Why do 1970s Converse still survive? The story of vulcanized rubber and material changes
Why are Converse shoes from before the 1970s still around in wearable condition at vintage shops? minobe on note summarizes the reasons from the perspective of materials and manufacturing methods.
The starting point is the chemistry of the sole. Sports shoes from the 1980s onward adopted polyurethane midsoles, but that structure undergoes hydrolysis from moisture in the air and crumbles within a few years to a few decades. In humid Japan, many unworn deadstock pairs have reportedly reached the end of their life. By contrast, All Stars and similar shoes from before the 1970s were made by vulcanization, which adds sulfur to rubber and hardens it with heat, combined with cotton canvas. They have no bonds prone to hydrolysis. The article explains that this chemical stability is the main reason pairs more than half a century old can still be worn.
In the early 1970s, as basketball became faster, canvas sides tore easily, and Converse switched to leather. Models such as the All Star Leather (from 1969), One Star (1974–75), and Pro Leather (from 1976) appeared. However, leather shrank unevenly from the heat of vulcanization and its bonding surface with the sole peeled off easily, so the article argues that the early leather models had short lifespans.
From 1971 to 1979 the brand was under Eltra. The flagship All Star and the entry-level Coach created a tiered pricing structure. Against the backdrop of rising labor costs in the US, the entry-level line was moved to overseas factories, including in Korea, the article also says. (The article itself notes this part is unverified.)
Why do these shoes keep their value even though they lack cushioning and are not suited to long walks on hard pavement? The article points to their physical durability that lasts more than half a century, labor-intensive manufacturing, and the beauty of age. My view of secondhand shoes has changed a little.
Source: note (minobe)
The starting point is the chemistry of the sole. Sports shoes from the 1980s onward adopted polyurethane midsoles, but that structure undergoes hydrolysis from moisture in the air and crumbles within a few years to a few decades. In humid Japan, many unworn deadstock pairs have reportedly reached the end of their life. By contrast, All Stars and similar shoes from before the 1970s were made by vulcanization, which adds sulfur to rubber and hardens it with heat, combined with cotton canvas. They have no bonds prone to hydrolysis. The article explains that this chemical stability is the main reason pairs more than half a century old can still be worn.
In the early 1970s, as basketball became faster, canvas sides tore easily, and Converse switched to leather. Models such as the All Star Leather (from 1969), One Star (1974–75), and Pro Leather (from 1976) appeared. However, leather shrank unevenly from the heat of vulcanization and its bonding surface with the sole peeled off easily, so the article argues that the early leather models had short lifespans.
From 1971 to 1979 the brand was under Eltra. The flagship All Star and the entry-level Coach created a tiered pricing structure. Against the backdrop of rising labor costs in the US, the entry-level line was moved to overseas factories, including in Korea, the article also says. (The article itself notes this part is unverified.)
Why do these shoes keep their value even though they lack cushioning and are not suited to long walks on hard pavement? The article points to their physical durability that lasts more than half a century, labor-intensive manufacturing, and the beauty of age. My view of secondhand shoes has changed a little.
Source: note (minobe)
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