Alta Motors makes the most powerful off-road electric dirt bike that you can actually buy right now [edit: Alta filed for bankruptcy in late 2018, more details on this later]. There are several competitors that make a similar and adequate product (see our index of off-roaders here), but when it comes to power? Alta is currently in the lead. One of the reasons the technology you find in dirt bikes is worth keeping an eye on is that…their user-profile means they are constantly hammering their drivetrain and battery.
As a comparison, street motorcycles accelerate hard after the light turns green, but…then they enter a cruise-phase that can last for over 90% of the time they are running up to the next red light. And once you get on a main highway? you could cruise for as much as an hour without needing to stop and then accelerate up to cruise again.
Compare that to dirt bikes. The rapid-fire speeding up and slowing down on dirt bikes is hard on the motors, controllers, and batteries, so…if someone is making an electric dirt bike that does this well, then…the engineers at that company are doing something right. One of the things that distinguishes the Alta design is the advanced liquid-cooled motor, which helps it manage heat-spikes from rapid-fire acceleration cycles. I’ll get back to that in just a few minutes…
Where it began
Alta started out as a company in October of 2010, located in the southern part of the San Francisco Bay with the name “BRD”. It was started by four friends that were all motocross enthusiasts. They are…Marc Fenigstein, Derek Dorresteyn, Jeff Sand, and David Drennan.
No milestone event takes place in a vacuum, and…Alta was formed in 2010, just two years after the Tesla Roadster had been in production. The Tesla car proved that a lithium-battery based electric vehicle could have good performance. And…it also showed that one useful strategy for a new start-up in a completely new field was to start with a premium product for a small upscale demographic. Tesla’s early success also set the stage for smart entrepreneurs to see the opportunity and to be able to draw venture capital to fund new products that were appropriate for a lithium-powered EV drivetrain.
Marc is the CEO, and…although he has proven himself over the last few years to be a capable CEO, he also has an engineering degree. Here is a one-hour 2012 youtube presentation by Marc that not only spells out their early BRD days, it is one of the best examples I’ve seen of a market analysis in preparation for starting a new company in an emerging field.
Here is a podcast from 2015, where Marc is interviewed about Alta. The motorcycle section starts at 17:00, and Marc starts talking at the 19:00 mark. Aaand…here is a 30-minute podcast from October 2017.
The “D” in BRD stood for Derek Dorresteyn. He is an experienced off-road racer (his uncle is Dick Mann, who is in the AMA hall of fame, and his father Bill was a flat-track racer). He was the owner of a machine shop, plus…he taught classes in 3D design and CNC machining. so…he is VERY familiar with how to make high-quality parts from scratch [when he decides he wants something] and…nobody else is making it yet. Derek is not only an avid dirt biker, and also has an engineering degree. He now holds the ambiguous title of Alta’s “Chief Technology Officer” (CTO).
A line of 2017 Alta Redshift dirt bikes being prepped to send to dealers
Next up is Jeff Sand, who has…an engineering degree (I’m starting to see a trend here). Jeff started with experience in fabrication and welding, and then invented a step-in snowboard binding, leading him to founding his own company for it [called Swich]. He is also the designer behind Sutro Vision eyewear, which…may not seem to be relevant here at first, but…it shows that he has a certain expertise with the entire ‘design to fabrication-and-marketing’ flow.
Although Alta has refined their design over time based on their own experience and feedback from the factory racers, back in the beginning? They started with a reliable and respected system that used well-known principles that had already proven to be successful. The original 2011 BRD chassis geometry was modeled after the Honda CRF450R.
Even so, there are a dozen crucial decisions that needed to be made about the battery and drivetrain that ended up having embedded effects in the long term. The stakes were high, but…at every step of the way, it appears as though Alta made some very savvy choices.
BRD had been in operation since 2010, but didn’t really begin to take off until 2012 when it raised $850,000 in seed funding to produce its two production RedShift electric bikes, the dirt-focused Motocross-MX and street-oriented SuperMoto-SM.
So far, Alta has received a publicly-recorded known funding of at least $43.8 Million USD, and their investors include two Tesla founders, along with a little company called Harley-Davidson. They changed their name from BRD to “Alta” in October of 2014, and their first production unit was delivered to the customer in December of 2015.
