By Simon Smythe
British wheel brand Parcours has launched an all-new 650b version of its Alta gravel wheelset.
The new carbon 650b rim allows bigger gravel tyres for greater grip, extra comfort and faster handling without sacrificing clearance.
Like the 700c Alta, the new 650b rim has the 35mm aerodynamic profile that Dov Tate, an Oxford engineering graduate, wind tunnel-tested in North Carolina when he founded Parcours in 2016.
However, it has a much wider internal rim width: 25mm compared to the 21.5mm of the 700c version.
But the biggest change is that the rim is now hookless. Many of the leading wheel brands are going hookless for the wider stance, additional strength and improved aerodynamics of the resulting rim/tyre interface, which avoids the lightbulb profile of the traditional clincher rim and tyre. Hookless rims must be used with tubeless tyres, which most gravel riders already prefer for their ability to run at low pressures without pinch-flatting.
The Alta 650b gets 24 Sapim CX-Ray spokes in both the front and rear, laced in a two-cross pattern to precision-machined alloy hubs containing high-grade EZO cartridge bearings.
The hubs run 12mm thru-axles, with adaptor kits available for other standards, and use the Centerlock disc standard.
The Alta 650b is also available with a dynamo hub, built around the SON Delux 12, for bikepacking adventures when there isn’t a USB port for miles.
It’s a chunky looking, very robust wheelset, but the weight is an impressively low 1,360g.
Chris Hall, the ultra-endurance cyclist who recently completed a 450km, 25-hour ‘trenching’ on Box Hill, is a Parcours rider, using a prototype Parcours wheelset for his extraordinary 11,034 metres of descending (the depth of the Mariana Trench) that day. He said: “Having truly tested out the 700c Alta wheels cycling across Australia and then in Morocco on the Atlas Mountain Race the first thing I said to Dov at Parcours was ‘when’s the 650b option coming?’ It became clear to me that having an offering which allows you to have a much greater volume of tyre for super technical terrain in countries such as Morocco was a no-brainer but also would offer so much versatility to how far you could take your bike on your weekend ride.”
The price will be a pretty competitive £849 and the Parcours Alta 650b is available through www.parcours.cc.
We’ll be putting a set of the new Altas through their paces as soon as we can get our dropouts around them, so keep an eye out for our review. In the meantime, the Parcours Strade mid-section aero wheelset that we absolutely loved earlier this year features in our Editor’s Choice roundup of our favourite products. With its innovative differential rim profiles – the front is U-shaped whereas the rear is V-shaped – it is exceptionally stable at higher yaw angles.
Simon Smythe is Cycling Weekly's senior tech writer and has been in various roles at CW since 2003. His first job was as a sub editor on the magazine following an MA in online journalism (yes, it was just after the dot-com bubble burst).
In his cycling career Simon has mostly focused on time trialling with a national medal, a few open wins and his club's 30-mile record in his palmares. These days he spends a bit more time testing road bikes, or on a tandem doing the school run with his younger son.
What's in the stable? There's a Colnago Master Olympic, a Hotta TT700, an ex-Castorama lo-pro that was ridden in the 1993 Tour de France, a Pinarello Montello, an Independent Fabrication Club Racer, a Shorter fixed winter bike and a renovated Roberts with a modern Campag groupset.
And the vital statistics:
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