As a shy comeback, I would like to share my experience with the newest DASH hubs I've been building, riding and testing for a couple of months now. I know this is a component many members like for its lightweight and special design so I'm sure this topic will be interesting.
I have not been able to ride them a lot so far as there had some first-series issues to solve weeks ago. Finally the hubs are fully functional and we currently have a couple of sets being ridden on the road so I afford writing a first-hand report.
My personnal wheelset is 1120g, built with RAR Svelt clincher rims and 20/24 stainless steel spoking (Sapim Cx-ray).
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.
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 2x6802 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.
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.
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.
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.
I hope this topic will be informative enough and will bring some interest on the forum.
Have an excellent week-end.
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Adrien, please clarify. Does this design cost watts and speed for the benefit of weight savings?Adrien wrote: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.
Some extra information about these hubs. DASH is going to release another version of the hub.
I didn't think this could happen, but the suggestions I made to this company regarding this hub has turned into a new version. A stronger one with some nice features and a weight limit of 100kg contrary to 80kg for the light one.
What I mostly complained about is the spoke line. This new version features a more compliant one.
First there is an offset between the pulling and the pushing spokes. So the spokes do not bend, this generates no unnecessary stress.
Second, and I'm not sure yet about it, but the tabs holes should be drilled under an angle so the spoke will leave the tab in a perfectly straight line. Here again, this would mean no stress on the spoke.
The hubs work with a 15mm axle/6802 bearings for the front, and 17mm/6803 bearings rear. Rear freewheel is from Tune here again.
Here are the manufacturer claimed specifications:
SPOKE RING DIAMETER: 28mm
CENTER TO FLANGE: 42mm
BEARINGS: 2X 6802
NDS SPOKE RING DIAMETER: 30mm
CENTER THE NDS FLANGE: 36.5mm
DS DRIVE RING DIAMETER: 55.75mm
CENTER TO DS: 20.5mm
BEARINGS: 4X 6803
HammerTime2 wrote:Adrien, please clarify. Does this design cost watts and speed for the benefit of weight savings?Adrien wrote: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.
What I meant is that the feature is not making yo any faster nor any slower. This only lightens the hub.
metanoize wrote:Are these RAR 32 rims rebadged Reynolds Thirty Two?
Our SVELT rims are indeed made by Reynolds.
Mine were built into an 1188g clincher 49mm set (also using CXrays) in 24/20 using cheap chinese generic rims. I'm hoping that these will be my "do everything" wheels. I specced hybrid bearings on mine.
Edit: 2015: darn near won the best South Island series (got second in age
-group)..woo hoo Racy Theremery is back!!
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