Joe’s wheels: 29″ wheels for Surly Pugsley

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Wheels for Joe Cruz.


Front 29″ wheel for offset Pugsley fork

Rim: Velocity Synergy O/C

ERD: 604 mm

Spoke bed offset: -4mm/+4mm

Hub: Surly Ultra New Singlespeed Disc, 135mm

Center-Flange: 34mm/38.5mm

Flange diameter:58mm/58mm

Spoke hole diameter: 2.4mm

Hub offset: 17.5mm

Spokes: DT Swiss Champion, 2.0mm

Number: 32

Cross pattern: 3x

Left Right
Spoke length 291.7mm 295.5mm
Bracing angle 4.1° 10.1°
Tension distribution 100% 41%


Rear 29″ wheel for offset Pugsley frame:

Rim: Velocity Synergy O/C

ERD: 604mm

Spoke bed offset: -4/+4

Hub: SRAM X7

Center-flange: 34.5mm/20.5mm

Flange diameter: 58mm/45mm

Spoke hole diameter: 2.4mm

Hub offset: 17.5mm

Spokes: DT Swiss Champion, 2.0mm

Number: 32

Cross pattern: 3x

Left Right
Spoke length 291.7mm 294.9mm
Bracing angle 4.1° 6.6°
Tension distribution 100% 62%


All calculations and graphics from Freespoke.

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21 thoughts on “Joe’s wheels: 29″ wheels for Surly Pugsley

  1. That’s very nice Nick, I went with almost the same setup but used a 506 hub and a machined rim – these parts are quite hard to get in Europe. What do you think of the build? I’ve only had about 120 km on mine, running skinny 32 conti rubber but absolutely love it so far. Pugs makes for a great and agile road bike. The freespoke numbers also look great, don’t they?
    Thanks for sharing.

    • I selected the X7 hub because it has cartridge bearings, for only a few dollars more than the 506. If the freehub proves to be reliable, this may be the hub that we have been looking for! Many of us have had issues with Shimano disc hubs loosening in the rear. The price of the X7; in the States is about $50-55, more than a Deore and less than an XT.

      The rims are machined Synergy O/C rims as well. I tensioned the wheels conservatively in reference to this older article warning against some limited failures due to high tension:

      I presume the manufacturer has sorted out these problems, but at high tension the eyelets began to lift away from the rim, so I avoided any additional tension. I would have liked just a little more tension, but I figured too loose and the wheels may need adjustments in the future…too tight could lead to failures.

      I also considered some options to build a better front wheel, without using a rear hub with a hefty freehub body attached. For a minute, I had planned to build with an inexpensive cassette-style singlespeed hub (Origin 8), which may have improved spoke angles a bit. I couldn’t verify any hub info from the distributor before the build, so I went with the Surly hub– simple and reliable.

      The wheels are in the mail, so at this point it will be up to Joe to share his thoughts. Hopefully they will run straight and strong for many miles. On such experimental wheels I would have preferred to put some miles on them myself. Oh, and I dished the wheel about a mm towards the drive side. As I was getting close to a perfectly centered wheel, I figured one mm or so towards the drive side will help the wheel, and the frame has plenty of clearance for it.

      I built a similar wheel with a non-offset rim (Salsa Disc Semi-29) last spring and it held up fine over a couple hundred miles of riding in town. I’ve seen many others in Anchorage that have been riding for years.


      • Thanks Nicholas, I definitely tensioned my spokes higher than you – though I didn’t notice any odd stuff happening to the eyelets on my rim. Before committing to the build I have approached Velocity regarding the cracks. They were cool to deal with, addressed this and all my questions – apparently it was due to some manufacture issue and things are sorted now. I’ll keep a close eye on it though.


    • A little funny, as you might expect. The drive-side spokes are undertensioned for sure, although not quite “soft”. This probably would’t be the ideal drive wheel, especially for hard SS use. The spokes exiting the outside of the drive-side flange also take a hard turn towards the rim. The rear wheel came out very nicely.

  2. Nick—Thanks for the build! I look forward to receiving the wheels and giving a full assessment, acknowledging the experimental nature of the endeavor. Wouldn’t have it any other way, really.


  3. I’ve considered building some 29er wheels for my Pugsley as well. If you use the Surly Rabbit Hole rims you get nice spoke tension at the cost of 200g per wheel over something like the Synergys.

    I’ve pretty much talked myself out of that and into keeping my Pugs fat and having a dedicated 29er MTB in the garage since I have the space.

    I’ll be keen to see how the Synergys hold up over time. Thanks for posting the info.



