TECH NEWS: RBA TECH: PRAXIS WORKS CHAINRINGS
September 2, 2011


What was once a hot market, the aftermarket chainring craze died about the same time the “Seinfeld” finale was airing. At the time, most of these aftermarket chainrings were CNC machined, but due to the amount of time involved in making a full CNCmachined ring, they were cost-prohibitive and typically looked better than they actually shifted. Once Shimano,
and then SRAM, upped the ante in chainring shifting performance (with their use of specially designed shift ramps), most of the aftermarket brands disappeared as quickly as they had arrived.

Enter Praxis Works. This Northern California design shop is doing something that sets them apart from nearly all the other chainring makers: forging. Until Praxis started making OEM chainrings in 2007, Shimano was the only chainring maker using the forging process. In a few short years, Praxis has gained a reputation in the industry for their ring technology, catching the eyes of the “Big Three” component makers.

THE TECH

How can a small company from NorCal do what only the massive and diverse Shimano is able to? Like most young upstarts, they rely on their parents, of course. Praxis’ parent company, Asia-based Dragon Tech, has been forging since the ’60s, making parts for Singer sewing machines, Ducati motorcycles and everything in between. The forging process uses a minimum of 300 tons of pressure, causing the 7000- series aluminum that is used to undergo compaction and grain alignment. This creates a more rigid chainring than what’s possible with stamping or CNC machining alone. Since the tooling and equipment needed for forging makes it so cost-prohibitive, the majority of chainrings on the market (except Shimano) are either machined or stamped.

Timing is everything, especially when it comes to chainrings. LevaTime is Praxis’ name for their aggregate shifting ramps and tooth profiles (every tooth on the outer ring is slightly different) that create the ring’s shifting performance. Shift timing is so precise that Praxis engineered their chainring sets conjointly—so much so that they make two different 50-tooth rings: one designed to work with a 34 tooth inner ring and the other to work with a 36.

The third process for the Praxis chainring is liquid anodizing. The ring’s thick, lustrous anodizing isn’t just for looks alone; the hard-anodizing process adds longevity to the chainring while Praxis claims the liquid anodizing’s slippery finish aids shifting.

THE SETUP

We mounted our 50/34 compact chainrings on a SRAM Red 110 BCD crank. Both chainrings have alignment tabs to help ensure proper placement in relation to the crankarm, making setup painless and easy. Since the outer ring we were replacing was the same size, a front derailleur adjustment wasn’t necessary.


LevaTime’s intricate teeth and ramp design are what give the Praxis quick and reliable shifting.

THE RIDE

Ease of shifting and smoothness was on par with the SRAM Red chainrings we swapped the Praxis rings for, not noticeably better or worse. Shifting up to the outer ring from the inner ring took about half a crank revolution before the chain was pulled up by the LevaTime feature; again, comparable to the Red rings. Where the Praxis rings stood out was their stiffness. Cresting a hill and immediately throwing it in the big ring while trying to accelerate up to speed makes most rings skip a beat, but the Praxis ring handled the power shift, sending us sprinting down the road at full speed. Downshifting under load was slightly delayed, but ultimately made the shift without derailing the chain or causing any chain-suck issues.

BOTTOM LINE

As well as the Praxis chainrings performed, getting people to swap their current rings is a tall order; unless, of course, they’re due for a replacement. That’s what Praxis is banking on.

Offering a stiff, light and cost-efficient alternative that doesn’t sacrifice shifting performance gives consumers another option when having to pony up for some fresh teeth. While the Praxis rings shave off 22 grams compared to the SRAM Red rings, which are stamped, they’ll cost you about a dollar more per gram of weight savings. While Shimano’s Dura-Ace 7900/7950 chainrings are proprietary to their crank, Praxis won’t be seeing any of those customers. But for anyone running earlier Shimano rings, the Praxis could be a consideration. And all you Italian component diehards out there should know that Praxis has a 135 BCD Campy-compatible chainring in the works, which would save you over $100 compared to the original.

STATS

Price: $165 compact set, 50/34 or 50/36 (110 BCD); $170 standard set, 53/39 or 53/42 (130 BCD)
Weight: 118 grams (pair)
Praxis Cycles

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