One early summer day in 2000, the shop got a call from an engineer working on a project he told us was secret. All he needed from us was some simple mechanical work.
"I want you to take apart the front wheel of a mountain bike and replace the hub with one I'll send you. The spokes will need to be about 7 inches long."
"How did you derive that number?" I asked.
"Well, that's just the 26-inch rim diameter, minus the diameter of my hub," he said. "That'll do it, right?"
"Not quite," I said. "Got a pencil?"
The bike spoke length formula is a longer chunk of math than most of us readily deal with, involving cosines and square roots and stuff. Personally, because I had difficulty with math class, I would only tackle it with a calculator. I reeled it off to the engineer.
"Whoa," he said. "I thought bikes were simple."
"Maybe, but not that simple. You're looking for a tangent running from one circumference out to another. Your spoke has to be long enough to reach with ample thread, but short enough not to stick into the area where the inner tube goes.
"It will be cheaper to build you wheels than to sub in your hubs, too."
We ended the conversation and each ran the calculation using his hub dimensions and the effective rim diameter of the rim I suggested.
Over the course of several days and numerous phone calls and emails, we determined the wheel would have to be spoked radially, because the dimensions he had already specified meant that we couldn't adjust anything to make room for tangential, crossed spokes.
"You shoulda come to see me sooner," I said.
We ordered the parts and extra tooling we would need to produce three front wheels for the three prototype bikes he finally told us he was developing. Then we waited for the hubs.
The engineer did not know a lot about the specific details of bike construction when he started with us, but he knew them by the time we finished. He'd gone into this not knowing the standard diameter of a front axle or the over-locknut width of a front hub, yet he hoped to use stock forks. So he had parts being machined before he knew exactly how to make them fit existing pieces of his planned structure.
A friend of mine describes an engineer as a person with all the common sense taught out of them.
He had enthusiasm and a willingness to persevere. Good thing, too, because our shop put in a lot of hours. I would ride this thing through to a billable result, come what may.
Despite his assurance that the product would make a big splash when it came out, and his promise that he would send us any press items about it, the wheels went out and his payment came in, and we heard no more about it.
Then, last summer, a local family brought in their spiffy new electric bikes. The wheel configuration looked oddly familiar. The motor was no longer in the front hub, but the front hub was still a large drum to accommodate the battery.
Ralph and I rode the bikes after we peformed the minor repairs they needed. They're fast, with two power settings, a low-power cruise mode that supposedly yields a 20-mile range, and a "turbo" setting, for very snappy acceleration.
Like all electric bikes, they weigh a lot, around 50 pounds, so no one is likely to pedal them much. Like all electric bikes, they're really just a clean-running, rule-beating small motorcycle. Shhh. Don't tell the government. You'll have to register them and stay off the bike path. But they're the best example I've seen so far, much sportier than the EBikes another customer brought in.
The models we saw use regular rim brakes. These are definitely inadequate for a vehicle of that mass. At the very least, pad wear will be rapid. The arms flex alarmingly under hard stopping.
Of course you may not notice the brake arms flexing if you're distracted by the way the standard mountain bike suspension fork bends under its load.
Bike stuff is light because the human motor is weak, so the vehicle itself has to be built lightly. Motor vehicle stuff is heavy because fuel or batteries, and motors, engines and drive trains are chunky, to contain and direct the forces generated with that extra horsepower. It is hard to merge the two. Any motor, even a woefully inadequate one, will make a bike weigh much more than a rider of any ability will want to push around by muscle power. The better it is as a motor vehicle, the more irrelevant its pedals become.
That being said, I'd rather share the road with electric motorcycles than gas-guzzling barges.
It was a fun project. We all learned a lot and shared what we knew.
So what will this summer bring?
Tuesday, March 29, 2005
Look what the engineer dragged in. We got a call in 2000 from an engineer at WaveCrest Labs, asking if we could spoke up some wheels for an electric vehicle prototype. The hub shells were being machined in Tuftonboro, so we were the closest bike shop. We had to calculate the spoke length and make 108 custom spokes before building the wheels. This interesting project turned out to be an early stage in the development of the bikes now marketed under the Tidal Force brand name. The production hubs are smaller, allowing for slightly longer spokes.
Posted by Hello
Monday, March 28, 2005
Friday, March 25, 2005
Intermodal Adventure
The train swayed and clacked over the rails. Afternoon sun beat in through the windows of the boarding doors of the car’s vestibule.
I leaned my bike vertically against something that didn’t wiggle and work every time the train jostled. Holding the rear brake lever, I could keep it from rolling around as I tried to maintain my balance. I was in the space between two cars, watching their two platforms jerk back and forth.
This was intermodal transportation in 1980.
Somehow I had gotten the idea that one could ride a bike to the train station and board the train with the bike to cross greater distances than one could conveniently ride. Scraps of articles, vague conversations with other riders alluded to this sensible concept.
