De Dion Tube

Author
Discussion

Nampahc Niloc

Original Poster:

910 posts

78 months

Monday 24th February 2020
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Simple question. Why do Caterham use a de Dion rear suspension when the rest of the world abandoned them decades ago?

BertBert

19,025 posts

211 months

Monday 24th February 2020
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I think it's because it's very simple, strong and works rather well.

Also it's quite hard to package irs into that same space.

Bert

DCL

1,216 posts

179 months

Monday 24th February 2020
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Yes, the simple answer is that it works rather well on a very light car like the Caterham. Ultimately independent rear suspension may be better if set up with skill and precision, but having four roll centers to balance is much harder than three.

Equus

16,852 posts

101 months

Wednesday 26th February 2020
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DCL said:
Ultimately independent rear suspension may be better if set up with skill and precision, but having four roll instant centers to balance is much harder than three.
EF(slightly more)A... you only have two roll centres (and it actually isn't that difficult to 'balance' them, now that we have specialist computer software to calculate the suspension geometry).

The justification that Graham Nearn gave at the time they introduced the de Dion was that they simply didn't have the money to develop an IRS properly.

The CSR was an attempt to move to a more modern set-up, but it seems that the market didn't much like it.

Ironically, people are critical of cars like the CSR and Westfield SEi because their IRS gives a more compliant ride, which they seem to perceive as taking away some of the rawness of the car.

N.G.Near

27 posts

50 months

Wednesday 26th February 2020
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Funnily enough, I found the suspension of the first Lotus Elise I drove to be very uncompliant when compared to my de Dion Caterhams. That came as a complete surprise as I was expecting the Lotus to be the more compliant. The de Dion tube set up that Caterham use is very fit for purpose, well it is now they’ve sorted out earlier problems with cracking!

Equus

16,852 posts

101 months

Wednesday 26th February 2020
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N.G.Near said:
Funnily enough, I found the suspension of the first Lotus Elise I drove to be very uncompliant when compared to my de Dion Caterhams.
Really?!

What springs/dampers was it on?

I know some people fit stupidly stiff aftermarket springs/dampers to their Elises, but I've owned a Caterham and two S1 Elises, and driven many more, and on standard Lotus springs/dampers the Elise is WAY more compliant.

Edited by Equus on Wednesday 26th February 22:06

N.G.Near

27 posts

50 months

Wednesday 26th February 2020
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Equus said:
Really?!

What springs/dampers was it on?

I know some people fist stupidly stiff aftermarket springs/dampers to their Elises, but I've owned a Caterham and two S1 Elises, and driven many more, and on standard Lotus springs/dampers the Elise is WAY more compliant.
Definitely not the standard S2 SC I drove for an extended period. The suspension in that was very crashy compared to the 7. Mind you, I still ended up buying a Lotus and would never, ever go back to a Caterham.

Equus

16,852 posts

101 months

Wednesday 26th February 2020
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N.G.Near said:
Definitely not the standard S2 SC I drove for an extended period. The suspension in that was very crashy compared to the 7. Mind you, I still ended up buying a Lotus and would never, ever go back to a Caterham.
Sorry, that just does not compute. The standard S2 has a better ride quality than the S1, and even the S1 is a world apart from the Caterham, in terms of ride quality and compliance.

If what you're saying is true, then there was something badly wrong with the Elise you drove.

N.G.Near

27 posts

50 months

Thursday 27th February 2020
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Equus said:
Sorry, that just does not compute. The standard S2 has a better ride quality than the S1, and even the S1 is a world apart from the Caterham, in terms of ride quality and compliance.

If what you're saying is true, then there was something badly wrong with the Elise you drove.
There was nothing wrong with it at all. The Elise SC I subsequently bought was exactly the same. Even my wife was given to remark how much less forgiving and more crashy the Lotus suspension was compared to my previous 7s.
The Exige V6 I went on to buy was much better in this respect, possibly due to being heavier, but the suspension compliance was more resolved in that car, with none of the “crashiness” over small potholes that was very obvious in the Elise.
Neither of my 7s were as bad as the Elise.

upsidedownmark

2,120 posts

135 months

Thursday 27th February 2020
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May also depend on the caterham? My roadsport (i.e. not 'race' oriented springs/dampers) is impressively compliant. Can't say I thought the elise was bad either, but was just a test drive a few years ago.

N.G.Near

27 posts

50 months

Thursday 27th February 2020
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upsidedownmark said:
May also depend on the caterham? My roadsport (i.e. not 'race' oriented springs/dampers) is impressively compliant. Can't say I thought the elise was bad either, but was just a test drive a few years ago.
Quite possibly yes. Neither of my Caterhams were race orientated and whilst obviously more stiffly sprung and damped than ordinary tin tops, were definitely more compliant than either my Elise or the one I had road tested.
That’s not a criticism of the Lotus but more of an observation from many years of ownership of both types.

BertBert

19,025 posts

211 months

Friday 28th February 2020
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Not my experience. Whenever I got the elise/exige itch, I used to drive to B&C in my Caterham, test drive the Lotus and then drive home in my Caterham.

Outcome was always that the Lotus was soft, squidgy and didn't change direction properly in comparison to the Caterham biggrin

N.G.Near

27 posts

50 months

Saturday 29th February 2020
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Maybe it’s just the SC suspension then but I definitely know what I felt with it.

Eugene7

739 posts

194 months

Sunday 1st March 2020
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I have a highly modified live axle 7, and a very standard Elise S1.

The suspension on the 7 has been heavily worked on over the 35(ish) years I've had it

To my style of driving it is far more 'compliant' than the S1, and has far greater handling capabilities.

But, I have always found the standard Caterham set too soft on springs, and too hard on dampers. I have basically swapped that around, and run much stiffer springs, and much softer dampers.

But, I still runs bushes, not rose joints on the 7 (Polyflex though), while the Elise as a lot more rose joints. I think that is where a lot of the perceived 'cashiness' possibly comes from with the Elise?

Either way, they both handle in a league well above other cars.

N.G.Near

27 posts

50 months

Sunday 1st March 2020
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Eugene7 said:
I have a highly modified live axle 7, and a very standard Elise S1.

The suspension on the 7 has been heavily worked on over the 35(ish) years I've had it

To my style of driving it is far more 'compliant' than the S1, and has far greater handling capabilities.

But, I have always found the standard Caterham set too soft on springs, and too hard on dampers. I have basically swapped that around, and run much stiffer springs, and much softer dampers.

But, I still runs bushes, not rose joints on the 7 (Polyflex though), while the Elise as a lot more rose joints. I think that is where a lot of the perceived 'cashiness' possibly comes from with the Elise?

Either way, they both handle in a league well above other cars.
That is the answer I think. Also, in my view, some of the crashiness (not sure that’s actually a word but it does describe what I was experiencing) comes from the fact the aluminium chassis acts like a big sounding board every time you hit even a small pothole. It seems to send a shock wave through the entire car, which the Caterham tube chassis doesn’t.
My last 7, particularly, was a very much developed car with non standard inboard springs and adjustable dampers at the front. Maybe a lot of the compliancy came from that. The rear was standard DD tube but with different springs and adjustable dampers.
It handled like a dream and would outperform pretty much anything else on the road.
In the end though I just found the 7 package too compromised for me. I enjoyed the ones I owned for many years but not sorry to move on and would never go back now.



Edited by N.G.Near on Sunday 1st March 10:08