British sports car maker works with Reynolds Technology and Simpact to develop butted tubes that are up to 50% lighter

Caterham has confirmed that it wants to produce an ultra-lightweight version of its Seven sports car at the start of 2017, by integrating bicycle tubing technology into its spaceframe construction.

Working with bicycle tubing expert Reynolds Technology and computer aided engineering (CAE) consultancy firm Simpact, Caterham has already created a prototype Seven 270 with a chassis that’s 10% lighter but retains the torsional rigidity the current production car.

The project, which took six months to finish and was funded by Innovate UK, was demonstrated to at the Niche Vehicle Network Symposium earlier this month, and his since gained traction thanks to strong support.

The carmaker now hopes to offer the technology to Seven customers from the start of 2017, as an optional extra that would cost between £1000-£2000. It expects as many as a fifth of Seven sales to include butted tubing.

The way butted tubes are able to reduce weight while maintaining strength is due to their unusual shape. Unlike regular tubes, they are thicker at the ends than in the middle, so joins remain strong but overall material usage is reduced by up to 50% in some parts.

In a car with a frame that weighs as little as 55kg, a 10% weight saving would shave about 5.5kg from the overall figure. Though that may seem small, on such a light vehicle (the 270 weighs 540kg) it'd have a measurable effect on bhp/ton figures and overall efficiency.

Interestingly, Caterham says even more weight can be saved because the prototype uses Reynolds' 453 high tensile butted tubes, but far more exotic materials are available.

“Caterham has made its name as a purveyor of lightweight sportscars but we believe more can always be done to reduce weight and, therefore, emissions,” said Simon Lambert, CTO of Caterham.

“Caterham and Reynolds are two proudly British brands and there is a real synergy between customers of Caterham and cycling enthusiasts, so it’s even better that the technology that has made this possible has come from the two-wheeled world.”

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The Caterham Seven is the essence of a stripped-down sports car

The Caterham Seven is a stripped-down sportscar offering one of the most pure driving experiences available. It is a true classic.

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Comments
8

30 March 2016

Alex Moulton (1920-2012) would have bettered that.

30 March 2016

Good to see that I'm not the only one reminded of Moulton. Wonderful engineering there. Shame they're not doing so well now.

30 March 2016

what're caterham composites busy with?! their website isn't working. i was expecting a caterham equivalent of the westfield fw400 a long time ago! considering how light the chassis is already, isn't this looking in the wrong place for weight savings? any chance of some comparative crash tests? i don't doubt that this is a good design, it's simply that it's now being designed for intended loads only, and not the random ones you get during collisions; if a tube is 50% thinner along its centre third, how will it react to be struck upon away from the joints? how will it deform?

30 March 2016
russ13b wrote:

what're caterham composites busy with?! their website isn't working. i was expecting a caterham equivalent of the westfield fw400 a long time ago! considering how light the chassis is already, isn't this looking in the wrong place for weight savings? any chance of some comparative crash tests? i don't doubt that this is a good design, it's simply that it's now being designed for intended loads only, and not the random ones you get during collisions; if a tube is 50% thinner along its centre third, how will it react to be struck upon away from the joints? how will it deform?

If you read the article the tube specification was achieved using CAE by the firm Simpact so the crash protection should be the same or better than using constant wall thickness tubing. The tubing wall thickness will vary throughout each tubes length to obtain the desired result. Usually the thickest at each end with reducing wall section towards the middle of each piece of tubing.

31 March 2016

and my point is still valid

30 March 2016

I would love to see a composite Caterham. I don't think it would save a massive amount of weight but surely it would hugely increase stiffness and crash protection? Anyone have any ideas about comparative weights between tubes and carbon?

30 March 2016

Headline: British sports car maker works with Reynolds Technology and Simpact to develop butted tubes that are up to 50% lighter

Actual News: Overall car is 1% lighter

30 March 2016

I can't believe they weren't already using double and triple butted tubing. They are only about 20 years behind the bicycle industry. Imagine the shock and disbelief when they discover carbon fiber!

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