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CATERHAM DE DION SUSPENSION
Ben Corley | July 7, 2007
The easiest way to describe a De Dion suspension is to say that it is a suspension system in which the rear, driven wheels are bolted to a transverse rigid beam. Power is delivered to the wheels by CV jointed half-shafts attached to a differential mounted on the chassis.
Image courtesy of The Car Bibles
BENEFITS
One obvious benefit is that since the wheels are rigidly linked by the transverse rigid beam, they remain perpendicular to the road surface regardless of chassis roll while cornering, resulting in relative stability. In comparison, in most independent suspension setups, camber angle may change while cornering or during up and down movement of wheels in unison. It is also lighter compared to a live axle since there is less unsprung weight.
CATERHAM’S DEVELOPMENT STORY
As Caterham continued with Seven production, it became apparent at about 1983 that live axles would become increasingly difficult to source as Front Wheel Drive cars become the norm. In late 1983 Caterham employee at the time Clive Roberts (an ex Triumph employee and post-Caterham a Lotus employee) noticed that the new Ford Sierra had an interesting rear differential which had loads of possibilities. He promptly asked Ford for one.
Caterham’s management team consisting of Graham Nearn, David Wakefield, Clive Roberts, Jez Coates, Reg Price, Mick Lincoln and Peter Cooper met to discuss the De Dion proposal.
It was realised that the De Dion system would allow:
- Live axle style wheel location without the complexity of a fully independent system
- Fewer structural changes to the chassis
- Lower component costs (about UKP100 compared to fully independent suspension, in 1983)
- Simpler development
- Better durability
- Precedent in the case of the Lotus Eleven
Clive Roberts and Reg Price (a teacher who, at the time, worked part time at Caterham), set about developing the suspension. They took just weeks to finalise the concept and within a month had built the new De Dion system into a development chassis. The CV joints, differential, hubs and brakes were borrowed from the Ford Sierra while the De Dion tube, locating links, hub carriers (or ‘ears’) and driveshafts were developed by Caterham. The De Dion tube itself was a straight tube, with ears at either end
By April 1984 the prototype De Dion Seven was running after numerous tweaks and adjustments had been made. Clive Roberts and Reg Price had racked up over 16,000 kilometres during the development period. An added advantage was that for the first time in the history of the Seven, tubes were added along the transmission tunnel, contributing to stiffness.
ロータス / ケイターハム スーパーセブン ビルダー
SOURCES:
1) Caterham Sevens: From Conception to CSR, Chris Rees
2) Lotus and Caterham Seven: Racers for the Road, John Tipler
3) The Car Bibles
Topics: Chassis |
