Our verdict on Silca’s range of tyres
With the Protocol series, Silca is venturing into the world of its own bicycle tyres for the first time. The design combines high volume with thin casings and different tread patterns for road and gravel. Whether the promised benefits in terms of rolling resistance, comfort and puncture protection hold up in everyday use remains to be seen, and will be determined by independent measurements and practical tests. The new tyres are already on their way to our editorial office – stay tuned!
In the spotlight: gravel and road cycling
Silca is entering the tyre market for the first time with its Protocol series. The US manufacturer with Italian roots, previously best known for its pumps, tools, lubricants and other cycling accessories, is launching three gravel tyres and one road tyre.
According to the company, the tyres have been specially developed for modern rim standards and lower air pressures. Silca aims to take a different approach to many established tyre manufacturers. Rather than adding extra rubber to traditional road tyre designs for gravel use, the company has drawn inspiration from the characteristics found in cross-country mountain biking.
The new range of tyres is designed to combine larger volumes with comparatively thin casings. According to Silca, the tyres feature high-density casings with 120 TPI. This is said to result in reduced weight, greater comfort and lower rolling resistance.
At the same time, the manufacturer promises a high level of puncture resistance. Silca cites its own laboratory and field tests, in which the Protocol tyres were found to be faster and more durable than rival products. We have requested the new Silca tyres and will be testing the manufacturer’s claims both in the laboratory and in real-world conditions – so stay tuned!
Lower air pressures thanks to a new design
Silca refers to this design approach as ‘inverse proportional design’. This refers to the combination of a larger tyre volume and a thinner carcass. At lower air pressures, the reduced tension within the carcass plies is intended to help absorb impact forces in a controlled manner.
According to the manufacturer, this could enable the tyres to combine comfort with puncture protection without significantly increasing rolling resistance. Practical testing will have to show whether this balance can actually be achieved in different applications.
One of the technical features shared by the range is the so-called ‘Pulsar’ compound. According to Silca, this is based on solution-polymerised styrene-butadiene rubber and silica reinforcement. What lies behind this rather unwieldy name? According to the manufacturer, the compound is designed to reduce internal energy losses during rolling whilst also enhancing braking and cornering grip. As mentioned, we will be testing these purported properties both in the laboratory and in real-world conditions.
Another distinctive feature is the carcass construction. According to Silca, this is specifically tailored to the tyre’s shape and construction profile in order to stabilise the carcass under load and minimise hysteresis (energy loss due to deformation). Furthermore, the models feature tread blocks of varying heights arranged asymmetrically. The outer blocks are designed to dig into the ground even at low lean angles.
Greater stability thanks to the carbon bead
For the tyre bead, Silca uses carbon fibres instead of conventional Kevlar fibres. According to the manufacturer, this design is intended to prevent moisture absorption and stretching. This should ensure that the tyre sits precisely on the rim throughout its entire service life.
According to Silca, its tyres are designed to fit modern, wider rims. Specific recommendations regarding rim width are provided for each model. A special coating is also said to make fitting easier and ensure better compatibility with tubeless sealant.
The Silca Protocol models
- Protocol RCG-1: The RCG-1 is designed for fast gravel races and mixed routes featuring both tarmac and gravel sections. According to the manufacturer, a low, ramp-shaped central tread pattern is designed to minimise rolling resistance. Elongated side lugs are intended to provide additional grip when cornering.
- Protocol RCG-3: The RCG-3 is designed for rougher gravel routes, such as those associated with Silca’s Unbound and Big Sugar races, amongst others. The closely spaced central lugs become larger towards the shoulders. A puncture protection layer beneath the tread is designed to increase durability. According to the press release, Silca recommends an initial pressure for this model that is approximately eight per cent higher than that of comparable racing tyres. This is intended to prevent excessive flex, an unstable contact patch and punctures.
- Protocol RCG-4: The RCG-4 is designed for routes featuring mud, sand and loose ground. The widely spaced tread pattern is intended to prevent sticky soil from becoming lodged between the tread blocks. A continuous puncture protection system running from bead to bead is also intended to protect against cuts in the sidewalls. Silca is therefore positioning this model for demanding adventure rides, unpaved tracks and challenging weather conditions.
- RCR Protocol: The RCR is designed as a high-volume road tyre. According to Silca, the aim is to avoid unnecessary weight. Instead of additional layers of rubber, the greater air volume is intended to provide some of the shock absorption. The 29-millimetre version is optimised for modern hookless rims with an internal width of 25 millimetres and designed in accordance with ETRTO specifications. The 38-millimetre version is said to offer the maximum possible volume within the UCI’s regulatory limits and is suitable for fast riding on poor-quality tarmac and cobblestones.
Price and availability
Silca intends to set a recommended retail price of 119 euros for all Protocol models – which would place the American company at the top end of the price range in the tyre market. Silca’s first in-house range of tyres is set to be available through selected specialist retailers and directly via the company’s website.
Josh Welz
Editor-in-Chief