This is the part that interests me. The newest version operates with a nominal 355V (96 Lithium-Ion cells in series, 96S). The early version from 2010 used 270V, but other than that…they are very similar. So, let’s peel back the wrapper and see what’s inside, shall we? In a video [linked below, and also here], CEO Fenigstein solidly credited CTO Derek Dorrensteyn as the architect of their drivetrain configuration.
The early BRD used a 2-stage geared RPM-reduction between the motor and the output sprocket (which then drives the exposed chain). The newer Alta uses a one-stage primary geared reduction with a 3.5:1 ratio. The final drivechain has some reduction in it (53T to 12T, making it 4.4:1), but once you decide to use a non-hub motor with a chain-drive to the rear wheel, then the final exposed chain-drive will be the same whether you use an electric motor or a gasoline engine.
The primary reduction uses gears in a sealed oil-bath rather than a roller-chain like most common engine cam-drives. Mercedes also chose gears to drive the cams in their 300D engines, and they have a record of often running past 500K miles. And even after the engine wore out, it was not the gear-drive to the cams that failed. An internal chain-reduction from the motor to the output shaft would have been slightly cheaper, but…for a few dollars more you can have a system that will last many times longer.
One of the major choices to make in an EV system design is whether to have active cooling of the motor and controller. Liquid-cooling adds cost and complexity, so…what are the possible benefits? In the words of Colin Chapman…it adds lightness.
In spite of the weight of the added auxiliary cooling components, the motor and controller can then be lighter, measurably lighter than the added weight of the coolant, pump, and radiator. Although the early BRD’s have a radiator, it is small enough that can be neatly tucked away behind the head-tube, safe from damage in a fall. The newer Alta’s cleverly use the aluminum frame as the liquid-cooling “radiator”.
The 12,000-RPM spec and the high reduction from the motor down to the drive-sprocket RPM’s tells me that this motor is a brushless inrunner. The most often cited reason for engineers to use an inrunner is that they can easily shed their peak amp-heat to the shell, allowing the rider to get the maximum possible power from the smallest possible motor.
As stated earlier, the first 270V version of the BRD drivetrain was equal to a 250cc gasoline model, and that was a conscious choice. A 250cc dirt bike may be a modest performer by US standards, but…it is the default size of urban transport around the world. Achieving a design familiarity and expertise with this size of electric transport would put BRD right in the middle of the fattest global segment of transport.
Another thing that they discovered was that…if you are designing a light motorcycle with a short wheelbase and a higher center of gravity, it performs better than many larger motorcycles when used in a city environment. Of course, once you factor in a route that crosses a long interstate highway, a longer wheelbase coupled with a lower center of gravity would perform better at that type of long-range cruising. However, around short city commutes?…not only did the early BRD design perform better, but the modest-range batteries of 2010 were not a handicap in that application. In fact, they were perfect for that job. This led to BRD making sure they had a street-tire model, and if you are racing that style, it is called a supermoto.
The early BRD frames [along with the modern Alta frames] are not borrowed from an existing motorcycle and converted to electric drive. They were designed from the ground up to be perfect for this particular application. It is made from two forged alloy halves that are joined, and then finished by two separate 5-axis CNC machining operations. The joining welds are specifically located in low-stress areas in a way that Alta has patented.
One of the benefits of starting a clean-sheet design from enthusiast engineers that have deep funding is that…they didn’t have to sketch up their early version, and then afterwards try to figure out how to manufacture it. Alta was able to envision the modern manufacturing methods that they wanted to use from the beginning, and then the design was seamlessly created from the start as a production-ready product. All of the principal players at Alta are young enough that they came of age being very comfortable and familiar with Computer Aided Design (CAD).
A couple of videos, and some links
When I started researching Alta, I found myself frequently stumbling across links to “Asphalt & Rubber”, a site dedicated to ALL motorcycles. When I’d search for something more specific, I’d check out a handful of sites, and…A&F consistently turned out to have the best info [like the video link below], so…if you are ever interested in something related to motorcycles, start your search on Google with “site:www.asphaltandrubber.com insert search term here”
Here’s a link to a one-minute video showing a timelapse of an Alta Redshift assembly.
And here is a link to a 5-minute video of “Tech Crunch” when they did a spread on Alta in 2016
If you want to find videos of off-road riders reviewing the Alta MX, there are so many, it’s difficult to find a single “best” one. So…here a link to a list of youtubes
Here’s a great video of an Alta battery pack teardown
B’s Motolab in Wichita Kansas
I live in Kansas, and fortunately for me, there is an Alta dealer only two hours’ drive from my home. It’s B’s Motolab in Bel Aire, near Wichita. It’s owned by Brandon, and the majority of his business is repair and tuning of gas dirt bikes of all brands.
