Friday, 26 June 2020

My take on Triathlon wheels

Freedom of components selection is the best thing in the wheelbuilding profession. If you're not forced to a specific brand and you understand how the good wheel works, then you are able to create and build the best wheels possible. 


In today's entry, probably the best triathlon wheels I've ever made. Truly aerodynamic, quiet, without any drag, and constantly engaged. I'm very excited to introduce to you the Onyx hubs!
This build was made for Ronald, the triathlete who is passionate about this discipline and puts a lot of effort to train and obtain really good results. He also rides the most sophisticated TT bike I've seen so this is the guy who knows the stuff very well.

My job was to upgrade his Zipp wheels to something better so not an easy job...



What I was looking for was the following:

- carbon rims, pretty narrow due to Cervelo clearance
- hubs which have narrowly spaced flanges (more about this later)
- smallest drag (bearing, freehub) possible
- solid and long-lasting
- aero spokes

The most difficult part was to find the proper hubs. Before we go further on my choice, there is one specific thing with high-profile carbon rims which is worth ironing out here:


Bill Mould gives an excellent explanation of why deep carbon rims will flex. Knowing that there is no point to fight with physics and trying to make those rim laterally stiff, instead, I decided to leverage the opportunity of the deep rim (aerodynamics) and choose the hub which is also aerodynamic.

What means aerodynamic hubs for me? Take a look at both pictures below:



What do you see?

The first picture shows the hub which is aerodynamic. Narrowly spaced flanges, allow to hide the spokes behind the rim, so no drag for the wind. The second picture shows BORG hub in triplet design. Widely spaced left flange makes the wheel super stiff but creates the drag for the wind. Two different hubs, two different purposes.

In the TT wheels project, I decided to use a narrow hub to provide as little as possible resistance to the wind and try to hide all the spokes within the deep section rim.
Which hub does that? There are few: Soul-Kozak, DT Swiss 240, Hope, and the very special one, which I used in this project: Onyx hubs.

Onyx is a totally different hub than anything else on this planet. Besides the geometry, it uses a patented clutch which is silent, always engaged, and drag-free. All those elements are crucial in TT wheels (and not only in TT)

How does this work? Watch this or better this:


Yes, those hubs spin forever although constantly engaged and they are completely silent & drag-free. Why this is so important for TT wheels? Well, a few things to consider:

- deep section rim with no resistance freehub allows you to ride faster with less power input
- constantly engaged hubs resolve the problem of squared legs. Pay attention when you are super tired and pedaling. Often, you have sort of empty strokes where the hub doesn't engage due to too little leg power input. Familiar now? With constantly engaged freehub you transmit 100% of leg power into the wheel. No more empty strokes, it's sort of fixed wheel but with no drag... Now, when you put that into TT context where you swim, ride, run, every watt saving is crucial and therefore those hubs are so interesting for such wheels projects. 
- spokes which are hidden behind the rim? Explained before, simply faster wheels. Combining that with a TT bike and proper body position makes you really fast.


This was my recipe for unique, damn fast and efficient TT wheels.

Also front rim is narrowly spaced, unique thing for Onyx hubs

Onyx road hubs in candy red color (slick!) Patented inserts on the freehub, another interesting innovation. Well done guys!

Rest was easy, Duke Baccara SLS1 (18mm inner width) in 65mm profile on front and 88mm on the rear.


Pillar Wing 20 aero spokes (the lightest and most aero on the market) on front and rear NDR side. Wing21 on DR side.

Result? Sub 1850g wheelset which is truly aero, fast, and unique. There is no second set like this. Wheels designed for a specific job and they will do that job very well. 

Price tag - 1749CHF The price includes the wheels, brake pads, tubeless tape, spare spokes, nipples, and shipment. 

I guarantee that the riding sensation on those wheels will be different from anything you had on your bike so far. I truly recommend such or similar configuration. 

@Ronald - all the best with your new wheelset. Good luck with your competitions!

Cheers
Tomasz

blog-wheelbuilding

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