Tumbleweed Sunliner Review: A Timeless Mountain Touring Bike –

The Tumbleweed Sunliner ($3775 complete) continues a long-held tradition of equipping a mountain bike with touring accoutrements. Since the mountain bike’s inception, people have been bolting racks and strapping bags to them, taking advantage of its beefy chassis and wide gearing to pedal deeper into rugged terrain than ever before. John has been riding the Sunliner all year in the Southern Rockies, both unloaded as a trail bike and loaded on camping trips. Read on for his thorough assessment of this timeless touring bike…

Tumbleweed Sunliner Quick Hits

Size XL reviewed here
John is 6’2″ with long arms and long legs and is 190 lbs
Weight: 30 lbs on the nose (with bottle cages and pedals)
Weight: +/- 33 lbs (with racks, Bags by Bird bag, bottle cages, and pedals, as shown above)

Frame Specs:

Sizes: Small, Medium, Large, Extra Large
Price (frame and fork): $1400
Price (standard spec complete build): $3775
Tubing: Heat-treated, size-specific Chromoly tubing. Oversized triple and quad butted main triangle with integrated gussets
Colors: Forest Green or Rhubarb (dark pink), both with gold Tumbleweed graphics
Tire Clearance: Optimized for 29 x 2.6”, clearance for up to 29 x 3″ (tested with WTB Ranger tire on 40mm internal rim width)
Head Tube Diameter: 44 mm I.D. for ZS44 upper, EC44 lower cups
Bottom Bracket: 73 mm BSA threaded
Spacing: Boost 148 mm x 12 mm thru-axle (included)
Seat Post Diameter: 31.6
Seat Collar Diameter: 35 mm (included)
Dropper routing: External routing on down tube with internally routed seat tube
Driveline: 1x drivetrain specific. Not designed to accommodate a front derailleur
Chainring clearance: 38 tooth max
Brake compatibility: 180 mm or 160 mm IS mount, front and rear with external cable routing
H20 mounts: One set on seat tube, one 3-pack mount on top of downtube, one 3-pack mount under down tube. Size small has two mounts on top of downtube.
Rack and Fender mounts

Fork Specs:

Tire clearance: 29 x 3 (Tested with WTB Ranger tire on 40mm internal rim width)
Spacing: Boost mountain – 110 x 15 mm thru-axle (included)
3-pack mounts angled rearward
Low rider rack mounts
Upper fork crown rack mounting points
Center hole on fork crown
Generator wiring port on lower right leg
Rack & Fender mounts at dropouts
440 mm Axle to Crown with 55 mm offset

1983 Ritchey Everest with a Touring Package add-on spec (left), Tumbleweed Sunliner (right)

Taxonomic History

In the late 1970s, the American mountain bike was evolving from its BMX and paper-boy cruiser roots. I say “American” because there are plenty of examples throughout history of balloon tire bikes with flat bars designed to traverse rough terrain, many of these bikes included racks and portage equipment to carry items for travel by bicycle.

With their lifestyle-centric approach to marketing, Californian personalities of the era took components from moto, touring, and BMX to assemble somewhat of a bricolage bicycle designed to transport its owner deep into the backcountry. Many of the first production models of the early mountain bikes, like my Everest (above), featured rack mounts for bicycle touring and bike camping.

In a somewhat serendipitous, self-reflective, and referential manner, I made the notes for this very review on a ride up Mount Tam in Marin County late last summer with some friends, the very place where cruisers became klunkers, and the modern mountain bike was born…

First and foremost, a mountain bike can have racks. This is nothing new. Those racks can hold panniers or bags and do not inhibit the bike’s ability to be absolutely shredded (albeit lightly) on legitimate singletrack. Granted, I do not ride my 1983 Everest in the same manner as I pilot the Tumbleweed Sunliner, but that’s because vintage bicycles were not built as robustly as their modern counterparts. They had considerably lighter-duty frame materials.

We’ve come a long way in terms of chassis engineering in 40+ years.

Chassis: Light vs. Heavy Duty

The Sunliner is a flat bar version of the Stargazer, Tumbleweed’s flagship drop-bar 29er touring mountain bike, with a few geometry tweaks to accommodate for the loss of extension “fit” when switching from drop bars with hoods to flat bars with levers. This includes a slightly longer top tube and an increase in stack. The Stargazer is still the bike to this day that I recommend to people who want one drop bar bike that can do it all.

For gravel roads, doubletrack, and even light singletrack, the Stargazer can very much be wielded to great success on various surfaces. I jokingly called it a “mixed terrain bicycle,” or MTB, to someone once – referring to how people are willing to label a bicycle with fat tires an ATB without rhyme or reason or qualifiable classification – just to avoid calling it a mountain bike. But I digress – back to the bike at hand.

