I tried posting this yesterday but due to tablet errors I had to abort.....so here it goes again..

Although the role the spoke bracing angle has in determining the wheel lateral stiffness and stability/durability has been exhaustively discussed, I read post after post analyzing spoke quantity/type and rim weight without much consideration to hub geometry.

As a reminder, a higher bracing angle on the NDS offers higher wheel lateral stiffness. High lateral stiffness is desirable to conserve energy otherwise lost due to wheel flexing and also to the wheel rubbing onto the brake pads. I also happen to consider wheel rubbing to be an irritating nuisance, to be avoided when one builds a custom wheel. BUT, the higher the bracing angle the lesser the resulting tension on the NDS spokes becomes, down to the point where the lowered tension can not reliably prevent the spokes from loosening up when the wheel goes over a bump or simply due to repeated use, thus affecting the wheel's stability/durability. This becomes more prevalent when the rider is heavier (>200lbs), more powerfull (>500w) or imposes higher lateral forces (tilting the bike climbing standing up). A lighter rider capable of moderate output (300w) does not need to be concerned as much.

The following listings tabulate the calculated Bracing Angle Ratio (BAR) between the nds/ds spokes using Spokecalc. The tables also tabulate the resulting tension for the nds spokes (Tnds) using a formula accounting for the spoke length and flange offset ratios. This approach is envisioned as more accurate rather than simply taking the inverse of the BAR to calculate the tension ratio.

The rim used is a 23x28 with an ERD of 588. Lacing is with 32 spokes for the rear; results were similar for 28, I dont do 24 as is pointless, to me at least, to go after lateral stiffness if low spoke count is the primary consideration. In addition, I have not taken in consideration the adjustments in spoke stiffness and arrangement (heavier spokes on DS, triplet lacing, etc) that could be made to enhance stiffness. This just analyzes the effect of hub geometry, everything else kept equal.

Hubs cover a broad array from boutique to basic. Tension T values in kgf.

Alchemy ORC-UL-S10

ds/nds Tds Tnds BAR

3x/3x 125 67.4 1.9

2x/3x 125 69.8 1.8

3x/2x 125 65.8 1.9

2x/2x 125 68.2 1.8

Alchemy ORC-UL-S11/C11

ds/nds Tds Tnds BAR

3x/3x 125 58.9 2.1

2x/3x 125 61 2.1

3x/2x 125 57.6 2.2

2x/2x 125 59.6 2.1

CK R45 S11/C11

ds/nds Tds Tnds BAR

3x/3x 125 59.4 2.1

2x/3x 125 61.3 2.

3x/2x 125 57.6 2.2

WI T-11 S11/C11

ds/nds Tds Tnds BAR

3x/3x 125 53.4 2.3

2x/3x 125 55.3 2.3

3x/2x 125 52.2 2.4

BHS SL218

ds/nds Tds Tnds BAR

3x/3x 125 58.1 2.2

2x/3x 125 59.8 2.1

3x/2x 125 56.8 2.2

DT Swiss 240*

ds/nds Tds Tnds BAR

3x/3x 125 65.1 1.9

2x/3x 125 66.9 1.9

3x/2x 125 63.4 2

2x/2x 125 65.1 1.9

*used 45(32.6/16.9) due to discrepancies in listed measurements

Ultegra 6700

ds/nds Tds Tnds BAR

3x/3x 125 61 2.1

2x/3x 125 62.7 2

3x/2x 125 59.4 2.1

Considering the above, the following thoughts develop:

1. There is no hub that is the best for everything and everyone. The trick and the value of the wheel builder is to find the best compromise for the rider/use.

2. BAR ranges from 1.8 to 2.4. Some consider 2.0 a viable compromise between stiffness and stability for the average rider. Heavier, more powerfull riders will do best going above that while keeping the Tnds at check.

3. Tnds ranges from 52kgf to 69kgf. IMO, anything above 65kgf is excellent. Above 60kgf is pretty good. Below 55kgf I would use Spokeprep. Below 50kgf I would not use the hub. Notice I used 125kgf for Tds to help Tnds a bit, however I would not do that for a light weight or box shaped rim.

4. Interestingly enough the DT 240 shows decent numbers; better than hubs I expected to show better. However, i should note that I did find quite a discrepancy on the flange dimensions depending where I looked. Finally I used the numbers from a source I consider reliable. You will do best measuring the hub yourselves as is not clear whether the flange thickness is accounted for from any of the manufacturer's published data.

5. Differences between Xs are very subtle.

I hope it helps somebody to build a better wheel.

cheers

EDIT: The BAR values between 2x/3x and 3x/2x were mistakenly reversed due to a typo. Thanks to orfitinho for bringing it to my attention.

- Reviews /
- Forums /
- User Reviews /
- Classifieds /

Now FREE ! - Hot Deals/