The Alta configured the battery and location for the lowest and most central possible CG. That meant placing it further forward and resulted in a 50/50 weight distribution (most ICE bikes are around 55-57/65-63). The Varg pack is slimmer but much taller with a good portion of the pack high in the frame above the drive train. This moves weight to the rear but also makes the CG higher. A higher CG results in more dynamic weight transfer to the front when braking or hitting bumps/whoops and to the rear when accelerating and makes initiating lean angle harder. There are pro and cons to everything, but simply making the front end lighter alone doesn't automatically make a bike handle better.
STARK VARG (Something new is coming!)
- Thread starter TCMB371
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F451
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The first Altas came out in 2016?
I find it entirely believable that in every area of performance the Stark Varge in 2021 is an improvement over the Alta.
I don’t know why that is so hard to believe, but apparently it is, Lol.
But again, we will see. Meanwhile I’m enjoying the anticipation and hoping it lives up to the hype.
I find it entirely believable that in every area of performance the Stark Varge in 2021 is an improvement over the Alta.
I don’t know why that is so hard to believe, but apparently it is, Lol.
But again, we will see. Meanwhile I’m enjoying the anticipation and hoping it lives up to the hype.
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@Mark911 curious your thoughts on the cell configuration? Laying the cells horizontally and mating then directly to the case should help provide more efficient and even cooling of the cells when riding. I suspect they're will still be a temperature gradient in the center core of the pack, but at least each cell has an equal distance to airflow. Could you mock up a quick solidworks or ansys and see how it theoretically performs?
If they are indeed using the same elcon 3.3kW charger in the 440v variant, i wonder if they are also limiting the charging amps like Alta did. I suspect they'll have similar thermal issues induced by charging, maybe a little better.
If they are indeed using the same elcon 3.3kW charger in the 440v variant, i wonder if they are also limiting the charging amps like Alta did. I suspect they'll have similar thermal issues induced by charging, maybe a little better.
enjoythesilenc
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Yes the cell configuration and case is interesting. The Alta battery is like a four layer cake while the Stark battery is like a tortilla folded in half. If this is a major improvement, I can imagine reconfiguring Alta modules wouldn't be impossible and might have been a natural eventuality
F451
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Interesting MX Large interview with founder Anton Wass from Dec. 18, 2021: MX Large | Anton Wass interview - Stark Future
"I don’t really want to comment about on how many orders we already have at the moment, but orders are already coming in fast, and the numbers are rising quickly. Right now we are selling one bike every minute."
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MX Large
Anton Wass interview - Stark Future
Posted on December 18, 2021
When the press release dropped this morning that a new bike was being introduced to the market, well, I for one was surprised. For starters, I had never heard of Stark before and the fact this project has seemingly been a hidden secret for more than two years is just amazing. It seems exciting and for sure we will all sit on the edge of our seat waiting for the orders to be filled and opinions being spread on social media, or on motocross websites around the World.
Anton Wass, Stark Future CEO and Founder sat down with MXlarge today to talk about his amazing new project, which seems to be ready to change the sport forever.
MXlarge: Firstly, congratulation on this new project, I can imagine the whole World is buzzing about this news?
Wass: Yes, it has been crazy. We have so much traffic the website keeps on crashing and to be honest, it is an issue, but again, it is exciting, because we didn’t expect this type of traffic on the site. We anticipated high traffic, but this has exceeded our expectations and we are really pleased to see the reaction all over the World on YouTube and social media.
MXlarge: Obviously we have the Japanese and European motorcycle brands heading in this direction, so we expected bikes like this to be arriving, but we never expected a Stark VARG bike. Where did this idea start?
Wass: It is a long story. My background is originally in motorcycle mechanics, but I fell into business at an early age, where I was one of the founders for the World’s largest online store, 24MX. We started with three of us and 24MX does now have 150 million EUR revenue and 400 employees or so. That is my background, but I have been dreaming about building electric motorcycles for many years. I decided to leave my previous company a few years ago, because I wanted to do something new, and I wanted to work with something with sustainability. This dream of building a electric motorcycle factory seems like a pretty stupid idea, because this is a very difficult dream. I was in the position to start, and I didn’t think anyone was doing it well, so let’s give it a try. We started researching what was possible, with the power density of electric motors and the energy density of batteries. We then came to the conclusion we can build an electric motocross bike and we can out-perform the fastest fuelled bikes of today. We built a team of highly experienced people, who built motorcycle and power electronics before, and we made it reality.
