Tubeless Fatbike Guide: Nate to Rolling Darryl

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Living in New Mexico last winter required the adoption of tubeless tire systems.  Arriving in Albuquerque on a Pugsley, I was foiled by goathead punctures on a daily basis.  Naturally, as other mountain bikers in town already knew, “going tubeless” was the answer.  At Two Wheel Drive, we developed a method to bring fatbikes into the tubeless realm using the split-tube method, also known as “ghetto tubeless”.  

For a detailed guide to the split-tube method, check out Fatbike Tubeless, Tubeless Moonlander, and Does it work?.  In short, a 20″ or 24″ tube is split along its outside seam to create an airtight rim strip.  The tire is mounted atop the homemade rimstrip, without a tube, and a blast of air seats the tire.  Finish with liquid sealant, trim the excess rubber from the split tube, and ride.  This method has proven reliable, and may be preferred for anyone concerned about tire burps, such as an aggressive rider on rocky trails.  For a completely burp-free system, it is possible to apply an adhesive between the tire and the split tube to create a permanent seal, also allowing the tire to be moved from wheel to wheel without breaking the tubeless seal.  These two methods typically reduce wheel weight when compared to use of a tube, but not by much.  

The final procedure for converting an existing wheel to a tubeless system is very simple in theory, and is the lightest method.  A layer of tape is applied to the rim to create an airtight seal.  The tire is mounted and seated, and sealant is added.  Finally, sealant is distributed inside the tire to seal the bead and any pores in the tire.  While the concept is simple, there are several challenges.  Seating the tire on the rim can be difficult, especially in the case of a very loose-fitting tire.  Some tire and rim combinations mate better than others, due to inexact tolerances and texture along the tire bead.  Some of the texture designed on the tire bead is intended to improve the bead lock, reducing the risk of the tire walking on the rim at extreme low pressures, but creating some challenge to sealing.   

 The beginning front wheel weight is 7lbs 15oz (3.6kg) for a Salsa Mukluk 135mm hub, custom drilled (1.5″ holes) Surly Rolling Darryl rim, butted spokes and brass nipples, 160mm rotor, stock 26×4.0″ tube, 27tpi Surly Nate tire, and about 75 Grip Studs.  This will not be a super light wheel, but with all the features– studs, aggressive tread, elimination of puncture risk– it will be just right for my needs.  For about $10-$20 per wheel, this is the cheapest way to lighten a fatbike, or any bike.  Of course, wheel weight is always more pronounced than weight on the frame.  Reducing the friction between tube and tire is also a theoretical gain, evidenced by the rubber dust found within the tire from rubbing at low pressure.

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Remove tire, tube, and rimstrip.  The Surly rimstrip weighs about 90g.

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The naked wheel weighs exactly 3 lbs.  The stock tube weighs 15 oz (about 425g)

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I take the opportunity to true the wheel.

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A layer of high-visibility DOT approved reflective tape is applied to the rim, which will be visible through the cutouts, improving safety in traffic.  Similar tape is available in a variety of colors.  Look for safety or sign stores catering to industrial and construction accounts. 

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Finish with a piece of tape.

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Next, a layer of Gorilla Tape is applied tightly to the rim, up to the very edge of the bead shelf, just under the hooked edge of the rim.  Another layer is added to the other side, meeting in the middle to create an airtight seal.  It is theorized that laying the tape right up to the bead helps create a tighter fit at the bead.  It certainly helps to seat the tire initially.  Other sources suggest several layers of tape.

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Mount the tire with a tube to ensure every inch of tape is securely adhered to the rim.  This also allows one bead to be seated, reducing the challenges of seating the tire without the tube.

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Mount the second bead onto the rim.  A cheap 26 ” rubber rimstrip helps to force the tire bead towards the edge of the rim, on the bead shelf, where the tire is most likely to contain air.

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Removing the valve core is essential to a quick burst of air.  A good compressor is also necessary.

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The tire accepts the air on the first attempt, and pops into position.  I deflate the tire and install 4-6oz of Stan’s sealant (more if you want, especially in thorn country, or with even bigger tires) through the valve core, although it is possible to dump sealant into the tire before seating. Spin and shake the tire to ensure a good seal all around.  Bring the tire up to maximum pressure (30psi).  If possible, ride the bike to simulate any disturbances that might arise in real world conditions.  This also helps to distribute sealant.  Some tires may spit sealant from the bead or from under the valve during installation (120tpi Dillingers on Darryls have done this in my experience), but this 27tpi Nate sealed without a drop.  After my experience with Knards on Rabbit Holes, I am amazed.  I will revisit that combination soon.  

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The final weight of the front wheel is 7lbs 5oz.  This is a 10oz (283g) weight reduction.  For greater weight loss, it may be possible to use a lightweight packing tape without the thick reflective tape that I installed.  Wide Stan’s rim tape is unofficially available through Speedway Cycles in Anchorage.

