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Long-Term Test: Is the Forbidden Dreadnought Inefficient?

Using a power meter to get to the bottom of this high-pivot craze

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The Forbidden Dreadnought was only the third bike we tested here at Beta. We launched on a Tuesday, it launched on a Wednesday, and my test bike had only just arrived the Friday before. We had a whirlwind three days together before I went on camera for our First Ride video, trying to look fast and sound smart.

Those three days were just enough to learn what the Dreadnought is good and bad at, but not enough to imagine how it would feel to actually own one. To know what life would be like if it were my only bike. The methods I normally use to figure that out would short circuit when I tried to apply them to the Dreadnought. The way Forbidden chose to balance this bike’s strengths and weaknesses defy all convention. On rough, loose, wide-open terrain, it is the fastest bike I’ve ever ridden. But it’s a lot of bike to move around, and a lot of bike to get up a mountain. It sent me into one of those unwinnable thought experiments where you imagine how much you’d give up for something you really want. Would you own the most capable trail bike ever made, even if it meant you could never do a manual again? Would you own a bike that had the stability of a downhill sled, but it would never be under 34 pounds? Would you own a bike that will literally make you a better descender, even if it meant you could only ride it for five hours before it wore you out?

That last question is the one I struggled with the most during the several weeks was putting off sending the Dreadnought home to Forbidden. I would never own a bike that I couldn’t ride from sunrise to sunset. I love big days, but it seemed like this bike did not. About 1,000 vertical feet before my average Saturday epic would end, I would go into survival mode. And it wasn’t because of the Dreadnought’s long travel, or even its high pivot. I’ve ridden bikes with less travel that were still mushier under pedaling force than the Dreadnought. Its linkage is not inefficient. But I’d never ridden a bike with an idler pulley. I figured that must be where the energy was disappearing. 

So, I devised an experiment that would find out. Using a crank-based power meter, I was able to learn how much work it took (measured in kilojoules) to get to the top of my favorite climbs. I ran at least two laps on each route over the period of a week. I then swapped the power meter onto my Scott Ransom. I also installed the same wheels and tires, kept them at the same pressure, and I put a small weight on the frame to match the weight of the Dreadnought. I also made sure my weight was the same before I left the house, and I loaded up the same quantity of water at the bottom of each climb. 

I focused on moderately smooth fire roads. Although technical singletrack might have revealed a whole new set of data, it presented too many variables. I might lurch gracefully up a root on one day and clumsily bash a pedal into it the next. Unsure how slim the margins would be, I tried to be as accurate as I could. 

I checked with a couple experts in the power-meter field, and they believed the logic of this test was sound. If I could successfully control my variables, a crank-based power meter would pick up on drag in the drivetrain if I did it over a long enough distance. And measuring kilojoules, it wouldn’t matter if I was hammering or spinning. The net quantity of work it took to get to the top of the hill would be the same. My first two rides seemed to confirm this. On the same climb on the same bike, I was getting a variation of less than a half a percent, and that stayed consistent throughout this process.. 

So, with almost 15,000 feet of comparable climbs on the Dreadnought and the Ransom, how much harder was it to climb on the Dreadnought? On average, 01.13 percent. That’s it. Below is an example of a 1,750-vertical-foot climb, and how it compares on the Dreadnought (top image) and my Ransom (bottom image). It only took 12 more kilojoules to get the Dreadnought up to that peak than my Ransom. That’d have gotten me a whole extra 24-foot head start on that hour-long climb. Once I put this together, I went on a last loop on the Dreadnought before I sent it back to Forbidden. Having proved to myself that my assumptions about significant drivetrain drag were 98.87 percent bullshit, I had a relatively quick-feeling 7,000-foot ride without hitting a wall. 

A ride done on the Forbidden Dreadnought, with one prticulr 1,750-foot climb highlighted.

A different ride, done on a Scott Ransom, with the same climb highlighted.

Before you go using this as evidence that human bike testers are flawed, I offer this defense: The Dreadnought was not meant for the rides I was doing on it. With pedals, two bottles and a spare tube, hanging off it, it’s just under 38 pounds. And with appropriate tires, it is not a quick bike. I had to make my Ransom into something pretty different to get it to compare to the Dreadnought. It just turns out that the Dreadnought’s overall nature, not its idler pulley, seems to be the culprit. So, armed with these hard-won facts, I asked myself again: Could the Forbidden Dreadnought be my only bike?

No, it couldn’t. I think I may have known that all along, but I felt like the choice was clouded by this nagging question about its efficiency. It is capable of doing the climbs I like to do, leaving me free to decide based on how it does the descents I like to do. And after nearly three years of riding a lightweight but long-legged 29er that some may call overkill as a daily driver, I’ve learned that the Dreadnought truly is overkill. 

But it is only overkill for me. That’s something this bike highlights better than any other bike I’ve tested in recent memory. It is not meant to be all things to all riders. More brands should design bikes this way. To serve the needs they want served. The Dreadnought, along with other over-the-top high-pivot bikes, pushes the limits of what is practical. And there is a chance that, if you have the skill and the trails that demand it, it actually is practical for you. And now you finally know how many more kilojoules it will take to get to the top of those trails.