    • Vik,

      According to manufacturer specs (and eyeball verification) the spoke holes on the Rabbit Holes are offset 5mm, while the Synergys are 4mm. Given the small difference, this did not influence Joe’s decision. Even with a RH rim, the front wheel is pretty weird (assuming an offset Pug fork and Surly SS hub)

      The Necromancer configuration actually works out to be a nice platform for 29″ wheels, as a symmetrical 135m fork is used.


      • All of this debate continues to pique my interest. Although the Rabbit Holes appear to be a great choice, and I quite enjoyed riding the Krampus, the greater expense of a full-on Krampus wheel/tire setup, and somewhat of a purpose overlap with my NecroPug’s stock wheel/tire might make me lean toward more typical 29er rims. That would also allow me to use standard 29er (or even skinnier 700c) tires if I so desired.

        Then again, I’ve gone fat and I don’t know if I really want/need to go back. In any case, great job on the wheel build, and I look forward to hearing Joe’s take on how it all plays out.

      • I had the RHs pegged at 7mm offset. Too bad Surly didn’t spread them even a bit further apart.

        The symmetrical Necro fork builds a nicer 29er wheel, but it’s going to need to be funky with the 135mm front hub and you can’t swap the wheels front to back so you might as well use a normal 29er front wheel in a 100mm Pugs fork. For the $99 to buy a new fork it’s worth being able to use a normal 29er wheel if you have other bikes that can share it.

        It’s a bummer building expensive wheels that you can’t use on more than 1 bike in the garage.

        All in all I think I’m keeping my Pugsley fat.

  4. Why the choice of a 23mm rim like the Synergy, which seems narrow in this context? Why not the Blunt, Blunt 35, P35 or whatever they call it? Was it eyelets, cost, need for rim brakes? It is interesting to see people using non-fat specific wheels on these frames. It would seem that there could be BB height/pedal strike issues coming out of lowering the bike as you would. What are the motivations for doing this? To gain access to more types and styles of tire, or is it a desire to try and make the Pug/Necrolander be an “all rounder”. It seems like a possible misuse of frame design to put something like slick 32mm tires on bikes like these. I’m not trying to be overly critical, just curious to hear the reasons and benefits of doing this build and conversion.

    • 23mm rims aren’t narrow for touring or XC type tires. The Synergy was chosen because of the 4mm spoke hole offset, which improves the spoke angles and tension considerably. The bike is not lowered with a 700c/29″ wheel, no matter the tire size. The Synergy is the only offset rim available in 700c/29″.

      I ran a 2.35″ tire on my 26″ Marge Lites, which lowered the BB, but only to the point that is was the same distance from the ground as a Surly LHT frame. The bike was great on pavement and mild dirt roads and allowed me to pass several thousand miles of roads through Canada this summer before refitting fat tires (3.8″) in Montana.

      This is not a conversion, but simply one of many uses for the frame.

      • Hmm interesting. I had assumed the bike was a pug, which is 26″ and didn’t catch that one was fitting 700c wheels with smaller tires in the frame. I had thought you built up another set of 26″ wheels, that was why I asked about BB height etc. It is crazy that one can fit 700c wheels in a Pug/Necro/lander. It still seems like a conversion to me but that is neither here nor there honestly.

        Still, if you can fit a wide tire, and are running disc brakes, why not use a wider rim? Sure 23mm wide rims are standard for touring bikes and some other Road and Cross rims, but why not max out the rim width and get a better tire profile. Again splitting hairs with a few mm I guess.

        It seems though that the driving force for the choice of rim was the need for offset? Was this what you were talking about with the 4mm, or are you speaking to how the eyelets are offset from each other in the spoke bed of the rim? Is the offset of the rim to help build a better wheel due to the frame and fork offset?

        Maybe I should just go read your site more thoroughly and I would probably have these questions answered. Thanks.

      • Mr. Grumpy,

        Yes, the Pugsley frame is built with a 17.5mm offset to allow the use of wide rims/tires AND a full mountain bike drivetrain. The other way to accomplish this feat is to use a very wide rear hub, 170mm or wider. The solution on the Surly Pugsley frame (and others) is to pair an offset frame with a wheel that is build asymmetrically. Fatbike rims allow wheels to be build with spoke hole offset greater than 10mm (from the center line of the rim). In total, this puts the wheel along the centerline of the bike, allowing big tires and lots of gears, all using standard 135mm mtb hubs. These days, there are a lot for options for 170mm hubs, although 135mm hubs are still cheaper and easier to find, but wheelbuilding requires some of the trickery we have studied above. Additionally, Rohloff hubs and other IGHs cannot usually be manipulated to work on frames designed for 170mm hubs, so the design of the Pugsley is still valid for these purposes.

