No hub motor powered electric bike has previously ever made it to the top of Pikes Peak, although many have tried and failed. This is because hub powered bikes generally are not as good at mountain climbing as mid drives which are able to use the bicycle’s gears to change the motor’s gearing. This year the results of the Pikes Peak electric bike race were surprising. A hub motor bike not only finished, but finished well ahead of five $13,000+ Optibikes, and was actually the first electric bicycle (with two wheels) to reach the top. (read full race result story here)
Adam Griffin, a 39 year old civil engineer out of Janesville Wisconsin, is an E-bike enthusiast who has been building and riding E-bikes for 3 years now. He commutes to work two days a week on his electric bike, and enjoys the freedoms and intrinsic benefits that E-biking bring him. He made the 15 hour trek to Pikes Peak with his wife, teenage son, and his home built electric bike in the back of his minivan. He had no idea if his E-bike would make it to the top of the Peak, much less actually place in the top three. His plan was to have a 4-day family vacation enjoying Colorado Springs, and then race up Pikes as the pinnacle of the trip.
Despite all the talk on the DIY E-bike builders forum endless-sphere, this year Adam was the lone Endless-Sphere entry. A lot of this was because of confusion before the race as to whether this event would actually happen at all, and if electric bikes would be allowed to compete in what is mostly a pedal bicycle race. Adam came to this race as a lone soldier on a mission, not an electric bike company, not a sponsored rider, and with no ulterior motive of financial gain.
When you look at the pictures of the starting line, you can imagine Adam’s plight. He was racing against factory teams Optibike and FFR Trikes and they were sporting slick looking rides and dressed like professional riders. Adam is on his garage built electric bike wearing gymn shorts and a plain white T-shirt. Says Adam about the starting line experience: “It definately felt like a race. There were hundreds of riders at the starting line (this included pedal bike racers). Most had high tech bikes and wore lycra. Team Optibike and team FFR were lined up next to me. This is an intimidating feeling. I felt like I brought a sharp stick to a gun fight.”
Little did Adam know he was about to become a hero for electric bike home builders throughout the world by having a solid finish in this race on a bike that cost him only $1,600 to build.
- Photo credit Nicholas Turner of Optibike
How did Adam arrive at this weird juncture in his life, at the starting line on a home built electric bike about to race some of the most powerful (and expensive) commercially available electric bikes to the top of one of the countries highest mountain peaks? Adam became inspired to conquer Pikes Peak after reading about the results of the 2011 race in which Optibike had dominated the race entering 7 bikes and taking 1-7th place. He had built one electric bike before this and wondered if he could build a bike that could withstand the rigors of Pikes Peak. Adam has always been the type to take on huge challenges, and believed he could put his engineering skills to the task. Says Adam, “I’m just crazy enough to think I could make it to the top of Pikes. From then, I started planning my trip.”
Selecting the motor
Before he started his Pikes build, the most critical choice was which motor to use. Since Adam did not want to put up with the time and expense of building a mid drive, and already had past experience with a hub motor and modifying a hub motor, a hub motor was the easy choice. To decide which hub motor and which winding to use he utilized the ebikes.ca motor simulator which has been a godsend for many DIY electric bike builders. Adam settled on the 9C 2810 Motor and he purchased it from Methtek for $100. (read our review on the 9C motor)
Hotrodding the motor
As you can see by reading our hub motor hot rod primer, the biggest enemy of a hub motor you plan to crank a lot of watts through is heat. No better example of heat stress on a hub motor is racing up Pikes Peak. First things first, Adam did not want to fry any of the wires going into the motor so he upgraded the stock wires with thicker guage wire. Here is a photo of his motor rewired:
- modified 9C hub motor
Next big problem to solve was how to cool down the motor as Adam’s plan was to over-volt it. It has been theorized by many DIY hot-rodders that by using some kind of cooling you can double the amount of wattage you can run to the hub motor without smoking it. By using some kind of cooling system, Adam was able to use a much lighter and smaller hub motor (compared to the heavy Crystalyte 5404). As a comparison the 9C motor Adam used weighs less than 15 pounds, the hub motor the Stealth Bomber uses weighs 25 pounds. Adam contemplated a few different options for cooling. First he considered the easiest method, which is to drill holes in the cover of the motor for air ventilation like this photo:
Second, he considered mounting a water sprayer system on the bike. He actually attempted this but was not too happy with the results. His system consisted of an electric switch which allowed a car windshield washer sprayer to mist the hub motor with water. He wasn’t able to get good cooling data, since there are no hills steep or long enough in Wisconsin to effectively test. He finally settled on an oil-cooling system after a few other members on Endless Sphere had good results with this method. Also, being an Engineer, oil-cooling seemed like the simplest, cleanest way to cool the motor. You can read how Adam set up his cooling system by reading his thread on Endless-Sphere. Also Adam wired a temperature probe into his motor.
