Introducing the BMC URS LT: The Ultimate Gravel Bike with Full Suspension
Take a quick look at the new BMC URS LT and you’ll miss what makes it unique. Hidden inside the head tube is a custom and patented suspension fork by HiRide, providing 20mm of travel without changing the bike’s geometry.
This roughly matches the rear wheel travel, thanks to its MTT softtail concept based on elastomers, creating a full-suspension gravel bike designed to maximize traction, confidence, and comfort on any type of terrain or race. And it performs very, very well. Here’s what you need to know…
URS LT stands for “Long Travel”
The original URS gravel bike was a bold statement for BMC, something that resonated with them and represented the way they used to ride bikes. It aggressively entered BMC into the gravel market with a capable frame and ample tire clearance for 45mm tires.
But it turns out they always had front suspension in mind, and the new URS LT uses the same frame and maintains exactly the same geometry, even with the addition of 20mm of front travel.
The technology behind it is a collaboration with HiRide, leveraging BMC’s Swiss engineering with HiRide’s suspension expertise. LT stands for “Long Travel,” and it’s BMC’s common nomenclature, also shared in their mountain bikes, for the longer travel versions of existing models.
In this case, it’s precise yet relative, as the addition of 20mm of front travel technically gives the URS LT more travel than the URS. The goal was to create the perfect bike for gravel riders who are stepping up to the next level of terrain… or simply spending long hours in the saddle.
With the new BMC Roadmachine X at the faster and smoother end of the “all-terrain” spectrum, and the regular URS in the middle, the new URS LT sits closer to the mountain bike end of the spectrum.
MTT Suspension Technology for Improved Comfort
Years ago, BMC introduced their Micro Travel Technology (MTT) to their hardtail mountain bike. The goal was to reduce vibrations and improve traction, and it worked well enough that they added it to the URS gravel bike.
Essentially, it’s a small elastomer on the top of the seatstays that provides around 15-20mm of usable travel on the rear wheel.
t’s not much, but enough to absorb vibrations. Inside the elastomer are two alloy pins that keep it moving in a straight line and maintain lateral stability of the rear wheel. It acts as both a spring and a damper, providing controlled compression and rebound with a wide working temperature range.
The D-shaped seatpost adds some flex to the rear MTT, further mitigating impact forces on your body. However, with such an aggressive bike like this, they knew that some riders would want a dropper seatpost. It is compatible, with internal cable routing ports near the head tube; you’ll just need their adapter to fit a 27.2mm dropper seatpost.
BMC Suspension Fork with Micro Travel for Gravel
BMC is known for pushing the boundaries of innovation in the cycling world, and they’ve done it once again with their new suspension fork designed specifically for gravel riding. In this article, we’ll take a closer look at their groundbreaking “micro suspension” concept, how it works, and why it’s a game-changer for gravel enthusiasts.
The Birth of a New Concept
BMC didn’t just stumble upon the idea of adding suspension to the front of gravel bikes. They conducted rigorous testing and analysis to determine the optimal solution.
To do this, they equipped a test bike with sensors and sent it on hot laps through a forest trail with an asphalt loop. This allowed them to measure various parameters such as vibrations, accelerations, power efficiency versus speed, and tire-suspension interaction.
Why BMC’s Fork Stands Out
At the time of their research, the only existing option was the original Fox AX fork, which was essentially a trimmed-down XC fork. BMC identified a crucial need for a different kind of fork because their tests revealed that vibrations on gravel roads typically fell within the 20-40Hz range. This frequency range demanded a suspension system with minimal stickiness, far lower than what traditional suspension forks could provide.
Reduced Vibration Energy
When combined with BMC’s rear Micro Travel Technology (MTT) suspension, their front fork reduced overall vibration energy by a staggering 46% across the entire frequency spectrum encountered in mixed-surface riding. This innovation results in a significantly smoother and more comfortable riding experience on rough terrain.
The Engineering Behind the Fork
The suspension components are ingeniously housed within the steel and alloy head tube. Coil springs support the load and manage suspension movement, while a hydraulic damper controls damping. Even with just 20mm of travel, the damper ensures a smooth, controlled ride without excessive bouncing.
A Lightweight Solution
BMC’s engineering team faced the challenge of creating a lightweight damper system capable of handling small vibrations. They achieved this using simple steel coil springs to maintain low sealing pressure. The absence of bushings between the tubes minimizes friction, resulting in an incredibly smooth suspension action.
Adjustability and Ease of Use
Despite the complex technology within, BMC’s suspension fork maintains adjustability. The fork length and stack height are fully customizable, allowing riders to fine-tune their setup. Additionally, the fork supports standard stems, albeit with a 1-1/4″ opening. BMC offers three different springs and pre-load spacers to cater to various rider weights and preferences.
The Future of Gravel Riding
BMC’s HiRide steerer fork, which made its debut on the Pinarello Dogma FS, has found its true calling in the world of gravel biking. With carbon fiber legs in the lower part of the fork to dampen vibrations and keep weight low, it’s a testament to BMC’s commitment to enhancing the gravel riding experience.
The fork’s durability and stiffness surpass traditional telescopic suspension forks, and it’s designed with maintenance in mind.
BMC’s suspension fork represents a significant leap forward in gravel bike technology. Its ability to reduce vibration energy, maintain adjustability, and provide a smoother ride on rough surfaces is a game-changer for gravel enthusiasts. Stay tuned for our full review, and be sure to check out the accompanying video for a closer look at this revolutionary suspension system in action.