I have a glass fibre car with a rotten mild steel space frame chassis. Is it feasible to replace (partially replace) with your carbon fibre tubes and sections? I mean would they be strong enough. The main rust is in the main backbone chassis and the sections that come out along the sills. If i have a 1inch mild steel tube section what would i replace that with for same strength?

I would replace complete section for instance the whole backbone not just patch up the rusty bit.

Graham

Hi Graham,

It's feasable but there would be lots of considerations specific to working with composite tubes compared to more conventional steel tubes (which the chassis was designed for).

One example would be to consider how the tubes would behave in a crash situation; composites, and particularly carbon fibre, are very strong until the break but once they do they tend to break completely. The spaceframe of your car creates important protection for the driver and will have been designed with some knowledge of how the frame would crumple in the event of different impacts. Simply swapping metal tubes for carbon tubes would change the crumple characteristics of the chassis considerably which could have major consequences in terms of safety.

Another consideration is the type of forces that will go through the tubes and whether they will be sympathetic with the fibre orientation of the tubes (composite tubes are stronger in some directions than others). Our roll wrapped tubes have a good spread of strength but it's still worth thinking about. Their 0,90 fibre orientation means they're not very strong in torsion (twist).

Another consideration is how you will connect between the carbon fibre tubes and the exisiting tubes; you'll need to make special metal fabrications which the carbon tubes can be bonded into but which can then be bolted up to the metal tubes. This alone would be quite a bit of work.

I hope this helps. You might conclude that in this case you'd be better sticking with metal tubes in which case I think I would agree with you but like I said at the top of the post, it would be possible.

Kind regards, Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Thank you for coming back to me. I used to own a lotus elan +2 which had a steel backbone chassis  - after an accident i replaced the chassis with an aftermarket Spyder spaceframe chassis. My current car which i have had from new is a 1998 5.0l Chimaera but after about 10 years the chassis has rotted through. I live on Anglesey exposed to the sea air all year round. I can buy a new chassis but i am more than annoyed that when you buy a car with extensive corrosion protection on the chassis i need to buy a new one. The problem being the new chassis is exactly the same as the old one. Powercoated - which falls off.

All the above not your problem but it was to give you an idea why i was considering it.

thanks anyway.

Graham