With the Grid-Gravity-Radial carcass, Specialized changes the thread angle in the tyre structure. The aim: more ground contact, better damping, stable cornering. Measurements show clear differences to the previous construction.
70° instead of 50°: the new thread angle
Specialised has changed the angle of the carcass threads. Instead of 45 to 50 degrees, the new tyres work at 70 degrees. The construction remains a classic bias-ply design. It differs significantly from real radial tyres from the automotive industry. Nevertheless, the new angle noticeably changes the stiffness behaviour.
The development was carried out at the S-Works Tire Factory. There, Specialized produced several prototypes with different angles and tested them externally in the laboratory.
Less radial rigidity, stable lateral guidance
Measurements on the rolling resistance test stand show clear effects.
Test conditions:
30-millimetre rim, 1.3 bar air pressure, 55 kilogram wheel load.
Result:
- Radial stiffness: minus 30 %
- Lateral stiffness: minus 7 %
The tyre yields more towards the bottom. Laterally, it remains largely stable. The contact patch increases by around 30 %. The aim: more contact with the ground without spongy cornering behaviour.
Constant properties over a wide pressure range
The measurements covered 0.9 to 2.1 bar.
With classic carcasses, radial and lateral stiffness increase in parallel with the air pressure. The radial hardness in particular increases significantly. This reduces ground contact.
The new design behaves differently:
- Lateral stiffness increases slowly
- Radial stiffness remains significantly lower
The effect is maintained over the entire pressure range. Drivers do not have to change their air pressure.
Sweet spot angle instead of extreme values
Tests with several thread angles showed clear limits.
Small angles hardly provide any additional compliance. Large angles reduce the lateral guidance too much. The required air pressure then increases again. The selected 70-degree angle marks the compromise between compliance and stability. Specialised calls it the "sweet spot".
Two models, two blends
The new carcass will initially be available in two tread variants:
- Specialised Butcher Grid Gravity Radial T9 TLR
- Specialised Eliminator Grid Gravity Radial T7/T9 TLR
Price: 69 €
Features:
- 29" and 27.5"
- 2.4" width
- Tubeless-ready construction
The previous Grid Gravity casing remains in the programme. It is still aimed at riders focussing on maximum lateral stiffness, for example in the bike park.
Focus on natural trails instead of bike parks
The new carcass is aimed at technical trails with changing surfaces.
The larger contact area improves contact:
- Roots
- Rocks
- oblique passages
At the same time, the lower radial stiffness reduces vibrations. The wheel follows the ground more smoothly. The design therefore does not change the profile. It changes the structure of the tyre itself.
Dimitri Lehner
Editor
