Saturday, February 11, 2017

Jeny and the Race: Tired.

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In recent years the deep snow that was a constant companion on the ITI from the late '90's onward has twice been replaced by a veritable sidewalk of ice: Not hardpack, but ice so firm that studded tires were absolutely mandatory.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.

8 comments:

  1. Curious what you are using for your "go to" tubeless fat set up. I've been messing through a few different Clownshoe Bud/Lou tubeless iterations, and the latest and seemingly greatest version is based off 100mm wide Siga Wigluv tape. This tape, while expensive, fits perfectly on a 100 mm rim. It's sticky as hell, fibre reinforced and air tight, as it used for sealing building exterior membranes. No longitudinal seams on the tim to worry about. This tape does need some reinforcement between it and the rim strip, as its stretchy, but so far it has the standard ghetto Gorilla tape set up beat hands down.

    ReplyDelete
    Replies
    1. Hey Paul-

      I've liked and believed in tubeless for bicycles for almost 2 decades now. It follows that I had to do lots of experimenting with stacking layers of tape to make things work tubeless way back when, and again ~6 years ago when I started fiddling with tubeless fat, because there were no readily available rim or tire options.

      That process can be both intensely rewarding and frustrating -- as you are undoubtedly well aware -- and often both within minutes of each other. Fiddling with layering tape and struggling to understand why some setups worked and some didn't was very educational and I'm glad to have done it.

      But every tape setup has eventually failed. Some lasted ~1000 miles. Most lasted far, far less. They rarely fail in the warmth of the shop/basement/garage, which adds to the frustration of the failure. So you stick in a tube, then try to scrape the schmutz off your hands before putting your gloves back on to keep riding. During a day ride? Not the worst thing. Many days out from home? Frustrating, unnecessary, and potentially unsafe.

      There are a few fatbike rims these days that are turn-key tubeless ready. I build with all of them several times a week. Of these, the Bontrager Jackalope's are my favorites. Jeny will be using them on this trip. They require one lap of normal mtb width (~22mm) tape to seal the spoke holes. That's it. Once that lap of tape is installed, you can inflate and seat the tires using the teeniest, weeniest mini pump out there. No compressor. No floor pump. No hopping on one foot while holding breath and hoping. No drama at all. Jeny proved this to both of us yesterday as part of her 'mechanical prep'. I wanted her to have confidence that if she flats she can fix it -- whether that means plugging it from the outside, patching it from the inside (which would then require her to re-seat the bead), or simply sticking in a tube.

      So, in short, my answer is to stop fiddling with the layers of tape and use a real tubeless ready rim.

      Thanks for bringing this up.

      MC

      Delete
    2. Point taken re. TBR. Messing around indeed! Have you built with the 90mm Alex TBR rims yet?
      I could live with 10mm less width, but 20 could be the proverbial straw when you are seeking max float.
      Cheers eh
      PC

      Delete
    3. There are a few 100mm tubeless ready rims out there, but only in carbon, and with a corresponding price tag.

      I have neither built with nor even seen the 90mm Alex rims to which you refer.

      Delete
  2. Hey Mike,

    I've been running 26" Jackalope rims this season (Nextie Wild Dragon 90mm the last couple) and love them! Dual Bud is my favorite combo for most conditions. I have found that the Buds have a tendency to burp at low low pressures on the Jackalopes. They are a looser fit than the typical Bontrager TLR. Have you had this issue?
    I've added two layers of Mulefut tape from bead to bead to create a snugger fit and this has helped slightly. Have also been liking the Bud and Dunderbeist combo for loose conditions.

    Happy trails!
    ~Stephen

    ReplyDelete
    Replies
    1. The original generation of Jackalopes fit a few tires loosely -- Surly tires most noticeably -- with the result that some tires would burp air when run at less than ~3psi. The fix was indeed what you have done: Increase rim diameter by adding a layer of tape at the bead.

      Current generation Jackalopes have increased in diameter such that this seems to have been solved. I recently mounted a used Bud on both an older and a brand new Jackalope. I could mount it by hand (no tire lever) on the old rim, but needed a lever to get the last bit of bead on with the new rim.

      Delete
  3. Totally worth keeping this idea exchange happening.
    Mike, you're not a fan of Lou? Too slow/resistance?

    ReplyDelete
    Replies
    1. Huge fan of Lou, as is Jeny. For this event you have to consider energy output, and Lou allows you to ride more than almost any other tire. Sometimes walking is a *good* thing -- as it allows you to conserve some energy, use a different muscle group, maybe stretch and eat a bit too.

      Bud rolls just a bit more efficiently, and breaks loose a bit sooner than Lou.

      If we were talking day rides, you'd never pry Lou away from Jeny.

      Delete