UnCruel 

I thought I was done with the fatbike experiment. For about fifteen months, I had a Mongoose Dolomite ALX. It didn't turn out to be as much fun on the beach as I had hoped. However, it was a monster in snow/slush/ice, especially with the studded Dillinger 5s I put on it. Still, it was exhausting to pedal: I put in as much work to go 8 mph on flat pavement as I did to go twice that fast on my other bikes. The low quality components (microSHIFT groupset, mechanical disc brakes) were also a bummer. Overall, I wasn't enjoying it, so I got rid of it (donated it, actually).

However, I couldn't stop thinking about a bike for snow. Specifically commuting in snow, slush, and ice. I was thinking about some MTB with studded tires. I made the mistake of talking about this at my LBS, and to make a long story short, they convinced me that a fatbike was the way to go, and that the Trek Farley was going to have much better geometry than the ALX, and with decent components, I would love it a whole lot more. I hope they're right, because I placed an order for a frameset. It came in today.

This is going to be my first time building a bicycle. I have rebuilt a couple of bikes before, but this will be my first time working out all the correct components. I expect to learn much in the process, and I hope I don't make too many mistakes along the way. I've already started asking questions.

• I'm thinking carbon rims. The bike accepts 27.5" wheels, but I still have the 26" Dillingers, which I like, so I think I'm going to stick with that. (I'm a small guy, and the frame is a size S, so it should be a good match.) I haven't decided on which rims. I think I want the width to be around 80-85mm (external).
• I'm thinking SRAM NX Eagle 11-50t drivetrain with a 32t chainring. I'm fairly happy with this on my Giant Trance X 2. Trek builds the Farley 5 with a 28t chainring and the higher end Farleys with a 30t chainring, but this seems unnecessarily low for commuting. According to Trek, 32t is the max chainring size, unless I want to go to a 2x, which I don't.
• Probably 165mm crank arms. Short legs.
• Probably 720mm or 750mm handlebar.

I'll keep y'all posted as I go along, so you can see how the newbies do it.

(Also, my pocketbook is moaning about my evident addiction. I won't be buying all the parts tomorrow.)


2022 Trek Farley AL Frameset

Airfehr

I run a 9-46t with a 30t CR. 27.5 wheels on my Farley. That maxes out the range on a Shimano XT which is where I like it. Without doing some ciphering not sure how my gearing compares with a different wheel size. My range suits my needs which is 99% off road. So with nothing in common enjoy this useless information.

27.5 wheels fit that frame very well. If you get 26ers you will wish you went bigger. 80/85 wheel sounds good for a 4" plus wide tire. I would think the wider the wheel the more prone to rock damage. Less tire to protect it. Selling off your old tires should cover half the cost of a new pair of 27.5s. WTH, it's not my money.

Beach sand that has had heave traffic can be tough to ride in even with super low tire pressure. Trackless sand can be a lot of fun. That Farley build will be less than half the weigh of the Mongoose. The Farley will be different experience. It's going to be awesome.

flieger

Beautiful area! Where is it?

Airfehr

^^^It's here https://www.bikeforums.net/southwest...-dunes-ut.html

UnCruel 

Thanks. You got me thinking about it, and after some research and opinion polling, I decided to go the 27.5" route.

I've added/ordered:

• Bontrager Kovee Elite 35 MTB Handlebar, 720mm and Kovee Pro 35 Stem, 13° × 50mm
• Bontrager Rapid Drive front and rear hubs (with a Shimano freehub to go with the SRAM NX drivetrain I'll be using)
• Nextie Wild Dragon (Premium Lite) 27.5" rims, 85mm external width
• 45NRTH Dillinger 5 tires, 27.5" x 4.5", 120 TPI

I'll have to figure out spokes and stuff next.

UnCruel 

The rims arrived today (3˝ weeks after ordering), and I've had the hubs for a while. Time to get serious about wheel building. I need to make measurements on the rims (just in case the published specs are wrong), and then order spokes and nipples.

I also need to learn about rim tape, choose something, and order it. Planning to go tubeless, of course.

Latest ETA on the tires, which are back-ordered, is December 10.

pipeliner

Fatbiking is generally a low speed, higher resistance affair. I run a 28 chainring with 12spd XT and would not want to go any bigger up front than that. I did try a 32 for a gravel riding experiment and quickly did away with that.

UnCruel 

I'm having trouble finding any crankset that meets my requirements: 76.5mm chainline, 165mm crank arms, 32t chainring.

