Sanchinguy
Sanchinguy Reader
10/3/19 9:07 p.m.

Hey all, 

After 37 years on the day job treadmill, I decided to retire. After taking some time off to explore doing nothing, I decided that I needed a part-time job. I considered a number of options but they all had to meet a few important criteria - the work needed to be tangible, the environment needed to be fun, there needed to be opportunities to learn new things, and it needed to help people. After looking around a bit, I found the job that checked all the boxes: A part-time job at a really cool local bicycle shop working as a mechanic/sales guy/gopher.

I've been an avid recreational cyclist for decades. Not a racer, not a mega mile tourer, just a slow old fat guy (SofG) that likes to be outside riding my bike whether its a century ride or a quick 10 miles on a nice afternoon. As a result of some poor life choices and some unfortunate genetics, I've accumulated a number of what I call "grumpy old man problems" - multiple knee surgeries, major reconstruction of my right shoulder, numerous blown discs in my lower back and my neck, and some other stuff. As a result, I really can't ride a conventional bike any more. Fortunately, recumbent bikes accommodate all of my limitations.

After years of riding a bunch of different 'bents, I'd focused in on what I liked and disliked and got a very clear idea of what I wanted in a bike - a relatively upright riding position, a low bottom bracket/crank, the capacity to ride well on pavement and gravel, durability, and all-day comfort. Weight was also a factor, but only in light of the other priorities. (Let's face it, its easier and cheaper for a SofG like me to take pounds of of myself rather than taking grams off the bike.)

After some thoughtful discussions with my boss, a plan took shape: A long wheelbase bike with light, tough wheels that can run a generous tire, a rugged wide range drivetrain, powerful brakes that can haul my considerable girth to stop when needed, and a supremely comfortable ride. I also wanted to push the technological boundaries a bit when it made sense to do that.

I'm happy to report that I've achieved all of those things, while taking the classic approach to recumbent bikes in a slightly different direction.

I'll share the build process and some of the decisions that went into it in greater detail in following posts.

Here we go...

 

 

Sanchinguy
Sanchinguy Reader
10/3/19 10:31 p.m.

The first challenge was to find a long wheelbase (LWB) frame that would accommodate the tires I needed to run. The classic long wheelbase 'bent is the Easy Racers Tour Easy or Gold Rush Replica, but that design is decades old and lacked frame clearance for wider tires. Further, the company that made them had gone out of business, which took them off my list. Other LWB bikes from Lightning, Bacchetta, and a couple other makers were considered and abandoned for similar reasons.

Out of this process, a great option emerged. RANS Bikes (ransbikes.com), a recumbent bike maker based in Kansas, has been making a variety of beautifully engineered 'bents for many years.  A few years ago, they decided to do a clean sheet of paper design for a new LWB 'bent that would be light, stable at all speeds, reasonably fast, and would accommodate all the recent technical advances in drivetrain and other components. The result of this effort was called the Phoenix. The Phoenix includes a number of design elements from previous RANS bikes, including using two full size 700C road wheels, and takes the classic LWB design to a new level. A few conversations with the fine folks at RANS and the frameset and some other components unique to that bike (seat, handlebars, and a few other things) was ordered.

Next came the wheelset. There's a huge number of options available when it comes to wheels. I wanted to be able to run a 40 to 45mm wide tire for both ride quality and gravel road handling. I considered carbon fiber rims, but abandoned that idea for cost and reliability reasons. Carbon rims are very light and can be built up into truly fast wheels, but good rims are really pricey and have fairly high failure rates. I'm not a light guy and recumbent riders can't "unweight" the bike over bumps, so these wheels need to be able to take a beating. Ultimately, I chose the AllRoad Pro wheelset from Mavic. Designed for cyclocross/gravel racing, they easily accommodate the tires I wanted to run, are tubeless compatible, have excellent bearings, provide for disc brakes, and are reasonably light given their mission. Done.

The decision regarding drivetrain was complex. 'Bents have historically relied on touring and mountain bike drivetrain components as they demand a wide gear range. 'Bents don't typically climb as easily as conventional bikes because the rider can't stand on the pedals and use their weight and upper body to power up hills, so the seated rider instead needs to keep the pedals spinning to get there. Touring bikes have largely been ignored in recent years as the industry has turned its attention mountain bikes and gravel/adventure bikes. Once common, the triple chainring crankset is a vanishing beast and high quality components are difficult to source. Similarly, the front derailleur needed to shift multiple chainrings is also disappearing.

