Jeff Wolf has been building gasser bikes for quite a while, and his skills have produced some great examples. Now? He recently became interested in electric bikes, and here’s what he put together.
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Gasser Bicycles, and Wolf Creative Customs
I’ve been a forum member of motorbicycling.com for a while. When an electric bike friend asks about them, I describe them (with great affection) as “chainsaw kits”. The majority of these use a Chinese 2-stroke gasoline-fired engine, and many of them embrace a style that is reminiscent of the “board track” motorcycle racers from the 1900-1929 era..
You can find Jeffs build-thread here at Motorbicycling.com, which is the premier forum for enthusiasts to share information about the gasser world. And, you can’t read about their most admired builds for any length of time without realizing that…one of the most respected builders there is Jeff Wolf.
The Wolf Creative Customs’ flathead boardtracker. He added a shock to the Monark springer fork to improve the handling. I also love the DIY seat supension. This…is a work of art.
Whether it was the noise of the gasoline engine drawing too much attention, or that sometimes the local police wondered if Jeff’s gasser bicycle is street-legal (it is, and registered as a moped), Jeff decided to put together an electric version, in order to quietly glide into work each day without any hassle, which is just a short distance from his home.
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What frame? The Dyno
Back in the middle 1970’s, a young Bob Morales was a pioneer in promoting the new BMX bicycles (BMX = Bicycle Moto Cross), that every teen in southern California seemed to want. He was involved in freestyle stunt-riding, and formed the BME company to create and market products that mainstream bicycle parts suppliers were ignoring. Did I mention that when he did this…HE WAS 14! Later, when Bob was 20, he changed the name to Dyno Design.
Dyno products became very successful quite rapidly, with a following among young BMX enthusiasts who liked stunt-riding. Only two years after Dyno became a brand, the global company GT Bicycles bought them, and retained Bob as a designer, so that is where the Dyno name came from.
In the two pics below, notice the amount of space between the rear wheel and the seat-tube. On a true boardtracker, this is where the “oil tank” would be located (see the tank in this pic with a number “3” on it). Also notice the slack seat-tube angle (it’s practically a “crank forward” geometry). Then notice the slack head tube angle. This bike would not have a sharp “sports car” style of handling, but…it would be more stable at a higher speed, compared to a standard road bike geometry.
The Dyno frame. Stretched, and laid back
In 1996, GT Bicycles had another young designer named Jeff Soucek, and here is a quote from him.
“The idea of this Roadster frame actually was conceived after Sean Flickinger (one of the other GT Industrial Designers) designed the standard Dyno cruiser frame. I was responsible for the geometry of that bike, and at the time we wanted a standard cruiser that would simply blow away the old Schwinn cruisers that were so popular at that time. We kept kicking the geometry back and slacking out the frame until it had (what we called at the time) a “6 pack geometry” This meant you could be half-lit and still ride it to the store and then back, with one hand on the handlebar, and a six pack of beer in the other.
The next part of the story goes like this. Bill Duehring (Director of R&D at GT, and now President of Felt Bicycles) knew we had just designed a great cruiser, and wanted to create something to stir up some excitement about this new “standard” cruiser. We really wanted to highlight the new “six pack” geometry of this bike. There was a small custom builder in the Huntington Beach California area where our office was, called HB CRUISERS (now called “HBBC”).
This guy had made some super stretched-out cruisers that we had seen the locals riding down at the beach. This gave us the idea to take our standard cruiser design and “six pack” geometry, and then stretch it out to the Roadster length, creating a “show bike” for the Interbike release that year in Anaheim California. This would be such an obviously different bike, that it would help draw attention to the “standard” cruiser line.
It’s not just the stretch and slope of the frame that distinguishes a Dyno, the seat stay has a reverse curve coming off the top-tube, and the “tank” support tubes have a sensuous compound curve. The chain-stays are set back far enough that the builder can add a large chainring if you want, and that entire region of the frame provides a solid base for mounting a motor, or a battery (The forks shown are not stock)
So I went to work hand-building the first prototype of this Roadster with the help of Dan McGrew (master frame-builder in the GT tooling room). We hand-formed, bent, flared and machined everything from scratch. Next, we had the front half of the frame chrome-plated and painted it custom with classic chrome darts, electric blue pinstripes, and black from there on back. Even the front fender and chainguard were half chromed and painted. It was a beautiful job done by the Custom GT paintshop in Colorado, who were responsible for all of the Custom frames made by GT at the time. All of the other bits were triple chrome-plated to car show quality, down to the 12-gauge spokes and nipples. It even had an internal generator front-hub with a headlight and internal wiring.
Once the bike was complete, everybody was freaking out about how cool it was, so it was time to show it to the boss Richard Long (owner and president of GT) We approached him with the bike the day of the yearly sales meeting where all of the sales reps from the entire country were in the building. We brought it up to the meeting and called Richard into the hallway were we had the bike sitting there to surprise him, and to ask him for permission to show it to the Sales reps.
I still remember his words when he came out and saw it “Are you serious, you actually think you can sell those?”. We said “let us bring it in and show the sales reps, and see what they say”. He reluctantly agreed, and…we left the meeting with the Reps cheering. The bike was now set to be shown at the 1996 Interbike in Anaheim. Needless to say the bike caused quite a stir at the show.