Tumbleweed’s crowning achievement with the Sunliner comes down to two points: it is comfortable, so it is easy to control in rough terrain, and its tubeset is designed to carry a heavy load associated with fully loaded touring, but it still rides very mild-mannered when unloaded.

Tumbleweed and their manufacturers have really nailed the tubing here!

My Meriwether Ponderosa (above, right) is not a fully loaded touring bike. It’s lighter and flexier than the Stargazer, but what differentiates it is the chassis. Its light-duty chassis has more road DNA than MTB DNA since it’s not boost-spaced and features a road bottom bracket (68 mm wide).

The Stargazer and Sunliner are 148 mm boost-spaced with 73 mm bottom brackets, so they are mountain bikes. If you’d like, you can call them “mixed terrain bicycles.” ;-) They also use robust, larger-diameter, butted tube sets engineered to haul a lot of weight.

If you’re looking for an even heavier-duty chassis, the Tumbleweed Prospector is for you. Ryan Wilson has been living off his full-time for the past several years.

It is also worth noting the size small can be built with 27.5 x 2.8 – 3″ tires to aid in more standover height and control for shorter riders. Tumbleweed can actually built any size Sunliner with 27.5+ wheels, but they don’t recommend anything narrower than a 27.5 x 2.6” due to bottom bracket height concerns.

Run the Numbers: Sacred Geometry

Ride quality is as much about the tubing selection as it is geometry – and parts spec for that matter, which we’ll touch on in a bit – and the Sunliner offers one of the best geometries I’ve tested in this class. The bottom bracket drop of 65 mm is in line with a 29 x 2.6″ wheeled mixed terrain bicycle as I reviewed it here – while noting the Sunliner can fit up to a 3″ 29er tire – offering sure-footed pedaling without rock strikes on singletrack and even-keeled cornering, even when loaded down.

I, a 6’2″ 190 lb human, somehow made this massive bike look relatively small!

A 69º head and 73º seat angle aid in the Sunliner’s off-road prowess, and the 456 mm chainstays mean your rear panniers (if you choose to use them) will be heel-strike-free, even with my size 12 or 13 shoes (depending on flat or clipless pedals). Thank fucking god the Sunliner has an appropriate stack number for a non-suspension corrected bike! The XL sports a glorious 664 mm stack with a 210 mm head tube. Nothing bums me out more than to have to put 4 – 6 cm of spacers under a bike like this to have it fit me. The tall head tube puts the bars level with the saddle – a must for any touring bike.

Detailing

Racks rule. They really do. If you can buy a bike like the Sunliner and simply tighten down eight bolts to have a completely secure and painless off-road touring experience, why wouldn’t you? Bags that strap to your saddle rails and handlebars are great for many reasons but in my opinion, the optimized experience for touring on gravel or double/singletrack on a rigid mountain bike relies on front and rear racks. For riders that use smaller frames, no more hassle of having your saddle bag or handlebar pack hit your tires. Strap stuff to the top of the rack, or modern panniers to the sides. It’s easy.

Lightweight panniers like the San Util models pictured here or the Buckhorn or Revelate, offer plenty of cargo capacity and keep the weight lower on the bike, making it easier to control off-road. The days of having bags flop all over as you rattle down a fire road could be over, if you’re riding a dedicated touring bike.

Guys like Tom Ritchey knew this back in the 1980s, and over the past decade, the marketing of “bikepacking” bags has outshined the humble touring bike. If the first mountain bikes were specced with rack mounts, it makes sense that modern bikes like the Sunliner also ought to. This is the main difference between a mountain touring bike and just a mountain bike; the latter doesn’t have rack mounts.

Apologies for the digression. This is a passionate subject matter, but it’s a worthwhile note to make clearly. Bikes like this are exquisitely detailed for bicycle camping, sub-24-hour overnighters, short and long bicycle touring, and straight-up bicycle overlanding, like what Ryan Wilson is doing. If you want the best experience of all the above, go with a bike that is engineered to offer just that: the best possible experience.

The Sunliner has cargo bosses on the fork blades, as well as fender, and rack mounts. The frame has cargo bosses under the downtube, as well as the seat tube, with water bottle bosses on the downtube and rack/fender mounts at the dropouts. To get the most out of the tire/chainring/chainstay clearance trifecta, it has a drive-side chainstay yoke. All these considerations give the Sunliner a whopping 29 x 3″ tire clearance.

All the cables run with full-length housing, as do the brake houses. The seat tube has routing for an internal dropper, and the fork has routing for dynamo lighting, too!

Specced to Shred

A touring bike ought to be built with reliable componentry and, in my opinion, battery or electronics-free. The spoke nipples ought to be external, the frame/fork/racks made from steel, a metal that is easily repairable, the tire clearance and spec robust, and the components made from metal to avoid damage while shipping, transporting, and shredding the bike.

