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ERW or CDS?
Jesus-Ninja - 18/8/08 at 11:10 AM

As per the title...

Marcus - 18/8/08 at 11:19 AM

ERW

Jesus-Ninja - 18/8/08 at 11:24 AM

quote:
Originally posted by Marcus
ERW


because...?

nick205 - 18/8/08 at 11:27 AM

...it's cheaper!

flak monkey - 18/8/08 at 11:30 AM

CDS is unnecessary for a chassis, and also not really a requirement for suspension parts either (with careful positioning of the seam).

David

Alan B - 18/8/08 at 11:30 AM

How can you ask someone to elaborate upon an answer to such a vague question?

Jesus-Ninja - 18/8/08 at 11:35 AM

quote:
Originally posted by Alan B
How can you ask someone to elaborate upon an answer to such a vague question?


Fair comment

It's been suggested to me that I should use CDS rather than ERW as it is significantly stronger for the same guage.

Strikes me that the chassis is the one thing you get one pop at, so it may pay dividends to go CDS.

Alan B - 18/8/08 at 11:43 AM

quote:
Originally posted by Jesus-Ninja
quote:
Originally posted by Alan B
How can you ask someone to elaborate upon an answer to such a vague question?


Fair comment

It's been suggested to me that I should use CDS rather than ERW as it is significantly stronger for the same guage.

Strikes me that the chassis is the one thing you get one pop at, so it may pay dividends to go CDS.


First of all CDS is NOT significantly stronger, and as Flak says used correctly ERW is fine for most applications.

Also, have you actually looked for and found CDS in square section?...not saying it's not made, but it is very rare and hard to find..I think I've only ever seen it in chromoly.....and so very expensive.

smart51 - 18/8/08 at 11:50 AM

I've seen plenty of pictures of crashed kit cars. Never have I seen the seam of a tube split. Maybe it can happen but then aren't the tubes held to each other by weld?

I'd be tempted to use CDS if using thinner walled tube. The extra cost of making it might be offset by the lower material cost.

[Edited on 18-8-2008 by smart51]

Jesus-Ninja - 18/8/08 at 11:51 AM

Thanks guys! I'll leave my order for ERW as is then!

[Edited on 18/8/08 by Jesus-Ninja]

Peteff - 18/8/08 at 04:09 PM

Where can you buy CDS in square section? I've only seen it in round and ERW in round, rectangular or square.

Jesus-Ninja - 18/8/08 at 04:15 PM

quote:
Originally posted by Peteff
Where can you buy CDS in square section? I've only seen it in round and ERW in round, rectangular or square.


I dunno! I don't even know if the place I ordered it from does it. But I got a mail from a friend (who knows a thing or two)


quote:

If you can change that to CDS rather than ERW, I would if I were you. CDS is nearly twice as strong for the same size although it will be more expensive. I'm pretty sure that like for like the difference in strength is a factor of 1.8/1.9


Hence my questions

Still, sounds like ERW is fine. So I have a great pile of steel arriving tomorrow!

Rasteirinho - 20/8/08 at 01:00 PM

Sorry, but what ERW and CDS means?

Alan B - 20/8/08 at 04:26 PM

quote:
Originally posted by Jesus-Ninja
quote:

If you can change that to CDS rather than ERW, I would if I were you. CDS is nearly twice as strong for the same size although it will be more expensive. I'm pretty sure that like for like the difference in strength is a factor of 1.8/1.9


What a load of bollocks..

The question was a comparison of production method. CDS is NOT inherently any stronger ERW.

Now if you are comparing different metalurgical specs...that's a different story..but ERW and CDS of SAME material have very similar mechanical specs.

iank - 20/8/08 at 04:35 PM

quote:
Originally posted by Rasteirinho
Sorry, but what ERW and CDS means?


ERW = Electrically Resistance Welded
CDS = Cold Drawn Seamless.

There is also DOM (Drawn over Mandrel) to add some more confusion.

It's the way the tube is made, ERW is made from a sheet which is folded and then welded so it has a noticeable seam where CDS is manufactured without a seam.
DOM is ERW that is then processed to smooth down the seam.

It's theoretically possible in a crash for a seam to split, but in reality, if your chassis is well designed, if it does you have a lot more to worry about as you'll already be dead from the shock loads of the massive deceleration you'll have been through.

rgdavid - 2/1/09 at 07:14 PM

good evening,
could someone please give me the materiel specs for ERW chassis making square tube, in BS or europeen or prefrably french standards (cos i live in france),
this would be a great help to find the equivalant here to order my tubes, thanks & happy new year!, david

alistairolsen - 8/1/09 at 02:48 PM

so cds isnt worthwhile for a chassis,how about for wishbones?

Hugh Paterson - 8/1/09 at 06:35 PM

Depends on who u ask (as always), IMHO CDS is "ideal" for wishbones, but I have also used ERW. If cost is not an issue, I would use CDS however and recommend its use to customers
Shug

alistairolsen - 8/1/09 at 07:08 PM

quote:
Originally posted by Hugh Paterson
Depends on who u ask (as always), IMHO CDS is "ideal" for wishbones, but I have also used ERW. If cost is not an issue, I would use CDS however and recommend its use to customers
Shug


Id agree on it being the ideal solution, but since cost is always an issue except in F1 Im wondering what I can get away with without compromising safety!

I dont want to make any decisions that might cause injury to me or my passengers, but if I can safely halve the costs of my wishbones then I will!

Hugh Paterson - 9/1/09 at 06:17 PM

Hi Alistair, I would suggest for the cost of buying enough CDS to do your wishbones its a "no brainer" have u been given a quote?
Shug

rgdavid - 14/1/09 at 04:20 PM

quote:
Originally posted by rgdavid
good evening,
could someone please give me the materiel specs for ERW chassis making square tube, in BS or europeen or prefrably french standards (cos i live in france),
this would be a great help to find the equivalant here to order my tubes, thanks & happy new year!, david


Bump , helpy help please, thanks, dave

[Edited on 14/1/09 by rgdavid]

[Edited on 14/1/09 by rgdavid]

Peteff - 14/1/09 at 09:05 PM

It's just mild steel 25x25 with 1.5mm wall thickness Dave. Nothing special or exotic is needed. You might have to have 2mm wall but it isn't going to make that much difference overall.

rgdavid - 15/1/09 at 12:40 PM

thanks a lot, but quite suprised its nothing special,
i use EN 10219 S-235JRH everyday for making gates etc, its nothing special at all !
trying to find a grade between that & 25cd4s

love your signiture !
all ze best, dave