        This post shows some assym fatbike rims, and explains how I see the fatbike as a tool for all seasons, if not always with “fat” tires:

        Again, the Synergy was chosen because it is the only offset rim available for 700c/29″ wheels. It greatly improves spoke angles and tension. The only other option in this category is the new Surly Rabbit Hole rim (designed for the Surly Krampus, with 29×3.0″ tires), which is so wide at 50mm that it excludes the use of narrower tires. The Synergy will happily accept commuting and touring tires, studded 700c/29″ tires in winter, XC mtb tires in summer, and anything in between. The outside wheel diameter of 29″ tires and 26″ fatbike tires is almost exactly equal. Fatbike owners have been building “summer wheelsets” for years, so that their bikes can see all-season use.

        Can a fatbike be ridden when the snow melts? Certainly, I toured from Alaska to New Mexico on my Pugsley this past summer. Joe has ridden the length of South America on his Pugsley. Check out Joe’s travels here:

        This is not a conversion as it is not intended to be permanent. It will remain as one of several options for Joe to choose from throughout the year.


  5. Nicholas,

    Thank you for the thorough response.

    It has been interesting watching from the periphery the fatbike market grow so much over the past five years or so. I haven’t interacted or really paid much attention to Fatbikes until recently when we got a Moonlaner demo bike into the shop I work at. It is interesting to see how folks use these bikes, the versatility, strengths and limitations, how they are talked about and promoted, etc. I’ve also been thinking about where and when fatbikes are appropriate and when they are less so in terms of ones physical location and riding preferences and style.

    Again, thanks for talking me through this particular topic.


  6. Thanks for the detailed discussion. I’ve been looking forward to reading about these wheels since you mentioned it back in January.

    Sorry to zombify a dead thread, but, not being wise in the ways of wheelbuilding science, I want to be sure I understand.

    Seems to me that, if availability and price were no issue, the ideal fatbike configuration would be a symmetrical frame/fork with 170mm spacing fore and aft, allowing non-offset wheels of both fat and 29-inch variety as well as fore/aft swappability.

    Sticking with the more easily available offset frame/fork with 135mm spacing, we would prefer a variety of mid-wide rims—such as Psycho, P35, or Gordo—available with offset drilling.

    Am I correct?


    • Bob,

      I think you are right about this. I’m not sure that fore/aft swappability is a big feature for a lot of people (this wasn’t even a feature until the Pugsley, or the custom designs that preceded it), but it seems to be on the list of features that some people are looking for. Of course, freehubs do fail and fatbikes can take you into some nasty conditions.

      Scott Felter’s new longtail fatbike by Rick Hunter shown at NAHBS uses a 170mm spacing front and rear.

      I think offset drilled rims in all sizes should be more widely available, as all normal multi-speed derailleur wheels would benefit from a few mm offset. Offset 29″ wheels for fatbikes benefit by using the rim in the opposite orientation.

      Here is a “normal” 29″ rear wheel that takes advantage of the offset on the new Surly Rabbit Hole rim:


  7. Phew, thanks, Nick, for fielding all these questions about my motivations! You’ve reported them exactly correctly, and I really appreciate the fine wheel build. Serious testing is coming soon.

    I’m also appreciating the discussion, above, as it’s showing a way people might think about their Pugsleys or other fatbikes. The only thing I’ll add is that, yes, I have a bunch of 2-9 bikes that I absolutely love for local trailriding and short trip bikepacking. On the other hand, the Pugs is the bike I’ve spent the most sheer hours on over the last three years. As a result, the setup, the configuration, the braze-ons, the familiarity of the quirks and parts are all such that it’s the bike that I’d like to be able to grab for any ride, including slick tire high speed touring. Now I can.

    All the best, all

    • Ben, I rode 60mm+ Big Apple tires on 65mm rims for several thousand miles of pavement, including several hundred miles of dirt roads, and a few bits of doublesingletrack. I was using big platform pedals at the time (Suntour XCII) and only noticed pedal clearance issues on rutted tracks, and when larger rocks protruded from dirt roads. Otherwise, it was a great all-day pedaling set-up. Personally, if I was building a new set of wheels I would build the 700/29″ wheelset like I did for Joe, for both road riding and XC-mountain biking. Otherwise, the 26″ version would be more of a “road-only” wheelset.

      Any chance you’ve got 65mm rims? A 2.35″ Schwalbe Big Apple or Fat Frank tire might be a cheaper solution than a new set of wheels.

      • Funny you should mention that..

        Thanks to this blog, I’ve currently got a pair of Big Apples Mounted to some Large Marge’s. Works a treat (thanks!), but man those rims are heavy… I was just thinking that it would be nice to have a set of ‘road’ wheels for the Pugs, and I can get a great deal on some Synergy OC’s in 559.

        That, and I have some 559 tires already, nothing in 700c.

        I should probably just wait until I’ve got several hundred miles on the Pugsley, and then decide which way to go.

        Thanks again for the input. I really enjoy the blog.

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