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The final rear wheel weighs in at 9lbs 2oz.

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Time to ride home for the night.  First impressions are that the bike feels like a rocket.  I explore some urban crust on the way home, mounting snowbanks along the roadsides, doing my best to challenge the system.  Anything that makes riding more fun is worth it.  One and a quarter pounds (567g) less weight in the wheels helps a lot!

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In the morning, I go outside for the real test, to see if the tires have held air overnight.  Sometimes, small air leaks are impossible to detect during set-up, but will make themselves apparent by morning.  If the tire is soft in the morning, add air and agitate.  More sealant may help as a failsafe against leaks during initial installation.  If possible, put the bike in a stand or turn it upside down, and spin the wheels every time you walk by.  Thanks to Kevin at Paramount Cycles and Timely at the Trek Store for advice and encouragement.  Thanks to Chris at The Bicycle Shop for assisting the process, and allowing initial explorations on the wheels of his Salsa Beargrease.

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Fun, safe, and lightweight– nothing not to like!

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Future explorations include other rim and tire combinations, lighter weight preparations (for customers, presumably), and testing at extreme low pressures.  

Studded Nate (Grip Studs)

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A single ride across Anchorage in winter encompasses a greater variety of surface conditions than an entire summer or riding between Holland and Ukraine.  Riding conditions change over time with the weather and with the impact of other road and trail users.  Conditions also change across town, from road, to sidewalk, to trail.  Sidewalks are a necessary part of winter commuting routes in Anchorage.  

Five days after a fresh snowfall with stable freezing temperatures, trails are firm, sidewalks are cleared but feature a light crust of snow, and roads are icy.  Two days after snow, trails are criss-crossed with tracks and mostly soft-packed, sidewalks are covered in layers of road slop with the texture of brown sugar, and roads are smeared with layers of snow over sheer ice.  The day of a fresh snowfall, everything is blanketed in snow.  This pattern repeats itself throughout the winter.  Often, a layer of fresh snow makes much of the urban riding more predictable.  In a way, it is easier.  

In a final twist, the month of January often brings Chinook patterns– warm, wet wind from the sea, further influenced by adiabatic heating as air descends over mountains.  Light rain and 33°F today, leads to an even glaze of ice tomorrow.  Yes, it is raining in Anchorage, with above-freezing temperatures are expected all week.

From past experiences as a daily commuter in Anchorage, I’ve learned that the right tool for reliable transport in such diverse conditions with regular snowfall is a big, aggressive tire.  The first time I replaced a worn Surly Endomorph tire with a Nate, my eyes were wide.  Still, I rode an entire season without studs on that bike.  I promised myself that next time I ride though an Anchorage winter, I’ll have fat tires and studs.  

45NRTH does manufacture a studded fat tire, called the Dillinger, but the tire is currently out of stock from distributors (there may be some online, or in shops elsewhere).  While made to a very high quality, the Dillinger is expensive (about $225), and features a less aggressive tread pattern than the Nate.  The two most difficult conditions on the streets of Anchorage are deep, greasy reconstituted road snow (the brown stuff below, often called brown sugar, which is always plowed onto sidewalks), and ice-glazed streets.  Adding studs to an existing Surly Nate tire offers the best solution.  

Grip-Studs are a tungsten carbide stud with an auger-like base, designed in many sizes as an aftermarket solution for footwear, bicycles, motorcycles, and cars and trucks.  I picked up one package of Grip-Studs (#GST-1000) at The Bicycle Shop, along with a manual installation tool (#4000M), and set out to experiment with the installation procedure and stud patterns on the Nate.  The result, just in time for glazed roadways, is a studded Nate.

Below: Four inches of fresh white snow makes for predictable riding, as fat tires dig into the hardpack beneath.  The reconstituted high-density brown snow is plowed from the roadways; fat tires ride high on this concoction, smearing across the top.  The streets are glazed with ice from the passing of thousands of cars daily.  This road is divided by a median, and cars travel at 35-45mph.  Like most roads in Anchorage, it loses a lane or two in the winter.  Riding here in the winter is interesting, to say the least.  A cyclist was recently killed only a few blocks away, and the local TV station solicited me for some comments about commuting in Anchorage.  

For more insight into winter commuting in Anchorage, check out Lael’s story Sidewalk Singletrack, describing her experience riding through record snowfall in the winter of 2011-2012.

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Nate is a heavy-hitter even without studs.  I’m glad to see this tire on stock fatbikes from Surly and Salsa.  When conditions are tough, either in the city or in the backcountry, it helps.  Still having trouble?  Bud and Lou might be your new friends.

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A package of 100 Grip Studs is much lighter than expected.  In a reversal of my usual grams to dollars ratio, these are more than a dollar per gram.  Still, even at 100 studs per wheel, this is a cheaper solution than buying a new set of 45NRTH Dillingers, even if they were available.  The Dillingers might be a better choice if you lose sleep over rolling resistance, or plan to jump into a few fatbike races and don’t plan to swap tires.  Dillingers and light and fast.  Nates are chunky, for sure

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The 6mm tall knobs on the Nate are enough to fully engage the threaded base of the Grip Stud, without penetrating the casing and puncturing the tube.  The siping on the knobs doesn’t seem to affect installation.