MXLarge: Building that team, I can imagine starting from scratch, which isn’t an easy job. How did you build that team?
Wass: I have contacts in the motorcycle industry before from 24MX and it was basically from my personal contacts. When you know somebody who does a good job, they usually know somebody who does a good job and that is how we built the company. Good people always know other good people.
MXlarge: Okay, it was presented, everyone is excited, but what is the next step? Do you have a lot of products already made, or just a handful?
Wass: The finances aren’t a problem; the investors are a group of successful entrepreneurs who have built successful companies before. Let´s just say the finances aren’t a problem. We have invested heavily, and we want to do it right. I don’t really want to comment about on how many orders we already have at the moment, but orders are already coming in fast, and the numbers are rising quickly. Right now we are selling one bike every minute. I am glad a lot of professional dealers are also in contact, and we are busy finalising those details.
MXlarge: When we went from two strokes back to four strokes, we did have a period where some of the brand’s bikes were not that reliable. I am sure that reliability is a really important part of going forward.
Wass: Yes, of course and we don’t want to do this incorrectly, reliability is something that is very important. It depends on how you develop a product and we decided not to take short-cuts. When we started this company, we bought all the best bikes in the market today and we analysed them, scanned all the chassis of the top bikes in order to understand the geometry, ergonomics and we also measured the center of gravity and the flex of the chassis, both horizontal, lateral and torsional. With all this data we set the targets for how we believe we could build a better bike. And that is what we have done. We are working in the same quality process as the big manufacturers, because that is the experience our team has from before. We are able to move faster, because we don’t have 200 managers and we can make fast decisions.
MXLarge: So, when you have the bikes made and you get guys like Sebastien Tortelli or Justin Josh Hill riding the bike, a two-time World motocross champion and a leading AMA rider from the past. How was that when they rode it and going by their comments they were blown away with the performance of the bike.
Wass: That was just incredible. You have this dream of how it will be, and you imagine it for so many years. Even for me as a novice rider and then you take a two-time World champion, and his opinion of the bike is so great. Straight away he was faster than on the 4-stroke bike. Normally, if you ride a two stroke and jump on a four stroke, it takes some time to get used to it. This bike is so easy to ride, within a few corners you feel at home. We are not trying to change everything, but it feels normal, just lighter and easier to ride.
MXLarge: Is it a Spanish bike or a Swedish bike?
Wass: Well, it a Spanish company, but my heritage is from Sweden, but it is a Barcelona based company.
MXLarge: How is the weight of the bike compared to the current fuel bikes?
Wass: It is lighter than the current bikes, at least lighter than all the Japanese 450s and our bike is 110 kilos, and it is also lighter than the new KTM. Potentially it is the lightest of the 450s. More importantly it feels significantly lighter, due to the massive reduction in rotating mass. And we also have the lowest centre of gravity, so it feels a lot lighter than the other bikes.
MXLarge: Did Sebastien compare the bike against the other brands?
Wass: Yes, of course and it was fun. Sebastien was riding one of the 450s and he rode our bike and then rode the 450 again and he thought the 450 had something broken. He thought the brake was dragging or something, but there was nothing wrong.
MXlarge: Because he felt so comfortable on your bikes?
Wass: Yes, that was his comment. He felt it was the rear brake dragging, because it felt heavy.
MXlarge: As far as going competition racing, in MXGP or AMA, is that a goal?
Wass: Yes, for sure. Our ambition is to prove our bike is superior by lining up on the start gate with the gas bikes. We want to race in MXGP and AMA supercross. We are currently talking with federations about that. We would look at doing some races in 2022, but full-time in 2023. Everyone believes the electric bike is the future and our ambition is to race MXGP in 2023.
MXLarge: WOW, that is ambitious.
Wass: Of course, it depends on the FIM, but we hope they will let us compete.
