A Low Fat Alternative

The hills around where I live are vivid green and choked with wildflowers. This is a very temporary state, and already the first hints of the coming summer brown are beginning to show in the fading miner's lettuce and the wilting shooting stars. But the vetch is still going gangbusters, the poppies are hanging tough, and a couple recent rains have slowed the headling rush toward summer and the inevitable fire season that follows. It is, however, most definitely not winter anymore. And even though using winter around here to justify a fat bike is pretty sketchy logic to begin with, the questionable need for overkill tires has very obviously passed.

It is instead time to think of that sandy and rocky place to the south of me: the Baja peninsula. It is also time to decide how to rig the Fezzari Kings Peak that I have been using to scratch my fat-curious itch for some arroyobiking.

At the outset of this whole exercise, I had thought that really fat tires would be the key to arroyobiking satisfaction. But after a few weeks pushing around the absolutely MASSIVE 27.5x4.6" Terrene Cake Eaters that came stock on the Kings Peak, I came to the conclusion that it is absolutely possible to have too much of a good thing. Those tires are beyond huge. I am sure they work great in crusty snow at 2 psi, but damn, they were a workout everywhere. So I decided to make turn the Fezzari into something a little less fat:

This was a bit of a leap, but I asked people who know more than me if I was committing some sort of crime, and they said that it was only a really small crime and not the kind that would go on my permanent record...

So, Mike Curiak spun up a beautiful set of hoops: Derby TR40i rims, DT 350 fat hubs, stainless steel DT spokes (shiny and silvery, the way all spokes should be). I slapped some Bontrager 29x3.0" XR4s on them, and then realized that the stock cassette (SRAM SX Eagle) doesn't use an XD driver, it uses an HG driver. Now, any sane person would just order up a new driver and go on with life. But since the stock SX cassette weighs in excess of 650 grams, I saw an opportunity to squander some cash and ordered up a Garbaruk 10-50 cassette.

This set of wheels, without sealant, with the fancy Garbaruk cassette, chopped more than SIX pounds of weight off the bike! The stock wheels, all in, weighed a combined 8.11 kilos (17.8lbs). The 29+ setup that Mike built weighed 5.3 kilos (11.6lbs) ready to ride. Admittedly, the Cake Eaters and big heavy tubes were a big factor, but so were the stock Sun Ringle Mulefüt rims.

The effect on the bike was, as might be expected, profound. I felt like my legs were 30 years younger. The strange heavy steering/pitted headset sensation that no amount of tire pressure experimentation could alleviate went away. The bike was transformed into a modern geometry hardtail that feels ready to go after just about any kind of trail. Stable, longish, slackish, with a ton of meat on the ground; this felt like a bike I could ride just about anywhere.

That newfound snappiness did not come without a price though... Expensive rims, expensive hubs, primo handbuilder labor - this is a $1900 USD setup - basically as expensive as the bike's initial retail price. Add in another $286 USD for that fancy cassette (which is a bargain compared to an XX1 cassette), and no, it's not a free ride. But holy transformation, Batman. What a massive difference. We'll get into that more in a bit.

The wheels alone, while a hefty investment, made for an awesome upgrade. There are options out there for fat spacing/29+ wheelsets that are plug and play, and a lot less expensive, but I really wanted 40mm wide rims, and I really wanted to finally get some time on Derby rims, and I really wanted a set of wheels built by Mike Curiak. So, there I went.

I totally dug the way the bike behaved after the wheel swap, but Mike also twisted up a set of ultra-swank 27.5" fatbike wheels. Once again using DT Swiss 350 hubs, he laced them to Nextie carbon fiber rims. These are single wall, super lightweight rims that Mike swears by for his hellfests in the back of beyond. Being single wall rims, there is no air cavity and there are no vent holes drilled in the rim, which, apparently, is a thing to consider when you're packrafting in Alaska. Holes mean water can get in, and sometimes it takes a long time for that water to drain back out. Noted. Anyway, these beauties, set up tubeless with a set of Bontrager Barbegazi 4.5 tires, are only about 100 grams per wheel heavier than the 29+ setup, and also represent a quantum leap in the rideability and enjoyability of the bike.