I got up at 5 a.m. to ride from Annapolis to the New Carrollton Amtrak station. I’d been riding the rails all winter to visit my girlfriend at Rutgers, in New Brunswick, New Jersey, but now it was spring, and I was training on the bike again. I was tired of having to bum a ride to New Carrollton or Baltimore.
The 6:30 Metroliner rolled in. I stepped up to the doors with the handful of other passengers. A conductor stopped me.
“Whoa, whoa, you can’t take that on the train,” he said, pointing to the bike. He was nice about it. We knew each other by sight, after my months shuttling up and down the line on missions of what appeared at the time to be true love.
I explained my plan, indicating the various trains I’d stitched together in my timetable.
“Tell you what,” he said. “I’ll let you ride as far as Philly. You can get a train with a baggage car there. That’ll take you the rest of the way to New Brunswick.”
He showed me into a car with a large space behind the last row of seats. I leaned the bike up against the wall and hunkered down beside it. We were on our way.
Those first accommodations were pretty cushy. The conductor even dropped by to see how I was doing. He apparently approved of my low-key presentation.
We said a cordial farewell at Philadelphia. I went to the platform where my next train was supposed to be.
Feeling confident after the friendly treatment the first conductor gave me, I walked up to the burly man in uniform beside this train and explained that I needed to put my bike in the baggage car.
“We don’t open the baggage car here,” he growled. “And your bike has to be in a box. Take the Conrail.”
After some negotiation, he told me to wait until the train was just about to pull out and then hop on through the doors of the car right in front of me. I could stand between the cars as far as Trenton, where I could get a Conrail train the rest of the way.
So now I stood on the dimpled metal flooring of my jostling cell, meditating on the beauties of the slums and industrial wastelands through which the rails ran.
Voices emanated from the leading car. I gathered it was the club car. As the muffled altercation grew clearer, I determined that the burly conductor was arguing with a railroad employee traveling for free, who had gotten drunk and disorderly.
The club car door slid open. The burly conductor shoved a smaller man roughly into the space I occupied with my bike. They continued their argument. Then the smaller man swung a fist at the larger one. The larger one felled the smaller one, swiftly kicked him and pulled his leg back to kick again.
I met his eye. Enough was enough. The burly conductor straightened out his clothing and withdrew into the club car.
The smaller man backed into the corner opposite mine. I didn’t really want to hear his story. I wouldn’t let the big man kick the crap out of him in my presence, but I had no way to judge any other merits of his case. We lurched on in silence for a few more minutes until the train slowed, then stopped, in Trenton.
As soon as the doors opened, I hopped out and headed away from the train. The police were arriving. Since I had not been supposed to be there at all, it seemed like time to disappear. I went looking for a Conrail train.
The Conrail conductor was another grouch, but he finally agreed to let me get into the back of a car and squeeze into another seatless space.
A woman in the next seat was convinced I must be some globetrotting adventurer. She wouldn’t let go of the notion, no matter how many times I told her I was just some schmoe trying an ill-conceived experiment.
Before I could be tempted to start making up stories to satisfy her craving for vicarious adventure, the grouchy conductor came up as the train was starting to move and told me to get the hell off, because he’d changed his mind.
Trenton’s not so far from New Brunswick. I could look in on my grandparents and grab a bite of lunch.
After a nice visit, my grandfather gave me a lift a few miles out of town and released me into the wild.
I broke a spoke coming into Princeton, but college towns always have bike shops. I bought a spoke and managed to snake it into the wheel, working on the steps out front. I’d fallen for piano-wire spokes when I’d built this wheel set, and I was regretting it regularly.
Back on the road, I wound down the last miles to New Brunswick. In the middle of town, I dropped into a left turn and immediately crashed because my front tire had been going flat and I hadn’t noticed.
I dragged my scraped and tired body out of the intersection and trudged the last couple of blocks.
Companions make all the difference, even if you just have them for a short time. When I tried to board a train to return home at the end of the weekend, my girlfriend was with me. This was a one-shot deal, one train all the way to New Carrollton. All I had to do was get aboard.
The conductor, yet another one, started to deny me boarding.
My girlfriend broke down in tears. I don’t even remember what she said, but it was a grief-stricken torrent of hard luck and need.
“All right, all right,” he finally said. “Get on, keep quiet, and if anyone gives me crap about it I’ll throw you off.”
My girlfriend shut off the dramatics instantly.
“There you go,” she said briskly to me. “Call me when you get home.”
A quick kiss and I was on my way.
I leaned my bike vertically against something that didn’t wiggle and work every time the train jostled. Holding the rear brake lever, I could keep it from rolling around as I tried to maintain my balance. I was in the space between two cars, watching their two platforms jerk back and forth.
This was intermodal transportation in 1980.