MXLarge: I have to admit, it has to be the best kept secret in the sports history, because it seems nobody knew about this bike.
Wass: Yes, it was, and I am even surprised by it. There are several patents on the bike, so we had to keep it all confidential. And everyone that has been involved in the bike has signed an agreement to not mention anything and we made it very clear please keep it that way. I am really grateful, because it was kept a secret for over two years, which is just incredible.
MXLarge: What about the look of the bike. In the press release it is red, but will there be special graphics or anything?
Wass: If you go to the website, you can see there are red, white and grey.
MXlarge: Obviously the sound is the most important thing?
Wass: I don’t know if you know, but in the last 10 years 20% of all tracks in Europe have closed, due to noise. That is one in five tracks, an important factor that this is a way to save this sport. At the same time, we said lets only built an electric bike that is also better than the other bikes and more fun.
MXLarge: What about an electric bike as far as charging the bike goes?
Wass: The battery will last as long as a full tank on a 450, so if you arrive at the track with a fully charged bike, which should get you through the whole day. If you are an MXGP rider you would need to charge it between motos. What we have found is half the tracks we have visited already have electricity and maybe this is a way for the tracks to make some money, by charging for electricity. It the way to charge the batteries, will also evolve over time.
MXLarge: Or maybe have a spare battery?
Wass: The battery is the most expensive component of the bike, for race teams okay, it is possible, but for the novice rider, then it would be too expensive to have a spare battery.
"I don’t really want to comment about on how many orders we already have at the moment, but orders are already coming in fast, and the numbers are rising quickly. Right now we are selling one bike every minute."
---------------------------------------------------------------------------
MX Large
Anton Wass interview - Stark Future
Posted on December 18, 2021
When the press release dropped this morning that a new bike was being introduced to the market, well, I for one was surprised. For starters, I had never heard of Stark before and the fact this project has seemingly been a hidden secret for more than two years is just amazing. It seems exciting and for sure we will all sit on the edge of our seat waiting for the orders to be filled and opinions being spread on social media, or on motocross websites around the World.
Anton Wass, Stark Future CEO and Founder sat down with MXlarge today to talk about his amazing new project, which seems to be ready to change the sport forever.
MXlarge: Firstly, congratulation on this new project, I can imagine the whole World is buzzing about this news?
Wass: Yes, it has been crazy. We have so much traffic the website keeps on crashing and to be honest, it is an issue, but again, it is exciting, because we didn’t expect this type of traffic on the site. We anticipated high traffic, but this has exceeded our expectations and we are really pleased to see the reaction all over the World on YouTube and social media.
MXlarge: Obviously we have the Japanese and European motorcycle brands heading in this direction, so we expected bikes like this to be arriving, but we never expected a Stark VARG bike. Where did this idea start?
Wass: It is a long story. My background is originally in motorcycle mechanics, but I fell into business at an early age, where I was one of the founders for the World’s largest online store, 24MX. We started with three of us and 24MX does now have 150 million EUR revenue and 400 employees or so. That is my background, but I have been dreaming about building electric motorcycles for many years. I decided to leave my previous company a few years ago, because I wanted to do something new, and I wanted to work with something with sustainability. This dream of building a electric motorcycle factory seems like a pretty stupid idea, because this is a very difficult dream. I was in the position to start, and I didn’t think anyone was doing it well, so let’s give it a try. We started researching what was possible, with the power density of electric motors and the energy density of batteries. We then came to the conclusion we can build an electric motocross bike and we can out-perform the fastest fuelled bikes of today. We built a team of highly experienced people, who built motorcycle and power electronics before, and we made it reality.
MXLarge: Building that team, I can imagine starting from scratch, which isn’t an easy job. How did you build that team?
Wass: I have contacts in the motorcycle industry before from 24MX and it was basically from my personal contacts. When you know somebody who does a good job, they usually know somebody who does a good job and that is how we built the company. Good people always know other good people.
MXlarge: Okay, it was presented, everyone is excited, but what is the next step? Do you have a lot of products already made, or just a handful?
