The Led Sled
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It was a hot summer afternoon in Pleasant Hill, California and I stood back, sweaty and irritated, debating whether the best path forward was to drive this two year project to the dump. The lead acid batteries, the entire two-person bike, all the custom mounts. Even the tools were cursed at that point. I didn’t care about heavy metals seeping into the soil or repurchasing new end wrenches, needle nose plies and sockets. The whole situation was an expensive, time-consuming disaster with no end in site. I never wanted to look at it again.
I’d bought the side-by-side bike naively thinking it would be a fun project for learning about motors with my 12-year-old son. Someone at Burning Man put me in touch with a fellow in San Francisco who had sourced him a 750-watt motor for his bike. (Starting with the motor turned out to be the biggest mistake.) The sourcer could not have been a nicer guy and he designed a motor/controller/battery/charging system based on his years of experience. Was his experience good? I should have known what was in store from looking at his garage the day of delivery. The place was a cave stacked floor to ceiling, front to rear with 50 years of junk. We actually walked through a corridor of junk to reach his work bench. Jony Ive he was not.
After parting with more than a grand for these parts, we had a chain-driven motor, five feet of motorcycle chain, two 12-volt lead acid batteries, two chargers, a controller and a bunch of parts with no manuals. None of it was designed to work together. This was not the deterrent it would be for most people because, among other things, I learned to develop software using Javascript/Node. It took me almost two years to finally understand what I’d bought: Something extremely heavy, that sparked so much that I repurchased tools with rubber handles, created so much torque that it threw chains constantly, and generally created more problems than it solved.
Principles: Our Product North Star
I basically put a tarp over the whole project 18 months ago and avoided thinking about it. My son kept asking about it and that was a bummer. Failure. I told him we’d research something simpler, build something simpler that worked and return to this later.
We spent hours researching batteries that didn’t scare their owners, the world of low rider bicycle customizing, electric bicycles and everything in between. Before long, we had three main requirements before moving forward:
- The battery and power system must be dead simple and not scare me. Anything home grown was illegal.
- It must look like a bicycle, not an e-bike.
- All design decisions must be in alignment with the computer term: bare metal server.
Like guitars, bicycles are collected and obsessed over for their design. Bolting a black plastic briefcase on a downtube always felt like the equivalent of a wearing a fanny pack with a suit. Does anyone really like the way their e-bike bike looks?
After the Rube Goldberg experience with the side-by-side bike, I became obsessed with the idea of simplicity. In my professional life, nothing represents that more than the term bare metal server: A physical computer specifically designed to run dedicated services without any interruptions for extended periods. It is highly stable, durable, and reliable. It invoked an image of a lean, mean machine.
Batteries: It was hard resisting our temptation to buy a killer frame, the latest motor people were raving about on forums, or anything else until we had solved the problem of disguising the batteries in harmony with the frame design. I spent six months emailing every conceivable brand of third-party electric bike company asking about small batteries, batteries that I felt comfortable taking apart (violating design principle 1) and even asking companies like Luna to custom build batteries for us. We struck out for months and were getting discouraged until I came across Grin’s Ligo batteries. In retrospect, one of the most fascinating aspects of this project is how long it took us to find out about Grin. None of the articles or DIY bike forums talked about them. And we researched and read just about everything.
These batteries are unbelievable.
Grin’s design north star for the batteries references flying on a commercial airplane with them, which is strange but definitely gave us confidence they’d support principle one about not scaring us. Not only do they come as modules, they have a sleep mode that guarantees we couldn’t drain them to death, each module has a set of green lights so you visibly see how much charge is left in each one, they come with Anderson Power Pole connectors and… oh my gosh. Just watch this video. It was like the first time I saw an iPhone. Don’t believe me? There’s only one third-party video review of them and the electric bike shop owner talks about how they’re too smart.
