Stark Varg Reviews

Derpin' DJ
Posts
6414
Joined
5/27/2011
Location
Newcastle, AU
6/24/2022 12:29am
Roczoff wrote:
Fill me in: Being in a specific gear at a specific throttle setting helps us judge speed off jumps. Will it be difficult to judge that...
Fill me in:

Being in a specific gear at a specific throttle setting helps us judge speed off jumps. Will it be difficult to judge that speed when there's less noise and only one gear?

Alot of the people testing the bike had made those comments that is was hard to judge at first, but really it's a matter of retraining yourself. There's still sound there, you'd just have to realign it with the pitch of the whining sound of the motor. You'd be surprised how much you're brain can correlate other things, like the different frequencies of vibration in the handlebars also.

Mountain bikes have even less indicators, but people can still judge the speed they need for jumps reasonably well.
3
#434
Posts
1913
Joined
3/23/2017
Location
DE
6/24/2022 12:34am
Roczoff wrote:
Fill me in: Being in a specific gear at a specific throttle setting helps us judge speed off jumps. Will it be difficult to judge that...
Fill me in:

Being in a specific gear at a specific throttle setting helps us judge speed off jumps. Will it be difficult to judge that speed when there's less noise and only one gear?

Yeah, in the tests multiple guys stated that they had problems judging the speed for jumps, but that they eventually got used to it.
1
fs
Posts
36
Joined
11/8/2011
Location
HR
6/24/2022 12:44am
#434 wrote:
Were there any infos about the internals of the Varg? Here some rough calculations for the internal gearing: If the Varg is geared for 130 km/h...
Were there any infos about the internals of the Varg?

Here some rough calculations for the internal gearing: If the Varg is geared for 130 km/h or 80 mph or 36 m/s top speed with a rear wheel circumference of about 2 m, the rear wheel needs to spin with ~1000 rpm. The electric motor has a max rpm of 14000. Assuming a standard 13:50 outside gearing means that the internal gearing has to be about 1:3.5, which would be possible with just one set of gears. This would also mean that the motor of the Varg spins backwards, which would counteract wheelies while acceleration and so on. The inertia of the electric motor is of course less than that of a crank, but still there.
A lot of MotoGP bikes have backwards spinning cranks, but has any manufacturers ever tried that on an MX bike?

Please check the math. I’m already five beers in..
Close... Screen grab from media reviews shows 51km/h at 5,125rpm [img]https://p.vitalmx.com/photos/forums/2022/06/23/556481/s1200_Screen_2.jpg[/img] Website advertises maximum motor speed of 14,200rpm, so top speed of 141km/h or 87mpg. 19"...

Close...
Screen grab from media reviews shows 51km/h at 5,125rpm



Website advertises maximum motor speed of 14,200rpm, so top speed of 141km/h or 87mpg.

19" rear wheel has 2.168m circumference.

5125 * 2.168 * 60 / (51 * 1000) = 13.07 total reduction.

Photos of bike show 13 front sprocket and 49 tooth rear sprocket, so 3.77 final drive reduction.

13.07 / 3.77 = 3.47, so 1:3.47 internal gearing.
Your are almost spot on with the gear ratio Smile

one reduction stage (two gears)
four bearings (two on rotor and two on counter shaft)
3
#434
Posts
1913
Joined
3/23/2017
Location
DE
6/24/2022 1:20am
#434 wrote:
Were there any infos about the internals of the Varg? Here some rough calculations for the internal gearing: If the Varg is geared for 130 km/h...
Were there any infos about the internals of the Varg?

Here some rough calculations for the internal gearing: If the Varg is geared for 130 km/h or 80 mph or 36 m/s top speed with a rear wheel circumference of about 2 m, the rear wheel needs to spin with ~1000 rpm. The electric motor has a max rpm of 14000. Assuming a standard 13:50 outside gearing means that the internal gearing has to be about 1:3.5, which would be possible with just one set of gears. This would also mean that the motor of the Varg spins backwards, which would counteract wheelies while acceleration and so on. The inertia of the electric motor is of course less than that of a crank, but still there.
A lot of MotoGP bikes have backwards spinning cranks, but has any manufacturers ever tried that on an MX bike?

