A5. Continued (1 of 2)
Alt text of the article in the above post:
Great Inventions of Cycling 4.5 billion years ago: Gravel
Gravel is, along with "the excuse", the oldest thing in cycling. Gravel forms from the erosion of bedrock, with quartz as the most common mineral. The shards of rock produced are quite sharp, but the edges are normally rounded off as they're washed downstream in a river. It's important that not all the sharp bits are eliminated, because otherwise gravel wouldn't be nearly as useful for creating punctures.
For its first few billion years gravel was essentially useless, since no one had invented the bicycle. Even when that finally happened, for the following 150 years if it was used at all it was for making surfaced roads, which was as misguided a use for it as you could possibly think of.
Worse than that, in races it was common to get marshals to go and look for gravel on the inside of sharp corners and then actually, unbelievably, use brooms to remove it.
Happily, in recent years, all this has changed. Gravel has taken up its rightful place at the centre of every major bike manufacturer's marketing strategy.
![=H |S2= 1.26-2.5 |Very coarse
) Pebble
-6 64mm in gravel
-4to | 16- 0.63-1.26 Coarse
) Pebble
-5 (32mm [in gravel
sols 0.31-0.63 Medium
) Pebble
-4 16mm |in gravel
—PA41(c) ONS 7 )
4-8 mm ] Fine gravel Pebble
= 0.31in
-1to 0.079- Very fine
2-4 mm i Granule
= 0.157in [gravel](https://files.mastodon.social/media_attachments/files/116/116/391/507/831/883/original/670493c6ef70e98f.jpg)
