Technical illustration: Tandem Eccentric

Front bottom bracket eccentric mechanism on a tandem bike

Front bottom bracket eccentric mechanism on a tandem bike

Some tandem bikes feature¬†an eccentric front bottom bracket, allowing the rider to adjust the timing chain tension. I picked this as a technical illustration project (using Illustrator) because I’ve sometimes had to adjust the position of this eccentric on the road – say, after a wipeout, when the timing chain fell off.