Sep 30, 2006

Pugsley Fatbike

A well thoughtout, 'first' dedicated production 'fat bike' frameset:

  • relatively inexpensive
  • versatile amenities brakes, racks and gearing
  • 135mm spacing front and rear, interchangeable
  • clearance for large rims and snow tires
  • solid construction w/ reasonable overall weight

Pat & Kathy's 160 mile bicycle beach ride
from near Hope to Homer,Alaska

Pugsley Canning Stock Route Adventure

Jakub's CSR Pugsley Adventure (from Surly website)

A Report on the 2006 Knik Glacier Expedition


Surly Pugsley Blog

Sand/snow bike build blog

Pugs on Snow

Pugsley Riding Tips

Pugsley Blog

Pugsley Transport

29er SnoCat offset wheelset for a Pugsley

Pugsley at Tour de Felasco

Need Pugsley Snow Bike Setup Help

Pugsley Pics From Today

Large Marge, Setup Info From Surly Spew


Pugsley Chain-line








The premise behind Pugsley’s design is based on the allowance of tires with a larger-than-average footprint. Our frame and fork will accept 4” tires on 26” rims. The floatation and traction gained by using large-volume, low-pressure tires can get you over and through otherwise-unrideable terrain: ice, snow, sand, mud, wet rocks and roots. In many conditions, bigger is better.

There are design problems associated with using wide tires, however: the tire can rub on the chain, the chainstays, and the front derailleur. We’ve addressed these issues by using a 100mm-wide bottom bracket shell and providing an E-type front derailleur mount. The 100mm shell allows us to widen the chainstays for more tire/frame clearance, and it moves the chainrings outward for more chain/tire clearance. An E-type bottom bracket-mounted front derailleur positions the derailleur cage outboard of the tire. In order to maintain a good chainline with this setup, we offset the rear hub 17.5mm to the drive side...the same distance that the chainrings moved outward (compared to a standard chainline). The result is a straight chainline and the ability to use a standard drivetrain (compact mountain triple crankset with a full cassette of cogs on a 135mm-spaced hub) without chain/tire/front derailleur interference. Pugsley has horizontal drops with a derailleur hanger, so you can set it up as a single-speed or internally-geared rig if you don’t want to use derailleurs.

Note: After lacing up some Pugsley offset wheels, we’ve decided to modify some Large Marge rims to give you more disc-side dish and more even spoke tension. Use these special, asymmetrically-drilled (6mm offset) Large Marge rims on the Pugsley. Non-Surly rims, intended for use in Pugsley wheelsets, should be drilled 6-12mm offset to the drive side.

Now, think about trying to shove a 4” (102mm) tire through the dropouts of a fork designed to accept a standard 100mm-wide front hub. Add a disc brake caliper to narrow the gap. It all adds up to a big hassle when trying to get a wheel, with an inflated tire, in and out of the fork. We solved the problem by designing the fork to use a wider hub. Pugsley uses a 135mm hub on the rear, so it seemed logical to use a 135mm hub on the front, too. We offset the fork the same distance as the rear end, so the wheels will be interchangeable. Why would you want interchangeable wheels?

1. If you’re using your rig as a single-speed, differently-sized freewheels can be installed on each wheel to give you high and low gear options

2. You may want a fixed-gear/freewheel option, in case there is a risk of your freewheel seizing up or not engaging when riding in extreme conditions. A fixed cog always moves you forward. And, it can be used to slow you down, if you choose not to use brakes or if your brakes stop working

3. If you use the same model of hub front and rear, you’ll only use 1 or 2 lengths of spokes versus 3 or
4. Less confusion and fewer spare spokes to carry if you’re on a remote tour.

If you decide that you don’t want to use the Pugsley fork, our Instigator fork (as well as many 100mm-travel suspension forks) has the same axle-to-crown length. You’ve got plenty of fork options with this frame.

We provide disc brake tabs on the frame and fork. If you’re using discs, you’ll have to use rear brakes or rear brake adapters for the frame and the fork. Absorb that for a second: rear hub & rear brake on both ends of the bike. Not everybody needs or wants disc brakes, so we also provide 120mm-spaced cantilever pivots for those of you who want to run traditional cantilevers. Keep in mind you’ll need to use our Large Marge rims to use these types of brakes. The pivots are thread-in type, so they’re removable if you don’t want ‘em on there. V-brakes and other types of rim brakes will not work; the tire interferes.

The ride quality of the 1x1 has proven itself over the years, so we decided not to stray too far from the tried and true. Pugsley's geometry is a bit relaxed compared to the 1x1 frame, so the Pugsley is comfortable but still responsive and maneuverable. It handles essentially like a mountain bike, but it is far more stable on and in the slick stuff compared to most bikes. Large-volume tires (we highly recommend the Surly Endomorph 3.7 tires) allow it to float over snow, sand, and mud better than any bike you’ve ridden to date. And, like all our frames, it’s durable, too.

