Rubber Side Down (RSD) bikes may only have been around since 2012, but the company’s history stretches back over 25 years. The Toronto-based company’s owners fell in love with their first hardtail bikes decades ago, and as their passion for the sport grew over the years, they decided to start building their own. RSD is a relatively small company that only produces mountain bikes, and they design their bikes to be versatile enough to be ridden nearly anywhere.



The Mayor looks to rule the fat bike world with a campaign built on versatility, performance and value. The Mayor may not be the only bike in most riders’ quivers, but it is an affordable way to jump into the fat bike world without giving up much on performance. This is far from a dedicated race bike, but we raced it. It would be great on snowmobile trails, but we enjoyed it on the dry and dusty summer SoCal trails as well. This is a fat bike that’s exactly what you’d expect from looking at it. It’s not going to win any cross-country races, nor is it going to be a downhill superstar. Instead, the Mayor is designed for fun all the way down the trail.


RSD builds the Mayor from aluminum with hydroformed 6061 tubing. The frame sports Boost 197-millimeter rear-axle spacing, a tapered head tube and enough tire clearance for tires up to 5 inches wide. The fork is a custom-built carbon RSD with no travel but plenty of clearance.

Carbon first, upgrade later: The custom RSD carbon fork doesn’t deliver any travel, but it is very lightweight and precise. Some riders will opt to upgrade this for a suspension fork down the road.

rsd-7Aluminum and all business: The price of the RSD is impressive, especially considering the overall build quality of the frame. The welds are neat, the paint is perfect and we were impressed with nearly every aspect of the build considering the low price tag.


The price is the impressive standout here. This is a high-quality fat bike with a carbon fork that comes in well below the $2000 mark. The components are a solid mix of Sun Ringle, SRAM, Easton and Race Face. While it may not be the ideal kit for winning a fat bike national championship, it’s certainly light enough for most riders and more than reliable.

The Maxxis Minion fat bike tires ended up being our favorite stock part on the bike. Those big, fat chunks of rubber not only rolled relatively well but delivered more traction than we’ve ever seen with any tire. In fact, with the tire pressure set too low, the Minions will actually grip too much.

rsd-4Simple but elegant: The RSD uses a simple single-ring drivetrain with a Race Face crank and SRAM X7 derailleur. It’s not the flashiest build, but it gets the job done.

rsd-6Big Maxxis: The Minion FBF and FBR fat tires certainly are not the lightest, nor do they roll the fastest. However, they deliver more traction than we’ve felt in nearly any tire we’ve ever tested. All you have to do is find the right pressure.


Bike setup:

The Mayor is remarkably easy to set up, thanks to the hardtail design and rigid fork. All you really need is a floor pump, since the pressure in the tires provides all the suspension. Too much pressure here will seriously affect the ride quality by making it too harsh. Too little and the bike will grip too much in the corners. We found our sweet spot between 10 and 13 psi. We could see dropping the pressure for sand or snow riding, but for the dry conditions we tested in this seemed to be perfect.

Moving out:

One look at the Mayor frame and you can tell RSD is serious about its fat bikes. The custom tubing is welded to huge, 197-millimeter dropouts and a matched ultra-wide bottom bracket. The chainstay yoke provides plenty of tire clearance and is welded to some beefy chainstays to handle the rigors of those big fat tires.

rsd-3Mounts included: The dropouts on the Mayor could easily be adapted to fit racks, panniers or fenders for the adventurous bikepacker crowd.


As with any fat bike, you’re going to feel the weight a little when the trail points uphill. The traction of a nearly 5-inch- wide tire simply won’t float uphill like a cross-country rocket; however, the Mayor will climb nearly anything if you’ve got enough gumption and low-enough gearing. Since this is a single-ring drivetrain, it’s important to be realistic about the chainring size you choose. The 28-tooth stock ring matched with the 36-tooth granny gear provides enough torque for most climbs, but riders looking to claw their way up the steepest elevator-shaft climbs may want to upgrade to a cassette expander with lower gearing options.

rsd-9Perfect traction: This is the only way we can describe the big fat Maxxis Minion tires. With the right pressure, we couldn’t find the tipping point where the traction would give out.


Those big fat tires have essentially unlimited traction when they’re inflated properly. If the tires are too firm, the rider feels like a basketball bouncing down the trail. Too soft and the traction causes over-steering that is nearly impossible to control. The geometry is fairly conventional, but the traction in the tires is what makes diving into a corner a unique experience on this bike. The handling is sharp and surprisingly quick. You can lay this thing over as hard as you want in the corners, because the tires won’t break loose. The only limiting factor is your skill in handling a bike with minimal suspension in rocky or high-speed turns.

rsd-10Ready for adventure: You may not be the quickest rider on the trail, but this fat bike is ready for long rides if you have the leg power to push it.


Since it is a fully rigid bike, we never expected the Mayor to be a downhill shredding weapon; however, thanks to those big tires that deliver boatloads of traction and a bit of cushion, this bike can pick its way down some surprisingly steep sections of trail. A dropper post would be a welcome addition to allow the rider to get further behind the seat, but a skilled pilot will be able to pick and choose lines down anything short of the most technical and steep chutes. The RSD doesn’t like to be playfully jumped or flicked down the trail. Instead, it prefers to keep the rubber glued to the ground and carefully pick its way down descents.

rsd-fullTechnical riding? No problem: The big tires offer enough suspension to tackle some of the technical lines on any trail. The lack of suspension will keep you from riding these lines fast, but the impressive traction will allow you to pick down rock gardens surprisingly easily.


While we enjoyed the simplicity of riding the RSD with the stock rigid fork, we found the ride was improved with the addition of a suspension fork. We swapped the stock fork for a Lauf Carbonara fork, which is a leaf-spring-design, carbon fat bike fork with 60 millimeters of travel. This little upgrade made a big difference in the rideability of the bike. You could also go with a traditional fork, like a RockShox Bluto; however, we think the simple functionality of the Lauf fits this bike well.

The Avid BB7 brakes work exceptionally well, with plenty of power to stop those big tires, but they need to be set up properly to achieve maximum power. A poorly adjusted brake won’t be able to stop those big wheels. Take time to set the brakes up properly.



The RSD Mayor isn’t the flashiest candidate in the race for fat bike supremacy; however, the geometry is solid, and the features and build quality back up the claims that this is a serious fat bike that won’t break the bank. The parts won’t require any immediate upgrades, and the bike will whet nearly any rider’s appetite to try the fat bike craze. While we would have liked to see a suspension fork in the mix, there’s something pure and simple about allowing the cushion of the air volume in the tires to handle the suspension detail. The RSD is a solid choice for any rider looking to add to his or her quiver with a fat bike. We’re planning to take our base-model RSD fat bike and slowly build it with upgraded parts until it’s the fat bike of our dreams. Any rider willing to pay the reasonable $1700 cost of entry could look at this bike in the same light as a solid skeleton that’s worthy of upgrades and willing to grow with you as you grow to love fat bikes.



Mountain Bike Action is a monthly magazine devoted to all things mountain biking (yes, that’s 12 times a year because we never take a month off of mountain biking). It has been around since 1986 and we’re still having fun. Start a subscription by clicking here or calling (800) 767-0345.

Available from the Apple Newsstand for reading on your iPad, iPhone or iPod Touch.

Subscribe Here

Contact us via email at [email protected]

You might also like