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De Dion suspension specific questions...
PeterGT4 - 23/5/04 at 06:18 AM

May someone please provide the dimensions of the De Dion tube (O.D., wall thickness) used in either a Caterham, or other Seven-based kit.

I purchased and assembled the Tamiya 1/12th scale Caterham kit (awesome by-the-way!) and by scaling-up, I came to a rough size of 2"+ O.D., but would like to know just how light (or heavy) I would go in fabricating the real De Dion tube.

Thanks in advance.

Picture below of the model's suspension. Rescued attachment SSeven11.jpg
Rescued attachment SSeven11.jpg

type 907 - 23/5/04 at 07:25 AM

WOW !!!!

Thats the "best finished" Locost I'v ever seen.;

I like the anti roll bar.

If you can't scale up the car, scale down the driver? LOL

Paul G

britishtrident - 23/5/04 at 11:02 AM

It can also be built for a lot less than £250 :-)

Peteff - 23/5/04 at 11:19 AM

50x3mm wall CDS would be the obvious. A place near me build one off 4x4 chassis in it and they don't break in a hurry. They bent me a roll bar in it for £30 so it wouldn't break the bank either.

pbura - 23/5/04 at 02:35 PM

Found a Caterham newsletter indicating that they increased wall thickness from 2mm to 3mm a couple of years ago:

http://www.caterhamracing.com/downloads/newsletters/superlight240702.pdf

PeterGT4 - 23/5/04 at 09:35 PM

Thanks for the replies and providing dimensions, its a big help!

I was thinking to be on the safe side, I was planning on using 2.5 x 0.188", but now, what has been provided here, looks like I'll be way over-built... Perfect!

Cheers!

By-the-way, here's a picture of the complete model, which ended up costing around the Canadian equivalent of £250! Rescued attachment SSeven23.jpg
Rescued attachment SSeven23.jpg

F1 Mini - 23/5/04 at 09:47 PM

Thats a very straight tube is it not. Are the caterfields like that.
Most of the ones I've seen are bent round the diff.

blueshift - 24/5/04 at 12:09 AM

There was a thread on here a while back where cymtriks did his thang on the whole dedion tube material issue. various actual production tube sizes were quoted I think.

a search for posts containing "dion" by cymtriks might yeild fruit..

PeterGT4 - 24/5/04 at 05:27 AM

quote:
Originally posted by blueshift
...a search for posts containing "dion" by cymtriks might yeild fruit..


It did, except he spelt it "Deon"... No worries, I found them. Here's one of those threads:

http://www.locostbuilders.co.uk/viewthread.php?tid=5849&page=1

I also noticed a few times mention about lateral location devices. What are people's opinions of "Satchell Links"? Seems like it would be better.

I have done as a test welding a gusset in the centre of the tube, like the Caterham's, and noticed a fair amount of distortion (as expected). Would require straightening and I feel it would be alot of work, for nothing considering the Satchell Link pick-up's are at the ends of the tube (where the trailing links would be and at least one of them still as you need one with a Satchell Link), leaving the rest of the tube un-disturbed.

Granted, Panhard's are still the easiest, but thought this would be different.

???

PeterGT4 - 24/5/04 at 05:28 AM

quote:
Originally posted by F1 Mini
Thats a very straight tube is it not. Are the caterfields like that.
Most of the ones I've seen are bent round the diff.


All of the Caterhams feature a straight tube like that.

dannyboy - 25/5/04 at 12:49 PM

My seven is outside in the site car park. Rough scaling, using my scale rule gave an OD of approx 60mm.....very very roughly!!! and measured laying on the ground in the dirt with a plastic scale rule!

However, if you are making a de-dion, the latest Caterham design is quite poor for the shock mounting. Mine is an older version and the shock mount is through the centre of the de-dion tube. The latest ones have a lug at the base of the de-dion and there have been several failures! And they are straight..well mine is ATM

Nice model BTW!!!

PeterGT4 - 25/5/04 at 08:53 PM

quote:
Originally posted by dannyboy
My seven is outside in the site car park. Rough scaling, using my scale rule gave an OD of approx 60mm.....very very roughly!!! and measured laying on the ground in the dirt with a plastic scale rule!

However, if you are making a de-dion, the latest Caterham design is quite poor for the shock mounting. Mine is an older version and the shock mount is through the centre of the de-dion tube. The latest ones have a lug at the base of the de-dion and there have been several failures! And they are straight..well mine is ATM

Nice model BTW!!!


Thanks. I noticed the poor mounting of the Caterham's shocks and was thinking for mine, I'd build a support/gusset off of the De Dion ear. Should be better.

I built the model as a practice piece to building the real thing. Gave me the opportunity to practice painting. The nose cone and fenders feature five coats of paint, that were wet-sanded between each coat, with a final hand polish and waxing.

blueshift - 26/5/04 at 01:01 PM

Location methods have been discussed too, and the conclusion was that there were better ways that panhard rod, but the difference was so tiny that you might as well stick with panhard rod as it's simpler and a lot lighter.

josty - 23/6/04 at 02:34 PM

Why don't you build a completely independent rearsuspension when using independent rear diff.? Am I overseeing something?

What's the advantage of this methode compared to the double wishbone type like the Caterham or DaxRush?

A lot of questions...

Josty (Holland)

JoelP - 23/6/04 at 03:41 PM

quote:
Originally posted by josty
What's the advantage of this methode compared to the double wishbone type like the Caterham or DaxRush?

A lot of questions...

Josty (Holland)


theres a thread about this live at the minute. To summarise, with a dedion you dont get rear camber change under hard acceleration (squat affects IRS setups). plus its very easy to make, IRS needs more fiddling, thinking and planning.