Enter Chalktrail, available from online retailer Fat Brain Toys. While the idea is simple – a plastic holder that drags a piece of chalk behind you on the road as you ride – the results are enticing even for this playful old man.
The manufacturer claims that a single piece of chalk will last for 1.5 miles, and they have products that will fit “6 different wheel sizes, (12 to 29 inch diameter).”
It was unclear from the reseller’s website exactly how much chalk came with the initial package, priced at $19.95 USD. Assembly appears to use spring-tension built into the plastic arm to keep it over the rear axle (sorry – this probably prohibits the use of the Chalktrail on quick release axles.)
While presumably any chalk of the right diameter would work, the comments on the product page do indicate that there is a “special chalk” for this product. Presumably this is of a higher density then normal sidewalk chalk for that advertised “1.5 miles” of durability.
Now wouldn’t this be an interesting way to demonstrate to a city precisely which routes have the heaviest bicycle traffic?