Wass: The finances aren’t a problem; the investors are a group of successful entrepreneurs who have built successful companies before. Let´s just say the finances aren’t a problem. We have invested heavily, and we want to do it right. I don’t really want to comment about on how many orders we already have at the moment, but orders are already coming in fast, and the numbers are rising quickly. Right now we are selling one bike every minute. I am glad a lot of professional dealers are also in contact, and we are busy finalising those details.
MXlarge: When we went from two strokes back to four strokes, we did have a period where some of the brand’s bikes were not that reliable. I am sure that reliability is a really important part of going forward.
Wass: Yes, of course and we don’t want to do this incorrectly, reliability is something that is very important. It depends on how you develop a product and we decided not to take short-cuts. When we started this company, we bought all the best bikes in the market today and we analysed them, scanned all the chassis of the top bikes in order to understand the geometry, ergonomics and we also measured the center of gravity and the flex of the chassis, both horizontal, lateral and torsional. With all this data we set the targets for how we believe we could build a better bike. And that is what we have done. We are working in the same quality process as the big manufacturers, because that is the experience our team has from before. We are able to move faster, because we don’t have 200 managers and we can make fast decisions.
MXLarge: So, when you have the bikes made and you get guys like Sebastien Tortelli or Justin Josh Hill riding the bike, a two-time World motocross champion and a leading AMA rider from the past. How was that when they rode it and going by their comments they were blown away with the performance of the bike.
Wass: That was just incredible. You have this dream of how it will be, and you imagine it for so many years. Even for me as a novice rider and then you take a two-time World champion, and his opinion of the bike is so great. Straight away he was faster than on the 4-stroke bike. Normally, if you ride a two stroke and jump on a four stroke, it takes some time to get used to it. This bike is so easy to ride, within a few corners you feel at home. We are not trying to change everything, but it feels normal, just lighter and easier to ride.
MXLarge: Is it a Spanish bike or a Swedish bike?
Wass: Well, it a Spanish company, but my heritage is from Sweden, but it is a Barcelona based company.
MXLarge: How is the weight of the bike compared to the current fuel bikes?
Wass: It is lighter than the current bikes, at least lighter than all the Japanese 450s and our bike is 110 kilos, and it is also lighter than the new KTM. Potentially it is the lightest of the 450s. More importantly it feels significantly lighter, due to the massive reduction in rotating mass. And we also have the lowest centre of gravity, so it feels a lot lighter than the other bikes.
MXLarge: Did Sebastien compare the bike against the other brands?
Wass: Yes, of course and it was fun. Sebastien was riding one of the 450s and he rode our bike and then rode the 450 again and he thought the 450 had something broken. He thought the brake was dragging or something, but there was nothing wrong.
MXlarge: Because he felt so comfortable on your bikes?
Wass: Yes, that was his comment. He felt it was the rear brake dragging, because it felt heavy.
MXlarge: As far as going competition racing, in MXGP or AMA, is that a goal?
Wass: Yes, for sure. Our ambition is to prove our bike is superior by lining up on the start gate with the gas bikes. We want to race in MXGP and AMA supercross. We are currently talking with federations about that. We would look at doing some races in 2022, but full-time in 2023. Everyone believes the electric bike is the future and our ambition is to race MXGP in 2023.
MXLarge: WOW, that is ambitious.
Wass: Of course, it depends on the FIM, but we hope they will let us compete.
MXLarge: I have to admit, it has to be the best kept secret in the sports history, because it seems nobody knew about this bike.
Wass: Yes, it was, and I am even surprised by it. There are several patents on the bike, so we had to keep it all confidential. And everyone that has been involved in the bike has signed an agreement to not mention anything and we made it very clear please keep it that way. I am really grateful, because it was kept a secret for over two years, which is just incredible.
MXLarge: What about the look of the bike. In the press release it is red, but will there be special graphics or anything?
Wass: If you go to the website, you can see there are red, white and grey.
MXlarge: Obviously the sound is the most important thing?
Wass: I don’t know if you know, but in the last 10 years 20% of all tracks in Europe have closed, due to noise. That is one in five tracks, an important factor that this is a way to save this sport. At the same time, we said lets only built an electric bike that is also better than the other bikes and more fun.
MXLarge: What about an electric bike as far as charging the bike goes?
