ULTRA
THE UNSTOPPABLE MACHINE FOR THE TOUGHEST GRAVEL
ULTRA
If you’re like us, you love riding in rough terrain but live in a more urban jungle. So you need a bike that is fast on-road and capable off-road.
We designed the Ultra to fit 55-61mm wide tires: the whole aero package is made around those to keep the on-road speed high. If you ride on less extreme terrain, you can also fit 700c tires up to 45mm WAM (With As Measured) on the Ultra.
CHOOSE YOUR BUILD
ULTRA RIVAL 1X11 700c
ULTRA APEX XPLR AXS 1X12 700c
Toughest gravel frame with the most accessible electronic groupset on the market
ULTRA FORCE D1/EAGLE AXS 1X12 700c
ULTRA RIVAL XPLR AXS 1X12 700c
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BMW URBAN
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BMW GRAVEL
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ULTRA FORCE D1/EAGLE AXS 1X12 650b CRANKBROTHERS
Even more suitable for extreme gravel/XC style adventures with the addition of Crankbrothers dropper and Synthesis Gravel Carbon wheelset
IT ALL STARTS WITH THE TIRE
To make the fastest possible gravel bike, you need to start with the tire. Tire choice determines comfort & grip. But it also determines how you can shape the frame to redirect the 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. But it’s not easy, as the tire dimension depends on the rim you use, the pressure and of course how accurate the manufacturer’s claimed size is.
So we took hundreds of measurements to know the real tire widths (which we call WAM - Width As Measured and RAM - Radius As Measured) and use that to engineer the frame around.
SO WHAT TIRE DO YOU NEED?
The most important dimension is the WAM as that directly correlates to traction, puncture resistance, aerodynamics and rolling resistance. The WAM you need depends on three factors:
1. Terrain (traction, puncture resistance)
2. Rider skill (how much grip you need for control)
3. Rider speed (the slower you go, the more you bump/sink into the terrain)
The graph on the left indicates the WAM you need, and a more in-depth analysis can be found here.
Our favorite tires for the Ultra for each WAM and various rim widths are here.
Please note that running a front derailleur (especially an electronic version) will limit the tire width you can fit.
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.
ULTRA VERSUS RACEMAX
The RaceMax frameset is is fastest with 35-46mm WAM tires. That’s when its top speed rivals the best road bikes out there. So whether you’re on asphalt, easy or tougher gravel, you can be sure you have the fastest setup. But depending on where you ride and how fast you ride, you may want an even bigger tire for ultimate traction and control. Good news: 90% of the aerodynamic advantage of the RaceMax frameset still works with tires up to 61mm WAM.
In a way, the Ultra is the reverse. It is aerodynamically optimized for 55-61mm WAM tires thanks to its wider downtube near the front tire. This extra width better redirects the air coming off a bigger front tire. If you prefer a smaller tire, you can run a 700c tire up to a 46mm WAM. But as you go to a smaller tire, the Racemax becomes the faster choice again. In addition, the Ultra combines its aero seattube with a round seatpost so you can fit a standard, dropper or suspension post.
design in details
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!
60MM DOWNTUBE NECK:
Upper downtube necks down to 60mm to pick up the airflow coming off the front tire.
75MM DOWNTUBE BASE:
Lower downtube aero profile is 75mm wide to fully shield water bottle.
SIZE-SPECIFIC DOWNTUBE:
Reduced depth on smaller sizes to keep frame compliant and keep space for bottles.
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.
THREADED BB:
Most of our complete bikes come with threaded BBs for the best alignment and to avoid any issues. Yet we avoid gluing threaded alloy rings into the carbon (added weight, complexity and debonding risk).Read more here.
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.
INTEGRATED FENDER MOUNTS:
Invisible until you need them. Perfect for our custom fenders.
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 | XXS | 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 lenght | 510 | 527 | 545 | 559 | 574 | 593 |
| Seattube lenght | 436 | 463 | 490 | 518 | 549 | 576 |
| Seattube angle | 72.5 | 72.5 | 72.5 | 72.5 | 72.5 | 72.5 |
** 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.