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Even pressure, and about two to three full turns is enough to install the stud.  A little drop of water on the knob helps lubricate the threads, reducing friction and twisting.

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Thus far, the front tire has about 76 studs.  I intend another round of studs up front, and a full complement in the rear.   

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Update: Temperatures have risen above freezing for several consecutive days, and dropped below freezing at night, resulting in a city-wide ice rink.  Studded tires are necessary, while fat tires still have a place on deteriorating snow-covered trails and sidewalks.  Lael reports that Grip Studs– finally– have made her fatbike a reliable everyday winter commuter.

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Schofield Pass: Marble to Crested Butte

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From Carbondale, there are several ways to reach Crested Butte– none of them are paved the entire way.  Several routes from Aspen to CB are enticing, including the famed Pearl Pass route, but snow above 10,700 ft excludes them this time of year.  Pearl Pass is over 12,700 ft, and Star and Taylor passes are nearly as high, and include some singletrack.  McClure Pass is paved, but connecting Kebler Pass to Crested Butte is technically unpaved, although improved and in great condition.  The paved road from Carbondale to Marble connects to a dirt route through the town of Crystal and over Schofield Pass.  At 10,705 ft, Schofield was clear of snow.  On the other side of the pass awaits the famous Trailriders 401 trail down to the town of Gothic.  The ride over Schofield is the most direct, and holds the allure of the “401”.

The road from Marble begins with Daniel’s Climb, a lung-busting grade to Crystal.  Thereafter, the aspen are electric, and the road turns to a rough 4×4 track which is unrideable at times.  The Devil’s Punchbowl is a steep, narrow feature that is largely unrideable, but is a fun challenge on fat tires.  The Pugsley is a stellar slow speed rock crawler, but even a momentary loss of momentum is enough unseat me.  Cresting Schofield Pass, pockets of snow lurk in the shadows.

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The mill in Crystal is one of the most photographed sites in Colorado, drawing leaf-peepers from all over.

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Downtown Crystal.

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Turn left to complete the Lead King Loop back to Marble; stay right to Crested Butte.

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The road turns up, and degrades to a narrow 4×4 track.  Unimaginable, this was once a wagon route.  The other riders are friends of Joe Cruz.  In fact, Joe was Anna’s professor and they share a love of cycling.  She is now entrenched in a 6-year philosophy program, but has found time for some winter endurance racing including the Susitna 100 and the White Mountains 100.  That’s 100 miles, in the snow.  I’m working hard towards a PhD in bicycle touring.  Push.

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Wet feet.

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Rocky road.

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Finally.  Another world awaits on the other side.  From the top of the pass, turn up onto the 401 Trail to climb above 11,000 ft.  An epic descent awaits.

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The 401.  With a light cover of wet snow, the Pugsley has come full circle.  From snow to snow, this bike has been everywhere between an Anchorage winter and high mountain passes in Colorado.  The tread on my Larry tires is worn, and doesn’t hold well in soft terrain.  I’m dreaming of the Nate tire at times.  Lael’s Maxxis Ardent holds the trail well.

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Before cresting the ridge, an alpine park has views in all directions.  In the distance, the backside of the Maroon Bells.

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Going down.  Bundle up.  The soil on the other side is rich with organic matter, making for a lot of mud.  A gorgeous, but not so epic descent.

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Walking, to reduce our impact on this heavily trafficked trail.  A fine coagulation of cow shit and mud temporarily clogs our wheels.  Cass would be in heaven.  Raised on English mud, he loves this stuff.  Grateful to have a fender, I came out looking a lot like a human, rather than the mud-encrusted primates seen in cyclocross and gravel races.  Platform pedals always do their job, even clogged in mud.

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Rideable.  Coated in mud, the chains operate smoothly and silently.  Deore: +1.

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As promised (finally), a rideable descent and some memorable trail at the end of the day.

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No need to filter this water.  It comes directly from the heavens.  At least, it comes from a cow-free wilderness above.

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Camp.  Awake to clear skies, the frozen morning rapidly thaws into a t-shirt day.  The spoils of a frozen night are ideal lighting and a heavy layer of frost.  If only Lael had a camera, she could document me running around the frosty meadow in my long underwear with my camera.

Breaking the seal of our small frosty tent, I’m always excited to see how the world has changed.

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One of the nicest campsites of the entire summer.  Heat some water for tea, and ride into town.  Crested Butte is one historic home of mountain biking, and claims the Mountain Bike Hall of Fame and Museum.

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Gothic, seemingly named for the gothic arches encased in the mountainside.

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And a bike path into town.  Mt. Crested Butte looms overhead.

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