Fat Pursuit 2023 – Part III – Some Finer Details

Friend of the site and former Paceline co-host Patria Vandermark shares her experience of this year’s Fat Pursuit fat bike ultra-endurance race. All images by Rob Vandermark.

As I said, in Part I, a LOT went into getting to the start line for Fat Pursuit. Here are just a few of the finer details.

Tires and Tire Pressure

I rode studded tires (45NRTH Dillinger 5), even though they weren’t, strictly speaking, necessary. In preparing, I wanted to train on ice near home immediately before shipping the bike, and I also wanted to have as much time riding the exact setup I’d be racing since there was so little time to test everything out pre-race.

How many times I stopped to take air out of my tires, I’m not sure. As it warmed up, everyone was taking air out of their tires and pulling their jackets off. The warmth softened the snow, making it harder to ride (mashed potatoes!). Simultaneously, the warm air increases air pressure in your tires. This is the first time I have run my fat tires tubeless. I’ve been a big fan of tubes up until now for a list of reasons. The use case changed for Fat Pursuit.

I put Tyrewiz Bluetooth gauges on my wheels, so I’d know what pressures I was running. These really come in handy on the fat bike due to the low pressures you run on snow and being able to read to the tenth of a psi. I finally settled out at 1.7 and 2.1 psi front and rear by 6:30pm. I didn’t add any air after taking it all out. It never felt like higher pressure would allow faster forward progress even once the trail got groomed. Who knows? All I do know is that I was crashing a fair amount at closer to 3psi and it takes time to pick the bike and body up while waving the kind snowmobilers on as each one would stop and ask if all was okay. They were nice out there. I usually crashed when there were a lot of people around to watch.

What not to wear

If there’s one thing this event is not, it’s a fashion contest. Everyone looks frumpy, mis-matched, un-color coordinated, and the exact opposite of what cycling ads spend a lot of money promoting. All apparel is selected for warmth and comfort for 21-55 hours in the great outdoors. There isn’t a single apparel company that can outfit a rider since it’s such a hodgepodge of stuff.

No one was showing off team kit or sponsored apparel. It felt odd to be starting a race where we all looked so not pro.

Many riders don’t wear helmets at this event. It is much easier to manage head warmth and basic head comfort without the helmet, but I don’t feel safe without one. Next time, I’d go without the shell over my helmet, so my head can breathe. During the race, I was sweating a lot, and the shell was dripping sweat on me.

Due to the warm temperatures predicted, I made a last-minute decision to not wear wool pants under my 45NRTH winter cycling shell pants. I wore Velocio summer bib shorts, which allow quick “bathroom” breaks, knee-high socks, and then winter pants with vents. I was nervous about this decision, because my plan had been to wear the wool pants and a wool baselayer top as my fundamental race attire. The lowest temperature my Garmin recorded for the whole time I was out there was 25F. I think in actuality, in the middle of the night, it may have gotten down to 20F in terms of what it felt like, but that’s still just hot if you’re riding a bike in fluffy, mashed potato snow.

Sweating can lead to freezing. Staying cool is important. I ended up pleased with my decision on the wool pants; I rarely closed the vents on my shell pants. My legs stayed toasty throughout.

For my upper body, I wore a wool sports bra, wool base layer, and full-zip fleece layer. Over that was my hydration pack, then XL Nano down jacket and/or an XL wind jacket depending on how warm I wanted to be as I went along. These layers over the pack went on/off frequently. I stopped every time I needed to adjust my wardrobe. Not sure if other people are able to do this on the fly.

I kept a wool beanie and wool neck warmer on the whole time except when I stopped to bivy in the wee morning hours. The neck warmer froze into ice in the night, but it was still useful and good to breathe into when it was frozen.

With temperatures so warm, I was able to dry off after sweating prior to night falling and potentially freezing. From head to toe, I was comfortable the entire time I was out there, including when I was setting up my bivy, breaking down the bivy, and spending an hour boiling enough snow to make 3L of water the following morning. The only adjustment I might make in the future is to add a lightweight vest over the hydration pack.

For socks, I wore thin liner socks, and over those, some super thick expedition socks made by REI. These socks took up all of the space in those waaay-too-big boots and kept my feet toasty. Having toes that wiggled was just what I needed to be warm. Even after stopping to bivy, which meant leaving my boots outside for 1.5 hours in the cold of night, I kept the boot liners on my feet and by the time I’d put the boots back on, and the cold of the boots got through the liners, my feet were generating enough heat to stay comfortable! Woohoo, success!

Most of the time I didn’t wear anything on my eyes. During Day 1 it got sunshiny and bright, so I wore sunglasses for some of the day. I packed clear goggles just in case. It seemed like good insurance to have those.

Having lots of reflectivity on bike and body might have been useful. Should a light go out, reflectivity is really important for visibility. With snowmobiles and groomers out, you need to visible. I took lots of extra lights (3 rear lights plus extra batteries) but saw others struggling with theirs. Luckily, the snowmobiles stopped running after dark.

Obviously, I could sift through the details all day, but these were the basics. If you have questions, put them in the comments below, and I’ll share whatever I learned.

Join the conversation
  1. Jeff vdD says

    Fantastic effort out on trail, fantastic effort documenting your experience.

    1.7 and 2.1 psi blows my mind!

    My only fat bike race was the Stowe Derby back in 2015. It was my second fat bike ride ever. I had a 4″ tubed, general purpose tire that I ran at 10 psi. I recorded the race with on-board video, so I know for sure that I fell 22 times. I suspect that a wider, better, tubeless tire run at lower pressure might have lowered that number! But even on pure snow rides, I don’t think I’ve ever intentionally run less than 4 psi.

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