The Barbegazi tires are not anywhere near as hefty as the Cake Eaters, which, if one is riding in a landscape of sharp rocks, might be cause for concern. In snowy conditions, though, the five and a half pound reduction in rotating mass is (in my very limited experience and therefore questionable opinion) likely to be a much bigger performance draw than the potential ruggedness of ones tires. Feel free to crucify me in the comments on that one.

So, I loved the way the bike rode with lighter wheels, whether they were fat or just pleasantly girthy. Shocker. What I didn't love, however, was the realization that rigid bikes are still rigid, even at really low tire pressures, and that my wrists are still 58 years old. And getting older every day.

Enter the final pieces of the puzzle:

Yep, I got forked. I've tried going back to rigid a few times, but am coming to the realization that my wrists aren't too stoked even on smooth road rides anymore. So, enter the Manitou Mastodon Pro. Adjustable internally between 100 and 140mm travel, I'm leaving it at 120mm for now. This kicks the head and seat angles out by about a degree (from 67/75 out to a little under 66/74), and brings the bb height back up enough to make up for most of what I lost in the wheel swap.

This will be my first extended amount of time on a Manitou fork in a donkey's age, and I am mighty impressed with what I see so far. Separate hi-lo speed compression damping adjustment, rebound adjustment with a huge range, adjustable air volume, 34mm stanchions, cool hex-axle, rad throwback decals, and a welcome buttery smoothness right out of the box. I'm really looking forward to futzing around with it. Coulda saved a couple hundred bucks and lost a ton of adjustability by going with a Mastodon Comp, but at this point, who's even counting the money anymore?

And CushCore. I love CushCore. A few years ago I was doing some bracket testing between tires running CushCore inserts and tires without, and at any given tire pressure the change in cornering characteristics along with the damping of trail chatter was eye opening. As one tester described the ride feel; "more signal, less noise." But, being a weight weenie, I haven't been using them lately. Now, having chopped all this rotating mass out of the equation, but also still wanting to go low with tire pressures, it seemed like a good time to get Cushy again. Running CushCore Plus inserts with the 29x3.0" XR4s, I am currently exploring between 13 and 17psi. Not sure where things will end up, but even as low as 13psi the tires are holding up nicely in the corners. This is my first go with these particular tires in this size, though, so I need to get some real hours in a lot of different terrain before I spout off much more. Speaking of tires, here's the tale of the calipers:

Will the skinny/fat wheels work in Baja? I'm heading down in two weeks to find out. I'll be bringing the light/fat Nextie/Barbegazi setup as well, just in case. As for the bike, I am stoked with how it currently rides and handles. Far more impressed with its behavior than I expected I would be. The q-factor is still a country mile wide, and the hoped for cranks to slim that down haven't shown up yet, but it hasn't really bothered me either. I'm running flats instead of clips on this bike, so that may be a factor. I also haven't been grinding out huge miles, which is almost certainly a factor. But overall, I am pleasantly surprised by the Kings Peak (even though it now costs more than twice as much as when I started down this rabbit hole).

Does this have any relevance in the real mountain biking world, aside from some old kook chasing his curiosity around? I dunno. On one hand, I think hardtails absolutely need to be in the general mountain biking conversation. And I emphatically believe that utility, adaptability and versatility are crucial to the whole hardtail gestalt. In this case, the Fezzari rules. Even with Very Fancy Wheels, it is still a somewhat reasonably priced bike by today's standards. But there are caveats - it was on sale when I started this.

Now you'd be looking at a base price of $2499 USD to start this experiment. For that price, the Kona Honzo I reviewed recently has better parts, a narrow q-factor and comes with a suspension fork. But the Fezzari can fit a whole lot more tires in between its seatstays. And in my mind, that has got to be worth something. Even if I never take any of our well intentioned readership up on their offers to go spend a winter in the Upper Peninsula of Michigan, having a bike that can swing that kind of use, and still be a legitimate summertime rowdy hardtail that can get roped into bikepacking duty, well, that's kind of awesome.

But then add on a swank fork, and some tire inserts, and complain some more about my wrists, and... then the logic gets a bit fuzzy. So I'm not gonna make any hard calls here. I'm gonna go ride some janky arroyos and drink some beer and think about it some more.

All I gotta do now is run the gauntlet down to Baja Sur, strap a ballena into my King Cage, and head out into the empty desert.