Somehow I had gotten the idea that one could ride a bike to the train station and board the train with the bike to cross greater distances than one could conveniently ride. Scraps of articles, vague conversations with other riders alluded to this sensible concept.
I got up at 5 a.m. to ride from Annapolis to the New Carrollton Amtrak station. I’d been riding the rails all winter to visit my girlfriend at Rutgers, in New Brunswick, New Jersey, but now it was spring, and I was training on the bike again. I was tired of having to bum a ride to New Carrollton or Baltimore.
The 6:30 Metroliner rolled in. I stepped up to the doors with the handful of other passengers. A conductor stopped me.
“Whoa, whoa, you can’t take that on the train,” he said, pointing to the bike. He was nice about it. We knew each other by sight, after my months shuttling up and down the line on missions of what appeared at the time to be true love.
I explained my plan, indicating the various trains I’d stitched together in my timetable.
“Tell you what,” he said. “I’ll let you ride as far as Philly. You can get a train with a baggage car there. That’ll take you the rest of the way to New Brunswick.”
He showed me into a car with a large space behind the last row of seats. I leaned the bike up against the wall and hunkered down beside it. We were on our way.
Those first accommodations were pretty cushy. The conductor even dropped by to see how I was doing. He apparently approved of my low-key presentation.
We said a cordial farewell at Philadelphia. I went to the platform where my next train was supposed to be.
Feeling confident after the friendly treatment the first conductor gave me, I walked up to the burly man in uniform beside this train and explained that I needed to put my bike in the baggage car.
“We don’t open the baggage car here,” he growled. “And your bike has to be in a box. Take the Conrail.”
After some negotiation, he told me to wait until the train was just about to pull out and then hop on through the doors of the car right in front of me. I could stand between the cars as far as Trenton, where I could get a Conrail train the rest of the way.
So now I stood on the dimpled metal flooring of my jostling cell, meditating on the beauties of the slums and industrial wastelands through which the rails ran.
Voices emanated from the leading car. I gathered it was the club car. As the muffled altercation grew clearer, I determined that the burly conductor was arguing with a railroad employee traveling for free, who had gotten drunk and disorderly.
The club car door slid open. The burly conductor shoved a smaller man roughly into the space I occupied with my bike. They continued their argument. Then the smaller man swung a fist at the larger one. The larger one felled the smaller one, swiftly kicked him and pulled his leg back to kick again.
I met his eye. Enough was enough. The burly conductor straightened out his clothing and withdrew into the club car.
The smaller man backed into the corner opposite mine. I didn’t really want to hear his story. I wouldn’t let the big man kick the crap out of him in my presence, but I had no way to judge any other merits of his case. We lurched on in silence for a few more minutes until the train slowed, then stopped, in Trenton.
As soon as the doors opened, I hopped out and headed away from the train. The police were arriving. Since I had not been supposed to be there at all, it seemed like time to disappear. I went looking for a Conrail train.
The Conrail conductor was another grouch, but he finally agreed to let me get into the back of a car and squeeze into another seatless space.
A woman in the next seat was convinced I must be some globetrotting adventurer. She wouldn’t let go of the notion, no matter how many times I told her I was just some schmoe trying an ill-conceived experiment.
Before I could be tempted to start making up stories to satisfy her craving for vicarious adventure, the grouchy conductor came up as the train was starting to move and told me to get the hell off, because he’d changed his mind.
Trenton’s not so far from New Brunswick. I could look in on my grandparents and grab a bite of lunch.
After a nice visit, my grandfather gave me a lift a few miles out of town and released me into the wild.
I broke a spoke coming into Princeton, but college towns always have bike shops. I bought a spoke and managed to snake it into the wheel, working on the steps out front. I’d fallen for piano-wire spokes when I’d built this wheel set, and I was regretting it regularly.
Back on the road, I wound down the last miles to New Brunswick. In the middle of town, I dropped into a left turn and immediately crashed because my front tire had been going flat and I hadn’t noticed.
I dragged my scraped and tired body out of the intersection and trudged the last couple of blocks.
Companions make all the difference, even if you just have them for a short time. When I tried to board a train to return home at the end of the weekend, my girlfriend was with me. This was a one-shot deal, one train all the way to New Carrollton. All I had to do was get aboard.
The conductor, yet another one, started to deny me boarding.
My girlfriend broke down in tears. I don’t even remember what she said, but it was a grief-stricken torrent of hard luck and need.
“All right, all right,” he finally said. “Get on, keep quiet, and if anyone gives me crap about it I’ll throw you off.”
My girlfriend shut off the dramatics instantly.
“There you go,” she said briskly to me. “Call me when you get home.”
A quick kiss and I was on my way.
Wednesday, March 23, 2005
This is the drive for early season rides and slick roads. We don't need no stinkin' brakes -- although I do have a front one for times of urgent need. Otherwise just hop and backpedal. This is a stock shot. No plants will be green around here for another two months.
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