In the early days of mass produced bicycles, they were often used as simple affordable transportation to allow people and cargo to get from place to place easier. As automobiles came into mainstream American culture, bicycles became less common as utilitarian transport and were seen more as kids toys and novelty items. Gradually cycling culture came back as a common form of recreation for both kids and adults in the US. Over the years, bikes became more and more specific in purpose. Road bikes to race on the road. Mountain Bikes to race on the dirt. Utilitarian touring bikes became just a small segment of the cycling market. Recent interest in off road touring, ie Bikepacking, has led to more companies looking to add gear hauling capacity and comfort (not necessarily speed) to mountain bikes.
Chumba Cycles USA
Chumba is a company that has gone through an evolution. They company originally began as a gravity oriented boutique mountain bike company in Southern California. As bigger companies began to dominate the downhill and trail market with mass produced hydroformed aluminum and carbon frames, Chumba quietly drifted off the radar. Over the past several years, Chumba has re-emerged with a new owner, new base of operations in Austin, Texas, and a new focus: steel and titanium frames built in the USA.
Chumba Cycles Ursa 29plus
Let’s talk about the obvious notable feature of the URSA: American made steel with 29×3.0” tires. That is certainly a wild combination that I would not have predicted to exist a few years back. Mid-fat, plus tires, or whatever you want to call them, have certainly gained “traction” (see what I did there) recently! It is hard to walk into a bike shop without hearing someone having a conversation about the merits of “plus” tires. Compared to my normal 29×2.35 these things just appear enormous! But how do they do on the trail?
The frame is 4130 double butted chromoly. No doubt that this thing was built to take a beating!! As I built up the bike I was really impressed with how solid everything felt. I’ve spent too much time in carbon fiber land apparently because the feeling of chromoly was shockingly solid, taking me back to building BMX bikes (before I realized I didn’t know how to do any tricks so BMX didn’t make much sense for me). The sliding rear dropouts are supplied by paragon machine works and have 157×12 mm spacing with a thru axle. The super boost (or standard downhill) hubs allow for plenty of tire clearance and front derailleur compatibility with less risk of chainsuck.
Objectivity is important when evaluating any new or different product. Until the past year or so, I never had anything more than a 2.4” tire on any bike, with the majority of my time being spent on 2.2-2.35 XC and trail tires. So as I sat staring at the massive 29×3.0 Maxxis Chronicles, I could not help but have some concerns about how those tires would feel. I have spent some time on an aggressive trail bike with 2.8’s. I walked away from that feeling like plus tires were certainly interesting, but not my style for truly aggressive riding because of the vague feel and concerns with durability. The Ursa however, is not an aggressive full suspension bike. A fully rigid hardtail that is built more for adventure than all around trail shredding. Although that didn’t stop me from seeing how it would handle some solid trail riding.
First things first, rigid riding certainly necessitates adjusting your approach to riding. Especially when the tires leave the dirt. My first ride really was humbling. I quickly realized how much I truly rely on suspension to help me to smooth out the trail. Roots and rocks that I normally blasted through had me pinging around all over the place. Frustrated with myself and the bike, I finished the ride and tried to figure out what was going on.
TIRE PRESSURE. Seriously, this matters on a 3” tire more than you would imagine. For ride #2 I pulled out the digital pressure gauge and really worked to find the sweet spot. Too soft and your steering goes to crap, too firm you bounce all over the place. Everyone will have to experiment on their own to find the sweet spot. I bounced between 12-16 PSI.
Once I dialed in tire pressure (or at least got it closer), I began to relearn how to ride a rigid bike. This is a skill I left behind years ago in my BMX days. However, the bike and I really began to get along after a few hours of trail time together. I still preferred to keep the tires on the ground, but I was really having fun attacking the trail in an altogether different manner.
Cornering with a 3.0” tire is different. You really can lean into the turns. I had myself literally laughing out loud after hitting some turns with this thing. Riding rigid requires using your body as suspension, so you have to be relaxed and stable on the bike in order to stay on line. Which is really good training for all around trail riding. Ensuring that the tires had enough pressure to not squirm during hard cornering while still offering a comfortable ride is a tricky balance. Like I said before TIRE PRESSURE.
Aha! It all makes sense!
Throw 20 pounds of camping gear onto this bike and all the sudden 3” tires and a rigid fork begin to make a lot of sense! The frame is clearly built to survive the apocalypse. And honestly at my weight of 150 pounds, I felt it to be a bit harsh until I strapped a bunch of gear to it. All the sudden I had a nice comfortable and stable steel bike that I could pedal all day.
