owelly
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| posted on 22/7/09 at 09:30 PM |
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De-dion?
The rear end of my Magenta LSR is crap. It's currently running a standard Capri Atlas on trailing arms with a Panhard rod.
I've bought a Sierra LSD and cobbled together a De-dion. I've just spotted Rortys design and mine doesn't look too wrong but what do
you folks think??
And the reason for using the Diahatsu calipers......
To fit inside a 13" wheel.
I havn't welded the trailing arm brackets on yet as I intend using the brackets on the forward (car body) end to fix the subframe to hang the
diff off as there is no steel work rear of them!! I'll then move the trailing arms out a bit.
http://www.ppcmag.co.uk
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M$RK_VXRD
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| posted on 22/7/09 at 09:39 PM |
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i voted to fit urs!
but wouldnt it be better to just use one piece of bar with a bend in it rather than 3 welded together?
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owelly
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| posted on 22/7/09 at 09:45 PM |
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The only thin walled tube I had was 3" and I couldn't bend it!
http://www.ppcmag.co.uk
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M$RK_VXRD
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| posted on 22/7/09 at 10:06 PM |
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couldn you get a local engineering firm to bend it for you i cant see it costing much?
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owelly
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| posted on 22/7/09 at 10:09 PM |
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Costing much?? Have you seen the car?? A fiver would be more than it's worth!!
Did I mention I'm a tight arsed Yorkshireman?!
http://www.ppcmag.co.uk
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M$RK_VXRD
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| posted on 22/7/09 at 10:19 PM |
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lol so am i but if u went on a weekend to an engeering company when gaffers arnt in im sure a lad would do it you 4 £5 or £10 max
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Lars
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| posted on 22/7/09 at 11:17 PM |
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i have just finished mine and it looks remarkably simar to yours.
I also have it in 3 sections. Almost looks like a copy.
should be strong enough.
I have used a small shim on one side to align it just right.
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Volvorsport
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| posted on 23/7/09 at 10:43 AM |
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i thought the aim was to save unsprung weight ?
could have cut a 340 one up, there about a fiver from the scrappys .
www.dbsmotorsport.co.uk
getting dirty under a bus
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craig1410
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| posted on 23/7/09 at 11:49 AM |
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That looks fine, I'd just go with it although I'd be tempted to grind down the joints between the centre of the axle tube and the two
angled pieces and weld over the existing joint with some 3mm plate to act as load spreaders. Just takes a bit of the reliance away from the single
welded joints.
The only other thing you might have difficulty with is fitting a panhard rod because of the angle it would have to run at longitudinally to get around
the longitudinal depth of your axle. Easy solution would be to build a watts linkage instead which is technically better than a panhard rod anyway. If
you do decide to use a panhard rod then remember it needs to be as long as possible and should be parallel to the ground at ride height.
Watts linkage in Wikipedia:
http://en.wikipedia.org/wiki/Watt's_linkage
Good luck!
Craig.
[Edited on 23/7/2009 by craig1410]
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owelly
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| posted on 24/7/09 at 12:57 PM |
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Cheers folks. I'll go with the majority and fit the thing I've made!
I was intending to fit a Watts linkage and I've already welded a plate to the back of the tube to fit it. The welds that are on there are far
stronger than the rest of the car so I'm happy that they'll outlast the car!!
The set-up is light enough to lift with one hand and that's including the brakes and discs. The diff will add more weight but I'm sure the
whole lot will weigh less than the Volvo axle. If I'd had a Volvo axle in my shed, I would have fitted that as I'm prone to use whatever I
have close to hand!!
Cheers folks!
http://www.ppcmag.co.uk
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owelly
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| posted on 29/3/12 at 10:54 PM |
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Just a quick update as I've had a few minutes here and there...
De-dion and subframe made to locate on existing trailing arm mounts, fitted with diff, shafts, brakes etc, and the coilovers balanced on top to get an
idea of the weight...
It comes in at 105kg. I can lose a bit more weight by making a lighter Watts pivot and using thinner walled tube for the subframe, but I used whatever
I had kicking about the garage.
