In The Dirt – Movie night at Museum of Boulder April 15th
Come see "In The Dirt" movie at the Museum of Boulder on April 15 at 7pm By Lennard Zinn My wife Sonny and I were so taken by “In The Dirt”—a documentary about mountain biking on the Navajo Reservation—when we saw it at Chautauqua in Boulder a few months ago that we wanted all our cycling friends to see it. We are honored to invite you to see it with us along with the filmmakers at the Museum of Boulder on April 15 at 7pm. If you show up early, you can also tour the great exhibitions currently on display at the museum. We [...]
Testimonial: Zinn Custom Titanium Electric Road bike with Rohloff Hub and Belt drive
We recently had the opportunity to build a fully custom Electric Road Bike for Rolf Dietrich, founder of Rolf Prima wheels, a renowned premium wheel deign and manufacturing company that has been building high end cycling wheels for many years. Rolf has ridden hundreds of high end bikes and seen many handmade titanium bikes in his long career in the bike industry. It was an honor for us to be chosen to build his custom e-bike. Given Rolf's extensive experience with bikes, he had very specific requests for his bike. First, he wanted a titanium frame with custom geometry, [...]
Guide to Bicycle Wheel Size For Height
Are you a cycling enthusiast who is 6'5" or taller? If so, determining wheel size may seem like a difficult task. But here at Zinn Cycles, we make this process easy, and we specialize in custom-built wheels for riders of all sizes, particularly those between 6'5" to 7'5" tall. Here is our bicycle wheel size for height breakdown, where we'll discuss the specifics to help you determine the right wheel size for you. Wheel Sizes For Road, Gravel, & Mountain Bike Riders 28” or 700c Wheels 29”, 29” Plus or (30”) Wheels 750D or 30” Wheels For Road & Gravel [...]
How to ship a bike in a box
If you ship your bike somewhere, you prefer that it arrives there in good condition. This is a way to ensure that. Packing your bike in a box this way is a way to travel by plane without buying a specialty bike case or hard-bottom bike bag and still have your bike arrive undamaged. Find the right bike box. Bike shops constantly dispose of bike boxes, so they will generally be a willing source for a box. Ask the bike shop for a box well ahead of time in case they only have boxes too small for your bike [...]
Do Women need Women’s specific bikes?
Do Women Need Women’s Bikes? By Lennard Zinn Women’s bikes and women-specific components have become a big part of bike sales since appearing as a concept in the early 1990s. Historically, women’s bike products were mostly limited to apparel, some saddles, low-end small bikes, and “girl’s bikes” with a step-through “mixte-frame” design featuring a low top tube angling down toward the crank. Women could mount mixte bikes easily by stepping through the frame without getting their skirts and dresses caught on the saddle and tangled in the spokes of the rear wheel (some bikes even had netting attached to [...]
Bike Stability – Good or bad?
Bicycle Front-End Geometry Explained Why a stable bike weaves at low speed and when climbing By Lennard Zinn We all want a stable bike, right? Seems like a no-brainer. A bicycle that feels rock solid going downhill can form the foundation for a great feeling of security and more confidence at high speeds than you felt on less stable bikes. Thing is, there is a tradeoff between high-speed stability and low-speed control. A stable bike ridden slowly will tend to weave; it will take more effort to keep it rolling in a straight line when pedaling gently around the [...]
Traveling with a big bike
Traveling with a big bike By Lennard Zinn Traveling with a bike always presents challenges. Traveling with a bike built for a tall person or with a bike that has an extra tall front end for an upright riding position presents even more challenges. The ideal way to travel with a road or gravel bike is with one of our coupled travel bikes, which break down to fit in an airline-sized travel case to fly without additional oversized luggage charges. This post, Rather, addresses flying with a tall (and long) bike without couplers in either a hard bike case [...]
Veloswap! November 2nd at the Denver Western Complex
Come visit the Zinn Cycles Booth at Veloswap this year. Booth #152 and #153. We will be showing off some bikes as well as selling demo bikes and a ton of overstock components, including new and used parts. We will have parts from Sram, Shimano, Campagnolo, Magura, SQlab, Hayes, and more including: chainrings, brakes, shifters, derailleurs, handlebars, rims, wheels, tires, forks, suspension, and so much more. Prices will be discounted from 20%-70% original cost. We are trying to clear out a lot of overstock inventory so come in and take advantage of some amazing deals. If you can't make [...]
Race In My Shoes Against Skinny Athletes; CT Wike inspires big-bodied people
CT Wike lives on Snell Isle, in St. Petersburg, FL at four feet above sea level. Hurricanes Helene and Milton are the most recent punctuations in a life of overcoming huge obstacles. You see, Wike has lost over 100 pounds over the past few years from his 503-pound peak weight, when his doctor told him he would soon die if he didn’t make some big changes. He now competes in triathlons and will do his first Ironman in 2026 in Salem, OR. CT's first podium! It is hard enough being Wike’s size and physically taking on the [...]
