The french manufacturer Time bought Guy Frullani‘s patent one year ago. Frullani is the "inventor/creator" of the famous wheels of the same name. Even through Time deeply modified his concept, they still use some specifications of the wheels patented in 1997.
Before presenting the new wheels’ pictures, let’s clarify in concrete terms what are the breakthrough of this patented concept.
– The conventionnal wheels spokes are bent. They have to deal with useless stress because of the spoke tension around this bent. Frullani’s wheels use straight pull spokes to avoid this stress. This is not new but in the nineties this was not really common.
– Because of the numerous speeds, the bracing angles of standard rear wheels are different on both sides of the wheel. This causes an unbalanced wheel. Frullani’s concept reduces the bracing angle on the non-drive side: he brings the spokes closer to the center of the hub. He increases too the drive-side bracing angle until he gets the same angle on both sides of the rear wheel, which is synonymous of perfectly balanced wheel. Then, at the dawn of the 21th century, the speeds number got higher. Thus, the concept lost its sense since it was impossible to keep equal bracing angles without sacrificing consequently the lateral stiffness of the wheel. The unbalance was inevitable.
The latest Time wheels are unbalanced but still more balanced than a standard wheel.
Drawing of Frullani original rear hub
The rims
So Time bought this concept the last year and upgraded it with carbon hubs providing stiffness and look. The wheels, which are called Hi-Tense because of their high spoke tension, have 22 and 25mm alloy deep rims. The wheelset weight is claimed to be 1530g, which is not very light, especially when you consider they have flat rims. We hope the next versions with carbon rims will be more attractives.
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The hubs
The hubs bodies are in carbon. However, there are two inserts in aluminium to screw the spokes and to fit the bearings with high precision. The axles are in carbon at the front and in aluminium alloy at the rear.
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The freewheel mechanism has a fast engagement because of the 42 teeth. The accelerations are realized every 8°. As comparizon, Tune hubs only have 36 teeth, meaning an engagement every 10°. This is a small difference but it’s a good point for Time.
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The spokes
The aero spokes are 20 at the front and 24 at the rear. They have been made in relation with Sapim. Their size is 2.3-1.8-2.3mm for both the front wheel and the rear wheel non drive-side, the drive-side rear wheel has 2.3-2.0-2.3mm spokes. About the tensions, the balance is almost 1: 150kg on the rear wheel drive side and 140kg or 120kg for the the non drive-side (it depends on the system Shimano or Campagnolo). With classic flanged hubs, the balance is usually around 1/2 (150kg, 75kg for ex.).
A tip of the spoke is screwed in the hub while the other one pulls the rim. Thus the wheels are still truable thanks to a hex key one can insert at this tip.
)) Click to enlarge Photo ©: Gonzalo/arueda.com |
)) Click to enlarge Photo ©: Gonzalo/arueda.com |
The stiffness
Theoretically, because of the low bracing angle the rear wheel is not very stiff lateraly. The high spoke tension should delay the spoke bending when a lateral load is applied (see this article about the Mavic R-Sys) but it certainly won’t compensate the low bracing angle. Time promotes his wheels as being the stiffest from a test realized against an aluminium wheel of 1510g and a carbon one of 1150g. We don’t have any more information about the kind of wheel it is. This information is then hardly credible, all the more since the tests were performed by the manufacturer… to be continued!