Lennard Zinn is a bike designer and frame builder based in Louisville, Colorado. His shop, Zinn Cycles, offers "a full line of semi-custom and off the shelf bikes for riders from very small to very tall and everyone in-between." He’s also the author of Zinn and the Art of Mountain Bike Maintenance, one of the world’s best-selling guides to mountain bike repair.

In this first-half of our podcast discussion, Zinn talks about drivetrain maintenance, focusing on chains and lubrication. Later in the show we talk about the benefits of big 32-, 36-inch, and 750d bike wheels and designing bikes for riders both tall and small.

Understanding bike chain wear and elongation 0:00

• Chain wear is caused by dirt and oil-based lubricant sticking to the chain, creating a grinding paste that wears down the rollers, bushings, and pins.
• Zinn describes how the chain's inner links are made.
• The chain's flexibility increases as the bushings and plates wear, affecting shifting performance.
• A chain's lateral stiffness is crucial for proper shifting, and a worn chain can cause skipping during shifting.

Chain elongation and its effects 6:46

• Zinn discusses how a chain's elongation affects its performance, particularly when the distance between rollers exceeds the half-inch standard.
• He explains that a worn chain can misshape the cassette's teeth, leading to skipping and poor shifting.
• Chain checkers can be used to ensure the chain's length is within spec to prevent cassette wear.

Lubrication and its impact on chain wear 22:35

• Zinn explains that a dry chain will wear faster due to friction, while lubrication helps reduce wear but can attract dirt.
• He discusses the differences between factory lube and other lubricants, noting that factory lube is designed for machinery, not for low friction on the bike.
• Zinn recommends using a cleaner to remove factory lube before applying chain lube.
• He introduces the concept of chain waxing, which involves immersing the chain in molten wax to create a low-friction, clean-running chain.
• Zinn shares the benefits of chain waxing, including reduced noise, lower friction, and longer chain life.

Chain waxing process and benefits 35:43

• Zinn describes the process of chain waxing, including the need for a clean jar of mineral spirits and denatured alcohol for cleaning the chain.

• He mentions the cost-effectiveness of chain waxing compared to replacing chains frequently.

Wheel sizes and their applications 1:03:20

• Zinn discusses the advantages of larger wheels for tall riders like 32-, 36-inch, and 750d wheels, noting that 32-inch wheels can make a bike look proportionally sized.
• He explains the challenges of using larger wheels, such as increased weight and the lack of suspension forks.
• Zinn mentions the development of new carbon rims and tires for larger wheels, which could improve their performance and weight.
• Barber asks about the feasibility of using suspension forks with larger wheels, and Zinn confirms that rigid forks are the only option.

Challenges in designing bikes for small riders 1:16:58

• Barber asks about the challenges of scaling bikes for smaller riders, and Zinn explains the limitations due to the need for certain components.
• Zinn highlights the importance of proportional design, where larger wheels can make a bike look more proportionate for tall riders.
• He discusses the ergonomic issues for small riders, such as wider Q-factors and shorter steerer tubes on forks.
• Zinn mentions the UCI's weight limit in road racing as an example of how smaller riders are often disadvantaged.

Modern trends in bike design and their impact 1:18:46

• Zinn highlights the shortening of steerer tubes on forks which can be a problem for taller riders.

• He discusses the trend of wider rear ends in modern bikes, which can be detrimental to smaller riders due to increased Q-factor.

Find out more about the chain waxing service and bikes discussed in this episode at zinncycles.com.