Wednesday, January 13, 2016

Fat tire pressures for snow.

A good friend of mine recently got the fatbike bug, largely so that he could ride on snow, and wanted to better understand appropriate tire pressures for that surface.

He's ridden bikes for decades and skied for even longer, but the correct range of pressures for 5" tires on soft snow is not as auto-intuitive as you might think.




I spent a few minutes writing a detailed response, and after sending it to him it occurred that many here might benefit from it as well, if only as a resource for their new-to-fat friends.

Without further ado...




It takes some time to wrap your head around appropriate PSI for snow--it's probably gonna be a lot less than you think.  The standard credo for tire pressure when snow riding is 'when in doubt, let air out'.  




Best way to be sure is to take a little low-pressure (0-15psi) gauge with you for the first month or so, and check pressure frequently with both the gauge and your hand to get your hand calibrated.  The idea being to learn what works by feel, so that you can ditch the gauge sooner than later.




This is a rough guideline.  The absolute number is irrelevant, finding a pressure that works, and then being able to both recognize the conditions and duplicate the appropriate pressure is what matters.

10psi and up = pavement pressure.
6-8psi = *very* hardpacked snow.
4-5psi = softer or less consistently packed snow.
2-3psi = deeper snow, when more flotation is needed.  If you need this kind of
pressure, you'd probably be having more fun with skis on!  But
sometimes you start a ride on hardpack and have an ambitious
objective, then it snows or blows and you have to dump air to keep
riding.
0-2psi = what I most often ride at, due to lots of light, dry snow and very little traffic.






As temperatures and conditions change the appropriate pressure for the surface can fluctuate pretty dramatically.  1psi makes a big difference.  My way of staying safe (avoiding flats or rim damage) is to lean all my body weight on the saddle, while looking down at the rear tire.  Any wrinkles in the sidewall?  Add psi until the wrinkles go away.  That's your baseline for hardpack.  The flipside of that process is that for the softest, least-packed snow (the kind where you should have chosen to ride lifts with skis on that day!) you can go as low as four or five wrinkles in the sidewall as long as you're being delicate.  More than five wrinkles and you're generally just adding resistance without increasing float or traction.  That said, conditions in my neck of the woods often require 5+ wrinkles just to keep pedaling, and since pedaling beats walking...






One last bit of editorial: Not many people understand how far you can go in a short time on one of these steeds when conditions are good, but how absolutely hosed you can be if it's nuking or blowing or both on the return.  Like 7-8mph when it's good, and hours per mile when it's bad.  I don't take a sleeping bag with me on every ride, but I *always* have a puffy, firestarter and lighter, and some food on winter rides.  Seems like about every other year I get antsy to do something epic, and conditions change halfway through the ride, leaving me out for the night and into the next day (or til a sledneck comes along and packs the track back in).




Don't hesitate with questions!

Sunday, January 10, 2016

Winds of change?

This marks my 563rd blogger post, dating back to October of 2007.

I've been able to share a lot of stories, images, and information using this platform.  It has been a great tool.

Of late, and for the past year+, I find myself frustrated at the inability to *easily* customize the interface to make pictures larger and text more easy to read.  I have a few other minor complaints, but those two are really the meat of it.

When I write easily, I mean easy for a non-html-coding-type like myself to do.  I need drag and drop, plug and play type functionality.

So I've been looking at options.  Thus far, the most compelling one is Exposure.co.  I spent a few hours this evening learning the interface and was impressed, shocked even, at how easy it was to create (what to me is) a very visually compelling story.  


What I mostly want to know is if that ^ sort of storytelling is compelling to people?  Compelling enough that the storyteller should go through the rigamarole of jumping ship from blogger, and paying at least $100/year to have the photos and stories hosted at Exposure?

Do you have a better idea?  

Tell me, please, in the comments below.

Thanks.

Thursday, January 7, 2016

A ride, recently. Volume 72.

Sometimes we get out for microadventures that are interesting and unique, but somehow difficult to wrap a lot of verbiage around.

Often but not always we take photos on or of those rides, and the photos are worthy of sharing.  But still no words come.

In some cases, time (or a lack thereof) is the main ingredient in that dearth of words.  Just can't slow down enough to write.

For these occasions I have previously and shall, going forward, invoke the right to share pics without explanation.  

