ULTRA BOOST
You can ride the Ultra Boost just like your standard Ultra tough-gravel bike, only expanding your horizons.
Ultra Boost Urban have the same capabilities of Ultra Boost, just with a more upright position, ideal for commuting or granting additional control.
CHOOSE YOUR BUILD
ULTRA BOOST FORCE D1 AXS 1X12 FB 650b
ULTRA BOOST FORCE D1 AXS 1X12 FB 700c
ULTRA BOOST RIVAL XPLR AXS 1X12 DB 650b
ULTRA BOOST RIVAL XPLR AXS 1X12 DB 700c
ULTRA BOOST FORCE D1 AXS 1X12 FB DISCUS PLUS I28
BMW URBAN ELECTRIC
BMW GRAVEL ELECTRIC
THE HIDDEN BOOST
Review after review and award after award raves about the light, responsive & fun ride of the Exploro Ultra. So when it came time to make an e-bike version, we didn’t want to change anything: same geometry, same aero tube shapes, same agile steering.
But thanks to the e-bike system that hides inside, you have some extra power at your fingertips. Take that detour, climb that mountain or simply have a "no-sweat commute" to work and a great workout on the way home.
WHY GET A BOOST?
We love riding our Ultra into the unknown. Every mountain peak conquered is the result of your own effort. Still, we sometimes wonder what lies beyond that last peak and the extra Boost helps us find out.
Others may love to ride with a group of friends but don’t want them to wait up at the top of the climbs. A little extra Boost lets you arrive all together.
Or maybe you love to commute to work but want to arrive fresh. The Boost lets you get to the office without a sweat and enjoy an adventurous workout on the way home (after all that’s a lot more time-efficient than driving and having to hit the gym afterwards).
FOR AN EFFORTLESS EFFORT
All Ultra Boost & Ultra Boost Urban models come equipped with Mahle X20 system: 55Nm of torque, 350wh battery that offers additional Boost to your legs and helps keeping the weight down with the complete Ultra Boost complete bikes starting at approximately 12kg (Ultra Boost Urban Force AXS w/i28 carbon wheels model, size 54, no pedals).
The Mahle X20 system offers BT and ANT+ connectivity (Garmin ready), 3 Ultra Boost & Ultra Boost Urban specific “default power modes” + a 4th mode, fully customizable though MySmartBike app.
With a relatively gentle power management, it’s easy to reach more than 150km and 2000m of elevation*
If you need even more battery range, a 173Wh Mahle battery extender (just 1.1kg to be installed on the seattube’s bottle cage) can be purchased separately, increasing the bike range by 50%
*average for a rider below 75kg, on a hilly fast gravel/paved route, considering EU 25kmh speed limit
IT ALL STARTS WITH THE TIRES
To make the fastest possible gravel bike, you need to start with the tires. Tire choice determines comfort & grip, but it also determines how you can shape the frame to redirect airflow.
To aerodynamically engineer the frame around the tires, you need to know what their REAL measurements are. Not what’s on the label, but how they really fit. That’s REALFAST aerodynamics. It’s not easy however, as the tire dimension depends on the rim you use, tire pressure, and of course how accurate the manufacturer’s claimed size is.
We took hundreds of measurements to know the real tire widths (which we call WAM - Width As Measured and RAM - Radius As Measured) and engineered the frame around that data.
Max clearance information can be found here.
REALFAST AERODYNAMICS
The Ultra was our most difficult aerodynamic challenge to date. Start with massive 55-61mm tires and then make the bike aero. There’s nothing we can do about the tires, they’re big and the knobs don’t help. What we can do is take the airflow mess that comes off the front wheel and try to catch and redirect it. That’s why you will see the 60mm wide downtube placed closely behind the front wheel, going even wider as it gets closer to the BB.
Blending this into the headtube with an off-center aero profile along with loads of other tricks gives you a bike that feels so much faster than your brain can compute. Because let’s be honest, when you see those tires, your brain gets ready for that slow, boring paved performance of a mountain bike. But thanks to your riding position, the aerodynamics, the BB stiffness and the narrow Q-factor, the Ultra actually feels 100% like a road bike when you want to go fast. Even when muddy.
