Thursday 3 May 2018

Dura Ace EX HF-7261 build for Tom

Restoring or rebuilding the wheels based on classy hubs is always a nice change from every day-modern builds.
Very often such builds bring additional challenges as lack of documentation, dimensions and troubles to calculate the proper spoke lengths. Many people I know avoid such work as it's time consuming and sometimes not worth to take it.

However if the customer brings classy Dura Ace EX hubs the story is completely different...

Tom came to me and asked if I could build wheels for him using his hubs - Dura Ace EX hubs. 

They are really beautiful peace of work. Despite many years of service they still do roll very smoothly with minimal play. 
Tom wanted to get them laced with H+Son SL42mm black rims and black spokes.
Few mail exchanges and we decided to go for CX-Ray spokes and black brass nipples. Wheels won't be ridden on daily basis so the black braking surface on the rims should last pretty long.

Before ordering the parts I did measure the hubs by my self as you can't find any dimensions over the net.
Measuring the hubs was not the only thing to do. If you look closer the hubs have irregular spoke holes drilling. They are designed for "Direction-6" lacing pattern so the hubs have "paired" spoke holes.

In order to calculate the spoke lengths you need to use the specific calculator, which you can find here and you want to use tab called PAIR-HOLE-HUB-CHART
The Paired Hole Degree for those hubs is 10

Rest is easy, you get the adjusted crossing value and you can put that info your standard spoke calc, for example DT Swiss one.
In my case for the rim of 557mm ERD the front spokes were 273mm, DR 270 and NDR 273

Once you get the proper spokes you need to lace them properly as per drawing below:

If you do that correctly, the wheels should look like this:

Since they were used hubs I didn't want to push my luck and I tensioned the spokes a bit less than I usually do. I did the front for 90-95kgf and rear DR 110-115 / NDR 50/55 kgf.

With 32 spokes and brass nipples that should be enough without stretching the hubs too much.

Overall wheels are really beautiful, although personally I would use silver spokes

Tom, thanks for giving me the opportunity to build such beautiful wheels for you. I hope they will look awesome on your retro bike.
Happy riding!


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