after a while you start to notice that the central buckle does in fact ride up higher than it should because it gets pulled upwards by the shoulder straps. This means it doesn't quite sit right at all times, which is not only slightly uncomfortable, but it increases the risk of "submarining" in accidents (This is where you slide out from under the harness).

To sort this you can easily convert to a 5 point harness using Caterham crutch straps (I'm sure they should be called crotch straps!). So I decided to buy two of these in red to match my straps, one for each seat. It is worth noting that if you have lowered floors like me, you will also need to buy 2 Crutch Strap Bushes for each seat (so 4 in total).

Once you have all the kit, the first job is to remove the seats, which is pretty easy. Then, as I have carpet still in my cabin, I decided to first punch a few holes under where the crutch straps will be attached, these are the brackets sticking out of the bulk head near the floor.

Next up I used an 11mm drill and drilled down vertically to open up a hole in the floor pan. I found that using the bushes in between and drilling through them also helped align the holes. Once I was happy with the holes I then trimmed the carpet so it would fit around the bush. This is because the bush and spacers fit exactly between the floor and the bracket, so the carpet has to be removed below that area.

This is where you will notice a problem, if you want to be able to move your drivers seat all the way back, as I do, you cannot simply mount the straps as per the manual. The manual calls for the bush to be seated on top of the strap buckle, which would mean the buckle would rest on the floor, but also get in the way when moving the seat back. I decided that for the drivers seat, I would actually mount it the other way, so the bush on the floor first, then the buckle on top. I can't see this having any negative impact on the way the belt is designed to work, and doing it this way meant the buckle would fit between the rails and the seat as shown in the picture.

The order I fitted the bolts in was:

Bolt - SS Washer - floor - spacer bush - top hat - buckle bracket - thin black washer - chassis bracket rear - nut

I'm told there is no need for a washer on top of the chassis bracket. Once I was happy with the placements, I torqued them up to 47Nm as per the manual.

I did the same on the passenger side, except as this has no moveable rails, I mounted it as per the manual with the buckle on the floor first (top hat - buckle - thin black washer), then the long spacer bush on top.

An update on this, I ended up mounting them in the same way as the driver side, with the buckle on top of the spacer bush, it turns out the fixed rails could not fit correctly either with the buckles on the low side.

Adjusting the straps is a pain, and it is definitely worth messing with them before you commit to bolting the seats in place. I left my passenger one as per the photo, which is good enough for most people who ride with me. My drivers side was slightly shorter.

When bolting the seats back in place, they were torqued to 14 Nm as per before, and a bit of loctite was used again to stop any movement.