Please check the math. I’m already five beers in..
Close... Screen grab from media reviews shows 51km/h at 5,125rpm [img]https://p.vitalmx.com/photos/forums/2022/06/23/556481/s1200_Screen_2.jpg[/img] Website advertises maximum motor speed of 14,200rpm, so top speed of 141km/h or 87mpg. 19"...

Close...
Screen grab from media reviews shows 51km/h at 5,125rpm



Website advertises maximum motor speed of 14,200rpm, so top speed of 141km/h or 87mpg.

19" rear wheel has 2.168m circumference.

5125 * 2.168 * 60 / (51 * 1000) = 13.07 total reduction.

Photos of bike show 13 front sprocket and 49 tooth rear sprocket, so 3.77 final drive reduction.

13.07 / 3.77 = 3.47, so 1:3.47 internal gearing.
fs wrote:
Your are almost spot on with the gear ratio Smile

one reduction stage (two gears)
four bearings (two on rotor and two on counter shaft)
Do you guys think, that it makes a difference in handling if the motor spins forwards or backwards?
1

The Shop

fs
Posts
36
Joined
11/8/2011
Location
HR
6/24/2022 1:47am
#434 wrote:
Do you guys think, that it makes a difference in handling if the motor spins forwards or backwards?
It likely makes some difference but less than with a combustion engine since the rotation mass is so much less.
2
#434
Posts
1913
Joined
3/23/2017
Location
DE
6/24/2022 2:10am
#434 wrote:
Do you guys think, that it makes a difference in handling if the motor spins forwards or backwards?
fs wrote:
It likely makes some difference but less than with a combustion engine since the rotation mass is so much less.
Yeah, I thought so. Damn it’s such a neat and simple design.
The set of gears is straight-cut gears right? That’s where probably most of the noise comes from. Or is it actually the motor?
I was wondering too why your fan is so loud. Is this the final design of the fan? Does it run on constant speed all the time?
Sorry for all the question, but I‘m excited about the project and aeroacoustic is my research field.
1
fs
Posts
36
Joined
11/8/2011
Location
HR
6/24/2022 2:20am
#434 wrote:
Yeah, I thought so. Damn it’s such a neat and simple design. The set of gears is straight-cut gears right? That’s where probably most of the...
Yeah, I thought so. Damn it’s such a neat and simple design.
The set of gears is straight-cut gears right? That’s where probably most of the noise comes from. Or is it actually the motor?
I was wondering too why your fan is so loud. Is this the final design of the fan? Does it run on constant speed all the time?
Sorry for all the question, but I‘m excited about the project and aeroacoustic is my research field.
The gears are helical. Their contribution to the sound is significant, but the motor by itself is audible for sure.

The fan is high capacity to keep the coolant temperature low. Lower temperature equals lower copper losses and lower IGBT losses.

Normally the fan won't run when the coolant is cool. For the media event we used the fan as a "bike on" indicator. I am sure that if we did not do that we would have had some "inadvertent acceleration" accidents.

BTW, you can run the fan (and coolant pump) during charging. The idea is that if you want, the motor and coolant will be practically at ambient temperature when you start.

10
6/24/2022 2:29am Edited Date/Time 6/24/2022 4:59am
#434 wrote:
Yeah, I thought so. Damn it’s such a neat and simple design. The set of gears is straight-cut gears right? That’s where probably most of the...
Yeah, I thought so. Damn it’s such a neat and simple design.
The set of gears is straight-cut gears right? That’s where probably most of the noise comes from. Or is it actually the motor?
I was wondering too why your fan is so loud. Is this the final design of the fan? Does it run on constant speed all the time?
Sorry for all the question, but I‘m excited about the project and aeroacoustic is my research field.
fs wrote:
The gears are helical. Their contribution to the sound is significant, but the motor by itself is audible for sure. The fan is high capacity to...
The gears are helical. Their contribution to the sound is significant, but the motor by itself is audible for sure.

