Surly MWOD Chainrings: The “Easy Button” for getting Really FAT

A few years ago the 65mm Large Marge rim with a 3.7” Surly Endomorph tire was the pinnacle of fat. With this tire and rim combo, any bike with a 100mm wide bottom bracket could easily run three chainrings in the front and all nine cogs in the back. Once 80mm, 90mm, and 100mm wide rims hit the market, drivetrain options for fat bikes became less straightforward because of chain-on-tire rub issues.

MWOD Chainrings, Silver Mr. Whirly Crank Arms, and Chris King BB


If someone wants to upgrade to a fatter setup, there are a few drivetrain options:

One solution is to remove two or three of the small cogs on your cassette and turn your nine speed cassette into a six or seven speed cassette. The downside to this is that some rear derailleurs don’t have enough adjustment in their limit screws to accommodate such a drastic outboard setting. Older Shimano rear derailleurs like the Shimano M771 are the exception.

Another solution is to run a single chainring in the front and a nine or ten speed cassette in the rear. This is certainly a clean solution but for climbing hills and/or riding in very soft conditions this setup is not ideal unless you like long walks with your fat bike.

In my opinion, Surly’s MWOD (Mr. Whirly Offset Double) chainrings are the “Easy Button” for running the fattest rear tire & rim combo that will fit in your frame.

MWOD Chainrings

Who needs it?
Anyone who wants to run an extra FAT tire & rim combo

How does it work?
MWOD rings move the granny and middle rings to the middle and outer positions of the crank, effectively increasing tire clearance at the chain by 7mm without increasing your Q-factor and without losing your crawling gear. They are available in 20/33t and 22/36t.

What parts do you need to run MWOD chainrings?

• Shimano compatible outboard bottom bracket
• 100mm Surly Mr. Whirly Spindle
• Surly Mr. Whirly Crank arms - No spider required because the MWOD chainrings bolt directly to the crank arms
• MWOD chainrings
• 3x9 or 3x10 Front Derailleur – Although you are only running two chainrings, you need the extra outward “throw” provided by a 3x front derailleur

NOTE: Surly also sells a complete MWOD Crankset that comes with a bash guard and bottom bracket. I chose to buy the parts separately because I wanted to use a Chris King BB and don’t want a bash guard on my fat bike.

MWOD Crankset


What is the downside?
It is a very clever solution to gaining more chain clearance. The only downside is that you are limited to two chainrings in the front vs. three. Also, you need to be aware of cross-chaining in the big/big combo. I am running a 22/36t MWOD with an 11-34t cassette in the rear and I haven’t missed my standard triple front chainring. I have also been pleasantly surprised with how well the front shifts despite a 14t jump from the small ring to the big ring. I am a fan of running the biggest tire & rim combo possible for the added float and stability it provides. The MWOD has allowed me to run a 4.7” Big Fat Larry tire on a 90mm wide rim in the rear and retain all nine cogs. Greatness!

The Wheel Ski

I still have snow biking on the brain and one of my favorite aspects of snow biking is the endless tinkering.

A couple years ago, JayP and I geeked-out on the idea of a wheel ski for times when you knew that you would be pushing for sustained distance. Jay crafted one out of an old Pocket Rocket ski, tested it, and never used it in a race. I have seen a few random pics of bikes on the start line of the ITI 350 with wheel skis mounted on a rack but I have never seen or heard of anyone actually using one in the race.

The pics below are from this year's race and I heard that the owner pitched the ski only a few miles into the race. I wonder if he regretted that move when he got to Rainey Pass?





I still think this idea is valid if executed properly. How about a retractable, wide, carbon ski that floated both wheels?

Fog eVader Breath Deflector

In my prep for the Su100 this year I tested a few products in an effort to be more comfortable and efficient in the cold.

RU Outside's Fog eVader Mask

One product that made a BIG difference for me was the RU Outside Fog eVader Mask.

On one of my coldest rides I struggled with keeping my glasses from fogging and with being able to eat and drink while bundled up.

