What Thread Is Used to Sew Leather Jackets? (And Why It Matters)
The Invisible Hero
You can have the best leather in the world, but if the thread rots, the jacket falls apart.
Leather is heavy. It pulls at the seams with 10x the force of a cotton shirt.
Here is what you need to look for (and what to avoid).
The Standard: Bonded Nylon (Size #69)
What It Is: Nylon strands twisted together and bonded with a resin coating.
Why It Rules:
- Rot Proof: Unlike cotton, nylon does not rot when wet.
- Frictionless: The bonding agent allows it to pass through thick leather at high speeds without fraying.
- Strength: A single strand can hold 11 lbs of tension.
The Heavyweight: Polyester (UV Resistant)
For motorcycle jackets that see a lot of sun, Polyester is superior to Nylon because Nylon degrades under UV light over 10 years. Polyester does not.
The Fail: Cotton
Never buy a leather jacket sewn with cotton thread.
Cotton absorbs moisture. Oils from the leather seep into the cotton, causing it to rot from the inside out. Your jacket will literally disintegrate at the seams in 3-5 years.