Wass: The battery will last as long as a full tank on a 450, so if you arrive at the track with a fully charged bike, which should get you through the whole day. If you are an MXGP rider you would need to charge it between motos. What we have found is half the tracks we have visited already have electricity and maybe this is a way for the tracks to make some money, by charging for electricity. It the way to charge the batteries, will also evolve over time.
MXLarge: Or maybe have a spare battery?
Wass: The battery is the most expensive component of the bike, for race teams okay, it is possible, but for the novice rider, then it would be too expensive to have a spare battery.
Chadx
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- SW Montana
1,440 orders a day (one per minute) seems realistic for around four days after the release (That estimate looks to be on Dec. 18). Hard to say if the volume stayed that high over the first 2 weeks, but if so, that would be just over 20,000 orders.
Wass: The battery will last as long as a full tank on a 450, so if you arrive at the track with a fully charged bike, which should get you through the whole day. If you are an MXGP rider you would need to charge it between motos.
There's simply no way, not with current Li-Ion technology and a pack that size/weight. Not at any reasonable speed anyway.
Wass: It is lighter than the current bikes, at least lighter than all the Japanese 450s and our bike is 110 kilos, and it is also lighter than the new KTM.
Highly doubtful. Unless they're using exotic materials for the swingarm, hubs, spokes, rims, rotors, calipers, triple clamps/controls, tires, tubes, etc. Just go out and weigh those items on your current gas MX bike. You'll be surprised how much they weigh and how little the engines weigh by comparison. Most of the weight reductions over the past 10 years have been focused on the engines as the item mentioned have already been optimized for weight, strength, durability and cost already. There's simply not enough left in the total weigh budget to accommodate an electric motor, gear reduction, and battery pack and be only 110kg and lighter than the KTM (including the weight of the fuel). If they are including exotic materials I highly doubt they'll be able to meet the price point shown.
TCMB371 - The layout isn't that much different from the Alta. They'll need to have one sided cell connections just like the Alta and if wire bonded might have similar issues. The cells are connected to a heat sink/case just like the Alta, they'll need to be bonded with electrically isolating/thermally conductive epoxy or film adhesive just like the Alta otherwise the P groups will short out. The adhesive used will dictate how efficient the thermal path is so it's very important. The Alta used internal case partitions and heat pipes to draw heat from the sells to the radiating outside surfaces. The Varg is more direct and superior in this regard. However, based on my experiments the limiting factor ultimately will be the temperature delta between the case and the outside air as the greater the difference the more/faster the heat can be removed. But, unlike a car motor that runs between 200-220F degrees, Li-Ion cells don't like temps above 130-140F and therefore on a hot day, say 100F, there's only 30-40F differential to pull the heat out, not 100-120F like in a car. Tesla recognized this issue early on and that's why they use refrigerated water (cooled by the AC system) to cool their packs. Add the typical inefficiencies, some mud or dirt on the pack or anything that blocks air flow/contact and that'll make it even worse. Remember, Europe doesn't get as hot as we do in the states.
On cooler/colder days I'd say the Varg design will be adequate (thermally) for most riders except maybe fast A guys and pros if starting the moto with a cold pack on a harder pack track with minimal hills (not Glen Helen).
There's simply no way, not with current Li-Ion technology and a pack that size/weight. Not at any reasonable speed anyway.
Wass: It is lighter than the current bikes, at least lighter than all the Japanese 450s and our bike is 110 kilos, and it is also lighter than the new KTM.
Highly doubtful. Unless they're using exotic materials for the swingarm, hubs, spokes, rims, rotors, calipers, triple clamps/controls, tires, tubes, etc. Just go out and weigh those items on your current gas MX bike. You'll be surprised how much they weigh and how little the engines weigh by comparison. Most of the weight reductions over the past 10 years have been focused on the engines as the item mentioned have already been optimized for weight, strength, durability and cost already. There's simply not enough left in the total weigh budget to accommodate an electric motor, gear reduction, and battery pack and be only 110kg and lighter than the KTM (including the weight of the fuel). If they are including exotic materials I highly doubt they'll be able to meet the price point shown.