The current standard in mountain bike drivetrains is a single chainring driving a wide range cassette with  10 or more gears, often referred to as a "one by" system. There are a few advantages to this approach- the elimination of the front derailleur, shifter, and chainrings makes things simpler and incrementally lighter, improved chain management, and cleaner aesthetics. One criticism leveled at such systems is that the steps between the gears can be too large, making it harder for the rider to maintain a comfortable cadence and level of effort, particularly on-road. That's valid, but it can be mitigated by having enough gears between the lowest and highest ratios.

Another emerging technical aspect of bike drivetrains is electronic shifting. Both major bike components makers, Shimano and SRAM, have had electronic shifting in their road groups for a few years. The Shimano systems, known as DI2, use small control wires to link the shifters, derailleurs, and battery. The SRAM systems are wireless. This year, SRAM released its mountain bike electronic shifting system, called Eagle AXS XX1. It's currently only available as a groupset, and includes a carbon fiber crank, a massive 10-50 tooth 12 speed cassette, a wireless shifter control, a special chain designed to run on the 12 speed cassette, and the rear derailleur with its internal servo motor and integrated battery. Coupled with a slightly larger chainring for mostly on-road use, this produces a suitably wide range of gears that allows the rider to climb at 2 mph and spin out at a top speed north of 30 mph. So I ordered it.

Brakes were also an interesting consideration. Disc brakes were a forgone conclusion, but what kind? The current standard in high performance brakes are hydraulic disc brake systems. Essentially downsized motorcycle brakes, they are very easy to use, very powerful, and provide excellent modulation. On the downside, they're much more complex, some have proven to be less than wholly reliable, and  importantly they're rarely repairable roadside as that typically requires special tools that most folks (including me) wont carry while riding. While the advantages of hydraulic brakes are undeniable, there are mechanical discs that work very well indeed and in the end I went with a combination of a Single Digit lever from SRAM/Avid and Spyke calipers from TRP. The TRP calipers are interesting as they squeeze the rotor from both sides, rather than a traveling/static pad design used by others. This makes them both more powerful and easier to set up and maintain. The brake system was rounded out with some cool SRAM two-piece rotors (more rigid and better heat dissipation, but mostly they just look cool), and some Jagwire compressionless housing to keep everything connected tightly.

That covers the major decisions. Assembly and tuning are next...

ae86andkp61
ae86andkp61 Dork
10/3/19 11:23 p.m.

Cool. As a fellow bike-industry guy, I like everything about this thread! A recumbent with AXS sounds intriguing. Following with interest..

SnowMongoose
SnowMongoose SuperDork
10/3/19 11:25 p.m.

Seems pretty well thought out.  

One by gets my full approval, though I've been running 1x since before the advent of the modern huge ranged cassettes, so I might be biased.


That being said, the idea that hydro disc brakes are somehow unreliable or not repairable in the field is... ridiculous.  
They're dead nuts reliable...  the only folks saying otherwise haven't ever used them.   And all the tales I've heard of them needing repairs mid-ride have involved a major crash that would FUBAR *any* type of brakes.

(cough*road cycling rim brake purists*cough)  

In any case, looking forward to seeing your project come together.  
I assume you have the mandatory beard and helmet mounted mirror?

Sanchinguy
Sanchinguy Reader
10/4/19 5:26 a.m.

In reply to SnowMongoose :

I understand your view on hydro brakes - note that I said some were less than entirely reliable. My choice was based on my experiences servicing hundreds of bikes used in a pretty wide variety of circumstances. I've seen lots of blown master and caliper seals, frozen pistons, split lines, and innumerable systems that never seem to bleed properly, no matter what Santaria rituals are performed. If this was a performance mountain bike, I'd definitely run hydros, but for this application, I'm comfortable with the TRPs. Brakes are easy to replace, and I'm watching the market for future developments.

Now, on to the build...

ultraclyde
ultraclyde PowerDork
10/4/19 5:45 a.m.

Digging this. There were a handful of bents on the six mountain ride I did last weekend. I cant imagine riding a bent over 11000' of mountains.

I agree with SnowMonhoose on brakes though. On the long gravel and bikepacking rides I've done, the only people that had problems were the mechanical disk guys. I run TRP Hylex on my camp and commute bike. Been stellar. If you're willing to trust electronic shifting, hydro disc seems a small jump. 

But whatever, it's your build and it sounds awesome. Love eagle + fat road tires + bent. Cant wait to see pics!

Sanchinguy
Sanchinguy Reader
10/4/19 11:32 a.m.