Adam used a Cycle Analyst to limit the amount of amps the motor could draw, and also monitor his battery capacity. The other vital readout is a temperature gauge to monitor the heat in the motor. Here is a view of his monitoring systems taken at the top of Pikes Peak….mission accomplished (notice his battery usage data).
Getting into Shape
Adam decided that he would have a better chance of finishing Pikes Peak (and maybe even winning) if he was in better physical condition. He rode his bike every chance he could up the hilly terrain in his neighborhood and actually lost 22 pounds since the beginning of his training. Says Adam, “I rode the hilliest roads I could find in Rock County, WI, none of which came close to the length and slope of Pikes. Even after a year of planning and testing, I still wasn’t sure my plan to make it to the top would happen. I can only give it my best shot.”
At the actual race, his bike was putting out 2500 watts, so most of the work would be done by the electric motor. However, losing 22 pounds helped a lot because its less weight that the motor has to carry. Says Adam about race day, ” I pedaled fiercely the whole ride up. It was quite painful, as I’m not used to the thin air. I was extremely winded. My lungs burned, and I had cottonmouth. I hadn’t realized how much you need to focus in order to NOT ride off the edge of the mountain. It is quite dangerous, and there isn’t much room for error.” So the physical conditioning paid off in more ways than one.
Adams bike consisted of the following:
2011 Trek 3700 with disc brakes (disc brakes are essential in high speed electric bike)
9C 2810 upgraded motor (28mm wide stator, 10-turns per stator tooth)
My motor upgrades:
10-awg Teflon phase wires installed
30-awg Teflon hall wires installed
Temp sensor installed
Windings coated with VHT high temp brake caliper epoxy
Hub cover sealed with high temp silicone sealant
Lyen 18-FET using 4115’s
30S 12-Ah lipo pack charged to 4.15V/cell, 124V when fully charged, 111V nominal (1,330 watt hours)
Cycle Analyst: set to a maximum current of 23 amps
Tires: Specialized Armadillo
Breakdown of Costs of Adam’s Electric Bike
Here is the cost breakdown of what Adam spent building his electric bike:
Motor & Upgrades: $200
Cycle Analyst: $120
Miscellaneous Wiring etc.: $130
Electricity to charge battery: $0.20
$1,600 dollars for a bike that would end up defeating five $15,000 Optibikes in a mountain climbing race, and finish just behind two $8000 FFR Trikes. Now you see why many guys are into home builds! Performance for the buck…you just can’t beat the home built electric bike equation.
The Performance of Adam’s Electric Bike
Adam’s bike would do 42-MPH on level ground. It averaged 28-MPH climbing Pikes Peak and used 1009 watt hours on the ascent (Optibike claimed they used 500 watt hours but that is with slower speed and a rider who was in tip top condition). Obviously the bike was built to be bulletproof, and could ride at 42-MPH on flat ground reliably, and for a long ways given that this bike packs a 1300 watt-hour battery in the fabric triangle bag. Adam had his bike limited to 2500 watts so that he could make it to the top with little chance of overheating. But is is possible he could have cranked over 5,000 watts to the bike, and he would have been a lot faster but he’d have less chance of finishing without smoking his motor.