TCMB371 - The layout isn't that much different from the Alta. They'll need to have one sided cell connections just like the Alta and if wire bonded might have similar issues. The cells are connected to a heat sink/case just like the Alta, they'll need to be bonded with electrically isolating/thermally conductive epoxy or film adhesive just like the Alta otherwise the P groups will short out. The adhesive used will dictate how efficient the thermal path is so it's very important. The Alta used internal case partitions and heat pipes to draw heat from the sells to the radiating outside surfaces. The Varg is more direct and superior in this regard. However, based on my experiments the limiting factor ultimately will be the temperature delta between the case and the outside air as the greater the difference the more/faster the heat can be removed. But, unlike a car motor that runs between 200-220F degrees, Li-Ion cells don't like temps above 130-140F and therefore on a hot day, say 100F, there's only 30-40F differential to pull the heat out, not 100-120F like in a car. Tesla recognized this issue early on and that's why they use refrigerated water (cooled by the AC system) to cool their packs. Add the typical inefficiencies, some mud or dirt on the pack or anything that blocks air flow/contact and that'll make it even worse. Remember, Europe doesn't get as hot as we do in the states.
On cooler/colder days I'd say the Varg design will be adequate (thermally) for most riders except maybe fast A guys and pros if starting the moto with a cold pack on a harder pack track with minimal hills (not Glen Helen).
Let me clear a few things up.
The motor was designed in house. It is bigger and heavier (9kg) than the Alta motor, but it is more efficient under load. Being more efficient is just like adding cells, so that offsets the weight. Also, the inverter (also designed in house) is both higher power and lighter.
A little bit of battery cooling... It is obvious that the cells are being cooled via their bottoms. The area ratio of 21700 to 18650 (21^2 / 18^2) = 1.36 and if we compensate for cell length (65/70) = 1.26 which gives the 21700 a 26% advantage in area per unit of heat. Now look at the video of the case half. Each cell sits in its own "well" where the well depth is a mass versus cooling tradeoff. AFAIK I know the MXR cells do not sit in wells (please correct me if I am wrong). So the Varg starts off with a 30% plus advantage in heat conduction out of the cells. The path length to the air stream is obvious, but let us now discuss the air stream. The MXR pack is almost a cube. A cube has a high volume to area ratio. The rear of the battery (25% of the surface area) is not really in the air stream. The Varg has significantly more surface area for cooling and only a small portion of that area is not in the air stream. So we have:
A. Better heat conduction out of the cells.
B. Essentially zero length path to the air stream.
C. More surface area in the air stream.
Battery cooling is significantly better. You don't need to be a rocket scientist to see that.
On the Varg the battery case is stressed. On the Alta it is not; this comes with a mass penalty.
The Alta is front heavy compared to the Varg which is much closer to typical 450 ICE (not saying Alta weight distribution is bad, just letting people know the difference).
Varg uses KYB versus WP AER (again, your preference may vary).
The Varg is lighter, battery has significantly better thermals, motor and inverter are more powerful.
And finally, you will be easily able to make your own "maps".
I take it you are working on this Stark Varg project then?
A. Better heat conduction out of the cells.
B. Essentially zero length path to the air stream.
C. More surface area in the air stream.
It doesn't matter how well you conduct the heat to the case if you can't transfer that heat to the outside air. How do you transfer heat from the case to the air on a hot day with very little temperature differential. Do you run the cells much hotter? Do you plan of some kind of forced air system? Here in southern California temperatures are well above 100F during the long summer months. The pack will heat soak to that temp before the moto even starts (just by sitting in most garages here in SoCal). Air is a lousy heat conductor anyway. You can't change the laws of physics. Please explain.
A little bit of battery cooling... It is obvious that the cells are being cooled via their bottoms. The area ratio of 21700 to 18650 (21^2 / 18^2) = 1.36 and if we compensate for cell length (65/70) = 1.26 which gives the 21700 a 26% advantage in area per unit of heat.
The surface area comparison is not entirely valid as the main constraint is the negative electrode contact to the cell bottom/case as that's the choke point thermally unless you're using a tabless cell (which I assume you'd be touting). Also, the length penalty you applied is questionable as the relationship isn't linier.