Zinn Split30 Crank Installation Instructions
Split 30 Crank Installation Instructions Split 30 cranks combine the stiffness and reliability of a 30mm-diameter spindle with the versatility to fit on a wide variety of bottom bracket shells. One spindle half is integrated into the left crankarm and one into the right arm; a bolt connects them together in the center so that ramped crenellations on the end of each spindle half tightly engage each other and a spacer in between to obtain proper total length. Install BB386-type bottom bracket (or BB392-type for a mountain bike). These have wide-spaced, 30mm-ID bearings. Installation instructions for these bottom brackets are in Zinn & [...]
How to install Challenge Handmade Tires
How to install Challenge Handmade Tires Challenge handmade tires are known for their superior ride quality. The handmade nature makes for a more supple and faster rolling tire. Installing them can be a "challenge", so we have put together this video to help you with some tricks to make it work well for you. We recommend the Tubeless Solutions tire levers and clips. Click here to order online Use tire levers to get the first bead over the rim. Manually push on the other bead as far as you can go Use the tubeless solutions clips to keep the [...]
My Zinn eBike is the best bike EVER!
Dear Lennard and Nick, This is me before the metric century this past Saturday. The ride went well and I really enjoyed the comfort of the ride and the use of the motor on the hills. My friends, who are cheap skates, saw the beauty of e-assist as I had to wait on them to finish on the uphills. They kind of were a bit frustrated by a big man blowing them away on the hills and not working very hard to do so. And I stayed in the ECO motor setting for almost the entire time I used it. I still had 40% [...]
Lightweight Custom Ebike for 5’2″ rider
When people contact us after having searched for ages trying to find a bike that fits, we love telling them that we can make it happen for them. We want everyone to be able to get the bike they want with a great fit, so when this type of challenge comes our way, we jump at the opportunity. This custom titanium step through ebike was built for a 5'2" woman who flew out from California to be fitted. Apart from just wanting an ebike that fits, she also needed to be able to lift the bike up to load [...]
Hoop Stress and Why Tire Pressure Should Decrease with Increased Tire Size
Hoop Stress and Why Tire Pressure Should Decrease with Increased Tire Size By Lennard Zinn This report filed June 24, 2024 We recently delivered a gravel touring bike to a customer. When he picked it up, we gave him a rundown on his bike, including maintaining his waxed chain and the pressure to pump his tires up to depending on conditions and how much weight he has in his front and rear panniers. His new bike has 700 X 45C Challenge Getaway Tubeless Ready tires. I explained that, on gravel roads with his 185 pounds and no extra weight [...]
Short Cranks or Long Cranks on a mountain bike?
When considering crank length for a mountain bike, it is important to keep in mind the type of riding that the bike will encounter as well as the rider’s morphology. The considerations for technical riding are different than for riding on smoother surfaces, and the length of the rider’s legs are also critical to crank length. “Longer” and “shorter” cranks in this article refer to longer and shorter relative to the particular rider, not necessarily to extremes on the spectrum of crank length. Here, a “longer” crank is one that is greater than 21% of the rider’s measured inner [...]
Short Cranks or Long Cranks on a road or gravel bike?
Some Pros Are Winning With Short Cranks—Shorter Than What? By Lennard Zinn It’s been in the news recently that some high-profile pro riders, like Tadej Pogačar and Tom Pidcock, as well as many top triathletes, are using 165mm cranks. This is always described as a short crank. However, whether a measurement is deemed short or long depends on its comparison with another measurement. Pogačar’s and Pidcock’s cranks are short relative to what? It seems arbitrary to consider them short simply because that is the shortest length that big component manufacturers produce. Obviously, 165mm cranks would be long relative to [...]
Bikes for small riders – Improving bike design for cyclists under 5’5″
By Lennard Zinn I built my first bike frame for my wife in 1980, three years before we got married. To calculate its dimensions, I used bike-fitting formulas in a handbook published by C.O.N.I. (Comitato Olimpico Nazionale Italiano), which I understood to be the bible of fitting of the Italian bikes that all riders lusted after in the 1970s and early 1980s. Those calculations resulted in overly long top tubes for small riders (and the opposite for tall riders like me). Watching my wife ride that too-long bike and trying to adapt it with ever-shorter stems drove my quest [...]
What difference does a lightweight E-bike make?
By Lennard Zinn Lightweight Electric Bikes E-Bikes generally tend to be heavyweights. But since they have motors, who cares? You can just overcome the heavy weight with more motor assist, right? Well, a 60-to-80-pound e-bike is WAY too much bike to easily get up and down to an apartment. Even pushing it up a few stairs into a single-family home is a lot to ask. And it is overly unwieldy to put on a car rack for a destination ride. A 30-to-40-pound e-bike, on the other hand, is easy to put on the hitch rack of a car or [...]