The fan is high capacity to keep the coolant temperature low. Lower temperature equals lower copper losses and lower IGBT losses.

Normally the fan won't run when the coolant is cool. For the media event we used the fan as a "bike on" indicator. I am sure that if we did not do that we would have had some "inadvertent acceleration" accidents.

BTW, you can run the fan (and coolant pump) during charging. The idea is that if you want, the motor and coolant will be practically at ambient temperature when you start.

Thanks for that, you obviously know a bit about this machine. Do you know if it will overheat and go into a restricted mode if it does overheat? Apparently the Alta did. I am planning on using it in a 4 lap barrel race on the beach, with 750m straights.
#434
Posts
1913
Joined
3/23/2017
Location
DE
6/24/2022 2:32am
#434 wrote:
Yeah, I thought so. Damn it’s such a neat and simple design. The set of gears is straight-cut gears right? That’s where probably most of the...
Yeah, I thought so. Damn it’s such a neat and simple design.
The set of gears is straight-cut gears right? That’s where probably most of the noise comes from. Or is it actually the motor?
I was wondering too why your fan is so loud. Is this the final design of the fan? Does it run on constant speed all the time?
Sorry for all the question, but I‘m excited about the project and aeroacoustic is my research field.
fs wrote:
The gears are helical. Their contribution to the sound is significant, but the motor by itself is audible for sure. The fan is high capacity to...
The gears are helical. Their contribution to the sound is significant, but the motor by itself is audible for sure.

The fan is high capacity to keep the coolant temperature low. Lower temperature equals lower copper losses and lower IGBT losses.

Normally the fan won't run when the coolant is cool. For the media event we used the fan as a "bike on" indicator. I am sure that if we did not do that we would have had some "inadvertent acceleration" accidents.

BTW, you can run the fan (and coolant pump) during charging. The idea is that if you want, the motor and coolant will be practically at ambient temperature when you start.

Great infos, thanks fs!

Ok cool! Helical gears are a bit quieter than straight ones.

So you're aiming for 60 degrees max on the motor or even lower?

The battery temperature will fluctuate quite a bit riding in summer or winter. The battery concept looks like there's probably eough surface to keep the temperature close to ambient temperature at hot days, but what about riding in the cold? Is there a danger of getting the cells too cold?
1
6/24/2022 3:03am
#434 wrote:
Yeah, I thought so. Damn it’s such a neat and simple design. The set of gears is straight-cut gears right? That’s where probably most of the...
Yeah, I thought so. Damn it’s such a neat and simple design.
The set of gears is straight-cut gears right? That’s where probably most of the noise comes from. Or is it actually the motor?
I was wondering too why your fan is so loud. Is this the final design of the fan? Does it run on constant speed all the time?
Sorry for all the question, but I‘m excited about the project and aeroacoustic is my research field.
fs wrote:
The gears are helical. Their contribution to the sound is significant, but the motor by itself is audible for sure. The fan is high capacity to...
The gears are helical. Their contribution to the sound is significant, but the motor by itself is audible for sure.

The fan is high capacity to keep the coolant temperature low. Lower temperature equals lower copper losses and lower IGBT losses.

Normally the fan won't run when the coolant is cool. For the media event we used the fan as a "bike on" indicator. I am sure that if we did not do that we would have had some "inadvertent acceleration" accidents.

BTW, you can run the fan (and coolant pump) during charging. The idea is that if you want, the motor and coolant will be practically at ambient temperature when you start.

fs,

One issue raised by media test riders was, panic reving in the air, causes the rear wheel to accelerate to the bike's maximum speed, not a rev limit, like an ICE bike.

This could be an issue for novice riders, causing them to loop out.