Wass: If you are an MXGP rider you would need to charge it between motos.
Do you still stand by the statement that a MXGP rider (Herlings, Fabre, Cairoli, etc) can race one moto (30 mins plus 2 laps) at race pace on a single charge on a GP track?
The motor was designed in house. It is bigger and heavier (9kg) than the Alta motor, but it is more efficient under load.
If the Varg designers managed to squeeze more than 10% out of the motor they be better advised to sell that patent to Tesla or another auto mfg for more money than they could ever dream of making selling MX bikes! All electric motors have islands of efficiency that should be optimized for the rpm and load most applicable. In addition, If you tune for full power (max voltage) you'll lose power as the pack voltage drops. Tuning so that the max voltage the motor can see is still above the empty pack voltage (or close to) makes the power delivery more consistent throughout the moto. Everyone does that, it's not rocket science.
B. Essentially zero length path to the air stream.
C. More surface area in the air stream.
It doesn't matter how well you conduct the heat to the case if you can't transfer that heat to the outside air. How do you transfer heat from the case to the air on a hot day with very little temperature differential. Do you run the cells much hotter? Do you plan of some kind of forced air system? Here in southern California temperatures are well above 100F during the long summer months. The pack will heat soak to that temp before the moto even starts (just by sitting in most garages here in SoCal). Air is a lousy heat conductor anyway. You can't change the laws of physics. Please explain.
A little bit of battery cooling... It is obvious that the cells are being cooled via their bottoms. The area ratio of 21700 to 18650 (21^2 / 18^2) = 1.36 and if we compensate for cell length (65/70) = 1.26 which gives the 21700 a 26% advantage in area per unit of heat.
The surface area comparison is not entirely valid as the main constraint is the negative electrode contact to the cell bottom/case as that's the choke point thermally unless you're using a tabless cell (which I assume you'd be touting). Also, the length penalty you applied is questionable as the relationship isn't linier.
Wass: If you are an MXGP rider you would need to charge it between motos.
Do you still stand by the statement that a MXGP rider (Herlings, Fabre, Cairoli, etc) can race one moto (30 mins plus 2 laps) at race pace on a single charge on a GP track?
The motor was designed in house. It is bigger and heavier (9kg) than the Alta motor, but it is more efficient under load.
If the Varg designers managed to squeeze more than 10% out of the motor they be better advised to sell that patent to Tesla or another auto mfg for more money than they could ever dream of making selling MX bikes! All electric motors have islands of efficiency that should be optimized for the rpm and load most applicable. In addition, If you tune for full power (max voltage) you'll lose power as the pack voltage drops. Tuning so that the max voltage the motor can see is still above the empty pack voltage (or close to) makes the power delivery more consistent throughout the moto. Everyone does that, it's not rocket science.
Butch
Poseur
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- 529
- Location
- San Jose, California
If I recall correctly, the first bike (s/n 005) was delivered to a customer in December 2015 (there is a pic around here somewhere) but spent some time at the factory for further development. It was in the customer’s hands some months later when I was able to ride it at Carnegie.
I ordered one immediately thereafter. I took delivery October 25, 2016, as a 2017 model. That is my s/n 019, which I think is the first bike delivered to a “normal” customer.
I met Philip some months later at Hollister for an Alta demo day. He rode mine. Then he rode a demo bike, then he bought one… then he founded this site. Then he bought another Alta. And so on.
- Likes
- 990
- Location
- Connecticut
Is that Zootie's MX?
+1. Honestly, If the Varg is even close to my MXR and Stark stays in business for 5+ years post delivery, I'll be ecstatic.
Butch
Poseur
- Likes
- 529
- Location
- San Jose, California
And taller gearing.
Butch
Poseur
- Likes
- 529
- Location
- San Jose, California
I must brag here that my avatar is me with Ty Tremaine’s bike. The Alta guys were at Metcalf with it for some tuning. So I had to ride it. What a great motorcycle…
- Likes
- 2,798
- Location
- Pennsylvania
As far as I know that bike is now in the hands of our very own @73Thing
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New Stark EX Enduro announced, List of issues/unkept promises with current/original Stark Varg
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