Dura-Ace straight-pull hub wheel building

[PeterKim]

I got lucky and got a straight pull hubs form the WH-9000-C50-TU wheel.
I am trying to build a carbon clincher wheel out of this hub but there are some challenges I face.

• Getting right spokes

• • Length

• • Since it is a 2:1/triplet lacing pattern and a straight pull hub at the same time there isn't much information on how to calculate the spoke length.

• • Gage (preferably the gage of the Sapim CX-Ray spokes)

• • End? (check the image of the Dura-Ace spoke)

• • Dos the spokes need to be customized for this specific hubs?

[BdaGhisallo]

I can't recall where but I have read in the past that the heads on the straight pull spokes needed for these hubs are not typical and have to be "made".

[bm0p700f]

Yes the heads on the spokes need to be squeezed in a vice.

It's the Ds that's the real problem. Without knowing the spoke lengths of the original wheel it impossible to calculate the new lengths. You have to guess. See my post, just, in the wheelbuilder thread. There is no easy way of doing this. Moral is don't but straight pull hubs if eBay thinking it is a easy build. It's not. With all the straight pull hubs I use I have had to guess the spoke length then work out the fractional crossing. To do that for a one off build is not economic. Sell the hubs on eBay and buy 18f/24r da hubs instead.

[monkeyburger]

The only way I find a satisfactory length in the case of oddball straightpull hubs is to measure everything and draw it in CAD. Of course this is fine to do when I'm building wheels for myself, but pretty hard to charge a customer for hours of computer work when they've bought such hubs thinking they're going to build "slick" wheels on the cheap.

[chiumomo]

Check out the DT spoke calculator, they have formula for straight pull hub. Pretend you have a 28 holes hub when calculate the DS spoke length.

[bm0p700f]

that won't work. That calculator workably for DT Swiss after market straight pull hubs.

[F45]

I could do this without much trouble. I've built a front wheel from scratch and a rear wheel with a known ERD on the old rear rim and estimated erd on the new rim. Basically, I approximated everything to have the spokes be slightly long, laced them up, measured how much excess I had, then took the spokes around the corner and had them cut and rolled at the lbs. It was more work but not a whole lot for a guy not in a hurry.

[mattr]

I worked out my last straight pull wheel using basic trig, micrometer and a rule.

Ordered all the spokes, then found out that the manufacturer has a calculation thing on their website (Doh!).

I was about 1mm out all round, so actually ended up with the right spokes.

[joejack951]

If a CAD model is needed to assess the spoke length, shoot me the dimensions of everything (rim and hub, all relevant dimensions) and I can draw it up fairly quickly. I have some models set up for the task having built some oddball wheels myself (like a ISO 254mm rim with 16 holes laced to a 32 hole hub, converting my son's CNOC 14 to a BMX freewheel hub from a coaster brake hub).

[NickJHP]

You can use the DT Swiss calculator for calculating the spoke lengths for other brands of straight pull hub provided the hub manufacturer provides the pitch circle diameter and spoke hole offset values. I've used the DT Swiss calculator successfully for building both Hope and Newmen straight pull hubs:

Data for Hope hubs: http://www.hopetech.com/wp-content/uplo ... ND-PCD.pdf

Data for Newmen hubs: https://www.newmen-components.de/applic ... iption.pdf

[ergott]

https://www.wheelpro.co.uk/spokecalc/

[PeterKim]

Rim ERD: 541mm

The following images will contain the rest of the necessary dimensions <--- Hopefully
1st image: Flange Distance Left, Flange Distance Right on both front and rear hubs
2ed image: Pitch Circle Left & Right on the front hub
3rd image: Pitch Circle Left on the rear hub
4th image: Pitch Circle Right on the rear hub
5th image: Distance Between Spoke Holes Right on the rear hub
6th image: Offset Spoke Hole Right on the rear hub

Thank You

If a CAD model is needed to assess the spoke length, shoot me the dimensions of everything (rim and hub, all relevant dimensions) and I can draw it up fairly quickly. I have some models set up for the task having built some oddball wheels myself (like a ISO 254mm rim with 16 holes laced to a 32 hole hub, converting my son's CNOC 14 to a BMX freewheel hub from a coaster brake hub).

[F45]

The last one is the hardest to measure but has a direct impact on spoke length.

[ergott]

Center to Right of 14mm? that's aweful. A standard flanged Dura Ace rear hub will build into a much better wheel than that.

[PeterKim]

Do you know the method to measure it?

The last one is the hardest to measure but has a direct impact on spoke length.