Tuesday 23 June 2020

Duke Fury Jack - hard enduro wheels in Super Boost Plus standard

Although I'm 100% roadie / gravel rider I also enjoy building mountain bike wheels, and on this project, I had a unique opportunity to build a wheelset for very experienced and demanding rider. Moreover, the wheels were built in the latest axle's standards - Super Boost Plus.

Super Boost Plus is another innovation that was introduced into already crowded MTB wheels space. So far we had "Standard" (142mm), Boost (148mm), Downhill (157mm), and now Super Boost Plus (157mm). As you might note well, the axle width is the same in the last two standards... so what's all about Super Boost Plus hubs? 

The difference is in the flanges, specifically the offset from the centerline. That "small" change gives a much stronger and stiffer rear wheel as the bracing angle between the hub's flange and the rim is lower. A lower angle is not always the solution, especially in road hubs (130mm) but here we have enough space to make the flanges largely spaced from the centerline and still obtain high spoke tension on both sides of the wheel:

As you can see from the above calculation, in 32 spokes, 3-cross lacing I've got 85/100% tension ratio which is absolutely excellent and ideal to make a strong and long-lasting wheel, even in hard enduro usage. 

Building wheels for the racer and true downhiller is always a challenge. Given all inputs I've got I decided to go for:

- Duke Furry Jack carbon rims. Extremely wide, 32mm inner width and 39mm outer width, both in 3mm offset
- Wonderful Industry 9 Hydra hubs in Super Boost Plus standard
- Pillar PSR 2017 spokes, J-bend, 32 spokes front and rear, 3-cross lacing
- Alloy nipples with brass washers

Result? 1850g set, crazy strong, damn good looking with the Swiss knife-like precise clutch:

Hydra clutch from Industry 9 is simply insane. 690 POE (points of engagement) is nuts! Practically constant engagement will react into every pedal stroke you make without thinking. That is so important when you go down on very technical sections and need an absolute balance of the bike when standing on the pedals. 

As mentioned before, Fury Jack rims from Duke did a good job as well. Ultra-wide with offset allowed to balance well the spoke tension and provided enough space for monster tires

Two green nipples and green valve - small touch to match the wheels with the frame well. 

Spokes were laced 3-cross on both sides and both wheels. Due to excellent hubs geometry and offset rims, I used here equal spokes, 1.7mm Pillar PSR round with reinforced J-bend section, 2.2mm. That allowed me to obtain strong, but yet light wheels.

Building those, one name came to my mind: The Hulk. Yes, these wheels were called "The Hulks" - unstoppable, strong, and mad. These represent all that.

Price tag? 1650 CHF. The price includes wheels, tape, valve, spare spokes and nipples, and shipping costs.

If you're interested in that particular or similar build, give me a shout.


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