21st October 2013
With cyclocross on the rise and potentially becoming big business, Schwalbe have clearly invested in their cross tyres. They claim to have reduced the rolling resistance of the Racing Ralph tyre by 20% and reduced its weight by 30%, as well as making sure that the tyre now confirms to the UCI width limit of 33mm.
The claimed weight for these tyres is certainly light, though not as light as the 305g Rocket Rons, at 320g per tyre.
The profile is the same as on the mtb tyres, albeit adapted for the longer footprint of the 700c wheel. It consists of smaller central blocks with larger side blocks to help cornering grip. The knobs are not as well spaced as on the Rons suggesting a more mixed terrain tyre.
Schwalbe use their Triple Star Compound, known as Pacestar, an ‘extremely fast XC compound’, on theses tyres. It has an easy rolling base layer, overlayed with a medium compound in the centre section to facilitate fast rolling and a medium-soft rubber compound on the shoulder to create extra grip, which should come in handy when cornering.
The most interesting thing about this tyre for us was just how supple it feels. As with the Rocket Ron, the carcass is 127EPI, which stands for ends per inch, often defined as ‘Threads per Inch’ by other tyre manufacturers. It’s a measure of the number of nylon threads per square inch in the casing. Casings with a higher TPI/EPI are denser, more supple and lighter, though puncture protection will not be as good.
To save weight and produce a more supple tyre Schwalbe use only one layer, or ply as it’s known, on their top end tyres. Schwalbe actually reason why use three layers when one can be used to save weight and reduce rolling resistance. The Schwalbes certainly feel as supple as the Challenge Grifo XS we have on test, which are 300 TPI and out on the road feel like one of the most supple we’ve ever ridden. With this promising factor in mind, we are really looking forward to getting the Ralphs out in the mud.
The recommended pressure for the Racing Ralph tyres is the same as the Rocket Rons at 50psi minimum. We’re keen to see if this is strictly necessary as 50psi seems a bit excessive; certainly if the Rocket Rons are anything to go by we’ll be running these at considerably less.
The Racing Ralph is also available as a handmade tubular (as is the Rocket Ron) and the main advantage tubs have over clinchers is that they can be run at lower pressures. If we can get these to work at low pressure then that’ll be a big score for clinchers, as when combined with the increased use of wider rims on cross wheels, helping to prevent pinch punctures, we are convinced that clinchers are a viable option for cyclocross racers.
Schwalbe make make no bones about the fact that this is an out and out race tyre, with good speed and traction but limited puncture protection. Let’s see…
Schwalbe Racing Ralph cyclocross tyres, evolution line: £49.99 / $86.15
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