Who should ride Pugsley? Hunters of all types (animal, mineral, or vegetable), beach/desert riders, snow/ice riders, wilderness explorers, and anybody else in need of a bike that will provide extra stability, traction, and floatation when the terrain gets loose and unpredictable. Pugsley was created to go where other bikes may flounder. Who should ride a Pugsley? You should, but you may not realize it yet.


SPECS Pugsley Frameset


100% cro-moly steel. Main triangle is double-butted. TIG-welded

Rear Dropouts:

Surly horizontal dropouts with derailleur hanger. 135mm-spaced. Offset 17.5mm


Cantilever bosses with removable pivots, dual water bottle mounts, top tube cable housing guides for use with continuous housing, fender and rack eyelets

Seatpost :


Seatpost dia:

30.0mm, Surly Constrictor™ included


1-1/8" threadless

Front deraill:


BB shell:

100mm wide, 1.37 x 24t

Chainring clear:

Compact triple: 22-32-44t


Suspension-corrected... 447mm axle to crown, tapered straight blade, 4130 cro-moly. International standard rear disc mount and removable cantilever pivots spaced 120mm apart. 135mm-spaced dropouts, 17.5mm offset

Sizes available:

16", 18", 20" and 22" (measured from the center of the bb to the top of the top tube)


Barney Blue/Purple Pearl Sizzurple


18" medium- 5.66 lb (2.56 kg)
Fork - uncut = 2.52 lb (1.14 kg) uncut


Kuskokwim Kruzer...Miss Pugsley

Want to preface this posting with a big thanks to Surly...after a 10 year hiatus doing any serious expedtion riding here in rural Alaska, your products have renewed my interest...I'm thinking bikes again and waking with new project applications daily...we're creating our own Endomorph society here in rural Alaska...via la' Large Marge!


Link to the PhotoSet here!

Pugsley Kuskokwim River Kruzer Miss Pugsley 'work-bike'...getting the layup standardized...~3/4 the way there!



Surly racks are bombproof, great hardware, a little heavy but nothing a sawsall couldn't fix to modify the surly rear for the front...sealed the cuts with clear enamel nail-polish!


Single Paul Touring canti works well, more than adequate for beach and river riding's simple...key was retro-ing w/a salsa wide hanger - which changes the width and pull angle and enables plenty clearance.


Doug White Duo Freewheel 17/19 is ideal - bravo primo Americano...but need a chaintensioner to make manual gear switching convenient...will add one this week.


Jones Bar...goes full-tilt w/o saying! Once you use one....!

Frame Bagbike_pugs_frtwheelredzzipp_jonesproto1


SURLY NEEDS (thus far):

bottle braze-ons 'under' the downtube for litre fuel / water bottle hanger...every serious fatbiker I know is using a framebag in the main triangle for expeditioning - it's really the only way to go, so use of inside brazeons is limited!

access to rack braze-ons (esp near the head of the fork) are limited...need to move them out-board a/o have some longer bolts and poly spacers...especially for retrofit centering on the pugs offset frameset.

some good options for a cablestop for the cantis (esp the rear).

to get Phil Wood to make a 'real' bottom bracket for the Pugs shell...;)


Martin aoc

Link to the PhotoSet here!


Bear Protection...'not for the meek'

Follow the MTBR thread!

If you're one of those 'gravity fighters' cutting the handle off your toothbrushes to save weight...If you're one of those seasoned Alaskan veterans who likes the peace of mind that comes with carrying some means of 'hey, he's higher on the food chain than I am' bear protection...then this might be a solution for you.

It mounts easily to any bike...anywhere!

It's compact and v.lightweight

With reasonable extension...makes for a
pretty fair fight (read: last resort)

With some really simple safety features

bangstick5 packs one hell of a punch.

Also doubles as shark, sea lion, and stupid human protection.

"The meek shall inherit the earth...but not their rightly place in the food chain!"

To each their own...only in Alaska.

Lubes Summary spreadsheet

Greases...summary spreadsheet
from one of the bearing manufact.suppliers we've used...this is a pretty good summary sheet (albeit slightly outdated) for bearing lubricants / greases:

Link to the AST Lube Table

Note: as you would expect...the oil/mineral based products have limited temp ranges esp. @ minimums...flouros and silicones give extreme performance esp @ the low end...FEI, some of the thickeners are not compatible with bearing seals...don't be surprised by the cost of the aerospace formulas - the space shuttle budgets are traditionally alot higher than that of us expedition fatbikers!

The AST chart does not give indications regarding use of the various lubes is another table with comments that give better indications for application of each specific formula.

Link to AHR International 'all grease' table


IMHO our best resource for greases used in extreme, with the best relationship to winter fatbiking, is NOT 'the slope' BUT 'the Alaska Railroad'...maintenance issues in that industry iare highly researched and applied and here in Alaska they experience similar temps, wet-freeze-thaw and service conditions as us fatbikers...SO...if anyone is in the vacinity of the Alaska Railroad shops down at the port maybe query some of the mechanics, I think we'll get some v. good suggestions.