It should be possible to measure the bike's attitude, level, front high by 10°, 20°, etc and limit motor speed when the front wheel gets too high.
3
6/24/2022 11:42am
Roczoff wrote:
Fill me in: Being in a specific gear at a specific throttle setting helps us judge speed off jumps. Will it be difficult to judge that...
Fill me in:

Being in a specific gear at a specific throttle setting helps us judge speed off jumps. Will it be difficult to judge that speed when there's less noise and only one gear?

Ive found that i just use my sense of speed on all my bikes now, both electric and gas. It took all of about 3 laps to get used to jumping with electric.
3
1
Magoofan
Posts
10401
Joined
5/4/2021
Location
Shadow Glen (for those who remember), CA, USA
6/24/2022 11:50am
#434 wrote:
You start your hour long gibberish with „everything nowadays gets politicised“ and end up at „green nazis“… wtf?!?
...and you remind me of this every time someone isn't jerking off over these electric bikes like you are.

https://youtu.be/j3Cn7slInGo

1
11
#434
Posts
1913
Joined
3/23/2017
Location
DE
6/24/2022 12:44pm Edited Date/Time 6/24/2022 12:46pm
#434 wrote:
You start your hour long gibberish with „everything nowadays gets politicised“ and end up at „green nazis“… wtf?!?
Magoofan wrote:
...and you remind me of this every time someone isn't jerking off over these electric bikes like you are.

https://youtu.be/j3Cn7slInGo

I gotta admit, it’s a nice feeling to live rent free in your head.
3
2
6/24/2022 1:55pm Edited Date/Time 6/24/2022 1:58pm
#434 wrote:
Yeah, I thought so. Damn it’s such a neat and simple design. The set of gears is straight-cut gears right? That’s where probably most of the...
Yeah, I thought so. Damn it’s such a neat and simple design.
The set of gears is straight-cut gears right? That’s where probably most of the noise comes from. Or is it actually the motor?
I was wondering too why your fan is so loud. Is this the final design of the fan? Does it run on constant speed all the time?
Sorry for all the question, but I‘m excited about the project and aeroacoustic is my research field.
fs wrote:
The gears are helical. Their contribution to the sound is significant, but the motor by itself is audible for sure. The fan is high capacity to...
The gears are helical. Their contribution to the sound is significant, but the motor by itself is audible for sure.

The fan is high capacity to keep the coolant temperature low. Lower temperature equals lower copper losses and lower IGBT losses.

Normally the fan won't run when the coolant is cool. For the media event we used the fan as a "bike on" indicator. I am sure that if we did not do that we would have had some "inadvertent acceleration" accidents.

BTW, you can run the fan (and coolant pump) during charging. The idea is that if you want, the motor and coolant will be practically at ambient temperature when you start.

fs, One issue raised by media test riders was, panic reving in the air, causes the rear wheel to accelerate to the bike's maximum speed, not...
fs,

One issue raised by media test riders was, panic reving in the air, causes the rear wheel to accelerate to the bike's maximum speed, not a rev limit, like an ICE bike.

This could be an issue for novice riders, causing them to loop out.

It should be possible to measure the bike's attitude, level, front high by 10°, 20°, etc and limit motor speed when the front wheel gets too high.
The common statement was that it was really responsive to in-air input. So the fact that people over-compensate on ICE bikes and still don't get the response they are looking for seems more of an indictment of that platform, than to the electric.
1
#434
Posts
1913
Joined
3/23/2017
Location
DE
7/4/2022 7:37am
Looks like they‘re ready for big scale production.


Don’t know if the gif works, but it shows the automated assembly of the battery pack.
1
brocster
Posts
4569
Joined
6/9/2009
Location
Aliso Viejo, CA, USA
7/4/2022 7:52am
Roczoff wrote:
Fill me in: Being in a specific gear at a specific throttle setting helps us judge speed off jumps. Will it be difficult to judge that...
Fill me in:

Being in a specific gear at a specific throttle setting helps us judge speed off jumps. Will it be difficult to judge that speed when there's less noise and only one gear?

