Dash Cycles – Laufräder von RAR

Adrien von RAR – besser bekannt unter Roues Artisanales hat einen der ersten Laufradsätze mit Dash Naben zusammengestellt und den Aufbau ein wenig dokumentiert.

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Basis bildet ein 154 Gramm (angegeben werden 136 Gramm) leichtes Nabenpärchen, das mit Adriens Hausmarke Svelt clincher Felgen und Sapims CX-Ray Speichen komplettiert werden. Gesamtgewicht 1120 Gramm. Die einzelne 32mm hohe Felge wiegt 375 Gramm, der Umstieg auf die Schlauchreifenvariante würde 120 Gramm pro Laufrad sparen. Das nur nebenbei.

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Adrien weiter zum Aufbau der Naben:

What’s very special about these two hubs is the weight of course. With a claimed weight of just 33/36g the front and 103/106g the rear, DASH is pushing the envelope. No other company ever went to such a light hubset. Of course we know the Tune Mag90 which was unveiled two years ago but unfortunately this is not expected to be for sale before another year, and only on complete wheelsets.
Well, carbon shell, carbon axles, single piece engagement teeth ring and flange are its features.

Basically they seem to be soldering the standard Tune engagement teeth ring to titanium tabs receiving the straight pull spokes. They then wrap the carbon shell around it. This gives a direct torque transfer from rotor/pawls to spokes. Definitely this is not providing any extra watt not extra speed but this helps saving many grams. This is a lighter design.
On the other side of the hub, an alloy insert reinforces the carbon shell to radial spokes tension.

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Axle diameter is 15mm rear, over-sized to 17mm on the non drive side. The bearings are 6803 non drive side, 6802 drive side, and 2×6802 into the freewheel. The axle is thicker where the rider weight applies mostly: right below the drive side flange, at the two 6802 bearings junction. This makes the axle more resistant to the shear occurring between the 6802 bearing of the shell and the 6802 internal bearing of the rotor. The axle is multi-diameter and multi-thickness. As a parallel, Tune also found a different tip to reduce the rider weight strain on its – now old – 15mm carbon axles: they designed the XOT bearing having a larger contact area than a standard 6902/6802 combo.
Front bearings are 6801.

The hubs are working with standard 15mm Tune freewheels and they are closed like a Tune Mag170 or Mag150: a end cap is pressed onto the axle while an amount of washers sets the pre-load on the bearings and the play when the wheel is clamped on the bike through the quick releases.
The front hub works the same way.

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The front hub

receives a wide spoking triangle that will make strong and stiff wheels. The center to flange distance is 37mm which is definitely good. Flange diameter is 19mm which is very small but this is obligated to reach so light weights.
The rear hub has a quite standard geometry. Center to flange distances are 17mm drive side and 34mm non drive side. This is not a spectacular wide drive side flange distance but this is OK, close to most others hubs of the market and I think DASH could not go any further because of their special one-piece engagement ring/Ti tabs.
Rear flange diameters are 53mm and 22,2mm. Definitely good.

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Real weights and minor issues

The lastest set received last week hit the scale with 39g for the front and 115g for the rear which is a tad heavier than expected but crazy light anyway. Reason for this is that they beefed the axles for extra strength and reliability as well, I’m happy with this. Safety is worth a couple of grams. I weighted the first sets too but I don’t remember their weights.

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The few minor issues I met lately are mostly related to play. I mean lateral movement of the rim between the brake pads which are due to a wrong amount of washers between the shell/rotor bearings and the axle end cap. They will be solved soon. Also I think the components of the hubs still needs some tighter tolerances. Indeed the axles are a bit loose into the bearings, and the bearings are a bit loose into their shells. This should play a role into the play we currently have on the latest testing wheels, front and rear.

Photos: RARRoues Artisanales