I'm going to fast forward bits of this process as parts acquisition took a few months. The frame for this bike was essentially built to order as RANS hand builds these frames in small batches and my order was placed in between batches. That made it possible to consult with the frame builder about what I wanted to accomplish, the components I was going to use, and a few other minor things. The frame took about 6 weeks to get. The wheels happened to be in stock at work as we're a Mavic dealer, but I had to order an XD hub driver to use the SRAM AXS cassette with the AllRoad Pro wheels. Brakes were also on hand. The Eagle AXS groupset had been teased at races and industry events for many months, but was only released for retail sale this season and initially in limited numbers. I got in line as soon as I'd made the choice, but it was still a few weeks before I could get my hands on one.

So, the build started on a beautiful Sunday morning. My boss was kind enough to let me come in when the shop's closed so I could use the service area during non-work hours. It began like this:

I started by unpacking and inspecting the frame...

Ooooh, sparkly...

The frame arrived in perfect condition - no scratches, a check of the alignment showed it to be perfect. The finish is powder coat and the color is called "Illusion Orange" - There's a gold bass boat sparkle in it and it looks amazing in the sun.

Nice details abound. The dropouts and other frame fittings were cleanly installed and perfectly aligned. The frame is made from TIG welded 7005 aluminum.

Onto the scale:

This includes components that came mounted to the frame, such as the seat clamp assembly and return side chain idler pulley. With those removed, the bare frame would be comfortably under 6 lbs. Not bad for a bike that's nearly 8 feet long when assembled. Though not pictured, the fork weighs about 22 oz.

One of my habits when building up a frameset is to chase and clean all the threads in the frame. Thread cuttings, old lubricants, and stray powder coating can really create issues during assembly. In this case, there wasn't any powder coating in places its didn't belong and all the threads were very nicely cut.

 The first component I install is the bottom bracket bearing (BB) assembly. This SRAM component places the bearings at the ends of the crank axle and is designed to work with the Eagle AXS XX1 crank and simply threads into the BB shell. For this and the rest of the assembly, I used Dumonde Tech Micro Resistance grease. Super nice stuff.

And it's in. The bearing cups have to be torqued to spec using a special cup-shaped tool that attaches to the torque wrench.

Next is to install the crankset...

 

Sanchinguy
Sanchinguy Reader
10/10/19 8:28 a.m.

Sorry for the delay - life happened...

The Eagle XX1 crank is a dedicated single chainring design. It ships in the group set with a 34T chainring that's a bit too small for this application. I ordered a 38T chainring to put me in the gear/speed range I wanted. The chainring is intricately machined and mounts to the crank with three torx screws. There's thread lock on the original screws, so some care is needed when removing them, but the swap is simple.

Original 34T ring:

New 38T chainring:

It's a little hard to see in these crappy phone pics, but the tooth design on the chainring is fascinating. The width of the teeth alternates wide/narrow to fit the chain precisely and each tooth is shaped to ensure optimal engagement with the rollers at each link. This results in improved efficiency and better chain retention. The crank arms are carbon fiber and are remarkably light, stiff, and tough. The crank axle is bonded to the non-drive side crank arm. Its hollow and machined to match the bottom bracket bearings.

One cool thing I didn't get a picture of is the way the end play of the crank is managed. There's a couple small spacers to take up most of the gap. Then there's a wave washer (thrust washer), and then there's an intricate threaded collar that turns to set the final lateral tension. Hard to get in a picture, but ingenious.

With the crank in, installing the cassette onto the rear wheel was next. SRAM Eagle cassettes use a proprietary hub adapter referred to as an XD Driver. There's a MTB spec called the XD driver and a road version called an XD-R driver. They're different in some dimensions and that difference is important. XD drivers are specific to the hub they're mounted on and Mavic offers an XD-R driver for its wheels. The driver attaches to the hub and the cassette threads onto the driver. The driver contains the freewheeling mechanism that allows the wheel to coast. The Mavic freewheeling system is trick. Called ID360, it uses a pair of opposing serrated discs held together by spring tension. One is on the hub and ther other is on the driver body. Sorta like the paired serrated lock washer idea, they allow easy freewheeling, extremely solid lockup, and achieves full lockup every 9 degrees of rotation. In order to use the Eagle cassette on the XD-R driver, you need to install a spacer between the cassette and the driver. This assures proper spacing so the cassette spins freely on the hub.