UnCruel 

Whoa. I was looking at 32t because that's what I have on my trail bike, and I like it. I wanted to go with the same drive train on this bike. My trail bike also has 27.5" wheels, but 2.6" tires. I knew the outer diameter/circumference of the tire increased with width, but I didn't look up the difference until now. It's much more drastic than I realized, a 13.5% increase, in fact. To counteract that, a corresponding decrease in chainring is called for, which would be 28t (28.2 rounded down).

pipeliner

Yeah, with a modern 12spd drivetrain, a 30 or 32t is probably the choice of elite riders in the Leadville winter race series... not so much for recreational riders.

jp911

I just pieced together a crankset to meet this need: Raceface turbine crankset (165mm), Raceface replacement spindle (190/197mm), and a Wolftooth chainring compatible with Raceface Cinch. The hardest item to source was the spindle, but they are out there if you search (there are multiple lengths available, but 190/197 was right for my Farley). Also, this setup has a 30mm spindle diameter, so make sure your frame can take a bottom bracket that will work with that spec.

UnCruel 

Race Face doesn't make it easy, that's for sure. After exchanging a couple of emails, in which I specified alloy, they've recommended their most expensive alloy crankset, plus a secret spindle that they don't list on their web site. It will cost nearly twice as much as the SRAM option (which is only 30t).

I don't understand why manufacturers don't sell spindles, crank arms, and chain rings as independently modular items, even those companies that get so close.

AKTed

The SRAM or Truvativ fat bike cranks would work well IMO. The Fat 5 model has a 76.5 chainline, and is available with 165 crankarms. Here’s the GX model

https://www.jensonusa.com/SRAM-GX-Ea...All%20Products

The SRAMs do use an unusual chainring offset. I think to get a larger chainring you’d have to use the Wolf Tooth CAMO system, more $s unfortunately.

UnCruel 

Well, it's beginning to be roughly bicycle-shaped, now. The wheels are built, apart from rim tape and valve stems. The second wheel went much more smoothly than the first one, though it wasn't without errors.

The SRAM GX Eagle Fat5 crankset with a 30t chainring is what I ended up ordering. The chainring has a -4mm offset, and 30t is the largest they make that way. Looking at the numbers, the difference between 30t and 32t doesn't seem worth quibbling about.

AKTed

Looking good!

prj71

Looking great!!! If your trails have any amount of climbing you'll appreciate the 30t chainring.

jp911

Looking good!

I just finished my build on the same Farley frameset. I used XT 11-speed components, HED aluminum wheels, and Bontrager Gnarwhal tires.

Here are some pics from the first roll on local trails yesterday. So much fun!!!!

UnCruel 

Well, it is roughly together now, enough to call it a bike. The tires I ordered in early October finally arrived on Thursday. I took that as my cue to order the last of the drivetrain parts, and I put them on today. Sadly, I just missed my opportunity to ride it around on ice.

This thing currently clocks in at only 28.0 lbs!

Much to do yet:

• The brake hoses need to be cut to length and bled.
• I need to put in about a pound of tubeless sealant.
• 504 tire studs need to be installed.
• I can finally make a decision about the stem height.
• I've fairly well decided I want a dropper post, but I haven't thought much about which one.
• I have flat pedals on it now, but I think I probably want to put SPDs on it instead, and I think I might try a pair of the kind that has the platform around them.
• Someone at the LBS told me how I can get a 32t chainring on it: Wolf Tooth CAMO will adapt to the crankset with the right offset, and they have a 32t ring.
• Bottle cage, Garmin mount, light mounts

I've also learned that it doesn't fit in my bike rack. The rack held my previous fatbike, but that one had 26" wheels. I had to let the air out of the tire, and it barely made it in. After I have studs in, I won't want to do that.

CrimsonEclipse

That, sir, is a fine looking bike.

UnCruel 

Finished! Final weight: 29 pounds, 11 ounces.
(Basically finished. I am going to replace the dropper post cable with something else. The Jagwire cable/housing has a ton of drag in it. And it seems that I need to rebleed the rear brake.)
With the studs, very noisy on pavement. Very quiet on grass. The 108 hub sounds interesting.

The dropper post is a PNW Coast, which adds another 40mm of suspension (I was concerned about how upright my position is).
I rode it a bit with the 30t chainring. The Wolf Tooth Camo DM Spider for SRAM with the P2 Offset isn't as pretty, but it gives me access to a whole range of chainrings. I have a 32t on it now.
I'm not sure how I feel about the PD-ME700 pedals. They are heavy, and I haven't found any appreciation for the wider platform.





Here is where I ended up with the stem

Found a 32t solution

Seatstay blocks the brake pad retaining pin from being removed

CrimsonEclipse

Needs 203MM rotors...

pipeliner

Helluva nice bike.