Back before chain retention 1x rings antiquated the market for them, chain guides were e*thirteen’s main game. Nowadays, chain guides make up just a small part of what this east-turned-west coast company does, instead focusing its engineering muscle on widening its product offerings. Today, you’ll find the company’s asterisk on cranks, wheels, seatposts, even tires–and some really clever cassettes.
The e*thirteen TRS Plus cassette isn’t a new product altogether, but its gear range has just been widened to 511 percent, a range previously only found on the TRS Race. What you’ll get, aside from an extra Benjamin in your pocket, is essentially the same. The TRS Plus has the exact same 9-46t, 11-speed ratio, but different construction makes it a whopping 36 grams heavier. Of course, that’s still 17 grams lighter than SRAM’s X01 Eagle cassette.
What you’ll get by swapping your SRAM or Shimano 11-speed cassette out for this one, is Eagle-beating range for $250. Of course, you’ll also want to swap out your chainring for a smaller one, and replace that scrappy old chain while you’re at it, so you’ll want to consider that in your budget. And, of course, if you’ll be coming off a Shimano cassette, keep in mind that e*thirteen’s cassettes mount on XD driver bodies, so you’ll need one of those, too.
So how do these e*thirteen TRS cassettes have 11-percent more gear range than SRAM Eagle, with just 11-speeds, no mega-extreme gear jumps, and no giant 50-tooth cog? It’s that little 9-tooth at the bottom. With that few teeth, a one tooth change represents a larger gear jump than, say, a 4-tooth jump up higher on the cassette. So, where SRAM Eagle provides a lower low gear, e*thirteen focused on the high end. This is particularly good because it means you can run a smaller chainring, which means better frame and ground clearance. There are a fair amount of bikes out there that’ll only accept up to a 32-tooth, which on an Eagle drivetrain, might be too small for strong riders. Without the existence of e*thirteen’s 9-tooth whammy, the only way to get a faster max speed on bikes with this constraint would be going back to a multi-ring system, which–uh–no thank you.
Let’s say you’re comparing two drivetrains, one with a 32-tooth chainring and e*thirteen’s TRS Plus 9-46t cassette, and another with a 34-tooth ring and a SRAM Eagle 10-50 cassette. First off, the e*thirteen one will be lighter, but that’s not really important. Here’s the breakdown in gear inches (we calculated it with a 650b x 2.4 tire):
e*thirteen low gear: 19.45 | High gear: 98.94
Eagle low gear: 18.90 | High gear: 94.49
So, the e.thirteen drivetrain results in a significantly faster top speed, and a very close but slightly harder granny gear.
To achieve the 9-tooth small cog, e*thirteen had an engineering hurdle to overcome, namely how to get it on a wheel. Since the 9-tooth is such a small diameter, a normal cassette tool fitting wouldn’t work, which birthed e*thirteen’s inginous solution. The first three cogs, which are crafted from aluminum, get mounted to an XD driver body by way of what looks a lot like a bottom bracket lockring. Then the remaining cluster of 8 cogs, machined from one piece of steel, notches into that by using a chain whip. Being made out of aluminum, the three large cogs are more susceptible to wear than their steel neighbors, so you’ll be able to replace each of the two cluster components independently. So, that’s cool.
Considering how many patents drivetrain giants SRAM and Shimano collectively own around how chains and cogs interact with each other, e*thirteen did a good job creating a nice-feeling shift. They’ve struggled a bit with creaking issues where the aluminum and steel parts contact one another, which a generous slathering of grease usually wipes out. Other difficulties? Well, you’ll need a special tool to install the cassette, which it thankfully ships with. But to get it off, you’ll need to add a second chain whip to your tool collection.
And then there’s the relatively bigger issue that the tiny 9-tooth cog generates. A chain will run smoother on cogs with more teeth and rougher on cogs with fewer ones. Since the pitch of the chain is constant, the links can only bend at fixed points, so once you get smaller than a certain number of teeth, the chain has a tougher time bending around the cog and the rollers in the links might not land right at the bottom of the tooth wells where they’re supposed to. This causes vibration which, to the rider, feels like a rough gear, and it could also cause premature chain wear. For all kinds sciencey stuff, Google “chordal action” and “polygon effect”. This, according to SRAM, is why Eagle goes to 10 teeth instead of 9.
But for many riders, the benefits might outweigh the costs here. You can definitely feel that the chain doesn’t run quite as smoothly in the 9, but if you geared your chainring properly for your needs, you won’t be in that cog all day. Plus, most riders aren’t likely to be laying down extreme amounts of torque in that gear anyway, so that roughness likely won’t have a detrimental impact on performance for most.
Check out e-thirteen’s website to learn more about the newly released TRS Plus and slightly lighter, noticeably more expensive TRS Race 9-46t cassette here.