The phrase 'A ride, recently' often comes to mind when groping for a title, thus that'll be the name of this ongoing series.

And since I've wanted to use that title for years, and have only (that I can remember) actually invoked it once before, I'm going to presume that this, right now, is roughly the 72nd time I would have used it, had I taken the time to introduce the idea sooner.

Without further ado:  10,000' up in the Colorado alpine, on a warm January afternoon.










































One technical detail of note: Greg and I swapped bikes a few times on this ride, largely to compare differences between his classic Pugsley with 4" tires and Brrrrly with 5.2"ers.  The trails were largely packed enough that either bike could suffice, with enough attention and skill, for the day.

Right at the end of the ride I dug out my valve core tool and removed both valves, thus dumping all the air out of my tires.  0.0psi.  Then I put the valves back in.  Because these tires have so much volume and the casing is spread so wide by 105mm rims, once you add rider weight atop the saddle the tire pressure goes, just barely, back into the positive.

The 2XL tires' contact patches looked like this when Greg was sitting on the bike:


What, praytell, am I prattling on about?

With the tires set as such, we deliberately left the packed surface of the snowshoe/ski trail we'd been riding, and ventured out across a frozen, snow-covered lake.  With any other fat tire I've ridden over the past two decades that would have meant an instant stop as the front wheel buried itself past the hub.  End of story, except for the footnote where you dragged yourself back onto the trail platform, tail between legs, to resume riding.

Not this time.  I was able to ride, at a tick shy of 10,000' in the Colorado alpine, atop *feet* of virgin snow that had never been packed other than by settling due to gravity. 

Because it was completely dark at this point, I have neither pictures nor video to share.  When I rode back up onto the trail I handed the bike, giggling and gasping, to Greg.  Because it was dark he had seen me riding on the lake but didn't quite grasp it yet.  Then he rode down onto the lake, off the trail, and...

...continued riding, while giggling and exclaiming expletives of delight and incredulity.  

Later, Greg said he was afraid to stop pedaling or turn too sharply, because he wasn't sure how he'd get off the lake if he came off the bike.  Easy, I said: "You'd have been postholing up to your crotch".

Riding snow this deep at pressures this low was neither efficient nor particularly fun, if you know what I mean.  But it was possible, for the first time ever.  That fact ballooned in my head on the drive home.  

It was like a door had been opened, allowing us to consider wilder, more remote routes as still larger tires and rims become available.


Monday, January 4, 2016

This.

This is, truly, one of the more achingly beautiful things I have yet seen.




The only way I can imagine it being better is to be there in person.  The artist brings you right to the cusp of that experience.

Simply incredible. 




Monday, December 28, 2015

Inching closer.

With a few weeks of over-snow riding under our belts, this seemed like a good time to check in with some of the finer details on this build.




I'm anal to the Nth degree when it comes to sorting out a new bike, doubly so when there is no real precedent or benchmark for that bike.  In other words, during and after every ride so far I've been fiddling and fine tuning the position to put my CoG exactly where it needs to be to take full advantage of the massive float that this chassis is capable of.




Position aside, there are a few small details that add up to something bigger when it comes to riding in cold temps.  Because snow sucks so much of our power out, and because we're swaddled in so many layers of clothing (robbing yet more power), I think it's critical to maximize efficiency in every way possible.  Pedals on this bike are ISSI, and that's only important because they offer a +6mm and +12mm spindle kit to help you fine tune your fit and feel.  I installed a set of the +6 spindles right off the bat, largely so that I could eliminate crankarm rub from my writ-large winter shoes.

I also dug into the pedals so that I could remove the sticky-when-cold factory grease and install something thinner.  I have a stash of Morningstar "Soup" that I use for stuff like this, and the pedals spin much more freely at sub-zero temps now that it's in there.




Low gearing is critical for where/when I ride snow.  I'm using a SRAM 1 x 11 drivetrain, with a 26t Wolftooth ring and a 44t Wolftooth cog replacing the stock 42t.  That gives me 18.9 gear inches on the low end, and that gear ends up getting used the lions share of the time.  If Wolftooth gets enough call to make a 24t ring for the Cinch cranks, I'll be first in line to buy one.






