Although it is 2018 and SRAM now has 3 different levels of their newest drivetrain available, known as the 12-speed “Eagle”, I have not jumped on the bandwagon. At least not yet.
First, some context & history for you about why so many riders have been talking about or adopting the 12 speed system over the last couple of years.
Initially, the cost of entry was very high for the XX1 Eagle and X01 Eagle drivetrain group sets. They debuted exactly 2 years ago, but cost of these group sets were $1480 & $1193 respectively. The most enticing attribute was the 500% gear range cassette that showcased a huge 10-50t ultra wide range. The cassettes alone retailed for $420 & $360 respectively.
Two years later, and SRAM now has the GX Eagle available, unveiled in June 2017, which is a lot more budget-friendly at $500 for the group set. The 10-50t GX Eagle cassette only retails for $195, but while it will give you the same 500% gear range, it weighs substantially more than its brethren at 450g. The XX1 Eagle & X01 Eagle 10-50t cassettes both weigh 355g.
The thing I was most excited about when SRAM unveiled their XD driver, way back at Interbike in 2012, was the fact that they built it similar to a BMX driver which allowed for cogs smaller than 11t to be installed. Bike Radar reported that SRAM’s “Testing proved that a 9 tooth cog was too small to be pedalled comfortably. Such a small cog caused a shuddering sensation when pedalled under load. This is due to a phenomenon known as the “polygon effect,” which results from variations in speed as the chain transitions from one cog to the next.”
I thought to myself, “So why are so many BMX riders using a 9t driver if it pedals so horribly?”
The difference between a 10t and 9t cog seems small. 1 tooth. How much difference would that really make anyway? How much difference is there between 11t and 10t? Is it just cool to have a smaller cog so it sounds like a wider range? If you look at a gear calculator, like the one HERE, you will see that a 32t chainring combined with a 11t, 10t, or 9t cog produce significantly different speeds at 80RPM.
32×11 @ 80RPM =20 MPH
32×10 @ 80RPM =22 MPH
32×9 @ 80RPM =24.5 MPH
The Trek Stache I have been riding as my main rig over the last year has a maximum chainring size of 32t as recommended by Trek because of the elevated chainstay design used on the frame.
Check out the Bike Check video below to see all the components & accessories currently on my Trek Stache and why I chose them.
Because the maximum number of teeth possible for a chainring on the Stache is 32, and only a 1x drivetrain is possible, I wanted a very wide a range, but even more than that, I wanted the highest top speed possible. You see, I ride around Lake Hodges very frequently, and that means 10+ miles of my 20 mile loop are very flat. In order to get in the full 20 miles within my normally allotted timeframe of >2 hours, that means that my average speed has to be above 10 MPH. To achieve this, having my top speed more than double that is essential. 32×10 would be great, but 32×9 would be even better since I can often hit 25 MPH on very slight downhill sections if pedaling hard on 2×10 drivetrain rigs.
I heard about the e-Thirteen TRS cassettes in years past, but hadn’t heard from any friends who had been using them on their bikes. I looked them up and found that they had a 10 speed cassette. I was stoked because I still had a 10 speed Shimano XT shifter and a 10 speed Shimano XT rear derailleur installed on the Stache. The 10 speed TRS+ cassette from e-Thirteen is a very wide range at 9-42t, which gives a 467% gear range, only costs $279, and weighs in at 300g. This obviously doesn’t yield the same gear range of the 12 speed SRAM Eagle cassette at 500% for the 10-50t, but it does provide a higher top speed. What is really cool about the e.13 TRS+ cassettes is that they allow for replacement of the few largest cogs. The cluster of aluminum cogs on the TRS+ cassette are held on the same spider. Two cogs are held on that spider for the 10 speed model, while 3 are held to the spider for the 11 speed model (cost is $309, weight is 320g). The 11 speed 3 cog spider can replace the 2 cog spider to upgrade from 10 speed to 11 speed when the time comes, and only costs $104. I plan to test this scenario in the coming months. The largest 11 speed cog in this scenario is a 44t which would yield a gear range of 489%. In more recent years, e.13 released a new model of their 11 speed cassette with an even wider range. Now the cassette carries cogs from 9-46t, resulting in a 511% gear range!
I plan to test this new version of the cassette in the future as well.
For now, listen to my initial thoughts on the e.13 TRS+ cassette while watching me unbox it and the installation tool it comes with in the video below.