More Twombolt crank sizes

Twombolts: 170mm

We have some more Twombolt crank sizes and variations in stock. You can now get them in 180mm and 170mm lengths, in either LHD or RHD. Contact your local shops or mail-orders to get a pair. More photos and information can be found after the link, along with some physics questions…

Twombolts: 180mm

In our Dailyword archive, you can download the PDF manual and even watch a video how-to of installing these cranks.

From the Catalog:

Twombolt. Yes, we’re obviously aware that one-bolt configurations and two-piece cranks have been done before. However, what HASN’T been done before is the Twombolt’s unique wedge cluster. This cluster is the heart of the system, and it addresses all of the issues found on ordinary cranks. Now you can finally say goodbye to the “ankle-biting”, bolt-loaded chunks of aluminum and steel found on pinch bolt cranks. Better yet, The Twombolts will also let you bid a not-so-fond farewell to the difficult installations and seemingly endless loosening and “wobble” issues found on archaic spline designs.

The Twombolt’s integrated, ultra-hollow 22 mm spindle is nearly 17% stronger than 19 mm versions, while also managing to save a significant amount of weight. This weight saving helps to put the Twombolt in the same category as three-piece cranks that rely on weaker, expensive Titanum spindles.

The Twombolt arms (with their integrated hex-end spindle) are a 41-Thermal processed assembly, so their strength is backed by a legacy of products with a proven track record for reliability. Guaranteed for life against bending and breaking (as usual). Patents pending worldwide.


Here’s the physics questions: Based on the simple lever diagrams above, which classification(s) does a BMX crank fall into? And, more importantly, which length (180mm or 170mm) would potentially help you generate the speed needed to jump the Austin Church Gap?