This Carbon Chainring Weighs Just 39 grams
A carbon-fibre MTB chainring may sound about as durable as a chocolate teapot, but a Barcelona-based company called Gemini claim to have come up with some clever tech to make it work. They say they've put in more than 3 years of research and development, 500 prototypes, and thousands of kilometres of testing, resulting in two international patent applications and what they call "the most technologically advanced chainring on the market."
First, let's talk about why you'd want a carbon chainring. The claimed weight is just 39 grams (30 teeth). That compares to about 59 g for a 30T SRAM direct mount ring (one of the lightest made from aluminium); so we're talking about a 20-gram saving, which will only be worth considering to the biggest weight weenies and/or professional XC athletes. The press release also claims that it's more aerodynamic and reduces friction with the chain, but that sounds like an even more marginal gain. It goes on to say that the chainring offers an "unparalleled sense of finesse during pedalling." Super.
The wear-resistant aluminium core is set inside the carbon teeth.
The inside edges of the teeth are faced with aluminium.
More interesting to me is how Gemini have managed to make a carbon chainring which they say has "unmatched durability for a carbon chainring". On their website, it even says that "wear will be similar to that of an aluminium chainring."
The Gemini Rigel chainring uses a 7075 T6 Aluminum core, which is sandwiched inside the carbon teeth. Gemini then uses something called forged carbon, which involves pressing the fibres together with more than 100 tons of force. Gemini say "the fibers of the composite are arranged through the geometry of the chainring wrapping the metal core while providing a continuous structural organization along the tooth that provides high stiffness levels impossible to achieve with any other carbon chainring manufacturing process".
It's designed to be compatible with any 11 or 12 speed chain on the market, including Shimano, SRAM Eagle, and SRAM Eagle Flattop chains. It's available with 32, 34 & 36 teeth (30 and 38 coming soon), with a standard 3 mm offset (Boost). It only comes as a direct mount and round shape for now, but Oval and 104 BCD should be available soon. The supported crank interfaces are: SRAM 3 bolt, SRAM 8 bolt, Shimano, RaceFace/Easton, Cannondale Hollowgram.
The price? 125€
ridegemini.com
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Now I mean the actual thick Type III anodizing "hard" like what is used on your fork stanchions.
Would be more convinced by hundreds of thousands of kilometres, given the amount of protos.
"It's available with 32, 34 & 36 teeth (30 and 38 coming soon)"
Ok
Btw: Googling the product name before launch helps
my question wouldnt be chain wear life expectancy, its how does it cope with rock strikes..
Do I wish they made a 48t for my gravel bike? Yes
Would I impulse buy a 48t? OF COURSE!
How many carbon chainrings are there on the market to compare to?
No I'm not going to bother looking that up.
"BECAUSE IT CAN!"
Another dog ballz product hits the airwaves!
1 It is a cool technology that looks like it could carry over to other parts and industries (cassettes anyone?)
2 The weight saving is pretty substantial if you look at it in a relative way
3 It's so obviously a race day only product, that is just awesome.
Someone with more knowledge correct me if I'm wrong but doesn't SRAM Transmission use a 55mm chainline which would be 0 offset rather than a 3mm offset?
See charts here: www.wolftoothcomponents.com/collections/mountain/products/direct-mount-chainrings-for-sram-cranks
And for “forged” carbon, that’s just randomly chopped cloth, either pre preg or dry. No uniformity etc.
When your company has 1 engineer and 82 marketing associates.
erm, well, I do have one hypothesis
obviously
this product might not be the next big thing, but it could lead to the next big thing.