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Buyer’s Guide: How light is too light?

If rumors are true, we’ll soon see the end of the UCI’s 6.8-kilogram frame weight rule. What does that mean for the future of bike design?

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When is a bicycle not a bicycle? The Union Cycliste Internationale (UCI) has an outsized say in the matter, at least when it comes to race bikes. Designers must adhere to a host of regulations in order to create a bicycle the pros can take to the starting line. The 6.8-kilogram rule — which bars bikes that weigh less than 6.8 kilograms (14.99 pounds) from UCI-sanctioned races — has long been one of the irksome rules, presumably instated to ensure bicycles didn’t get so light they’d be unsafe.

But that rule may not be long for this world. Rumors have swirled for at least four years that the 6.8-kilogram limit will someday go the way of leather helmets, thereby freeing up new possibilities for bicycle engineers. (UCI press officer Louis Chenaille wouldn’t say when the regulation might change.) For now, the 6.8-kilogram rule is still in effect. But if and when it finally does go down, how light will bicycles get?

Probably not much lighter, actually.

“If we’re just limited to the frame and fork, we probably can’t [reduce weight] a significant amount without changing our high standards for safety and durability,” says Stewart Thompson, road product manager for Specialized. “If we’re looking at the entire bike system, there’s probably still some opportunity without sacrificing structural integrity.”

And that’s the crucial point: It’s possible to make a lighter bike, but the question becomes one of integrity, longevity and, of course, ride quality.

“Safety is usually thought of as black and white with impact standards,” says Chris Yu, director of integrated technologies at Specialized. “But when a structure’s weight is driven down aggressively, things like fatigue life start to become a decision. How long do you want the frame and fork to last? Defining consistent ride characteristics also becomes a lot more complex as the weight comes down.”

That seems to be the sentiment from component manufacturers, too. Weight matters significantly when it comes to frames, but it’s paramount for both safety and structural integrity in the wheel category.

“I don’t think it will influence wheel development,” says Jason Fowler, wheel category manager for SRAM. “We already aim to make our wheels as light as they can be. With a light enough frame, riders could be more easily convinced to ride deeper but more aerodynamic wheels like the Zipp 303 instead of the 202 on mountain days.” So, ostensibly, riders might use heavier but more aerodynamic wheels if frame weights came down.

Fowler may be onto something, at least if you ask Trek-Segafredo rider Peter Stetina.

“The 6.8-kilogram rule is archaic and has been around since early carbon to protect us from riding a ‘soggy noodle,’” Stetina says. “This rule doesn’t correlate to safety or handling of a modern bike. I’m not saying they need to abolish the weight limit, just update it for modern science and let the industry continue to innovate.”

Riders who make a living by eking out every possible second from their performance are compelled to look toward equipment for gains. Abolishing the weight-limit rule might not directly lead to those gains, but it opens up other possibilities in terms of componentry (think disc brakes) and aerodynamics (think deeper wheels).

To Stetina, it’s a matter of accepting the reality of technological advances. “The fact that anyone can buy a stock race bike, off a shop floor, that is lighter and just as stiff and safe as the pro’s bike is a joke,” he says.

In fact, pro bikes often are just as light, if not lighter, than a stock race bike off the floor. But in order to comply with the 6.8-kilogram rule, team mechanics often have to get creative in order to make the bike heavier. This has been one of the primary drivers of the campaign against the UCI’s weight rule.

The basic outline of what makes a bike a bike is unlikely to change with the abolition of the weight rule. But weight-obsessed climbers ripping up cols on 60-millimeter-deep carbon hoops? It’s not as ridiculous as it might seem.