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 elongation0:00
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 effects6:46
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 wear22:35
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 benefits35:43
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 applications1:03:20
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 riders1:16:58
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 impact1:18:46
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.
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