Daniel from Tumbleweed spends a lot of time working on his own branded components, like these new 20º sweep Persuader bars (I actually prefer the 30º sweep for singletrack riding, particularly when the bike is loaded down), and the Tumbleweed racks; T-Rack and Pannier Rack.

As for parts spec*, this Sunliner is built around the Shimano XT 12-speed mountain bike drivetrain, and holy hell do I love this kit. It’s sad to think that this might be the last great cable-actuated complete drivetrain from a big brand we might see, and this is now the third or fourth bike I’ve ridden this year with it.

*The production Sunliners are built from GX Eagle, another bombproof drivetrain, although the survey is still out if SRAM will abandon cable-actuated drivetrains in favor of AXS/Transmission.

Having a full-length dropper post, the PNW Components Loam dropper, is a game changer on a touring bike. On the size XL, I could have my Thermarest RidgeRest or a UL Helinox chair and still have full-dropper travel. It allows you to use the entire bike for body language while descending and yeah, jumps are a blast, too!

Speaking of riding…

Riding the Sunliner

As I mentioned in my First Look back in August, I’ve spent a majority of my time on the Sunliner riding it as a rigid mountain bike on my favorite singletrack rides here in Santa Fe. Whereas I’ll take bikes like the Kona Sutra LTD or my Meriwether Ponderosa on the more XC-friendly trails, I threw the Sunliner in head-first onto my more rocky “all-mountain” trails; rides I’d normally undertake on a hardtail or full-suspension bike.

Since the Sunliner is a heavy-duty chassis bike, meeting all necessary ISO or ASTM testing for mountain bike riding, I felt more comfortable jamming through our rocky chutes and glissading across chunder at top speed. There were plenty of “oh shit” moments during these rides but I was genuinely curious just how comfortable this “mountain” bike was in actual mountains.

People get so swept up in angles these days, with seat tube angles being a hot topic over here and modern hardtails going to 77º you might think a seat angle of 73º would suffer on steep switchback climbs. That’s where the bottom bracket drop of 65 mm and long seat stays really aid in the Sunliner’s ability to tractor crawl up tight switchbacks and gnarly rock gardens like it’s in 4-Low with both front and rear lockers engaged.

What’s worth noting is that the bike climbed even better the more it was loaded down. Bolt on the racks, strap on some bags, and load them up, and it redefined what it means for a bike to be “sure-footed” on climbs. My theory is that having the weight both over the front and rear hubs aided in the “planted” sensation while climbing, and then it was all up to gearing and pilot strength to do the rest.

Thanks to Cari for nailing these riding photos. Phewwww, they’re fun!

Similarly, when the weight is lower than traditional “bikepacking” bags at the saddle and handlebars, the bike fucking plows while descending. On a recent overnighter with Radavist co-owner and my better half, Cari Carmean, she kept calling me crazy as I flew through rock gardens that I’d normally ride a bit more reserved on a rigid bike. The Sunliner feels so predictable and planted that the desire to roll through everything in front of me at top speed outweighed those evolutionary pre-frontal cortex brain signals reminding me of self-preservation.

Then, every booter and side hit on the trail would just send you twice as far due to the extra mass of a fully-loaded mountain touring bike.

The reason I’m not worried about rallying a bike like that and why I wouldn’t do the same on a bike with a lightweight chassis comes down to the frame and fork’s engineering. Looking back to why chassis engineering matters so much, this is how the Sunliner is designed to be ridden and why when bikes aren’t designed to be abused like this, the brands will often add a disclaimer and use words like “lightweight tourer.”

I wouldn’t dare ride a gravel bike like this with a full load on these trails.

The Sunliner ain’t a lightweight tourer. It’s a stout piggy that likes to be smashed around in the chunky stuff, fully loaded, and it’s an addicting experience everyone ought to take a big hit of because you won’t know what you’re missing out on until you try it.

Daniel in Los Angeles, 2017, with his Prospector (left), Stargazer head tube badge (right)

Q&A with Daniel Molloy of Tumbleweed Bikes

Because Tumbleweed is such an intriguing brand in that it only makes touring bikes and accessories, omitting to chase the tail of the bike industry down its many trendy rabbit holes, I wanted to reach out to Daniel Molloy, the founder of Tumbleweed, to dig a little deeper into the modus operandi of his brand’s latest bike, the Sunliner. Read on for some tire talk about tubing spec, use-case, and what the future holds for the Sunliner.

Where did the name Sunliner come from?

Design-wise, the Sunliner is a cousin to the Stargazer, and I wanted a name in the same celestial genre. We happen to use an espresso blend from our favorite local coffee roaster called Sunliner, and it’s also the name of an old defunct motel around the corner from our shop, so I thought the name would have some fun ties to our other bikes as well as the neighborhood we are in.

