Surly ExtraTerrestrial Tires: First Ride Impressions

ET is back! Here’s our thoughts, and initial riding impressions, on Surly’s first dedicated, dirt road touring tire for here on Planet Earth.

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We’re not quite sure how they do it, but Surly appear to draw from an inexhaustible well of awesome product names. The latest in name calling greatness is their ExtraTerrestrial tire, which is, appropriately enough, designed for lands far away. Also synonymous with the brand is size; as such, the ET is pretty much the biggest volume, dirt road touring tire on the market, at 2.5in in width.

Tread wise, its unidirectional design is not dissimilar to Schwalbe’s celebrated Marathon series, with extra side knobs to add more bite when cornering off road. Quoting from their press release, Surly claim “a Kevlar cap between the treads for puncture protection, a nylon breaker in the sidewall for cut protection, a pattern molded into the sidewall to help prevent cut propagation, as well as a file tread between the main tread blocks for additional puncture protection.” All of which should help prolong its life as a heavy duty, multi use touring tire with dirt road aspirations.

Surly ExtraTerrestrial Tires for Touring, 26"

  • Surly ExtraTerrestrial Tires for Bike Touring, 26"
  • Surly ExtraTerrestrial Tires for Bike Touring, 26"

But how do they perform on Earth? While we can’t say we’ve had a massive amount of time with the tires so far, at least relative to their intended use, what we’ve experienced has been very positive. To get a better idea of how they’ll fare after a few more thousand miles on the clock, we’ve sent a set to long distance tourer Nick Gault, currently riding dirt roads across South America on his Surly Troll. Touring tires are all about long haul durability, so check back for a long term review.

Surly ExtraTerrestrial Tires for Touring, Big Dummy

In terms of initial impressions though, the tires roll quickly and quietly on pavement, and handle dirt roads with surefooted assurance. The larger volume certainly helps boost comfort levels on a rigid bike, and given how big tires opens up possibilities for lower pressures, there’s good opportunities for optimizing grip. Flats are the bane of tourers and commuters; so far, the tires have proved puncture free, both on bikepacking trips in the UK, a short portion the GDMBR in Colorado, and desert rides around New Mexico. Not wishing to tempt fate, they’ve even been unusually resistant to the goatheads that mine Santa Fe’s city roads.

Surly ExtraTerrestrial Tires for Touring, 26"

No doubt Surly will release a typically detailed blog post listing the intricacies of running such tires on various frames. As far as our testing has revealed, they play fine with a Troll set up with a standard triple and average-width rims (Rhyno Lites, in our case). Note that if you have aspirations of fitting them to 26in Rabbit Hole rims, you’ll need to change out your triple for one of Surly’s nifty O.D. crankset – which pushes the chain line further out, by displacing the middle cog with the smallest, and sacrificing the largest. You’ll also need to position the wheel further back in the dropout (though anyone running a Rohloff Speedhub shouldn’t have any such issues). If fat tires on longtails are your thing, we also noticed a slight grazing of the chain on the tire sidewall in the largest cog on Surly’s Big Dummy when running a triple. It’s not a safety issue, more of an annoyance, and luckily there’s a workaround: place a 4.5 spacer behind the cassette and ditch a cog.

Surly ExtraTerrestrial Tires for Touring, 26"

  • Surly ExtraTerrestrial Tires for Touring, 26"
  • Surly ExtraTerrestrial Tires for Touring, 26"

Surly suggest running the ET with rim widths in the 24-50mm range. If you want numbers, they quote an overall diameter of 688mm, a max casing width of 63.5mm, and a max knob width of 64mm. The tires use a 60 tpi casing; a nice surprise is that they’re officially tubeless compatible too.

Surly ExtraTerrestrial Tires for Touring, 26"

  • Surly ExtraTerrestrial Tires for Touring, 26"
  • Surly ExtraTerrestrial Tires for Touring, 26"

There’s no confirmed weight until the first production batch arrive, but expect them to tip the scales at comfortably less than 1kg a piece, which seems perfectly reasonable considering their size and intended use. Tires should be landing in the US this winter, and spring for rest of the world. Price is set at $60. Oh, and there’s rumour of a 29+ version somewhere in the Surly pipeline…

Surly ExtraTerrestrial Tire Specs

  • Size: 26 x 2.5″
  • ETRTO: 559mm
  • Casing: 60tpi
  • Suggested Rim Width: 24-50mm outer dimension. 19-45mm inner width.
  • Tubeless Ready Bead: Intended to interface with bead hook on Surly / Whisky rims.
  • MSRP: $60
  • Estimated US Instock: Winter 2015/16

Nov 13, 2015 update:

Surly have released a cross sectional diagram detailing the guts of the new ExtraTerrestrial. And we’ve heard back from our tester Nicholas Gault, currently pedaling the Trans Ecuador Mountain Bike Route: “Tires are awesome, so is the route!! Quick email to say both the tires finally arrived a couple of weeks ago and they are freaking awesome. They’re doubled my enjoyment of the trip.”



  • Lewy

    Can you do a report on the Tout Terrain trailer? I would love one of those.

  • Cass Gilbert

    I’m putting together a guide to family bikepacking at the moment; planning to include a review of the Singletrailer. In the meantime… it performs great both on and off road, much smoother than a Chariot over challenging terrain, and noticeably less ‘tug’ when kicking it up to speed. Downsides? Not as versatile in terms of multi-uses, and less carrying capacity than a two wheeler. Also, being a rotationally coupled trailer, it’s easier to sit and spin when climbing, rather than honking out of the saddle, as the trailer will swing from side to side. Cycle Monkey has now become the distributor of the Tout Terrain brand in the US, so they should be available soon… not sure about $$$ though!

