Sunday 12 May 2019

Red Tune build - finally some colours!

Tune are well known from their lightweight, however there are plenty of posts on forums showing hub's broken flanges. How was the build in my case and how to cheat physics a bit? Read further to find out. 

Remember some posts ago, I listed the three wheel's building triangle factors: weight, price, durability. They are all related so stretching two of them, like for example weight and durability will have an impact on price. 
This build had low weight and durability goals, price could be stretched a bit so the choice went for:

- Carbon graphene rims with textured brake surface. Ultralight version which is made mostly from Toray T800. That allows to get much more lighter wheels, in this case 45mm profile was about 380g on scale
- Red Tune hubs. Light, beautiful but with tension limits. Tune clearly states that front can be tensioned max to 100kgf and rear drive side to 110kgf. Also they forbid spoke tying and soldering so all in all the builds with Tune hubs are recommended only for experienced builders
- Aero Pillar Wing spokes. Here I mixed Wing21 with Wing22. I'll explain later why...
- Alloy black nipples and nipples washers

Before confirming the build as usual all components were entered into calculator to see how the spokes will be tensioned, how the geometry and bracing angles will look like. In this case I had a bit of limited choices as rims were available only in symmetric version and hubs had spoke tension limits. Due to that, my calculator was showing 49% - 100% spoke tension balance on rear wheel. In my standards this is on the edge so I decided to use old trick to cheat a bit the physics and pillar Wing spokes helped greatly in that.

Front wheel was simple as walk in the park. The only thing to watch out was tension limits, and here my tension calibrator tool came with great help. Front was built and precisely tensioned to 90kgf so 10kgf lower than Tune's limit which is 100kgf for front hub. That was with Wing21 spokes due to a bit narrow flanges (only 35mm). Precise and under limit tension guarantees that the hub's flange won't break due to exceeded spoke tension. 
In many cases, such failure comes from the facts that workshops do not use tension meters at all or if they do, they don't calibrate them so with time the values displayed are simply incorrect. To prevent that, yearly calibration is a must and brand new calibration must be done if the new type of spokes are used which are not on the calibration chart yet.

Rear wheel was much more interesting. Tune's drive side limit is only 110kgf so not so much left for non-drive side which is a key for long lasting wheel. 
One way to fix that would be to use rim with offset, but for me that was not an option so what I did was to use stronger spokes on DR side to increase tension of NDR. 
How does it work? To simplify that imagine that thicker spokes hold the wheel stronger, in our case DR side. The role of NDR spokes is to pull the wheel to the left to achieve symmetry. If you use thinner spokes on NDR they will have to use more force to pull the wheel to the left, therefore more tension. Now, Pillar Wing spokes are excellent for that as they come with the range of Wing20 to Wing23 so there is plenty room for mix and match. 
Taking into account the rider's parameters I decided to use Wing21 on NDR and Wing22 on DR. Using Wing20 on NDR would give even more tension but could result in some lateral flex so the trade between the tension and stiffness was mix of Wing21 and 22. 
Before doing that I weighted 12 Wing21 spokes and 12 Wing22. The weight penalty was only 8g so worth the trick. In addition Wing spokes have stronger J-bend section which measures 2.2mm instead  2.0mm in all other spokes so this is additional safety factor.
Doing that I achieved the NDR tension of 60-65kgf. If I'd use same spoke types on both sides I'd end up on 55kgf. It's not that huge difference but if the spokes are well stress relieved the tension will remain and higher tension on NDR side means better wheel. 

As said, using Wing20 on NDR and Wing23 on DR would give even better result but then it's important to think about lateral stiffness. It all depends on the riders weight, power and rim depth. Every case is different and that's why I love wheel building so much ;-)

Graphene rims with textured brake surface gives excellent braking in all weather conditions therefore such were used in this build

Overall wheels came up beautifully with impressive weight - only 1348g for 45mm profile rim. I could go lower about 15g by using thinner spokes but would mean less stiffness. 
Price tag for those - 1249CHF so very good value for money.

Wheels are available in my shop. Hubs come with different colours so be creative and give some fun to your new hoops! 

Thanks for reading


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