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I found this tweet from Greenpeace Colombia which says:

(In Spanish):

Con los materiales usados para hacer un auto se hacen 100 bicicletas.

(Translated):

The materials used to build one car could make 100 bicycles

Screenshot of the original tweet:

Tweet from Greenpeace Colombia

Is that assertion/claim accurate?

Oddthinking
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  • This seems a little vague. They could be including the materials used in the making of the car that don't actually end up a part of the final product. – called2voyage Apr 07 '16 at 01:00
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    Only if you just consider mass - a bike might weigh 10 kg, a car 1000 kg. But you would likely use different materials. – jamesqf Apr 07 '16 at 05:15
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    I don't have the calculations to prove it, but I'd guess 4 car tyres wouldn't make 200 bike tyres even if you took rubber for seals and other sources in the car – Mikey Mouse Apr 07 '16 at 09:40
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    The claim is kind of meaningless: a car can weigh 800 kgs - 2,400 kgs. – Oddthinking Apr 07 '16 at 12:46
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    @Oddthinking: Bikes probably vary about as much in weight. Consider carbon fiber & titanium racing bike vs heavy retro-style cruiser. – jamesqf Apr 07 '16 at 19:08
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    Even if it is true a 100 bikes still won't get me to work on time. –  Apr 07 '16 at 21:22
  • @jamesqf: Yes, making it even more vague. (I almost made that point too, but I wanted to be able to back up what I said with references, and I didn't have them for bikes.) – Oddthinking Apr 08 '16 at 01:09
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    @fredsbend my commute through the city takes twice as long by car as it does by bike – Qwerky Apr 20 '16 at 08:49

1 Answers1

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This is obviously not true. You have to look at the different materials cars or bicycles are made from because that statement doesn't restrict itself to a specific material.

This would require the rubber of 200 bicycle tires to be at most the amount of rubber used to make a car. Most of that rubber is found in the tires of which a car has 5 (let's give it a spare tire). Therefore you needed to be able to make about 40 bicycle tires from the rubber used to make a since car tire – which obviously by looking at the mass alone doesn't work out.

Since someone actually disputes this, here are some sources.

You can find here that a car tire has a mass of 22 pounds (9.98 kg). The page also states how a car tire is composed. It's 41% rubber which means that one car tire has 4.09 kg rubber. Therefore, each bicycle tire had to have 102 g of rubber or less. You can take from this page that the inner tubes alone have about that mass and the shells even add about twice that 102 g to the total mass of the rubber part of a bicycle tire.

You can find out from the first link that there isn't much other than rubber and carbon to the rubber part of a tire. But for the numbers to match up, more than two thirds of the rubber parts stated above had to be something different than rubber.

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    What are bike tires made of? How much rubber is in a car? What about waste materials? What about other components (this could easily be 'roughly true' even if tires are out by a bit). If you're going to do original research, you're going to have to try a lot harder than that. – NPSF3000 Apr 11 '16 at 20:31