The Atlas I took out weighs 80kg, including drums, coilovers, backplates, etc. So a 25kg increase in weight, but a lot less unsprung weight, disc
brakes and an LSD.
http://www.ppcmag.co.uk
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owelly
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| posted on 29/3/12 at 11:14 PM |
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And yes, it has only taken me three years to get around to finishing this.....
http://www.ppcmag.co.uk
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mcerd1
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| posted on 30/3/12 at 07:27 AM |
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that looks quite neat 
-
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DIY Si
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| posted on 30/3/12 at 03:25 PM |
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That's about what I reckon mine will end up weighing, although mine is a narrowed Caterham version, so has a straight tube. The only difference
is that mine is in a Sprite will extend the tunnel to mount the diff.
Rather than using a panhard rod, would it be any better to use the trailing arms angled outwards to provide lateral location? It would mean making new
ones though, and I'm not 100% sure if you'd have space at the outer edges of the tube to mount them.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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owelly
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| posted on 30/3/12 at 05:22 PM |
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The problem with triangulating the set-up using the trailing arms is that the beam becomes over-located. When cornering, the axle would be in a
twisting force. It wouldn't be a problem if there was a sliding joint in the de-dion.....
http://www.ppcmag.co.uk
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MikeRJ
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| posted on 30/3/12 at 05:47 PM |
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quote:
Originally posted by owelly
The problem with triangulating the set-up using the trailing arms is that the beam becomes over-located. When cornering, the axle would be in a
twisting force. It wouldn't be a problem if there was a sliding joint in the de-dion.....
Unless you only turn one of the trailing arms into a "wishbone", in which case there will be no binding. It's something I thought
about ages ago, but I've never seen it done so I presume there must be a disadvantage.
That's a hefty looking axle BTW, I doubt you'll be suffering from GTS syndrome (snapping in half at the welded section of the tube) and it
should at least be very rigid.
[Edited on 30/3/12 by MikeRJ]
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owelly
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| posted on 30/3/12 at 06:05 PM |
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I did think of making a single centre mounted A-frame type thing to mount of the subframe to the de-dion but that may be for a future developement...
http://www.ppcmag.co.uk
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DIY Si
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| posted on 31/3/12 at 08:50 AM |
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That's exactly how mine works, being a Caterham set up. In my case, the lower A arm is parallel at what should be ride height, so despite
sticking down a fair bit, it's still level with the sills.
How heavy is your main tube? I can pick mine up with just my little finger, but I've obviously got all the diff, shafts and hubs to add as yet
and they're most of the weight.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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owelly
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| posted on 31/3/12 at 07:41 PM |
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My plain tube with flanges and brackets, but no hubs, brakes, arms etc weighs about 6kg. Its very light!
http://www.ppcmag.co.uk
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froggy
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| posted on 31/3/12 at 08:21 PM |
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I preferred it going up the 1/4 in a clown car stylee myself
[IMG]http://i144.photobucket.com/albums/r187/froggy_0[IMG]
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owelly
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| posted on 1/4/12 at 07:23 PM |
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It's strange you should say that Froggy, I dissapponted a few folks by not taking the Tupperware Turd to Santa Pod yesterday. They all wanted to
see my crap car jumping up the strip....
http://www.ppcmag.co.uk
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froggy
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| posted on 2/4/12 at 08:39 PM |
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What you really need is a clown wig and red nose for Mallory park next month .
[IMG]http://i144.photobucket.com/albums/r187/froggy_0[IMG]
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Nickp
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| posted on 3/4/12 at 05:49 AM |
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quote:
Originally posted by froggy
What you really need is a clown wig and red nose for Mallory park next month .
How rude!! 
I think there might be less laughing this year and there may even be a shock on the cards at Santa Pod  If he can get the thing to actually steer!!
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TAZZMAXX
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| posted on 3/4/12 at 06:20 AM |
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Maybe this isn't the right place to ask but what actually is the advantage of a De Dion axle over full Sierra IRS? To me, it looks like it adds
weight unnecessarily or is it just an easier way of going from a rigid axle without fitting wishbones?
Thanks.
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owelly
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| posted on 3/4/12 at 06:32 AM |
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Discussed here: http://www.locostbuilders.co.uk/viewthread.php?tid=14769
I was on my way to buy steel to convert my car to IRS when I found an old steel lamp post at the side of the road, so I used it to make the De-dion
tube. That is why I chose De-dion......
http://www.ppcmag.co.uk
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