tavu

joined 2 years ago
[–] tavu@sopuli.xyz 2 points 1 year ago

Hi! I'm over here on lemmy, and created this post as a link to your post. I don't think there's a mutually compatible way to repost/boost a mastodon post into a lemmy community, but this seemed close enough.

[–] tavu@sopuli.xyz 10 points 1 year ago* (last edited 1 year ago) (1 children)

As per the quote below, a car loses about 0.08g of tread per km.

Compared to a car, a bike tyre is about the same diameter, 10% of the width (~20mm), 28% usable tread depth (~2mm), has 50% less wheels, and can travel 10% the distance (~10000km).

This suggests a (very approximate) tread loss of 0.08 * 10% * 28% * 50% / 10% = ~ 0.01g per km for bicycles.

For replacing longer car journeys less typically travelled by bicycle, rail transport is the best solution and removes the issue of tyre wear.

Quoting [deleted] in r/theydidthemath:

Using the same assumptions as above (215/60R16 tires, 7mm of tread loss over 100,000 km), I estimate the loss of tread by volume from each tire as follows:

Cylinder with a diameter of 664 mm and a height of 215 mm has a volume of 74,412 cm3. Cylinder with a diameter of 664-(2x7)=650 mm and a height of 215 mm has a volume of 71,307 cm3. The volume difference between a new and worn out tire is 3105 cm3.

Typical land to sea ratio of tires is 60-70% land, depending on the type of tire. If we go with an about average value of close to 65% tread, we get the lost rubber volume of about 2000 cm3 or 2,000,000 mm3 over a single tires lifespan.

Each revolution of a tire loses about 0,04 mm3 of tread, which, according to Wolfram Alpha, is a bit less than the volume of a medium grain of sand.

If we look at the entire car with 4 tires over a kilometer of road, we get 80 mm3 or about 0,08 grams of tread lost per car per kilometer.

[–] tavu@sopuli.xyz 10 points 1 year ago

I agree. It's just the title ABC News had on its article.

[–] tavu@sopuli.xyz 13 points 1 year ago (1 children)

BPA is found in polycarbonate plastics (acrylic) [...]

Polycarbonate (BPA monomer) is a very different polymer to acrylic/PMMA (methyl methacrylate monomer).

[–] tavu@sopuli.xyz 4 points 1 year ago* (last edited 1 year ago) (1 children)

Having wider tyres ~2"/50mm or so pretty much eliminates the risk (and gives a comfy ride). If you really like the speed of narrow tyres, it's really quite safe with the right technique -- crossing tracks at an angle to avoid mishaps (I find 30° is sufficient, 90° is never a problem), and when they're slippery, treating them like ice. It becomes second nature soon enough.

I think there are some rubber/elasromer inserts which have been developed which also eliminate the groove -- it presents a flat surface to bikes, yet squishes down for the tram wheel flange under the immense weight.

[–] tavu@sopuli.xyz 16 points 1 year ago* (last edited 1 year ago)

The nuance is recognising the Google hegemony is supported by choosing Chrome.

The understanding is realising what is happening to the open web as a result.

[–] tavu@sopuli.xyz 2 points 1 year ago (1 children)
[–] tavu@sopuli.xyz 5 points 1 year ago* (last edited 1 year ago) (2 children)
  • US: 77⁄256 cubic inches vs 0.50 US fl oz (~4.929ml vs ~14.787ml)
  • Australia: 5ml vs 20ml
  • Rest of World: 5ml vs 15ml
[–] tavu@sopuli.xyz 16 points 1 year ago (3 children)

WTF is a square pound!? You've ruined my day.

[–] tavu@sopuli.xyz 5 points 1 year ago

Sounds like you have too few geese/sheep, that's all. 😆

[–] tavu@sopuli.xyz 4 points 1 year ago (3 children)
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