Review | Upcycle your SRAM 1×11 drivetrain with the e*thirteen TRS Plus 12-Speed Upgrade Kit

This clever e*thirteen TRS Plus 12 Speed Upgrade Kit is designed to upgrade your SRAM 1×11 drivetrain to 1×12

Five or so years back, 1x drivetrains were fairly new, and making cheaper ones by converting existing cassettes with expander cogs was all the rage for a bit. I steered clear at the time, because it seemed like a slightly messy hack at best.

The conversion part of the e*13 12-Speed Upgrade Kit mostly happens at the shifter end though, with new innards for 11-speed SRAM GX, X1, X01 or XX1 shifters. As well as those, inside the box you’ll find a new cassette, some jockey wheel spacers, and a 12-speed chain.

Unlike with those expander cogs mentioned above, the 9-46t TRS Plus cassette is made entirely by e*thirteen. It has a 511% range, which is 10% more than SRAM’s 10-50t Eagle, and 1% more than Shimano’s new 10-51t XTR.

Thanks to a few very straight, very open downhills near me, the TRS Plus had been tempting me with a siren call something like “niiine tooooth sprooocket“. Sounds fast…

Fitting The e*thirteen TRS Plus 12-Speed Upgrade Kit

Considering shifters are full of springs and cables, monkeying around inside one was by far the most terrifying part of this, but it was surprisingly easy.

The little three pronged claw tool included with this kit acts as a base to bolt most of the shifter down to while you work on it, stopping anything from springing out. Very straightforward, and your shifter goes back together with an extra click.

The e*13 cassette too is nice and easy to fit, and at 336g, not a boat anchor. While it needs an XD driver, it doesn’t quite use the same interface. The larger, alloy sprockets go on first, and cinch down with a collar rather than screwing onto the XD threads.

Then, a plastic bushing goes on, and the steel part of the cassette pushes on at a particular orientation, turns a little to lock into place, gets bolted down to the alloy section, and you’re done. If you wear part of your cassette out, e*thirteen also sells the alloy and steel sections separately.

The only other thing to alter is the mech, which apparently needs the jockey wheels spaced further in toward the spokes in order to reach the 46t sprocket. This is a fairly simple matter of removing half your mech cage and the jockey wheels, then replacing it with the spacers and longer fixings provided.

Indexing & Setup

At first, I could not get this into the 9t cog, no matter how many times I reindexed. Wondering if they were a bit stiff, I tried penetrating oil on the pivots in the derailleur parallelogram, and also turned them a third of a turn with some needlenose pliers. I wondered if the spring in the mech was previously damaged. I double checked the mounting. Still no joy.

Going back to examine the mech movement closely, I realised the total range allowed by the limit screw range was slightly off compared to the cassette. In this case, for this wheel and bike, dropping the cage spacers from the kit fixed it. This is probably down to my frame, as I tried several different rear hubs with the same results. With the spacers, the 9t was impossible to reach, but without them, my mech could still always reach the 46t before hitting the limit screw.

Rather than worry about this, I dropped the jockey wheel spacers, indexed the gears and was certain the limit screws would prevent the chain from doing anything nasty, so rode it. It could be a bit sluggish to drop into the 9 tooth from time to time, but as I found later, that was down to the mech hanger.

It’s worth noting here that this kit is pushing hardware designed for 11-speed to its absolute limits, eking every last bit of movement it can out of them. Additionally, it’s far more likely you’ll be using this kit for a drivetrain refresh rather than converting brand new 11-speed. As such, there might be more parts of your drivetrain that need a tuneup before this will run perfectly…

Doing The Job Again, Properly

I got away with it for a few months, but as the test went on it was obvious my shifting was getting a little worse. I tried to tough it out, then decided to take a good look – it wasn’t any fault of the TRS+ kit, just that it had been put on a three year old mech that needed a bit more TLC than I’d given it.

I’d popped some fresh bearings in them recently, but the teeth on the jockey wheels were now worn well beyond their useful life. While swapping them out I also checked and straightened my mech hanger too – it had obviously had a smack or two. After three years, it was overdue some fresh gear outer too.

With all of that done, I reindexed and it was like a new drivetrain. It still worked best without the jockey wheel spacers, but all the shifts were prompt, up and down.

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The Ride

Now, because e*thirteen doesn’t have SRAM or Shimano’s R&D budget, and because as mentioned they’ve made a conversion kit that pushes 11-speed mechs pretty hard, don’t expect the shifting to be quite as clean as XX1 or X01 if you’re used to that. That said, the TRS+ upgrade kit works a lot better than some other modifications and third party cassettes I’ve ridden.

One thing that really shines on this is that, in the 46t sprocket, back-pedalling doesn’t cause it to move down the cassette at all. Unlike some drivetrains, it stays in gear when run backwards. This is obviously very good for attempting steep technical climbing challenges, where you may need to ratchet your pedals. One of the selling points e*thirteen list is the chainline, and it does seem to be good.

For me, the minor tradeoff in shifting performance compared to X01 is worth it, as I have more gear range. I’ve chosen to expand that range by having a slightly harder climbing gear, but getting a much higher top end. So I’ve 36-46 for climbs, which is okay for winch and plummet, but I probably wouldn’t do a fifty mile XC loop on it.

At the other end it has a whopping 4:1 ratio for blasting down stuff – though it is a little tall for spinning along on the flat with sticky tyres. That high gear without losing climbing ability is what I saw the potential for when I first read of the TRS+ upgrade kit, and it’s delivered in spades.

In the past seven months, it’s seen everything from choking dust clouds to Pennine grit and filth. Shifting is still good. Last summer I broke the chain once, but that was an unlucky rock hitting it at speed. 12-speed quicklink in, and it’s been fine since.

One thing I noticed was that, as the inner cable got gummy, the last shift down into the 9t cog lost its click. Fresh outer and cable sorted this and made it affirmative once more. Again, this just seems to be a side effect of pushing hardware closer to its mechanical limits.

Removal

I removed this to photograph recently, and it had been long enough I’d forgotten how to remove the cassette. It was also a tiny bit stuck on, but a little wiggling persuaded it. There’s good documentation on the manufacturer website, though I’d like to see downloadable versions for future reference – it’s not uncommon I end up wanting to service bits that are discontinued, and without the local folder I keep stuffed full of PDFs relevant to my bikes, I’d be lost sometimes.

The design of the cassette made it very easy to scrub clean in a small bath of degreaser, as it has no hidden nooks or obstructions to a toothbrush.

In all, cassette wear after eight months is acceptable, shifting is still good, and the chain is still nowhere near 0.75 worn. And no, that nine tooth cog has not exploded or worn horribly. For further proof, check out James’ separate review of the e*thirteen 11-speed TRS Plus 9-46t cassette.

Overall

This upgrade kit turns it up to twelve with a nice balance of performance, weight and price. This kit isn’t necessarily cheaper than part replacement costs for a drivetrain with a high end cassette, but the TRS+ has an enormous range compared to 11 speed, performs well, and is much cheaper than a new groupset.

Looking for some more options to expand the range of your drivetrain? Then check out our list of 8 huge cassettes for 1x drivetrains that aren’t Shimano or SRAM!

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