Quality fat tire options are incredible these days, to the point where analysis paralysis could be a legitimate concern for your average ITI participant.
Even removing all of the tires smaller than ~4" from the equation still leaves one with a healthy pile of rubber to choose from.
Having been on the ITI route through a wide variety of conditions gives me some depth of experience to draw from when considering options. I know that unless someone is holding a gun to my head I'd never willingly choose a smaller tire when a bigger one is available. I also know that the decrease in rolling resistance from running tubeless is substantial, and again I'd never choose to start with tubes if the choice was mine to make.
Bigger. And reliable tubeless. That's a good start, but there's so much more: Tread pattern, thread count, rubber composition, and the ability to (easily and reliably) run studs all have to be factored in, too.
Because we have a backyard mountain that's received over 300" of snow already this season, and because that snow is deep, cold, dry, and with limited traffic to pack things down, it is not a stretch to say that we have an ideal place to test tires. And we've been doing just that -- literally for years.
The snow is so deep up there that we can't get down to bare ice to test, but we have ice in the valleys and we can test ice performance down here.
The one thing our testing grounds rarely produce is real, strong cold: The kind you can expect in the Alaskan Interior in a "normal" winter. That last bit -- the "normal" part -- is the elephant in the room, because winters just aren't what they used to be in Alaska. -30's during the ITI used to be a given, with -40's common and, if you were truly blessed, you'd be gifted some precious time out at -50 and into the -60's.
In recent years the deep snow that was a constant companion on the ITI from the late '90's onward has twice been replaced by a veritable sidewalk of ice: Not hardpack, but ice so firm that studded tires were absolutely mandatory. Conditions like that are the rare instance when bigger isn't better for tires.
Because the ITI is still several weeks away there's no way to say what the weather is going to be. Thus the challenge becomes to test as many tires as possible in the conditions you think you might get, and to know which tires do well in which conditions, so that in the days leading up the event you can nerd-out on weather across the state, make some educated guesses, then install the tires that make the most sense.
With all of that as preamble, Jeny and I have already narrowed her tire choices down to three. Pictured left to right are the 45NRTH Dillinger 5, Vee Snowshoe XL PSC, and Surly Bud.
There are lots of other tires that are similar in size to the range represented here. Schwalbe Jumbo Jim, Maxxis FBF, FBR, and Colossus, Surly Knard, Surly Lou, Vee 2XL, and Bontrager Barbegazi to name a few. These are all quality tires without question, but each had some characteristic that rendered it undesirable for Jeny for the ITI. We're not going to go into detail on those -- instead we're going to focus on the finalists.
Of these final 3, the Dillinger 5 is probably the most popular tire among ITI participants over the last few years. I attribute this to the oddball weather that has twice produced the icy sidewalk stretching from Knik to McGrath (and beyond), and for which the studded version of the D5 was a great tire. I'll take it a step further and posit that had the "ice years" never happened, the D5 would never have found favor at the ITI. And that's quite simply because in unstudded form it's a mediocre tire at best, and significantly undersized relative to the 2 other finalists pictured above. 45N labels it a 4.8" tire but it comes nowhere close to that size even on a 100mm rim.
If the conditions morph over the next few weeks to where the route is ice, ice, and more ice, and a small-volume studded tire seems to be called for, the D5 will be it.
That leaves 2: Vee Snowshoe XL and Surly Bud. Worth mentioning that both of these tires use 120tpi casings and measure very close to 4.8" wide.
Pictured in the middle above is a visually distinct tire made by Vee, called the Snowshoe XL. Vee calls the creme-colored compound "Pure Silica". Once you remove the marketing geekspeak what that means is that the rubber has a slightly softer durometer that is less affected by cold temps. This is worth mentioning because anyone that's tried any black-compound Vee fat tire on snow, and particularly in cold temps, has thought to themselves "Jesus, did someone throw out an anchor?! as they looked around and tried to determine why they were working so hard to go so slow. Vee's normal black Silica tires are known to be very slow rolling, and that only gets worse as the temps drop.
The creme colored PSC compound rolls well in the cold, and this particular tire has a true 4.8" casing, on par size-wise with the Surly Bud tire sitting at right in the pic above. If course conditions look to have a mix of soft snow, hardpack, and any significant quantity (defined as more than ~30 miles, total) of hard ice, Jeny will ride these Vee tires fully studded en route to McGrath.
So that leaves Surly's venerable Bud tire, which is hands-down Jeny's all time favorite fat tire. I've ridden it to Nome and many, many others have ridden it to McGrath. It is a known quantity, and while it is definitely not the fastest rolling tire, nor the best for rear-specific digging, it is the best overall "one tire" compromise that we've found to date. It is a true 4.8" thus it has huge air volume for running at super low pressures when the snow is soft. But it also has big, blocky, siped and directional knobs that give steering control and confidence in every snow condition imaginable. Bud is unlike almost every other tire in that it works well in such a wide range of conditions, and yet somehow doesn't feel too slow when the trail is firm and the going is easy.
If Bud has a drawback it is that once you've gotten used to the confidence he gives, it's hard to seriously consider any other tire. If the ITI shapes up with "normal" snow conditions this year, which means little to no ice, Jeny will leave Knik Lake running Bud front and rear.
Without question there will be many that disagree with the direction our testing, thinking, and conclusions have gone. And some of them will have valid points for their disagreement. We're open to hearing these opinions, provided they are backed up with detail on how you arrived at them. In short, provide enough background so that we might all discuss and learn.
Thanks for checking in.