Technically Adam finished 3rd place in the race. But given 1st and 2nd were both trikes, it could be argued that Adam was the first place electric bike to finish. He is the first ever competitor to finish the race with a hub motor. And he is the first ever rider to finish Pikes Peak on a home built bike with no company behind him.
Adam tells a great story of the actual race. Here is his story:
After waking up at 3:45am and driving out to the start line, it was still dark out. Many times that morning, I was wondering what the hell I was doing here. This is nuts. You could die, be mamed, crippled, mangled, smashed, bloodied, or all of the above. Not letting that deter me, I get the bike ready. I have power, check. CA set to 23 amps, check. Helmet, gloves, check. Make my way to the start line, check. The 2 minute warning sounds and I’d better turn on the Ipod to get the race video. Apparently I haven’t practiced this enough, because I can’t get the video recording to start. Oh well, no time now.
I ease into the throttle, and still pull a bit of a wheelie, oops. Optis and FFR’s everywhere, better not hit them. The Opti’s take a quick lead, and I tuck in behind 2 of them at about half throttle. The FFR’s make their way to the front. 2 miles in, and the FFR’s have a couple football fields lead. I’d better make a move. So after drafting the Opti’s, I ease past them. This is where my game plan went out the window. I had planned to just pace the Opti’s to the top, then make a move at the end. I never was a good planner. I set full throttle and use all the 23 amps. Now I’m opening up a decent lead on the Opti’s, thinking that I’ll probably burn up the motor further up the hill. Oh what the hell.
I stay in the throttle hoping to catch up to the FFR’s. No such luck. Every time there is a hair pin corner, I have to hit the brakes hard and slow down. This is where the FFR’s open more of a lead on me. It is becoming apparent that I probably won’t catch them. Better focus on just making it up the hill. I remember that I probably should keep an eye on the temp gauge. At the start, my motor was at 4C (39F). Now I’m heating up a bit. By the 6 mile mark, I’m at about 80C (176F). I’m starting to wonder if I will fly off the cliff in a ball of flaming hub motor. By this time, I had opened up a good lead on the Opti’s. My lungs are burning, my guts are aching, and I have cotton mouth. The pain is taking a toll. Apparently, I’m not in as good of shape as I thought. At this point I have to tell myself to ease up, or I’ll fall over dead. The pain doesn’t really go away, so I swear at myself hoping this will help. It doesn’t.
I try to take in some of the sites. After all, I’ve never been to Pikes Peak, and I’d like to see the views. This is a very bad idea. I realize this when I hit the 2-foot gravel strip, right before it drops off into oblivion. More swearing. I have to tell my self to focus. I realize I’m swearing at myself and think I may be getting delirious. Not good on the edge of a mountain. Motor temperature climbs to 115C (239F) at about the 9-mile mark. Uh oh. Luckily, there is a bit of a downhill section, maybe half a mile long. I’m in luck! I hit 46-MPH and watch motor temp decrease to 103C (217F). At this point, I was pretty sure I was going to make it to the top! “Yes, keep pedaling damnit!” I see the last switchback curve and round it. The finish line approaches. I fly through the finish with a smile!
I slow and ride around a bit to cool the motor down. After making my way back to the finish line, I see the FFR guys and go over to congratulate. They do the same. Great guys. We talk for a bit, and watch the Optibikers finish. I think they were the next four riders. We all talked and admired each others’ rides. After about an 45 minutes, the FFR guys started down the hill. I left shortly after and caught them part way down. I followed for a few miles while we passed all the other riders still heading up the hill. The FFR guys were cheering on EVERY rider we encountered. What a class act! FFR pulled off to talk to some riders, so I pushed on.
After I was sure I had passed all the pedalers, I opened up the throttle (yes, down the hill). I hit 50.8-MPH at one point. A bit careless with hairpin turns, but you only live once, right? I fly back through the start line and check my regen stats. I had regened about 100-WH back down. Battery was still at 3.72V/cell, cool…And that’s it! I packed up the bike and went to an early breakfast with the family in Manitou Springs. What a great experience. If any of you home E-bike builders get the chance, do it! It’s an experience you won’t forget.
Written by Eric, July 2012