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Author: Subject: How much does your finished chassis weigh?
sgraber

posted on 25/11/03 at 07:03 PM Reply With Quote
How much does your finished chassis weigh?

Anyone weighed their bare chassis finished with all the paneling in place?


Care to share the details?

Graber





Steve Graber
http://www.grabercars.com/

"Quickness through lightness"

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stephen_gusterson

posted on 26/11/03 at 10:43 PM Reply With Quote
I worked this out once but cant remember the result!

Basically, you can work out from the book that its about 45 metres of tube in the car. You can also figure out the area of sheet pannelling.

Taking steel to be summat like 7.7 times density of water, and that a cube of water 100mm x 100mm x 100mm weighs a kilo, then a similar cube of steel will weigh 7.7 kilos.

so, if you work out the cubic area of steel in the chassis, you should be able to recon the weight, with a kilo or so extra for the welding wire.

anorak off.

atb

steve





quote:
Originally posted by sgraber
Anyone weighed their bare chassis finished with all the paneling in place?


Care to share the details?

Graber







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sgraber

posted on 27/11/03 at 02:07 AM Reply With Quote
Wow Steve, that was mega-anorak!

But entertaining nonetheless!

Thanks

Graber





Steve Graber
http://www.grabercars.com/

"Quickness through lightness"

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madforfishing

posted on 27/11/03 at 06:05 AM Reply With Quote
Does the CO2 / Argoshield trapped inside the tubes make the chassis lighter or heavier ?
Ron's book said about 35lb in one of the pictures - no sussy brkts etc






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kingr

posted on 27/11/03 at 09:46 AM Reply With Quote
Steve, what about the weight you save by grinding the welds flat?

I've got a strong suspicion that the figure of 35lb is a load of old cobblers. And the picture of RC holding a chassis is rubbish too - it's aluminium.

Kingr

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timf

posted on 27/11/03 at 10:06 AM Reply With Quote
quote:
Originally posted by madforfishing
Does the CO2 / Argoshield trapped inside the tubes make the chassis lighter or heavier ?



i want to fill mine with helium and the wheels to reduce sprung and unspring weight

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Bob C

posted on 27/11/03 at 01:10 PM Reply With Quote
oh dear - 2 problems
1) weight reduces much more than mass does - overall you are less able to accelerate - think about trying to run with enough helium balloons so you only weigh 1 gram - you couldn't do it.
2) helium in tyres - tiny molecule - no viscosity diffuses like mad - your tyres would keep going flat....

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craig1410

posted on 27/11/03 at 02:00 PM Reply With Quote
Hi,
I weighed mine by standing on bathroom scales and lifting first the front and then the back and subtracting my own weight. I only lifted it a centimeter or so from the axle stands so this should give an accurate figure. I weighed just the bare chassis. That is only the welded bits but this included the 16swg steel floor and footwell end plates. All suspension mounting brackets were in place as well but no suspension components. There were still some small brackets left to attach.

Anyway the weight was just over 60Kg's. I think it was 65Kg's in fact but don't have the figures to hand - will double check tonight.

Note that I used 2.0mm thick steel tubing instead of the 1.6mm stuff because it was all I could get locally at the time. Also note that my car is a McSorely 7+4" design and has extra triangulation in place to handle the V8 engine and de-dion rear suspension.

I'd expect a book chassis to be around 50-55Kg's again for the basic chassis (as held up by uncle Ron in that picture.) 35lb's my ar$e!! Even in aluminium it must have been at least 35Kg's!!!

Hope this helps,
Craig.

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blueshift

posted on 27/11/03 at 02:24 PM Reply With Quote
BobC: if you filled your chassis with helium your car would be less massive and accelerate faster than if it was filled with air.. remember you're not just filling it with massive helium, you're flushing out the more massive air.

for optimum mass reduction you'd pump out the chassis to a high vacuum, but you'd have tricky sealing issues and perhaps introduce odd stresses.

plus this whole idea is silly. air has a mass of about 1.2kg/m^3, there's probably less than 500g of air in a chassis.

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splitrivet

posted on 27/11/03 at 03:24 PM Reply With Quote
With my car its not the weight of the car that bothers me........its the fat twat driving it
Bob





I used to be a Werewolf but I'm alright nowwoooooooooooooo

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Mark Allanson

posted on 27/11/03 at 06:20 PM Reply With Quote
This is what my chassis weighed with no panneling, no floor,no pedal supports, but all the brackets fitted Rescued attachment Chassis Weight.JPG
Rescued attachment Chassis Weight.JPG






If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation

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GO

posted on 27/11/03 at 06:49 PM Reply With Quote
What about rollbars? Weights above are for plain book chassis which doesnt include the rollbar as part of the frame does it?

Just checking cos mine weighed a fair bit more than that, ~100kg but it included IRS (which I think means more support at the back), big arse rollbar with supports down to bottom (rather than top of rear panel), welded in floor, footwell ends, all brackets (inc handbrake, steering rack, etc) and powder coat!

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stephen_gusterson

posted on 27/11/03 at 07:30 PM Reply With Quote
I design x-ray machines that work on density so this stuff kinda rubs off on you


a sheet of steel 2400 x 1200 x 1.6mm works out approx 35 kilos.


approx 45 metres of tube with 25 x 25 x 1.6mm is about 55 kilos. That agrees nicely with marks figure on the scales.

SO, assuming you panel the floor and the rear bulkhead with steel, that uses about a sheet and a half if i recall, so thats about 108 kilos all up.

way out from uncle rons figures!











atb

steve




quote:
Originally posted by sgraber
Wow Steve, that was mega-anorak!

But entertaining nonetheless!

Thanks

Graber


[Edited on 27/11/03 by stephen_gusterson]






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Spyderman

posted on 27/11/03 at 11:20 PM Reply With Quote
Hey Steve, what do you do for a living and is your car a standard one?





Spyderman

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stephen_gusterson

posted on 28/11/03 at 12:08 AM Reply With Quote
design morgans and make x-ray machines at home.

or somethign like that.

xray morgans and stay at home......I could live with that.


atb

steve






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JonB

posted on 2/12/03 at 11:12 AM Reply With Quote
At this point in the build:



My chassis weighed between 80 and 90 lbs. It's very difficult to get the thing balanced on a bathroom scale, and I didn't want to attempt to hold it while standing on the scale, then weigh myself separately in the fear of finding out I've gained MORE weight.

I agree that the 35lbs figure in the book is complete nonsense. 135lbs at that point of construction would be more likely.

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suparuss

posted on 2/12/03 at 09:51 PM Reply With Quote
you cant ave built that, the workshop looks way too tidy! knock some boxes over and scatter some empty pot noodle pots here and there or no-one will ever believe you.





Russ.

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cymtriks

posted on 6/12/03 at 01:10 PM Reply With Quote
Calculated Weight

Not an actual weight but is a calculation that includes all the tubes and all the panels in 16 gauge:-

I got 181 lbs for the complete book chassis with all steel paneling.

I also got 159 lbs for the weight minus the luggage region, i.e. everything forwards of the seat back tubes.

As my computer models are very simple the weights tend to be slightly overestimated due to something called "mass doubling" which means that a small error creeps in at every tube joint.

By the way I've seen a list of weights on the Fluke Motorsport site. I think I recall a Westy Seven chassis given as 184lbs bare.

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