Action Tec is one of two firms selling Titanium chainrings. No one can say Titanium is inexpensive, but it's generally means that it's the last time you will ever have to buy that time again.
The Titanium used for these chainrings is an alloy of Titanium, with 6% aluminum, 4% Vanadium, and inertly, some Iron, Oxygen, Carbon, Nitrogen and Yttrium. This produces a Titanium alloy that is half as dense, (density is described as grams per cubic centimeter), or having half the weight of the same sized amount of steel, yet the Titanium has twice the strength, on a per weight basis as 21-6-9 aircraft steel.
Recapping half as much by weight, with nearly twice the strength, (for strength comparison 21-6-9 steel fails at 64,000 psi, while Titanium 3AL 2.5V fails at 115,000 psi), so in the same volumetric amount the Titanium is almost four times stronger than steel. For comparison sake, the best aluminum, 6061 treated to T6 fails at 40,000 psi.
Most chainrings are made from considerably softer 2014 aluminum, and a comparison to the softer aluminum isn't even available, because you would generally not use Titanium in place of 2014. All this is to give you a sense of how durable these chainrings are and to infer how long there useful life is. Truthfully, we haven't heard of one wearing out, the chain on a bike is softer.
The reason that these chainrings don't, by weight, appear to be appreciably lighter than the aluminum variety, is the aluminum ones are, and have to be made considerably thicker than the Titanium one to achieve the strength needed to stand against the steel drive chain. Titanium is a much more rigid metal and not subject to the same flex and distortion that soft aluminum is under load.
The Action Tec chainrings are cut from a piece of Titanium plate that approximately 2.0mm thick. The teeth are then ground for the tapered points. The final stage has the fixing bolt holes re-drilled, just slightly, for the bolt to fit flush.
Action Tec chainrings are available in Mountain bike fixing bolt patterns only, with 24, 34, 36, 48 or 50 teeth. Mountain bike bolt patterns are 74mm for the inner, 110mm for the middle and outer chainring and their is a 20 or 22 tooth inner Micro Drive/Hyper-C chainring using an oval hole that accomodates both 56mm and 58mm patterns. Weights for each of the sizes are listed in the accompanying table. $ Price and Sizes Available in Catalog
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