When we noticed that the big guys from most of our competition were in our booth checking it out, Richard had us pull the bike from the show after the first day, and gave us the go-ahead to make a production bike. The rest is history with this bike surprising all with the numbers sold over the few years it was in production”
Headbadge pic courtesy of Rat Rod Bikes
The Dyno Roadster series was first made around 1997, but GT Bicycles began having other issues, so in 2001…Pacific Cycle purchased GT, Schwinn, and Mongoose. An authentic steel Dyno is a full-sized cruiser that was intended for adults, and now that they are no longer in production…the remaining examples have gone up in price for a narrow niche of custom bicycle builders. The most valuable garage-find would be the “Mooneyes” edition.
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What Motor?
Jeff chose the mid-sized Cyclone from Sick Bike Parts. It is capable of more power than the currently popular Bafang BBSHD, but…the steel gears in the reduction are definitely louder. To be fair, the steel gears also mean you can pound them with lots of heat and power, but…they will always be a little noisy…
One of the benefits of the Cyclone is that the mounting brackets allow the motor to be located inside the frame triangle, and many builders are willing to accept several compromises in order to have that feature.
The Cyclone brackets are steel, so after some prep work, they could be chrome-plated.
The Cyclone brackets are affordable, but are known to flex in their stock form, when using high power. Builders have used a variety of methods to brace them, in order to prevent chain-drops.
Here’s a closer look at the Cyclone brackets, and a through-bolt that clamps them the the chain-guard mount.
The actual motor in the Cyclone is larger than the motor inside the BBSHD, and that is the main reason it can take more power. However, it also uses an external controller. This results in some wiring clutter, and also more bulk in the overall system, but…it does provide the builder with many options.
Here’s a closer look at the controller and motor mountings.
Jeff chose a common and affordable 12-FET 40A unit, which he mounted just above the motor, on the front of the seat-tube (so it would get plenty of air-flow for cooling). Using 52V X 40A is 2200W, and that is near the maximum limit for running power through bicycle chain and sprockets. Anything above that will wear out components rapidly, and sometimes break things…if you like popping wheelies.
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The Battery
It is quite a coincidence, that Jeff has the same battery and controller that I have on one of my ebikes. It’s a Luna Cycles 52V pack using 30Q cells. There are chargers that have more features than this $99 unit from Luna, and there are also chargers that are cheaper. This one has the features that I like the most, and does not have the extra cost of features that I do not need.
It can charge at 3A to keep the pack cooler, or at a higher 5A rate if I happen to need it charged up 60% faster. It can charge to 80%, 90% or 100% capacity, by flipping a switch. I believe that charging to 100% does not add enough range to make it worth the extra heat, but it’s nice to have that available. A low 3A charge to 80% will keep the pack very cool to help it last as long as possible. However, I normally charge at 3A up to 90%. This charger also has a digital readout of the current voltage at all stages of the charging operation (a 14S / 52V pack like this charges to 58.8V when it is at 100%). The digital readout of voltage is my favorite feature.
The Luna charger, and the 52V pack made from 30Q cells.
Jeff decided to place the battery box behind the seat-tube, in the boardtracker “oil tank” location. Here is a Worksman frame built in the boardtracker style with a fuel tank and oil tank added. At the turn of the century, there were no credit cards and monthly payment plans, so…it was not uncommon for a young man to buy a heavy-duty bicycle, and to then save up his money to add a gasoline engine kit to it later.
Jeffs aluminum battery box. I love the aluminum billet tube-clamps.
The awesome billet aluminum tube-clamps can be found here.
I like the location of Jeffs battery box, but…I would have extended the side-panels back father, and cut them to a curve that matched the shape of the rear tire. Of course…me saying that here? Its kinda like the janitor at the Sistine Chapel pointing to the ceiling and telling Michelangelo that “Hey, Mike…you missed a spot”
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Drop-outs, wheels, and other bits
To fit a battery this size behind the seat-tube, Jeff needed to extend the rear wheel backwards a couple of inches, so he made two aluminum drop-out plates. They were shaped to accept steel axle inserts that are common in the gasser bicycle world.
I really like working with aluminum for many types of custom parts, and making these to accept steel inserts is brilliant.
Look at how much room is between the seat-tube and the rear wheel, and look at how large of a chainring will fit there, between the bottom-bracket and the chainstays.
Jeff chose a well-regarded Sturmey-Archer 8-speed internally geared hub (IGH)
Jeff chose a wide rim, and a width of tire that would spread out to have a shorter sidewall and a wider tread.
The tire is the Simple “Road Star”, from Giant. 26 X 2.125
Jeff used the solid sprocket from “Sick Bike Parts” (SBP). He drilled access holes to reach certain bolts, and had his shop name laser-etched onto it.
Here you can see the common two-sprocket freewheeling bottom bracket. The motor drives one sprocket, and the other sprocket drives the rear wheel.
The custom aluminum rear drop-outs also made it easier for Jeff to attach a rear disc brake
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The Finished E-Bike
Jeff lives in Culver City, Southern California. This set-up can reach 33-MPH, and Jeff says that riding it to work and back is one of the best parts of his day.
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Written By Ron/spinningmagnets, February 2017
