The UCI is slowly preparing to scrap the rule stipulating the minimum weight of a bike which says a road or track bike must weigh 6.8kg or more. It’s about time given some teams have resorted to dropping chains or lead weights down the seat tube to add weight but if the rule is scrapped there are more profound changes to consider.
The rule stood on two principles. First was safety and the arbitrary limit was set to deter noodley bikes and second was equality to ensure riders and particular developing nations, could compete with others with more resources.
Go back to 2000 when the rule was introduced and it was debatable but the passage of time has made it harder to defend. Ideally the 6.8kg rule could have tracked time and the limit adjusted down every few years. The UCI has been candid about this, see this presentation from 2012:
On safety the UCI is now into the business of equipment regulation and validation. It’s a little-known (but blogged about) rule that you have to use a UCI-approved frame in competition and the governing body has a list of approved wheels too. So once you’ve got UCI-approved wheels and a frame, perhaps in small, and add a Shimano Ultegra or Campagnolo Chorus groupset and you can easily come in below the weight limit. Yet there’s nothing risky about the build, indeed you’ve followed the UCI list. All this has reached the farce of team mechanics dropping chains down seat tubes in order to add weight to frame.
However instead of adding deadweight to a bike it’s better to add items that have some use. As frames and components have got lighter it’s allowed weight to be added elsewhere, notably power meters, electronic gears with their battery packs and heavier rims. Which brings us to disc brakes. Arguably they’ve been part of this trend of adding weight. As frames and components get lighter discs are a good way to add weight. Instead of dropping a chain in the frame for deadweight you get a performance gain from superior braking which, if it comes with a weight penalty can nudge the bike back over 6.8kg or mean few chain links inside the seat tube. If the 6.8kg rule remains you might as well use discs.
But once the rule has gone? We know the lengths riders go to save weight and how even small savings help the all important W/kg ratio. Swap a 7kg bike for a weightweenied race machine and the savings are important:
As the table illustrates, save two kilos from the bike and, everything else being equal, a 65kg rider gets a gain equivalent to finding an extra 13W or put another way a 5kg bike takes them from 6W/kg to 6.2W/kg. Of course the “everything else being equal” line matters, better braking could help on a descent, a heavier but more aero frame could help save energy during a stage and so on, so the maths is reductive. The differences above are the difference between steps on the podium.
Given bikes with disc brakes have the added weight of the discs and hydraulic systems, not to mention the need for beefed-up attachment points on the forks and stays it points the possibility of racers having technical options in a race. To simplify we can imagine one aero frame with discs and deep section rims for fast flat days, or even segments of a stage, and lightweight climbing bikes designed to fight gravity with caliper brakes.
It all points to a future peloton where bike changes become more common. Many manufacturers already supply riders with two bikes, for example Cervelo, Canyon, Merida, Scott, Specialized, Trek and other World Tour team sponsors offer both an aero frame and a light weight one but with the weight limit in place the lighter version hasn’t been as beneficial if it’s had to have ballast added to meet the rule. This could all change, imagine a mountain stage where riders do cyclo-cross style rapid bike changes ahead of a climb in order to get their five kilo featherweight bike and once they reach the top they vault on to an aero frame complete with deep rims and powerful disc brakes that’s a porky 7.5kg. The rule change would make this more worthwhile; there are logistics like how to get the team car close since roadside bikes are not allowed but Alberto Contador is already keen on bike changes.
Better still from an industry perspective is the prospect of pro riders having two distinct road bikes. While you might think the bike industry is trying to force the sale of disc brakes on unsuspecting consumers, what if a whole new bike becomes the next sales push? No longer do you have one bike and maybe set of special wheels but replica “pro” bike is actually a package of two while machines. If this isn’t for you nor the industry then we could see more of a premium on light bikes and the associated marketing. We may read windtunnel claims but everyone can, and does, pick up a bike to feel its weight.
The rule is out of date, an arbitrary limit set years ago that’s stayed fixed while technology has changed. The UCI knows this and is considering how to scrap the rule. In many ways it has to, it can approving wheels and frames that are safe to race yet still require deadweight dropped inside to comply with the rules.
Abolish the rule and some will have lighter bikes to race on. Yet instead of a static change this could be the start of something bigger with teams making wider tactical equipment choices before and even during a race. If this happens it could spread to the consumer market. Many brands already have two models in their range but the differences could become more pronounced and certainly more visible on TV.