I just got this frameset for Joan back from JB and tomorrow it gets a new Dura-Ace kit hung on it. I thought I might share it with you as a good example of the proper tubes being used for a given size rider. Joan is neither tall nor heavy and frankly most bikes out there would be too stiff for her. She originally came to me for a JK Special but after getting to know more about her and how she was going to use the bike I thought that the JKS would be stiffer than she needed and that she’d be better off with a bike make from smaller diameter tubing than the JKS uses.

The diameter of the tubing used on a bike has much more to do with how stiff the frame will be than the wall thickness of that tube. So in Joan’s case I chose to use ’standard’ diameter tubes to make the bike lighter and to give it the appropriate stiffness. In the old days most all bikes used standard diameter tubes that had 1″ diameter top tubes and 1 1/8″ diameter down tubes. Somewhere during the 90’s this all changed and these diameters were bumped up by 1/8″ to 1 1/8″ top and 1 1/4″ down tubes to add more stiffness to the bike. This larger tube became known as ‘oversize’. Currently almost every builder out there only offers oversize tubes and to my surprise some don’t even know that other sizes are available. Most builders, even some that are highly renown, use the same tube diameter and wall thickness for every bike they make regardless of the size, weight, or power of the rider. So the 120 pound gal has the same tubes that the 220 pound guy has. And when you consider that the smaller person is getting a smaller bike that is inherently stiffer due to it’s smaller size it’s easy to see that the lightweight rider gets the short end of the stick.

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The Reacto 907 shares the Scultura’s design but in an aerodynamic frameset, with a sculpted top tube and down tube created to condition the air to flow smoothly along until it meets the deeply bladed seat tube. It also has a clever faux integrated seatmast, which is actually a dual-clamped aero post that matches the dimensions of the seat tube perfectly at the join between the top tube and seat tube. Merida are the biggest bike brand you’ve probably never heard of. While they have a succession of world championships under their belt from the world of cross-country mountain bike racing, the company haven’t had the same impact when it comes to... The parallel 73-degree head tube and seat tube angles, long wheelbase and 45mm fork offset all combine to give the Reacto greater stability at higher speeds – it’s a bike that blurs the lines between time trial potential and full-on racing. Simply put, the carbon tubes have a central internal ‘spine’ separating the tube, and the stiffness and strength of the tubes can be controlled by the orientation of this spine. 5cm top tube the reality is that it’s closer to a 57 or 58cm sized bike. That’s had a huge influence on the way the bike rides.

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