Motor: With the batteries seemingly squared away, we went with the Grin RH212 rear hub, which has been killer. It’s powerful to get up everything but the steepest hills in San Francisco and requires literally no thought. Some folks like like the look of front-hubs and that’s okay, but personally I think it puts the motor on display and violates principle 2. Mid-drive motors look like an e-bike. The rear-drive motor achieves principle two because about every fourth question from people is asking whether it’s an electric bike.
Controller: The Grin Phaserunner is a dream. With minimal help, my son followed the online instructions, hooked it up to their software programming suite on our Mac, set the specifications of the rear wheel and it.just.worked. (Video below) Plus, it’s small enough that you’d be hard pressed to notice it. See it there behind the seat? Didn’t think so. And that’s one of the reasons it’s so awesome.
Brains: If this bike had a brain, it would be the Grin Cycle Analyst display. The astonishing amount of customization available still makes me a touch leery, like I’m going to screw something up and spend hours getting everything to work correctly. Grin programmed it prior to delivery and, thus far, I haven’t done anything bad with it. Not only does it display the power/amps/watts/mileage, it includes cables for downloading data, hooking up external lights and more hundreds of other configuration options. The Cycle Analyst is not for the faint of heart, though. It’s the one piece of the bike I remind myself not to monkey with.
Frame After bookmarking a ton of photos for inspiration, everything wound up getting compared to the Hard Time design and we decided that couldn’t be improved on. By sheer coincidence, they’re imported and sold 60 miles from us by a guy named Dominic. My son was initially against the XL version that’s a few inches longer because he couldn’t reach the handlebars very well. But the stretch just looked badass in a naughty way and I reminded him he’d grow into it.
Dominic had made exactly one electric bike for a customer years before so this was essentially a brand new project for him too. In addition to selling bikes, he’s a welder and appreciated the bare metal aesthetic we were after. Still, I could tell he was somewhat leery about the motor, batteries and electrical system when we talked. I’ll build whatever you want as long as I’m not responsible for whether it works.
We mocked up where the batteries could go in about 20 different places and he suggested multiple ways they could be mounted inside a tank that hung off the top tube. But that would make it look a motorcycle, violating principal two. He wound up using thin strips of steel ribbing to build minimalist cages on either side of the rear triangle, adding a single vertical support tube for stability. They are functional and nothing more.
Wheels We ran a big wheel up front and a smaller one in the back to give it a cowboy rake, which is a term my dad used growing up to describe the opposite of a hot rod. Rather than jack up the rear wheels, the rear wheels are lowered so the weight is already in the back during a drag race. I have no idea if that’s true or ever was a thing. But the concept stuck with me and it looks cool.
Forks Despite having every possible cruiser fork out there, none balanced out the gear on the rear triangle. Dominic created a custom pair using aluminum tubing and crowns. The thick, straight pipes just look right.
After months of delays due to Covid, Dominic finally gave us word that it was ready for review. My son took one look and remarked how much it resembled a lead sled. It was undeniable. This was a two-wheel lead sled and the name stuck.
Dominic needed a few more days to put finishing touches on it. We’d originally wanted him to deliver everything in parts so my son could learn how to build a bottom bracket, install forks and everything short of lacing the wheels. But after months of pandemic delays, Dominic convinced us to let him deliver a functioning bicycle. That turned out to be a good idea because there would be plenty of stuff to fix soon.
After driving the rig home, we had to program the controller to work with the rear wheel and motor we’d chosen. That was effortless and, props to Grin, was a one-and-done operation. The video below demonstrates essentially the whole process.
The bike was an absolute hoot when we took it out the first time. We were both so excited he forgot shoes and socks. So smooth, so powerful, so quiet and… everything.just.worked. The satisfaction that comes from the last part is hard to understand unless you’ve failed 10,000 at something. Personally, that feeling is a bigger rush than any ogling stare from someone.
