Been thinking about this a fair bit recently, and I think I may have found a way forward but wanted to get a few opinions from you guys on here.
The usual harness bars won't fit a Roadster due to the roll over hoops situated just behind the seats, so I've been thinking of another way round this. Looking at it, there is enough room between seats and hoops to fit a custom-made bar and to bolt it through the existing seat belt mountings using some slightly longer bolts, and then using wrap around harnesses. You can remove most of the interior and mount something, but that's not an option for me at all: I want to keep the inside stock.
I've fitted a very similar system on my old VXR220, however that was an OEM (well, Lotus) designed bar that obviously had the weight of their technical knowledge behind it which far outstrips mine! It too bolted through the seatbelt mounts, however the loads on it were more horizontal that vertical as would be the case in the Zed.
My theory is that the bolts in the existing setup must have a fair amount of strength in them given that they hold the seatbelts in place and a considerable load could be put on them in an accident: However, that is offset by the fact that the pretensioners are going to be doing part of the work in reducing this force. My first question is am I right on this presumption so far? I don't profess to be an expert in automotive physics, just a guy with a passing interest from a practical point of view.
Assuming that the bolts and mountings are strong enough to withstand these forces on both a seatbelt AND my proposed harness bar in an accident, can anyone think of any other reasons why this can't be done? I'll take any advice on board as if it's going to be a safety issue then it's simply not going to happen full stop: I value my life slightly more than being held in some harnesses on track. That said, if this is a goer I've got a chap in mind who could knock these up day in day out and could possibly then offer them up for sale here for others to use.
As always, any and all views welcome chaps.