We did a 3 day bikepacking trip through Virginia to really get a feel for what the bike was designed to do. We had solid mix of singletrack, dirt, gravel, and pavement. The Chumba chugged along awesome! With water and food, my whole set up weighed in at 57 lbs. I didn’t carry a backpack, so everything was strapped to the bike. The Ursa never flinched with the added bulk. The steering that initially seemed a little slow became very stable and predictable. Even the tires seemed to handle better with the added weight. It was an awesome trip, check out the full writeup here!
From Chumba’s website:
“29 plus is a mid-fat bike wheel size that uses 3.0″ wide tires. The wheel size yields tons of fun, traction in the best and worst conditions and a smoother ride. The extra cushion of the mid-fat tires means you can ride this bike more aggressively and go farther. Riding on a 3.0″ tire you can lean the bike much harder into turns allowing you to maneuver quickly on the trail. Ride the URSA 29+ tubed at 10-20 psi, enjoy soaking up the trail chatter at even lower pressures when you convert to tubeless.”
There are a few places where I really can see the 29+ platform really standing out. The most obvious being anywhere with sand. Bikepacking routes such as the Baja Divide beg for a wide tire. The ability to keep pedaling through sand washes and across beaches makes a lot of sense. Long trips also make sense on the 29+. More rubber between you and the ground seems like a good way to fight off fatigue. But it does come at a price of being slower rolling, particularly on pavement.
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The build matters
We had two test bikes to try out with several component spec different between them.
I really preferred the MRP carbon fork over the Surly Steel fork. The Surly fork is really solid feeling (and heavy). The fork could probably double as a sledge hammer and then be put back on the bike good as new. The MRP is much lighter and seemed to offer far superior damping properties. I really was pretty surprised by this. But MRP has done a great job with making a comfortable lightweight fork.
If I were to own this bike I would probably get a suspension fork. The chunky terrain that I prefer is just more fun with suspension. However, on more mellow trails and double track, the rigid carbon fork was awesome. Chumba does offer a suspension fork upgrade, so just check that box when you are ordering if you prefer a little extra squish.
The bike I rode had a non EXO casing Maxxis Chronicle front tire paired with an EXO casing Chronicle on the back. Get the EXO casing tires if you will be riding on any rocky trails. After our trip I noticed a amall cut that had sealed itself. I believe Chumba is shipping all current URSA 29plus bikes with EXO casing tires, but just something to note for any 29 plus riders.
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I would love to try out some other tire options as I’m not super familiar with the 29 plus platform. That really is the tricky park for me. As I mentioned multiple times already, trying to dial in the perfect pressure on the Chronicles was tough. I believe part of my issue is being a relatively light weight rider, because adding 20 plus pounds to the bike improved the ride quality. With more and more plus tire options showing up, there are a lot more options out there to try.
The Complete Package:
Chumba offers the Ursa 29plus in 4 stock build kits (including single speed). All of the kits seem to be well thought out and well spec’d. Chumba also offers customers the opportunity to do full custom build kits on their bikes. So you can spec the bike exactly the way you want it without having to swap components. That’s pretty rad and one of the biggest advantages of working with a small US based company.
The quality of construction on the frame is fantastic. It’s obviously not some generic catalog frame from overseas. Chumba builds all of their frames in the USA! Each frame is inspected prior to paint for any inconsistencies. The URSA never made me question its durability! The bike was built like a tank. Chumba also has a light weight ti hardtail if that’s your thing. But the URSA is a beast meant to last a long time and carry a heavy load along the way.
Our bikes had been in the demo fleet for a while, so they showed some slight wear, but overall were in fantastic shape! The sliding dropouts were easy to adjust and creak free. The paint looked great. I really love the colors they offer and the simple branding. Nothing over the top, just a quality American made frame.
We are in the middle of a slightly confusing time for mountain bikers. Not only do we have 27.5 and 29 to choose from, we have a range of mountain bike tire widths from 2.00 to 3.00 inches (fat bikes are a different story). The tire width also dramatically affects overall tire height as well, so a wider tire is a bigger tire in every way. That pretty much explains why this bike has tends to just keep rolling no matter where you steer it. The Ursa isn’t as much rally car as it is Subaru Outback, comfortable, confident, and efficient, but a little slow to get up to speed. Just keep pedaling and it’ll keep trucking along confidently without much fuss. It’s an all day cruiser more than it is a trail shredder. Chumba has other bikes for you (see: Rastro) if that’s what you are after.
It is more of a tortoise than hare, but that doesn’t mean it won’t win the race given due time.