In the pic above, I surprised Brandon with an unexpected visit, so this is the way he keeps his shop every day. Very professional. I had emailed him, and thought we might get together in a couple months or so. But…an unexpected trip had me passing by there much sooner, so I stopped in to see him.
In the pic above, I drove two hours to get this shot of me on the bike using the stock factory suspension adjustments. I am 6-foot tall, and 200-lbs. My jeans inseam length is 32-inches, and when I rest my body weight on the seat, I can ‘just’ rest my feet flat on the ground if I am wearing work-boots. Brandon assured me that he can adjust the Alta to sit lower, by as much as 3-inches down. And this can be done while still having the suspension set-up properly, in order to keep all of the performance you are paying for.
How is an electric dirt bike better than gas?
The most obvious benefit of an electric dirt bike is how quietly it runs. We live in an age where more and more communities are restricting access to trails because of the engine noise. I don’t know exactly how that fight will evolve over the next decade, but…if you love off-roading, an electric dirt bike is a VERY good starting place. The low noise and lack of emissions also means that indoor tracks are much more tolerable in the off-season when the weather is bad.
Brandon and I were chatting, and although he has years of experience with gas dirt bikes, he was very enthusiastic about emphasizing the practical benefits of an electric dirt bike (which have nothing to do with “going green”). First of all, you’d need an oil and filter change every 5 hours of run time, along with cleaning the air filters…
20 hours? valve check and adjustment, clean and gap the plugs
40 hours? piston rings
200 hours? bottom end bearings, so…Electric dirt bikes have less repair and maintenance.
The Alta has a significant purchase price, but…once a similar gas dirt bike reaches the point where it needs the bottom end rebuilt? The Alta starts saving you money from that point on, if you add up all of the maintenance costs.
Operating in cold weather
Electric cars are VERY popular in Scandinavia. There are many different reasons, but…an often quoted benefit is that electrics will run in weather so cold, that…gasoline engines have a hard time starting.
No altitude adjustment
If you take a gas dirt bike up into the mountains at a higher altitude, you’d have to adjust the jets in the carburetor. It’s not a horrible job, but…it’s just one less thing electrics have to worry about. In fact, several electric motorcycles have done quite well at the Pike’s Peak race [in Colorado], because…there is over 7,700 feet of altitude-change in the difference between the start and finish.
The biggest benefit of electric is…
No shifting and instant torque at all RPM’s. In the split-second elbowing that takes place on a motocross or supermoto track, the fact that Alta’s never need to shift to get full torque cannot be overstated as to how important that is. The pic below shows an Alta with street tires and turn signals, which identifies it as the supermoto…
Of course electric bikes need a cleaning after a muddy weekend, just like the gas bikes, but..Brandon pointed out that the Alta’s waterproofing is so extensive, that…not only is it very easy to hose it off at the end of a day’s ride, but…he could ride across a creek up to his waist without worrying about any kind of problems with the drivetrain. He said you can’t do that on most dirt bikes, and you’d need an engine-snorkel kit to even try it.
From the podcast link above, the range is approximately 50 miles on the road, or roughly 2 hours on dirt trails. Two hours was a goal for Alta because that’s enough range for the length of many full moto races. They mentioned that they test the bikes on trails with a 220V generator to charge the batteries, and it takes roughly 2 hours to top them off.
Although gas bikes can be topped off in half a minute, many Alta owners feel a little better not having half-filled gasoline cans around the garage (or transport van) all the time.
The “Redshift” name
If you look at a distant white star, how do astronomers know if it is moving away from them, or moving towards us? Light is emitted in all directions from its source at the same speed, whether the star is headed towards us, no matter what direction it is going, but…the light waves can appear to be compressed (from our perspective) if the star is coming towards us, and the light waves appear to be spreading out (from our perspective) if it is moving away. Spectrographic analysis of the star might tell us that a certain star is white in color, but…if it is moving away…the color appears to have a longer wavelength and the apparent light from our perspective has a shift towards the red end of the color spectrum, so…
Things moving away from you at very high speed have a redshift.
A special thanks to the “altaownersforum.com” forum, for their help in completing this article.
Written by Ron/spinningmagnets, July 2018