Ive found that i just use my sense of speed on all my bikes now, both electric and gas. It took all of about 3 laps...
Ive found that i just use my sense of speed on all my bikes now, both electric and gas. It took all of about 3 laps to get used to jumping with electric.
What Bryan said

Think of it like switching bikes with your buds or your kids, 450, 350, 250 4t, 250 2t, 125.

You’ll figure out how to jump it quickly. It’s your brain that knows the speed needed.

Took 3 laps at a demo day on an Alta to get used to it. Next 5 times out, no problems.

Can’t wait to demo a Stark Ranks real high on my V2 things to buy. More than likely bonus time 2024 if available.
Dirtysmile56
Posts
2210
Joined
8/16/2006
Location
Bend, OR, USA
8/8/2022 4:29am
snillum wrote:
The write up says Tortelli could get 35-40 minutes on a charge. That is a bit disappointing but truthfully it was about what was expected. However...
The write up says Tortelli could get 35-40 minutes on a charge. That is a bit disappointing but truthfully it was about what was expected. However, for my purposes riding in my yard in the afternoon, this would be just fine.
vdrsnk04 wrote:
I find this comment interesting. Aren’t these pro’s who race the 35-40 minute pro motocross races running through a tank of fuel. Barcia actually has to...
I find this comment interesting. Aren’t these pro’s who race the 35-40 minute pro motocross races running through a tank of fuel. Barcia actually has to run an oversized tank for this reason.

So Stark is on par with industry standard if I’m not mistaken?
I guess except the fact that filling a tank with gas is a lot quicker than charging. For the record, I have a deposit on one. I have 24 acres in a neighborhood (surrounded by 1 acre lots) with epic terrain for a track(about 100ft of elevation change), we currently have a small track on our property but I have room to build an incredible track. I can't do that with gas bikes(my neighbors would lose their minds) but the electric is a game changer. The in town MX tracks that will pop up are going to give electric MX riders endless opportunities. The range and charging technology will just continue to improve as well so I'm not tooo worried about it.
10
Gungadin
Posts
233
Joined
7/8/2022
Location
Sarasota, FL, USA
8/8/2022 5:31am
#434 wrote:
Looks like battery pack production is up and running! Curious, if they also manufacture the motor and the power electronics themselves. View this post on Instagram ...
Looks like battery pack production is up and running!

Curious, if they also manufacture the motor and the power electronics themselves.

Old style cylindrical cells, not heaxagons or pouches.

Word from England is that full immersion in dielectric fluid battery cooling is being tested on a high powered E bike because of massive overheating issues for medium to high duty at the motors rated power.
#434
Posts
1913
Joined
3/23/2017
Location
DE
8/8/2022 7:27am
#434 wrote:
Looks like battery pack production is up and running! Curious, if they also manufacture the motor and the power electronics themselves. View this post on Instagram ...
Looks like battery pack production is up and running!

Curious, if they also manufacture the motor and the power electronics themselves.

Gungadin wrote:
Old style cylindrical cells, not heaxagons or pouches. Word from England is that full immersion in dielectric fluid battery cooling is being tested on a high...
Old style cylindrical cells, not heaxagons or pouches.

Word from England is that full immersion in dielectric fluid battery cooling is being tested on a high powered E bike because of massive overheating issues for medium to high duty at the motors rated power.
Yes, everybody uses cylindrical cell. Cars, eBikes, power tools… what’s your point?
Only flat devices like phones and laptops use pouches.
With the way Stark designed the battery pack, they‘ll have a high heat flow rate from the cells to walls of the housing. Cooling shouldn’t be a problem.
1
1
Gungadin
Posts
233
Joined
7/8/2022
Location
Sarasota, FL, USA
8/8/2022 8:59am
#434 wrote:
Yes, everybody uses cylindrical cell. Cars, eBikes, power tools… what’s your point? Only flat devices like phones and laptops use pouches. With the way Stark designed...
Yes, everybody uses cylindrical cell. Cars, eBikes, power tools… what’s your point?
Only flat devices like phones and laptops use pouches.
With the way Stark designed the battery pack, they‘ll have a high heat flow rate from the cells to walls of the housing. Cooling shouldn’t be a problem.
The best battery packaging for kWh density is hexagonal or square.

