PezCycling News - What's Cool In Pro Cycling : PEZ-Tech: Praxis Forged Chain Rings

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PEZ-Tech: Praxis Forged Chain Rings
So chainrings… No big deal right? I mean nobody makes a better aftermarket set than just getting stockers right? Wrong.


Judging by past efforts, those of us that “upgraded” likely found ourselves either tossing out the new ones immediately and buying stock replacements or spending a few months living a lie in that we could either feel the weight difs or that the look of the new ones made the dogsh!t shifting worth our money.


Praxis Chainrings in typical 53-39…

Enter Praxis Works who have roots in product development and manufacturing for companies who’s pub receipts total more than the R&D budgets of most cycling related concerns. Take that huge (and expensive) capacity and fill in a cycling related product designer with experience leading design efforts at a couple of companies with the largest budgets in cycling R&D, and you have Praxis Works.

The end result is a product that is better than virtually everything else (aftermarket and original gruppo production) shy of Shimano’s Dura Ace and a couple of other OEM specs that are made for companies by Praxis.

That’s down to one simple thing…

Praxis and Shimano are the only folks in the ring game to take on the massive up front cost to cold forge.


WikiForging…
To save me some hassle, best you take a quick trip to Wiki to explain forging.

The machine required to make the rings is a couple of stories tall and isn’t cheap. It’s set up to apply massive pressure and when I say massive, it’s substantially more pressure (hundreds of tons) than if you actually lowered a building a couple of stories tall onto the dies that form the rings.



There are a few different types of forging (really, you should go back and click that Wiki link and read…) and the cold process is the one that changes the actual make up of the metal. For those of you too lazy to read the Wiki thing, the cold metal blank of 7075 T6 aly has a grain structure in the metal… as I don’t have a Macro lens good enough to show you what I mean, the metal starts out with the grain arranged kinda willy-nilly…



Then Praxis smashes it with so much force that the grain is actually forced more into alignment…



The net results are two fold…

1. The part is now much harder than a standard machined ring, meaning it’s both more durable relative to bike related duty and will not flex as much.

2. The part can be made with far greater detail in a given time period (for a given cost) than can be done through machining.

And you can feel/perceive both of the differences in use (something that’s missing from LOADS of suggested advantages in bike parts…).


DeTaIlEs details…
There are pretty substantial differences in chainring detail when you really start to pay attention to them.



I honestly didn’t pay much attention to the large difs between rings in the past… Once you start to get a little info though, there’s no missing why some of the fancy aftermarket stuff from the past simply works like sh!t…

Chainring designs are down to a few basic features (or lack of) and their placement.

The pins are arguably the most important part of little to big ring movement and the detail for Praxis (bottom ring of three below) is notably different than stock SRAM (middle) or FSA (top).



What I believe you see with the Praxis are double stepped relief areas (red dots) that allow the chain to step up to the pin (remember you’re looking at the rings in “reverse”). The yellow dot I’m guessing is a bit of a “grabber”. The first green dot shows a shorter tooth for clearance for the chain to come over top (note that the “front” of that tooth also has more detailed relief than the other rings to allow the chain to pass). The second green dot is a much more pronounced (relative to the others) drop-in detail.

Shape details are important, but so is their placement on the ring itself. That’s what’s called “timing” and or what Praxis “LevaTime”.




The rings above are lined up as they would sit on a crank arm and it’s notable that one ring has 2 pick ups in the same primary pick up point that the other two rings have 3. You’ll also note that the Praxis ring (right) has the first pickup (at the bottom, as the rings rotate to the left in use) placed a bit sooner than the ring with 3 pickup points (middle). The second pickup is similar placement and the third pin (at the top) is slightly after.

Lots of chain rings are made without relative alignment over the entire ring. Praxis sell rings in matched pairs so that the pickup points are in exact alignment with the small ring teeth, so that the chain travels up (and down) the height of the small ring teeth for maximum interaction (minimum slop) between the small and big rings during up and down shift travel.

There isn’t much difference between the small rings for Praxis and the others.



But alignment is a critical difference between small and big ring teeth for some manufacturers.

The minitooth on the small ring…



…lines up with the silver post pin precisely.




And they’re mounted to sit directly behind the drive side crank arm.



And what goes up must come down so Praxis worked to make the drop from large to small happen with equal precision. Praxis not only tailor the shape well for pick up but put more detail into the let down sections as well.




One More Critical Component
All of the detail on the rings and properly aligned installation are important, but there’s one more piece of the puzzle that wasn’t completely clear to me.

What we’re talking about improving is the chain to chain rings interaction…

It makes sense that the chain also matters.



I initially ran this system with a stock SRAM Red chain and the results were slightly better shifting action than stock SRAM Red rings and notably better than stock FSA rings with SRAM Red chain.

Then in conversation with Praxis, I asked about chains and they said that I would absolutely get better action with KMC, Shimano or Wipperman… After making the swap, they were absolutely right.

The Chain Profile matters here…


Road Results
I said above that you can feel the differences between Praxis forged rings and that’s worth explanation.

First up, the forging process makes for a harder / stiffer ring versus another of similar weight.

The road result is less flex and that stiffness makes for crisper shifting under load / stress than stock Red or FSA.

The second part of forging is that the process makes for a highly detailed part that would be extremely difficult to produce by machining an alu blank for any sort of reasonable price point.

The road result of the detailing is better shifting under any conditions up or down shifting versus stamped / machined rings. Far less lag / a far crisper pick up and a simple pronouned drop than standar SRAM Red, FSA or any of the other aftermarket rings…

It was actually a good thing that I didn’t ask about chains until I had run the rings a bit. The result was a good-better-best performing group set comparison with a couple of popular rings…

Given the size / standard match I had two sets of everything (after buying a second set of Praxis rings) and got to run the same rings with different chains and also different rings with the same chains…

All of this was originally an effort in vanity… It was all about getting something Blacker for the AC/DC BLACK PROJECT PARLEE Z5…



Now I’m faced with the task of replacing all of the rings and chains on every bike I have (and spec’ing the rings on the next couple projects). Praxis Works forged rings mated with the KMC and Wipperman chains I have on hand are a substantial enough upgrade in performance that I’m not waiting for the others to wear out.

Sure SRAM have fixed front shifting with the new / unreleased Red, but there are LOADS of older and current group sets that will benefit…


For more info on the rings, hit PRAXISCYCLES.COM and pop over to Fairwheel Bikes if you’re hunting a retailer.


Have Fun,
Charles Manantan

 

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