When what’s out there fails you, take matters into your own hands.
When my search for baby-pink ultra-lightweight 11T derailleur pulleys came up empty, I knew I had to do something about it. The result is a set of pulley wheels lighter than anything currently on the market, color-matched in pink.
A careful balance of function-driven and aesthetic-driven form.
Numerous thin spokes give the pulley wheel excellent lateral stiffness for its weight and help support the thin outer rim of teeth against collapsing.
11 (# of teeth) is a prime number. So the only way to have an elegant distribution of spokes and teeth is to have 1 set of spokes per tooth.
Each spoke has been machined down to be only 1.4mm thick.
Designated material: 7075-T6
The use of a miniature MR105 stainless/ceramic bearing not only saves weight, but also reduces friction due to reduced surface contact area. Furthermore, the 5mm bore diameter negates the need for a shim for the mounting bolt.
The small bearing diameter makes the spokes look longer and more elegant, like an oversized pulley wheel, but not oversized.
Fully turned-down bearing end caps ensure clamping forces are only applied to the inner race. Excess material has been removed, and the end caps only cover the bearing itself.
Static load testing was conducted in FEA to assess stiffness along the way. Comparisons were made against competitor products to ensure my pulleys were at least on par in stiffness.
Tests performed included 1-tooth loading and 3-tooth loading at 60N to simulate a “dry shift”.
Cyclical fatigue loading was simulated to ensure product lifespan.
With the same 60N lateral load, each tooth has a lifespan of approximately 4 million cycles. Of course, in the real world, pulley wheels experience very low stress during regular riding, so this figure is less important compared to the plain stiffness test.
Custom CNC and anodized 7075-T6.
Produced two variants: the standard (uses conventional bearings), and the ultra-light (uses aforementioned MR105 bearings). The ultra-lights are currently in use daily on my weightweenie!