e*thirteen e13 12-speed conversion kit shifter sram

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

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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.

e*thirteen e13 cassette 12-speed conversion kit chain trs plus
The e*13 TRS Plus upgrade kit is designed to convert your existing SRAM 1×11 drivetrain to 1×12.

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…

e*thirteen e13 cassette 12-speed
The TRS Plus cassette features a 9-46t ratio to deliver a huge 511% range.

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.

e*thirteen e13 12-speed conversion kit
You’ll need to pull your SRAM 1×11 trigger shifter apart.
e*thirteen e13 12-speed conversion kit
The e*13 ratchet features 12 indexed positions.
e*thirteen e13 derailleur sram x01 12-speed
Jockey wheel spacers are designed to help align the mech with the larger 46t cog.

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.

e*thirteen e13 cassette 12-speed
The cassette splits in two, and uses a lockring to hold the bigger section to your SRAM XD freehub body.

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.

e*thirteen e13 cassette 12-speed derailleur
It took a while to get everything aligned with the 9-46t cassette.

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.

sram e*thirteen derailleur cassette chain conversion kit trs plus
No need to replace your perfectly beaten-up SRAM derailleur with a 12-speed version.

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.

e*thirteen e13 cassette 12-speed sram shifter
Now a 12-speed shifter.

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.

e*thirteen e13 cassette 12-speed
The 511% range is mahoosif.

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.

e*thirteen chain 12-speed
You get a 12-speed chain with the upgrade kit, and it’s performed a-ok throughout testing.

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.


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.

e*thirteen e13 12-speed conversion kit derailleur sram
A clever, and great value way to upcycle your existing SRAM 1×11 drivetrain.

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.


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!

Review Info

Brand: e*thirteen
Product: TRS Plus 12-Speed Upgrade Kit
From: silverfish-uk.com
Price: £289
Tested: by David Hayward for 7 months

David started mountain biking in the 90’s, by which he means “Ineptly jumping a Saracen Kili Racer off anything available in a nearby industrial estate”. After growing up and living in some extremely flat places, David moved to Yorkshire specifically for the mountain biking. This felt like a horrible mistake at first, because the hills are so steep, but you get used to them pretty quickly. Previously, David trifled with road and BMX, but mountain bikes always won. He’s most at peace battering down a rough trail, quietly fixing everything that does to a bike, or trying to figure out if that one click of compression damping has made things marginally better or worse. The inept jumping continues to this day.

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Comments (6)

    Why? GX upgrade kits are available for £50 quid less and work properly without any faffing about. Then you can also get cash back by selling you old kit.
    Admittedly not as posh if you’re already running XO or XX but then you’re getting rid of most of the posh internals anyway.
    No 50t, which is the big selling point of 12 speed to me and if you’re regularly spinning out 36×10 then maybe 1x drivetrains aren’t for you.

    Managed to pick up the shifter conversion separately but not fitted it to my XX1 shifter yet.

    Would be super interested to see if anyone has run the 10-50 cassette on an 11 speed XX1 mech yet.

    £289 is a lot for what is essentially a bodge. I honestly can’t see the point in this over just getting a GX Eagle upgrade kit that’s designed to be 12 speed in the first place.

    I was actually interested till I saw the price. £80- £100 less and I could have been tempted.

    Sorry, I’m lost here. The only selling point to me of 12 speed is a bigger range of gears – but ethirteen already make an 11 speed 9-46 cassette.

    My 5 cents about this product running on it for 4 months now and around 10 races. I’ve upgraded my x01 11s and changed the chainring and pulley wheels to a new one since my chain and chainring was not in very good shape. The conversion went smoothly and i was happy from it while cycling on flat or doing some moderate marathons. Then i’ve started seeing some strange problems:
    1. The chain has tendencies to drop and stuck between the derailleur cage and a pulley ring (had it several times)
    2. The pulley wheels extender is pushing the bearing out (especially after tough XC races it was visible).

    I’ve spoken about that with e13 and they didn’t find any problem with my setup. To overcome 2nd issue i glued in bearings anyhow didn’t find any reasonable solution for 1st issue. Unfortunately it lead to massive damage in my bike – while racing the chain went out of the pulley wheel and i hardly pulled the derailleur twisting it and pulling into the wheel. I ended up with massive damage:
    1. Rear wheel damaged – spoke was ripped off from the carbon rim – i had to rebuild the wheel (new rim and spokes+cost of rebuild!)
    2. derailleur hanger crashed
    3. x01 derailleur crashed
    4. Damaged (twisted) chain!

    so this all together costed me more than new xx1 eagle groupset

    I’ve decided not to give up and bought new eagle xx1 derailleur and chain. Since then situation has changed significantly – no chain stucks, shifting is much smoother anyhow this is not the end.

    Around a month ago while training on XC course i’ve changed too many gears (3-4?) going uphill and i’ve managed to bend the biggest steel cog! I’ve spent a few hours tunning the derailleur since i was suspecting something could be wrong with it or a hanger (never had it before). Anyhow i managed to straighten it finally – since then i am trying as much as i can not to change gears under load…
    I don’t know how strong eagle xx1 cassette is anyhow my previous xx1 11s lasted (and it’s still alive) for 2 seasons (in fact years since i am riding regularly and occasionally racing during winter) so approx 2-3k racing kms. Obviously i didn’t change the style i use it or preferred routes so it is a concern for me.

    Very recently i noticed that there is something wrong with stiffing on 2 biggest cogs – when i am pushing hard on 2nd and the hill requires to change for biggest gear it very often results in chain skip. It makes me crazy. I am not sure it’s because of the chain (i believe the one from YBN is more flexible sideways than XX1) or something else (premature alu cog damage?) I’ve also tried from 3rd biggest to 2nd under load and in this works fine if you can accept it makes unpleasant noise which makes me a bit worried.
    We’ll see how it will work longer term. I’ve bought new YBN chain so i will change xx1 to this one and will see if this is improving the situation.

    Oh – one more think i didn’t mention earlier (not that annoying for me) on smallest cog (9t) i’ve noticed chain skips both on modified 11s x01 and new eagle xx1 when i was going over rough terrain.
    And last but important – i am running it on HT – so less challenging situation than FS.

    As i mentioned above – it’s my 1st 12s system so i have no comparison to full eagle system – hard to say if i would encounter the same issues with Shimano or Sram.

    Price wise – it’s great deal – to buy a cassette from Sram, Shimano, or others like Leonardi or Garbaruk will cost you more than here cassette + great chain + obviously the rest.

    I’m running this currently. Coming from X01 to the e13, as noted, the shifting is acceptable, but the drop onto the 9t cog is a little sluggish…I’ll be trying different combos of the jockey spacers as mentioned. Overall, the biggest thing I noticed was the sound, the e13 cassette is much quieter than my old 11sp GX (factory) cassette. Some have mentioned the cost difference…here in the States, the conversion is about $100 cheaper than GX Eagle (no cranks), and that was worthwhile for me. I’m really looking forward to being able to rebuild specific parts of the 2-piece cassette, as required because of wear. E13 will have the individual components available with their new website shortly, according to their support team.

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