Stark have tacitly acknowledged they have battery over heating issues by limiting the ride times and loads when the writers were given those ride impression. There has been zero independent assessment, let alone the sort of extended tests the print publications have run with new bikes.

Strangely, Stark was touting their magnesium battery case. Magnesium is a poor heat conductor compared to aluminium
1
2
8/8/2022 9:04am
question i'm too lazy to find in this thread: What's the updated delivery date for the first buyers? Sure am curious to hear feedback from weekend moto guys.........
1
8/8/2022 9:59am
question i'm too lazy to find in this thread: What's the updated delivery date for the first buyers? Sure am curious to hear feedback from weekend...
question i'm too lazy to find in this thread: What's the updated delivery date for the first buyers? Sure am curious to hear feedback from weekend moto guys.........
I'm technically customer #1 worldwide and my current estimated delivery date is 23-Dec-2022.
8
2
ML512
Posts
16989
Joined
12/28/2008
Location
Wildomar, CA, USA
Fantasy
8/8/2022 10:03am
I'm technically customer #1 worldwide and my current estimated delivery date is 23-Dec-2022.
What was it originally?
1
#434
Posts
1913
Joined
3/23/2017
Location
DE
8/8/2022 10:09am
Sure, hex cells can be pack tighter than cylindrical ones, but are there any availible? Cylindrical cells are easy to mass produce and readily available on the market. I can't even find hexagonal battery cells for sale.

Did they? If read and watched a lot of tests and havn't heard of a overheating issue. Where did you find that?

Poor heat conductor? It's great heat conducter, just not as great as Al, but much better than steel or Ti for that matter.
It also highly depends on the alloy they're using. The thermal conductivity of alloys is usually a lot lower than of pure metals. Pure Mg has around 70% of the thermal conductivity of pure Al, but some Al-alloys have only 35% of the thermal conductivity of pure Al. So without knowing the Mg-alloy this is speculation.
2
3
8/8/2022 10:18am
I'm technically customer #1 worldwide and my current estimated delivery date is 23-Dec-2022.
ML512 wrote:
What was it originally?
23-Sep-2022. Most orders were pushed back roughly 3 months.
5
#434
Posts
1913
Joined
3/23/2017
Location
DE
8/8/2022 11:17am
question i'm too lazy to find in this thread: What's the updated delivery date for the first buyers? Sure am curious to hear feedback from weekend...
question i'm too lazy to find in this thread: What's the updated delivery date for the first buyers? Sure am curious to hear feedback from weekend moto guys.........
I'm technically customer #1 worldwide and my current estimated delivery date is 23-Dec-2022.
Nice Christmas present!
1
Zoom
Posts
1383
Joined
10/21/2012
Location
Cypress, TX, USA
8/8/2022 11:49am
#434 wrote:
Looks like battery pack production is up and running! Curious, if they also manufacture the motor and the power electronics themselves. View this post on Instagram ...
Looks like battery pack production is up and running!

Curious, if they also manufacture the motor and the power electronics themselves.

Stark has an equity stake in the motor company. So technically they manufacture the motor also.
4
2
Darrin Willis
Posts
1105
Joined
11/16/2020
Location
Red Deer County, AB, CA
8/8/2022 12:23pm
I follow this thread religiously. Yet I have zero interest in owning an electric motorcycle. Anyone else like that?
4
tek14
Posts
4929
Joined
1/26/2014
Location
Vantaa, FI
8/8/2022 12:32pm
I follow this thread religiously. Yet I have zero interest in owning an electric motorcycle. Anyone else like that?
Im waiting first real world reviews and waiting time to go down. Cant wait to buy one and if its Stark or Honda doesnt matter.
1

Post a reply to: Stark Varg Reviews

The Latest