  • Looks good! Wonder if they plan on a 700×41 for compatibility with the LHT, Straggler, X-Check family? 29+ for ECR/Krampus? Even a 700×35 for the Pacer/Steamroller would be cool!
    Death to the Schwalbe Marathon Mondial! This looks way nicer!

  • Wakatel Lu’um

    YES! I’ve so wanted some fat touring tyres for my Troll without having to rebuild to wider rims…

  • Eric Timmerman

    I am doing a world tour soon riding dirt as much as possible, on a troll with blunt 35’s. if you were doing this type of trip would you choose: a pair of dirt wizards, dirt wizard in back with a knard in front, or a pair of extra terrestrials? Thanks!

  • Cass Gilbert

    If it’s dirt roads you’re aiming for, I’d perhaps go with ETs. Gives you some extra tire clearance too, and they feel fine on pavement (because there’s inevitably going to be a bunch of that, however much you try and avoid it)

    However, if you’re really obsessed with seeking out the road less traveled – rough and tumble jeep tracks, sand, singletrack etc… – then Knards may be the better choice. Clearance will be tight – planning on running a Rohloff? And I expect they won’t last as long though, so you’ll need to think more about sourcing spares.

    I’m not sure I’d recommend the Dirt Wizard for a world tour, though it’s a great tire for more aggressive mountain biking.

    Let us know how you get on!

  • Eric Timmerman

    Thanks for the advice Cass,

    What i might do is an ET in the back and a knard in the front, i might carry a spare ET for necessary sections. I am a little too scared to go full fat (might be a little too heavy for my taste) and too scared of 29+ due to finding replacement wheels and tires in far off places.

    It seems like the closest to a 26+ touring rig would be a troll with knards up front. A troll can’t really handle knards in the back, so i am stuck trying to find a 2.7, in which case the dirt wizard seem to be the only option. Since dirt wizards are pretty aggressive that leaves me with the ET at 2.5.

    Brief thoughts on routes:
    Great Divide – couple months
    Hymalayas – 3-4 months – laura stone & pikes on bikes routes, annapurna circuit, manali to leh etc. Srinagar to Kathmandu basically.
    SE Asia – 5 months – switching to thinner tires for this part
    Mongolia – 1.5 month – on the steppe
    Europe – 4 months – gypsy by trade and stuff found on routes
    South America – 8 months – pikes on bikes, your routes, and others found on
    South Mexico & Baja Divide – few months or however long

  • dmorg

    I’m planning to use ETs on my trohloff this summer: Pathenkot – Sach Pass – Killar – Srinagar – Leh – Nubra Valley. I might see you on the road. Watch out for a purple troll…

  • Eric Timmerman

    sweet, i’d love to pick your brain about your route, message me at timmermaneric (at)

  • Chris Leydig

    Hi Eric. I ran Knards front and rear on my 20” troll. Clearance in rear is pretty tight and requires moving wheel near end of dropouts and precise alignment/securing using a tuggnut; any dropout slippage will cause rubbing. I also changed to a boost GX crankset (cheaper than Surly alternative) to move the chainline out a bit so I can hit my lowest gear in a 2x setup with no chain rub.

    Problem is still no mud clearance and I got a tire slice running tubeless. The casing is very thin. In the future I may run the ET rear, or a 650bx2.3 which is about same diameter as 26×3. Also be on the lookout for some new 26+ options from WTB – saw one at SeaOtter called Ranger

  • Jon Dicus

    Hey, Chris. Can you say what specific GX crankset you are using. Are you running 2×9? I, too, am needing to resolve chain/tire rubbing issues with Dirt Wizards on my Troll. Right now I am running a 122mm square taper spindle in the BB. Did the GX crankset totally resolve the issue? Otherwise, short of going to the Surly OD, I thought Cass’ idea of adding a spacer and dropping a cog from the cassette would be a good fix.

  • Chris Leydig

    Yeah Jon, I’m running 2×9 and It’s the GX1000 GXP Boost BB model. I got mine off ebay for $133. It totally resolved the issue and I can run Knards. The chain nearly grazes the tire on the lowest combo but as a climbing gear it rarely touches. Again you need to put the axle near the end of dropouts, and use a tugnut to secure/align – at least if you’re using QRs. There’s no mud clearance, though and the chainline isn’t perfect (smallest cog can be troublesome).

  • I ordered a pair of ETs (mounting on DT Swiss FR 570, 33mm outer) for my single speed Troll. I’m running Schwalbe Marathon Mondial 2.15 now and wanted something a bit fatter for my upcoming Burning Man and Great Divide trip (I have two whole days between the trips) in about a month.

    I’m planning to set them up tubeless, and I’ll have some words and pictures on a secondary blog I started:

  • 2 years later … one tire had to go because it developed a bubble on the tread, but the other is still going strong.

    They really shine tubeless on Rabbit Hole rims and seem to roll over everything. They’re fast (enough) on hard pack and pavement/tarmac and do well in moderate mud and sand. Gavel roads? Killer. Actual mountain biking? You bet. Burning Man? They shred in the baby power-on-concrete type environment.

    I plan to replace my current rear (2 year old) ET before my next desert trip in August.

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