AJA #51 Road Spray Aerodynamics and Argon Gas in Tires

Hottie and Fatty pepper Josh with tire questions. Specifically what is and is not a radial casing and how his team was able to move towards a radial ply angle without disrupting tire stability. Josh also explains how they arrived at Protocol's knob shapes and patterns.  From our listeners we have quesions on putting gels in cargo bibs. Does this result in unecessary heavy lifting? Josh answers one on the optimal place to mount a mini pump. On the downtube or the seatube? We also get into why in the spirit of manipulating air flow we don't see more pros wearing long sleeve jerseys?

The Leadville 100 Mountain Bike Race has long been grounds for equipment tinkering and experimentation with the hopes of shaving minutes .. even seconds off finish times. Drop bars on mountain bikes at Leadville may seem recent but actually it was first tried by a pro in 2009. Travis Brown showed us by putting road bars on his Trek Full Suspension 26 inch mountain bike that anything can and should be considered when setting up a Leadville race bike.  Drop bars, aero bars, and bar ends mounted inboard are now banned. But the experimentation and tinkering continues. We went to ten-thousand feet to find out how some of the fastest riders were planning to cheat the wind and reduce rolling resistance over the 100 miles plus of Rocky Mountain pain and suffering. Due to a nearby wildfire, the course was changed. Less climbing and more road was on the plate.  Riders were making adjustments in both tactics and tech. In this episode we take a look at the common threads as riders headed for the start line. Paige Onweller gives us an inside look at dialing a bike for this unique race. We also get some feedback on how 32 inch wheels perform when placings and prize money are at stake. Two pros – Zach Calton and Emma Langley – share their thoughts on riding big wheels on big climbs. And we get a full recap from the front of the men's race from a guy who has been there a lot. John Gaston details the attacks and alliances that defined the 2026 Leadville 100. Plus we hear about the tech he used and rejected for this year's edition of the LT100 MTB Race.  

If Bike sales were purely based on a beauty contest, Baum Cycles would be at the top of the charts. Baums are stunning, Titanium machines. Most of them are custom built by an out-of-the-box thinker in Geelong, Victoria, Australia: Darren Baum.  But what motivates us to choose one bike over another is more than just looks. A bicycle -- especially a performance bike -- has to deliver where and when it matters. Darren is dialed into that as well.  Darren has obsessed over geometry, center of gravity, and chainstay lengths for more than two decades. His mission is to not only make bikes look good on paper and in photos, but to make them accelerate, turn and climb like no other. In this interview we get a refreshing look at what it takes to build a custom, performance bicycle. Some things are just a tweak but other approaches by Darren are revolutionary.   

While listening to Paige Onweller answer our questions, we found ourselves wishing we could be more like her. Wishing we had her organizational skills, her critical thinking, her ability to adapt quickly. Paige has the tools to be the kind of Marginal Gainer that makes us think, "I wish I was more like Paige." Paige's focus on details started well before she ever saw a Gravel Race start line. She was a collegiate runner and after that, had a career in medicine. But like we've heard from many runners, her sport led to injury which led her to the bike. At first, her riding was for fitness while she healed. But then she discovered how good she was, and so did others. Namely team Twenty-Twenty Four. They brought her on board to do Zwift racing and Time Trials. Before she knew it she was on a start line in Nebraska at Gravel Worlds. Then her career in medicine was put on hold as Paige took her detailed approach to the Life Time Grand Prix.  Josh and Paige's partnership started this spring in the wind tunnel. The two of them got together for a focused approach on aerodynamics and women. They made some very interesting discoveries which we talk about in this show. Ever thought about waxing hair? You will after hearing them discuss Paige's aero bun.    

Josh sinks his teeth into questions on turning road spray on a frame into aerodynamic information, Argon gas in tires and deep, carbon wheels for XC mountain bike racing.  We also talk about Fatty's successful Everest challenge – the Marginal Gains that worked and the ones that didn't. And we get into some new happenings with Silca. 

A favorite topic on the Marginal Gains Podcast is rolling resistance, also known as CRR. It is one of the cornerstones of this show. While we have interviewed aerodynamic experts who have devoted hundreds of hours to CdA, we have found very few who have made CRR their passion. Tom Anhalt was an early guest but we can't think of another since. That changes with this episode.  John Karrasch makes a living from bike fittings. But John has made a name for himself through his tire testing. Using the Chung method, John has been putting tires to the test to see which ones live up to the hype. In just more than a year, he has amassed an impressive database covering just about every brand you can name. The beauty of John's work and results is he shares it with all of us at no cost.  In this interview, John shares his early beginnings with the Chung method, how he has refined his testing, and what some of the key learnings have been. The only thing between your bike and the surface you ride are your tires. John is one of a few who has been trying to quantify just how much power it takes to keep those tires rolling.

It's funny how tubeless freed is from tubes and years later some of us turned to putting something else in the space between rim and tire. Namely inserts. Most of them are foam and a real struggle to install. Then there's OPTIS: The Odyssey Tire Pneumatic Insert System. Cool acronym that basically means "inflatable insert." The people at Odyssey will be quick to say OPTIS is not a tube. While it does press up against the sidewall when inflated, it's job is just like a foam insert: to prevent pinch flights. OPTIS weighs significantly less than a foam insert, and its behavior is adjustable. We spoke with Jacob Hinton from Odyssey on this unique product that recently gained notoriety during a spring classic.  Up next is a look at radial tires for bikes. 32-inch wheels have garnered most of the buzz in 2026, but radial tires are also making waves. Two big tire makers have jumped into the space and made claims of enhanced grip for gravity-style riding. A third company, Delium, has also been developing radial tires. We hear from this lesser-known maker about how tech works and its potential in the bike space.  

Our 50th Ask Josh Anything! That's a lot of questions and answers and "It Depends." Thanks for hanging with us to the mid century mark. On the Q&A agenda this episode: The perfect padding for aero armrests.  Tire inserst for Unbound Breaking in tires for best CRR The right gears for an Everesting Narrow flat bars for Leadville Gravel wheels on a road bike and the rule of 105

Our first episode that covered the topic of 32 inch wheels focused on the bigger wheels being used on mountain bikes. Daniel Yang of Neuhaus Metalworks put us on a prototype rigid mountain bike and took us for a ride. It was eye opening. But it also raised questions.  At Sea Otter we saw a shift by some builders and manufacturers as to where they thought the big wheels might perform best. Drop Bar bikes supported by 32 inch wheels were just as common as Flat Bars at this year's show. Straight line speed and all day comfort was the reason given for developing a 32er gravel bike over a mountain bike. Like a lot of bike media, we set out to get some answers on the future of this "Big Idea." Daniel Yang is back with his report card on the trend. We also hear from two companies that were showing Gravel bikes that attempt to answer the question: Is bigger, better?  

We're not afraid to share an opinion on this show. At no time was that more apparent then when Josh let his thoughts known about hookless road wheels. It caused a bit of a reaction in the industry to say the least. And while we have some firm beliefs on certain technologies, we also believe in fairness. Which is why at Sea Otter we gave some wheel brands a platform to explain what has become a somewhat divisive topic.  Our guests work for three brands: ENVE, CADEX and Mavic. Two of them stand behind road hookless as a high performance and safe feature. The third has stuck with hooked rims. All three bring a unique perspective on what it takes to secure a tire to a wheel. We also talk to these wheel makers about their brands as a whole: what's driving innovation, how pro peloton success turns into sales and for one of them, what it takes to revive a heritage brand.