Post
by jtbo » 05 Apr 2009 12:58 pm
WRC rollcages have advanced quite far, they have ton of data from accidents and can calculate stress to cage with computers, so it is light and very strong structure.
There are few cases where I know cage been holding up just fine, but it had gone trough chassis of car because of missing plates, also seat mounting should be made enough strong, even in WRC there has been seat mounting failures in crashes, but not probably anymore as they have learned from those incidents.
One JM class race driver had made rollcage thinking metal bar is strong, so he had put one metal pipe bent like U-shape to front of his car's chassis (it was some rear engined fiat or something like that) there was no other support to that U-shaped pipe just it welded to 'firewall' then normal cage in cockpit. Crash was typical to that track, race was near Oulu, there was one light pole at main straight and it was quite normal for car to hit that pole as JM is kind of contact sports, so he rams to that pole dead center and finds pole where gear stick should been (Well, actually people that came to help found that). That U-shaped bar did nothing except for bending, normally there is few pipes more to make it rigid.
Some are also making cage from pipe that is used for water pipes, not too sure if that is best possible material.
Volvo 360GL -88 -under restoration-
Volvo 343DL vario -81 -running-
Volvo 240 Diesel -83 -undecided-
Citroen ZX Dturbo -97 -daily-
Anyway, the 343 has a few 'messy' bits on the arches, but is generally solid, and he's going to do exactly what you've done - repair the rusty bits, rather than replace the whole arch if most of it is solid. As long as you get all the grot out, there's no need to make work for yourself...
That is all...
Still, guess when it's done it's done. In the time it's been laid up, the steering gone funny, and the brakes have become useless. F*ck. Will strip brakes, no idea what could have gone on the steering though. Feels like tracking is about a million degrees out, and from memory I didn't hit anything lumpy in the road since I had that done. 