Daniel in Los Angeles, May 2018, during the premiere of El Silencio: Cycling the Peruvian Andres

What tubing spec does the frame use? Assuming straight gauge stays?

All of our tubing is custom drawn, heat treated (in an oven big enough for ten people to stand inside), mitered, and welded under the same roof, none of it is outsourced or ordered from an external supplier. It’s a custom tubeset made for us, the seatstays and chainstays are oversized straight gauge, the main triangle is triple- and quad-butted (with different butting profiles based on size) with integrated reinforcing gussets butted into the profile of the tubes themselves, which is how we can create a strong frameset without any externally welded gussets.

The bike rides very even-keeled loaded and unloaded, what do you attribute that to?

Our bikes are touring mountain bikes primarily. We make no allusions to designing performance-oriented bikes, but they are definitely a blast to ride. We are using a pretty balanced geometry and an oversized tubeset. We don’t use super short chainstays, they are long enough on all of our bikes to allow heel clearance with full-size panniers. The goal is to strike a balance in geo and tubing to create a bike that is fun to ride unloaded and doesn’t turn into a noodle when you put a legit touring load on it and take it on trails. Simply adding a rack mount on a dropout does not by itself make a bike good for touring.

Daniel at the 2024 MADE Bike Show in Portland

In my experience, a lot, but not all, of a bike’s perceived stiffness comes from its downtube diameter; what’s the diameter of the Sunliner’s downtube?

The downtube is one part of the equation, and ours is oversized (36.4mm) and reinforced where it counts. Our entire tubeset is oversized compared to most metal bikes designed for gravel or light-duty mountain biking, and the heat treating process also helps with stiffness and overall strength.

What are you most pleased with on this model?

For touring, I think the fit will be great for a lot of people. We gave the Sunliner quite a bit of stack for a flat bar bike, which offers a ton of latitude with cockpit positioning, and gives a monster front triangle since we decided to not to make it suspension corrected (98% of our customers don’t use suspension for touring and never will) for large volume framebags. This is our first bike model where you can just take an off-the-shelf wheelset and drivetrain and build it up. The Prospector and Stargazer are both a bit quirky in their own ways, mainly because I’m super opinionated about what a mountain touring bike should be and what I want to put my name on. The Sunliner ticks all of the boxes for me while being a bit more mainstream than our other models.

What would you want to change in the future?

For all of our bikes, we do extensive long term testing and quite a few revisions of the pre production samples (usually over the course of at least a year), and we don’t release them into production until we iron out any potential kinks. What ends up happening is that we make a series of small evolutionary changes with each production run. We build up a bunch of them and agonize about little tweaks to the cable routing, or other design details that would make the bike 2% better, and anybody who doesn’t build them every day would never notice. I’m constantly tinkering with and thinking about the future of our bikes, frowning about novelty drivetrains, and lamenting the loss of mechanical components and standards. I’d love for SRAM to not give up on mechanical shifting. I’m strongly against components that become less user-serviceable and more proprietary, especially from a remote touring perspective.

Thanks, Daniel!

The Rhubarb-colored Sunliner sitting pretty against a moody, monsoon sky…

TL;DR and the Wrap-Up

Tumbleweed’s flagship bike, the Prospector, led the brand to go all-in on bikes designed for fully loaded off-road touring. From there came the Stargazer, which is still best in class as far as I’m concerned. This inspired the Sunliner, a flat-bar counterpart.

This stout, heavy-duty chassis tourer epitomizes the brand’s dedication to self-sufficient bicycle travel. Yet it’s not just for fully loaded exploits; the Sunliner excels as a rough-and-tumble trail sled, making even the most familiar singletrack trails more engaging.

After nine months of having Daniel from Tumbleweed’s personal Sunliner build, I’ve put it through the wringer here in the Southern Rocky Mountains in Santa Fe both as an unloaded trail bike and a fully loaded camper. If there truly is a single bike for all things dirt, the Sunliner and Stargazer remain reigning champions of that space. It all depends on whether you prefer drop or flat bars.

By the way, the Rhubarb color really grew on me! If you’d like something more discreet, it also comes in British Racing Green.

Pros

Heavy-duty, mountain touring bike chassis
Geometry is dialed, especially for bigger riders
Clearance for 29 x 3″ tires, perfect for sandy/arid touring landscapes
Optimized for 29 x 2.6″ tires, perfect for mountain bike riding.
Dropper post routing
Mounts aplenty
Robust, stout loaded-down riding experience, yet surprisingly playful when unloaded
Rhubarb color is superb
Atavistic playfulness in a simple, no-nonsense, low-maintenance package

Cons