After purchasing the Fog eVader, I simply cut a small circular opening for my mouth and I was able to eat small bites and drink through the Camelbak without removing the mask. Greatness!

Here is what I like about the Fog eVader:
1) Easy to layer - I can add it on top of my favorite beanie or balaclava
2) Does not restrict my breathing
3) Prevents my glasses from fogging as advertised
4) Allows me to eat and drink efficiently (after slight modification)without removing it
5) Any ice buildup is usually on the nose piece away from your skin

RU Outside is based in Driggs, ID and is owned by my good friend and fellow snow biker Rick LaBelle.

The Fatback is Phat!

My new 19" Fatback frame is finally built up and I was able to get out for my first snow bike ride of the season yesterday.

This project began last February, the day after the Su 100, while Chris E. and I were visiting with Greg at Speedway Cycles. After sitting on a few bikes and playing with rim & tire combos I knew I had to pull the trigger on a Fatback. I applaud Speedway for putting so much passion into developing the Fatback and for sourcing the special parts that help take snow biking to the next level.



Two of my main reasons for buying the Fatback were:
1) Better fit with a 19” frame – my Wildfire frame is a 17” (Med) and is too small
2a) Better performance at low PSI – the new 80mm rim distributes the load more evenly than the 65mm Large Marge and I am no flyweight.
2b) It is dead sexy, in a voluptuous kind of way

After close inspection, I am very pleased with the build quality of the Fatback frame, the 80mm wheelset, and the steel fork/rack combo. Greg at Speedway has been awesome to work with. The rest of the parts were taken from my Wildfire FatBike frame and moved over to the new frame to complete the build.

I snapped a few pics to highlight some of the key features that set the Fatback apart from other snow bikes.

Ti frame - compliant, and zero corrosion issues

165mm rear disc hub by Hadley

135mm front disc hub by Paul Components

All 27 gears are usable

Enough tire clearance to go bigger in the future if I want

Clean cable routing designed for full-length housing

Nice welds

Steel front fork and custom rack

The custom rack turned out great and the design was based on the modification I did to my Old Man Mtn rack last year. I almost always have some sort of bag on the front of the bike so this was a key piece for me and Greg's builder did a great job.

12/17/08 Edit: Weight is 31.5 lbs with rack & Surly tubes in both tires. I don't trust the WTB 2.2-2.5 tubes at 4.5 to 5 PSI yet.

Rigging, resting, and riding a little

After deciding on Friday that I would not spend 14 hours on the bike in an effort to shake this annoying cold, I had a new goal and time to spend working on it. Fri evening and Sat afternoon were spent loading and unloading the bike to see what all of my options were. It is crazy how much time one can spend on this.

For the first time in a long time, we had a couple of days without fresh snow which means the potential for firm trails was good. Sunday morning I headed for Horseshoe Canyone to ride the FatBike fully loaded and was greated by an empty trailhead and FRESH CORD! Yeehaaaaw!



Fresh cord and no tracks



Mother Nature flipped the switch about an hour into the ride.



The animals were out and about prior to the storm







My 2+ hour ride confirmed that I will definitely keep the sleeping system on the front. I feel that getting as much weight off of the back tire is the best strategy although I may pay a penalty for it if I have to push for long periods in deep snow. My big seatbag only contains puffy items; wind pants, big mittens, and a down jacket.

I have to thank Eric who makes Epic Designs bags. I had it in my head that I wanted a double-roll-top handlebar bag and he built one for me exactly the way I specified and even added a few cool things I hadn't thought of. Now that I have played with it, I realize the shortcomings of the double-roll-top design. Although my design idea didn't turn out as I had hoped, the quality of the bag is excellent and the communication with Eric has been great.

Now it is just a matter of making sure that I know exactly which pieces will comprise my mandatory 15 lbs. of gear to meet the race requirements.

Lastly, I can't seem to shake this cold. It is one of those nagging ones where I don't feel all that bad but I am not getting any better either. Argh!