Photo c. Surly Bikes

If you have to ask why, the Surly Big Fat Dummy is probably not for you. But for those looking for a cargo bike that is stiffer, more capable, and will monster over anything in its path, look no further. If you’re not familiar with the original Big Dummy, it’s an extended wheelbase cargo bike that sort of set the scene for two wheeled cargo bikes to come. Long offered in 26″ wheels, the Big Fat Dummy is still 26″, just a whole lot fatter…


Starting with a completely new frame, Surly points out that this is not just a widened Big Dummy. Instead it’s a new bike that drastically increases the tire clearance, but also adds some other benefits at the same time. Just how big of tires will the Big Fat Dummy Run? Apparently, Surly went straight for the biggest, baddest tire that doesn’t even exist yet – a gargantuan 26 x 5.25″. That’s almost another whole tire more than the stock 26 x 3.8″ Nate.


The reason for the smaller tire spec is that in order to fit bigger tires, you run into some drivetrain limitations. Fitting a 197mm thru axle fat bike hub in a frame with 5″ tires and still clearing the tire with the tandem length chain while maintaining Q-factor turns out to be pretty tricky. But they figured it out. For the complete breakdown on every possible configuration, consult the chart above or check out the post on Surly’s Blog. The short of it is that the bike comes stock with wide Q-Factor cranks and 3.8″ tires on 80mm rims to allow for a 2×11 drivetrain – since low gearing is appreciated when pedaling up to 400 lbs (total weight limit including rider and bike). If you want to run bigger tires you’re gonna have to run a 1x drivetrain or lose some of the inboard gears on your cassette, but there are a lot of options to suit your needs. It’s like a ‘choose your own adventure’ book of booze-fueled trips to the grocery store. Surly also added new cast dropouts that run a thru axle, but are slotted to allow the wheel to drop out of the frame without removing the thru axle – this is to make wheel changes easier when fully loaded with bags since they interfere with the axle being removed.


Other important changes include updated geometry with a slacker head tube angle to make plowing into things a little less abusive. Riding a fully loaded extended wheelbase bike apparently makes it hard to lift the front end, so the slacker head tube and the ability to run a 100mm suspension fork in the 44mm head tube should help. The frame is also internal dropper post capable should you choose to go that route.



The Big Fat Dummy retains all of its cargo ability, though a few things did change. Namely, the top Xtracycle deck which had to be widened to fit the frame. The Dummy Rails and bags will still work, but Surly says the width and the Dual Wideloader mounts have changed so accessories at those to spots will not fit.

With a claimed weight of 54 lbs, 4oz, the 4130 Chromoly frame and complete build kit adds on 5lb 12oz to the original Big Dummy. Availability is estimated for April/May, and price is TBD.


    • Gef on

      I learned that the hard way. Loaded 4 car wheels/tires on my cargo bike, and struggled very much. Got home and my wife mentioned that I should have just hooked up the trailer, she was right of course. They each have their advantages and disadvantages, so may as well have both.

    • Champs on

      Trailers are how I roll and they’re fine. In fact, they’re still the best when it comes to space and cost.

      On the other hand, trailers are slosh-prone and can’t carry adults. I could live with those limitations until they were broken by a bike that can handle almost any non-technical terrain. It almost makes me want to live where there’s lots of snow.

  1. Gef on

    Seems like they could have engineered something to have a normal q factor, given the real estate they have to work with. It is exciting, I think super fat tires are a good fit for heavy loads.

  2. ShaneAtSilca on

    I’m surprised it took this long for them to do a Fat Dummy.
    I’ve had my big dummy since they were first released, and always expected a variant like this to come along. I was planning on rebuilding my original this winter…. maybe I’ll hold off.

  3. Von Kruiser on

    Use my cargo bike weekly when going to the market and love it. However it’s a heavy, big machine perfect for city use but an offroad version would be extremely slow on or offroad. Seems like a niche within a niche. How many units would they really sell annually? Feel for the purchasing mgr who has to forecast what “some” crazy PD mgrs get signed off somehow. Now an electric version of this might be cool but expensive.

    • Groghunter on

      I’m looking at one for backcountry trail work. the easier I can haul camping gear plus saws, the easier we can keep trails clear.

    • HDManitoba on

      That is how Surly has rolled since the beginning. How many people wanted a dedicated singlespeed in 1999? Or a fixed gear road bike in 2001? Or a fat bike in 2006? Or a cargo bike in 2007?

      Its pretty cool that a company that has resources to make reasonably affordable stuff uses those resources to make weird but very versatile, quality stuff. Not everybody who wants these oddities has the money it would take to get a custom built frame, not to mention all the special stuff needed to make them work.

      • Old School on

        enough people wanted the single speed for Bianchi to offer it 1 or 2 years before Surly and they’d been offering the Pista for who knows how long. The cargo bike was a dedicated development from the extracycle that proved the market and was in fact compatible with extracycle parts. I’ll give them the fat bike.

  4. Von Kruiser on

    Sorry, my bad. I do not live where it snows so this would be perfect in the North for all year use. Was not thinking about snow for some silly reason… duh.

  5. .: r|b :. on

    This bike fills a different niche but IMO Larry vs. Harry eBullitt with Shimano STePS pedal assist & Alfine Di2 is the best cargo bike on the market. We got one to haul the kids around and for bigger grocery runs and it kicks ass. Initially was a shock to the system considering I was used to only spinning feather weight carbon Bianchi and Canyons with Dura Ace Di2 but the eBullitt has been a great investment.

    The only downside is that I’ve busted the same homeless crackhead trying to figure how to steal it…twice.

  6. Reverend Dick on

    Uh, yes, I didn’t read the article and have never used the product but i have opinions and would now like to turn the attention to what we are all really interested in: ME. Me and my bikes and experience and wants.

    • OldDocThedan on

      I only read most BR posts for the comments.
      And yep- you pretty much summed it all up.
      But the truth of your words doesn’t take away from the hilarity of some posts.

  7. pierre on

    Extraordinary bike.

    I have the current version and will never sold this bike.

    The evo is just perfect.

    For haters or doubting people, just try this cargo and make a real honest opinion.

    Nobody who tried mine had was disapointed.

    Solid as a rock, comfy and versatile, its a real original project.

    Sorry for my bad english. 😉


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