Bodyfloat sus post has been a revelation for me.  I miss having a dropper for remounting the bike in soft snow -- the kind where you're ankle deep (and sinking) in fluff, and can't *quite* get yourself back onto the saddle to get restarted.  With that exception, I have been thrilled with the comfort and invisibility of the Bodyfloat.  Took me about a ride to get the preload set just right, and since then I've been consistently impressed by how unaffected it is by dropping temps or poorly chosen lines.  




Neoprene saddle insulator.  Tri geeks use these, albeit for very different reasons than I do.  Slips right on, stays on, mitigates cold getting to the nether regions.  I think these are important at any sub-freezing temp, and they become critical from about 0 degrees on down.




Whit's iteration of a Type II fork has been invisible thus far.  For a rigid fork, that's the highest compliment I can give.  Double bonus that it uses a Maxle Lite for super easy gloves-on wheel install/removal.






Hopey steering damper.  I keep it turned off most of the time, but with a quick twist of the dial on top it can be activated for uber-soft snow.  If you ride groomed singletrack you don't need this.  If you spend more time on ungroomed and especially wind-affected snow, you won't believe how much of an effect this little unit has in keeping the front end quiet so that you can stay on the bike longer.  Easy to test, too -- ride a mile with it on, then twist the dial to turn it off and be amazed at what a drunken sailor you've suddenly become WRT holding a line.




RWC bottom bracket.  The stock RF units have given me decent life but I wanted to try something new.  I flushed all of the stock lube, replaced it with Morningstar Soup, then trimmed the labyrinth seal to remove some spinning friction.  That last step is not recommended if you ride dirt or dust or mud with your fatbike, but highly encouraged if your fatty lives it's life in cold/on snow.




For literal decades I've run Hayes hydro brakes in the snow, and especially for my Alaska trips.  They are reliable as hammers and that's the main thing.  With no big AK trips on the horizon it seemed like a good time to try something new with the mechanical MX Experts.  I supplemented them with 2-piece rotors in an attempt to keep them quiet.  So far so good -- on both brakes and rotors.




Many more pertinent/geeky details to come on this bike -- will try to highlight them in the next week or two after holiday chaos has subsided.

Thanks for checkin' in.

MC

Monday, December 21, 2015

Back on the horse, the video version.

Fall in the alpine.  Mild days, cold nights, stunning scenery, empty trails.

Compelling as these reasons are, what got us out the door for an overnighter near Crested Butte was some combination of Pete and Jeny both having rare weekdays (before the forecasted snowfall) off, and my neck finally feeling good enough to ride all day, sleep in the dirt, then repeat.

I wrote those words a few months ago, to introduce a photo reportage of a bike trip the three of us had just finished.

I finally found some time to edit and upload the companion video.




One interesting factoid: Pete delicately packed and carried his drone so that he could get some not-possible-from-terra-firma shots of our trip.  In the video above you can see the Flag Creek descent from a unique perspective.  He also flew/shot at the Spring Creek crossing starting the Doctor Park climb.  The next morning in attempting to shoot Jeny and I leaving camp in the honey light of an October dawn, a firmware glitch brought his drone crashing back down.  

When it became obvious that it was now so much dead weight to carry up the many remaining climbs, he stashed it at a campground to be retrieved later.  It has since been repaired and lives to shoot future dronepacking missions.

Enjoy,

MC

Monday, December 14, 2015

3 weekends. Or, 'back'.

We often take our health for granted.  Not just the not-being-sick part, but the I-can-choose-to-do-and-am-capable-of-doing-amazing-things part as well.

This summer and fall life gave me a big smackdown that removed my ability to do for several months.

The last three weekends my family and friends have encouraged, enabled, and accompanied me on some baby-step trips to get back out there.  I feel (am) slow, old, fat, incompetent, unconfident, uncoordinated, and lots of other adjectives that you, too, would probably feel if you'd been sidelined for the past few months.

The upshot is that I seem to have hit bottom, bounced intensely, and am now clawing my way back up with the help of the aforementioned (and below pictured) friends and family.

The enforced downtime allowed me to finish several projects that should have been done years ago, build and debug a few new bikes, and start a few projects that I will likely procrastinate finishing for many years to come.  Because that's my prerogative, as the coolier-than-thou kids probably say, and getting out and enjoying your health should take precedent over pretty much everything else.  

Life's too short not to: Ask me how I know.

Please enjoy a few million pixels from the last three weekends of getting out around the Colorado Plateau.