Exerpts below:


Thus far, the winter winner is....


High Oxidation resistance
Great low temp performance
Seems compatible with plastics
Definately water resistant
At least -100dF cold start temp.

Only grease with properties intact after 3 days in the -140dF.


Cold weather testing

I would suggest the physical characteristics of your lubricants are not completely linear relative to temperture. Testing at -140dF may not be of great value if your extreme riding temp is -60dF. Also - have you testing any anti-seize? Years ago we used it (very lightly) for lube on track bike hubs.



I agree

I'm positive its not linear...and don't get me wrong...this is not a quantitative study by any means...I don't have that kind'a time. real need for a quanititative analysis as all of prominent industry bearing greases we're looking at have extremely comprehensive data sheets that spec out all the important performance criteria (and then some!) need to reinvent.

It is nice to see how accurate some of their data is though...running the greases beyond published low working temps does give us some qualitative indicators. i.e. I want to know when my hubs, hdset and bottom bracket are going 'rock' on me.

As per your suggestion...I will look at the the most prominent and applicable greases and run them from within and outside their published low working temps.

As per the antiSieze...will put some in the mix...not sure how well the antiseize performs in the long term 'wear' category...I assume they're designed as a static coatings more than anything else...will look into it.

Quyana for the input...




Drive Train Mods...

I'm definately NOT a derailleur type'a guy these days...since I was getting a custom frame from Wildfire Mark and building it up as an expedition bike, I let him convince me to put vert drops on it...the idea being make it as versatile as possible...he was correct...w/ the braze-ons, drops and other misc addons worked onto the frameset the bike could be whatever it wants to be!

The Rohloff Internal hub w/ single cog in the back warrants some chain tensioning.

Tried both the Surly Singlulator and the Soulcraft Convert on the Wildfire and Pugsley sets...both tensioners are functionally O K but still create that 'weakest link' - relying on a derailleur-like component hanging off the drop...for me, the Surly was giving me significant chain slap on the bumps nearly throwing the chain, the pulley is of poor quality and it is difficult to set up in the field (need a cone wrench to do it properly)....the Soulcraft is sweet construct but was difficult to tighten down properly and the quick release doesn't work well under conditions.

Started customizing my own spec tensioner but found the [URL=""]Rennen Rollenlager product.. it [/URL]is exactly the design I had in mind...mounts off of the axle and double supported using a beefy bolt off the derailleur hanger...bomb proof and more like the extension of the frameset I am looking for...quality is excellent including sealed cart bearing. Killer app...Here's what it looks like:

Rollen product shot 2





Changed the layout of the shifter and brake on the Jones Bar as per Jeff Jones original suggestion...had to cut down (dremel) the Rohloff twist shift to fit in the crux between the straight extension the the main bar, cut out bar tape to fit Avid brake lever...this puts the shifter forward of my common hand placement and still gives finger access to the brake. Works great:




Still working on the bottom end of the bikes...looking to build out some variability in the chain line at the BB / Crankset w/out stacking / spacing CR bolts...IMHO this is a temp solution for serious expedition bikers as it creates a definate 'show stopping' weak link. Parts arriving this coming week...two words: Profile Racing

Drive trains I'm accomodating are:
1) internal geared single cog rears,
2) derailleurless multispeed (DMS) and SS freewheels using Doug White's parts...these are truly the best freewheels I've ever riden - just awesome - American machining at it's best and the bearings are very accessible for repacking too - if you're SSing and not using these parts U R missing out,
3) the legacy WTB GG shimano cassette hubs with single cogs...the catch all and the standard trad hub config for sure.

Sep 26, 2006

Made in Alaska 'Wildfire Designs'

Buy Alaskan


Mark Gronewald is building 'Fat Bikes' here in Alaska...BUY ALASKAN! We're going to layup one of his frames for our winter trailing and summer beach work. Stay tuned for more work on this project. SPRING!

Mark has been involved w/developing Alaska 'Fat Bike' sport for many years and is a good source of technical information, parts, bikes, etc. You can find him lurking here: mtbr Alaska forum , he's 'wildfire'... note* read only unless you register! Check it out!


Check out Mark's report from his outing on the Knik Glacier...good stuff!

Wildfire Designs Bicycles
3901 N. Charley Dr.
Wasilla, AK USA 99654
Phone: (907) 745-2453


Mark and Charlie on ride-1
Marks FB w Surly
Pink FatBike
FatBike Fork

Great implementation on a great idea/concept! Whether winter expeditioning or just touring...this is the way to carry gear on a bicycle! ~$110.00

Frame Bag Oblique Frame Bag

Fatbike Excursions ... Alaska

Pat & Kathy, Hope to Homer

Wildfire Mark, 2006 Knik Glacier

TS Cheezy, Alaska Peninsula

Martin, Kuskokwim River Cycledelic