The cassette is a piece of technological jewelry:

The profiles of each cog in the cassette are shaped to facilitate rapid shifting and optimal chain engagement. There's a ton of subtle technology in this.

The 10-50T range makes for a massive cassette, something that becomes apparent when you see it on the wheel:

 

I also installed the brake rotors at this point. They're a centerlock design, rather than the common 6 bolt arrangement. Interesting tidbit - Shimano centerlock rotors ship with lock rings, but SRAM centerlock rotors don't. I asked SRAM why that was the case and they said that Shimano owns patent rights for the centerlock system. So I had to order lock rings from Shimano. Welcome to the crazy world of bike components.

Next up will be fork, brakes and derailleur installation!

 

asterisk
asterisk Reader
10/15/19 2:27 p.m.

Looks like a fun project. One thing to add: I'm not a huge fan of the stock TRP pads (at least those that came on my Spyres.) I've been using EBC sintered pads and they're great for wet weather or heavier riders and don't seem to glaze over like some of the organic pads.

pinchvalve
pinchvalve MegaDork
10/15/19 3:15 p.m.

New 38T chainring:

 

I know nothing about bikes, but that is awesome.

Sanchinguy
Sanchinguy Reader
10/19/19 8:40 p.m.

The next step in the build was to install the fork and handlebars. The fork is a nicely made Cr-Mo piece. A great deal of thought went into the design. RANS has made a number of other dual 700c 'bents in the past and applied the lessons they learned in this design - rake and trail hit a sweet spot that results in handling that is both secure and responsive. It's stable at all speeds, predictable, and despite everything, there is no wheel flop. That's remarkable.

 

The headset bearing cups press into the steerer tube. The lower bearing race presses onto the fork crown.  Sealed bearings rest in the upper and lower bearing cups. The fork goes through these bearings, and an upper race, dust shield, and cap go onto the steerer tube.

The headset bearing stack tension is set by an ingenious set of clamps and an expanding collar. The whole assembly is put together and lined up. The upper clamp is tightened onto the riser tube. Then the threaded collar is expanded until all of the slop has been removed from the assembly and everything turns freely, then the bottom clamp is tightened. In addition, there's a small pinch bolt in the collar that locks it into place. The handlebar is two pieces: A v-shaped bar that goes up to two clamps, and then the handlebar itself which attaches to that v-shaped bar. The handle bar is available in a variety of widths and bend angles allowing the rider to get a comfortable hand/wrist position.

After installing the fork and handlebar, its was time to install the drivetrain. First was the amazing Eagle XX1 AXS derailleur. At their most basic, derailleurs are spring loaded parallelogram hinges that drag the chain from one gear to another. The AXS is arguably the current state of the art - servo motor driven, wirelessly shifted, clutched cage pivot, indexed idler pulleys, carbon fiber cage, and immense gear range. It's also ridiculously easy to install and set up.

The shifter is a microswitch controlled wireless transmitter that pairs directly with the derailleur. Paring them is simple - install batteries in both, push a couple buttons and bingo, its good to go. The shift action is immediate - there's a little zip and bam, the shift happens. So cool... The shifter uses a simple 2032 disc battery and the derailleur uses a proprietary lithium ion battery. Battery life is impressive. Derailleur setup is really easy - put it in a specified gear, push a couple buttons, set the upper and lower limits and you're done. There is also an AXS smartphone app that allows you to control how the shifting behaves, which shifter button does what, how many gears to shift with each push, etc. It's simple and it works.

With that done, it was time to install the brakes and the wheels...

The TRP brakes set up very easily - open up the pads, center the caliper, and then close the pads until the clearance is just enough to let the rotor spin without contact. The brake levers were also easy to install. Because the cable run to the rear wheel is very long, I used compressionless housing to maintain a crisp firm lever feel.

The last things to install were the seat, chain, and my pedals. The chain is super cool, with a rainbow iridescent coating. This bike uses two full chains but the AXS rainbow chain was only available in the group set when I finished this build. They're supposedly available now, but our suppliers are perpetually sold out. A non-AXS 12 speed chain fills in until I can score another rainbow chain.

A few more small tweaks and voila, its done:

And the final result...

Without the seat bag pictured above, the bike comes in at a riding weight of 29 lbs., which is pretty impressive for a bike this big. I've now ridden a few hundred miles and it's everything I hoped for. And as a side note, it fits nicely in the back of my Honda Odyssey with the front wheel removed.

A quick but heartfelt thanks to Chad and Nicole Cottom, owners and my bosses at SPIN Bicycle Shop for making this project possible!

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