Urban version offers all the above features blended with a carbon flatbar for a more upright position (perfect for commuters or just more relaxed rides) or just even more control where the path becomes tough.
design in details
75MM DOWNTUBE BASE:
Lower downtube aero profile is 75mm wide to fully shield water bottle.
60MM DOWNTUBE NECK:
Upper downtube necks down to 60mm to pick up the airflow coming off the front tire.
SIZE-SPECIFIC DOWNTUBE:
Reduced depth on smaller sizes to keep frame compliant and keep space for bottles.
PERFECT AERO CUTOUT:
Close-fitting cutout to shield the rear wheel and achieve the most speed.
MIND THE GAP:
No oversized gaps between front tire & downtube for better airflow transition and less turbulence.
HUGE CLEARANCE:
The original Exploro set today’s standard for up to 54mm tire clearance. The Ultra has up to 61mm!
MINIMALIST CROWN:
Fork crown shapes haven’t changed much since brakes were attached there. Now that we have disc brakes, we don’t need that bulk of material and can reshape the crown for better strength, stiffness and weight. Plus better aerodynamics.
PURE-ROAD FORK LENGTH:
With the shorter crown, we can make our forks 25mm (1 inch) shorter than other gravel bikes. Exactly the same as a road fork. This offers better stiffness, lower weight, an easier steering geometry and better aerodynamics.
DOUBLE-DROP CHAINSTAYS:
Dropping the drive-side chainstay improves tire & crank clearance. Dropping the other side as well creates a much more efficient structure behind the BB for higher stiffness & strength as well as lower weight.
DIRECT-MOUNT REAR BRAKE:
Standard frames require an adaptor to use a 160mm brake rotor. We have integrated that into the frame, meaning you don’t need any extra pieces to attach the brake.
DIRECT-MOUNT FRONT BRAKE:
Standard forks require a flip-flop adaptor to set the correct brake rotor size. Our direct-mount pre-sets the caliper for 160mm rotors without any extra pieces.
SELF-ALIGNING WEDGE CLAMP:
Self-adjusting bolt angle for higher clamping forces with lower torque.
AERO SEATTUBE+ROUND SEATPOST:
The seattube is kept aero yet it fits a round 27.2mm seatpost so you have many round, dropper or suspension post options.
GEOMETRIES
| Size | 48 | 51 | 54 | 56 | 58 | 61 |
|---|---|---|---|---|---|---|
| Rider Height (cm) | 145-160 | 157-171 | 168-180 | 176-186 | 183-195 | 192 & up |
| Rider Height* (inches) | 4'9"-5'3" | 5'2"-5'7" | 5'6"-5'11" | 5'9"-6'1" | 6'0"-6'5" | 6'3 & up |
| Stack | 520 | 542 | 564 | 584 | 604 | 632 |
| Reach | 351 | 362 | 373 | 381 | 388 | 399 |
| "Road" Headtube | 122 | 142 | 158 | 175 | 196 | 225 |
| Headtube angle | 68.5 | 69.5 | 71.0 | 72.0 | 72.5 | 72.5 |
| Fork axle-crown | 375 | 375 | 375 | 375 | 375 | 375 |
| Front center | 597 | 606 | 602 | 607 | 616 | 636 |
| Rear center | 419 | 419 | 419 | 419 | 419 | 419 |
| BB drop | 79 | 79 | 77 | 77 | 75 | 75 |
| Toptube length | 510 | 527 | 545 | 559 | 574 | 593 |
| Seattube length | 436 | 463 | 490 | 518 | 549 | 576 |
| Seattube angle | 74 | 74 | 74 | 74 | 74 | 74 |
** Ultra FORK length is equal to a standard road bike, so this HEADTUBE length can be compared to road bikes. To compare to gravel bikes with standard gravel forks, deduct 25mm from these “road" headtube lengths for a proper comparison.