Kickstand I have always loathed kick stands, going back to my first red/white Schwinn Predator. Aside from the checkered pads and the hand brakes, there was no kickstand because those were for little kid bikes. Somehow I never got over disliking them.
Dominic sent the bike home with a kickstand and it looked sorta cool in a chopper kind of way. The first ride through Golden Gate Park, though, brought out the 10-year-old in me. And I dealt with it like a 10 year old.
We kept hear a slapping metal sound. Worried that we were trashing the bottom of the frame, I kept pulling over to look at the bottom frame tube. Nope, not a scratch. Finally, I realized the spring on the kickstand wasn’t designed to hold the arm flush against the frame during bumps at 20 mph so it was slapping constantly. By then we were miles from home, I was irritated from pulling over 19 times looking for this slapping sound, and I essentially tore the kickstand off the frame. Principle three in action It’s been on a shelf in the garage ever since.
Needs Improvement
Wheels The bike started to feel sluggish after a month so we checked the tire pressure, which was less than 10 psi and should be up to 40 psi according to what is printed on the sidewall. We aired them up to 40 psi, but within a few blocks, there was rubbing and scraping going on everywhere. By inflating the tires that much, we had contorted the rims, the spokes, and even thrown off the position of the disc brake in the front.
We disassembled the disc brake and recalibrated the brake pads, yet now the inside of the brake rubbed against the spokes. Plus the rim was no longer true. Sigh. Every adjustment threw something else off.
Finally, we took it to a bike mechanic who ‘dished’ the wheel. This involves truing the wheel so the rim is round again, yet the hub is off center to the right (intentionally) to create space on the left for the brake mount to pass without rubbing. Whew. We’re laser focused on never going above 30 psi anymore.
After all that, the tire rubs against the left fork… so we’ll likely have to buy wider crowns to spread the fork tubes apart. It is what it is.
Brakes: The bike came with the cheapest $25 two-piston disc brake on the market so we upgraded it to a four-piston one you’ll find on downhill mountain bikes.
Lights Dominic sold me that beautiful retro can light seen in the top photo. But what a pain. The toggle switch was hidden between the forks, it ran on AA batteries that needed to be swapped out after a couple rides, and opening it up was a horrible experience with itty bitty screws that held together an ill-fitting closure that was little more than plumber’s tape. Luckily, Grin offered a great set of options. The rear lights plug directly into the fourth auxiliary Anderson pole and the 12-LED headlight plugs into the display. Now they power up with the battery and there’s no charging anything extra.
The Polished Version
Led Sled AMA
How fast does it go? Far and away the most asked question, it’s a funny one to me because we never considered the top-end speed when building it. On flat ground with the throttle wide open, it will do 21 mph. We’ve gotten it up to 27 mph down a hill, but that feels sketchy.
How far will it go? One time I peddled it for three long rides on essentially flat terrain and sipped the throttle only when needed. The system went 43 miles before turning off. On a typical ride with hills and using it more like a lazy moped rider, it’ll do about 20 miles, which is around two hours of riding time. By then, you want to be home anyway.
Doesn’t that low frame scrape? It rides just fine over most speed bumps and anything else you’d want to cruise over. After a couple rides, we stopped scrapping the bottom at all. These days it’s just as practical as any other city bike.
Isn’t it uncomfortable? As of February 2021, we’ve put over a thousand miles on it. So it’s plenty comfortable. Here’s why:
- The rider sits between the wheels rather than on top of one. The frame flex contributes to a suspension feeling rather than sending road vibration up the seat into your tail.
- The fat tires at 75% inflation are cushy.
- At 72 pounds, the bike is heavy so it doesn’t bounce around much. It has a solid ride like riding in a dump truck.
What happened to the side-by-side bike? We put an ad on Craigslist titled “Science Project” and gave it away to the first people with a truck. Knowing when to tap out is an important lesson to teach a kid anyway. More than 20 people responded and it was gone within four hours. God bless those people, seriously, and good luck with that.
