Maximizing Range for the Stark Varg

[Theo]

I run 14/48 on 17" supermoto wheels at 100% regen and get right at 60 miles from a charge.

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If those 60 miles have been measured with the on-board odometer, and if that odometer works measuring the rotational speed of the rear wheel as I suspect, then the 60 miles value has been affected by the different size of the rear wheel.

 

[Raindog]

If those 60 miles have been measured with the on-board odometer, and if that odometer works measuring the rotational speed of the rear wheel as I suspect, then the 60 miles value has been affected by the different size of the rear wheel.

Well, it's twenty-two miles from my house to work. When I pull into the garage at the end of the day I usually have 29-31% charge left on the clock.

 

[Johnny Depp]

I run 14/48 on 17" supermoto wheels at 100% regen and get right at 60 miles from a charge.

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I assume you are using some other odometer besides stock, which reads the rear wheel? Racetrack or commuting?

 

[Johnny Depp]

Well, it's twenty-two miles from my house to work. When I pull into the garage at the end of the day I usually have 29-31% charge left on the clock.

That's decent, I'd imagine you could easily run much higher gearing. For under $100 bucks.

 

[Raindog]

I assume you are using some other odometer besides stock, which reads the rear wheel? Racetrack or commuting?

The speedo uses gps, there's no pickup for a traditional gauge and I'm not sure why anyone would want one. I commute on the bike during the week and mostly run the BRP on the weekends.

I could run a smaller sprocket on the back and maybe pick up a few miles if I ran interstate at sustained speeds but that's not how I use the bike. I'm in and out of the throttle on tight backroads for the vast majority of my daily commute.

I did a 200 mile day on my 2t motard a few months back and by the end of the day I was wishing I had taken the truck.

 

[Chaconne]

On this past Sunday I got 15 miles of slow mostly single track with some Enduro gnarly hills used about 35% battery. So I could comfortably get the same as @Johnny Depp in the slow gnarl.

I am mostly stock with my newer Varg. Some Acerbis parts and an AXP skid plate still running the Pirellies (with IRC heavy duty tubes) till they are worn out, they don't like the 8 psi...

 

[brongle]

The speedo uses gps, there's no pickup for a traditional gauge and I'm not sure why anyone would want one. I commute on the bike during the week and mostly run the BRP on the weekends.

I could run a smaller sprocket on the back and maybe pick up a few miles if I ran interstate at sustained speeds but that's not how I use the bike. I'm in and out of the throttle on tight backroads for the vast majority of my daily commute.

I did a 200 mile day on my 2t motard a few months back and by the end of the day I was wishing I had taken the truck.

Speedo is based on motor spin not GPS, it will be inaccurate if you change gearing or wheels.

 

[OpaTsupa]

Speedo is based on motor spin not GPS, it will be inaccurate if you change gearing or wheels.

Varg speedo/distance is inaccurate [lower] by ≈5% compared to a GPS watch which I trust.
This is for short rides of 20-30km.

 

[vic321]

I don't think you will get better range in hard Enduro with taller gearing. The wheel/motor speeds are so low you will stay well in its operating area.

There is plenty of torque on tap, but not a lot of power at crawl speed in sensibel horsepower modes. And in the end it's power that moves you, not torque.
That results in a ''slowish'' reacting bike when rock crawling with tall gearing. Offcourse you could just add hp so overcome the lack of power down low. But when it then whiskey throttles it's off to the moon and when doing steep hillclimbs that power puts you into wheelspin or backflip scenario's rather quickly.

No, its always torque that moves you. Horsepower is just a mathematical construct. Therefore HP is always abysmal in low rpm. By changing the gearing you always change torque, never the HP.

 

[Erwin P]

Torque is a stationairy force Nm. The amount of force that's needed to move an object is power in J or W (or HP so you will).

By changing the gearing you change the amount of HP per revolution of the rear wheel by changing the Torque part of the Formula. HP = Torque × RPM / 7023. Change the Torque at the rear wheel at the same wheelspeed (actually what you do when changing gearing) and you have increased/decreased HP.

 

[vic321]

Nope, you do not. The HP stays constant. HP= Torque*rpm. Simple math. you change gearing to 1/2", then you raise torque by doubling, and rpm by half. The multipilcation keeps the same. There is no way to change HP by changin the gearing.
What you suggest is to double the rpm for the engine per turn of the wheel. That has a limit in the rpm range of the engine. Nevertheless the effect you get is from larger torque. If you got more than enough torque from the engine from 0rpm on, these kind of games become meaningless. With the Stark you get much more torque (and HP) from the standard gearing, than you will ever get from changing the gearing on an ICE bike. Without the rpm limitation. A traction control would be much more handy.

 

[Erwin P]

The maximum amount of HP stays the same yes, the Torque will double as well. But the top HP will come at 1/2 the wheel speed since the motor will be running the same RPM at top power. Agree?

So as established above you have now lowered the amount of revolutions of the rear wheel needed to achieve max HP (or any HP).
Same goes lower in the wheel speed range. You now have double engine/motor RPM at any given range so you doubled (lets assume this is a simple straight line motor for this example) all HP per wheelspeed below top HP wheelspeed. Above that you are actually loosing, but if that's a speed you cannot ride or don't want to ride that's fine.

 

[vic321]

No, the top of the HP is always near the End of the usable rpm. At a certain point te torque curve drops faster than the rpm rises. That is the point of max HP. With the Stark the HP does not turn down, as it is downregulated from max HP by the electronics (I assume the maximum possible HP of the Stark engine at 120HP, and there you would probably see a max HP). And it is near the end of the usable rpm with other bikes. Because the torque curve is always qwite flate over the range. Completely Flat on a Stark.

HP does not matter at all at low speed. It is more useful to determine the topspeed of a bike. And HP is most useless on elecrical vehicles. All the effects you describe are due to higher torque. Nothing else.

 

[vic321]

Torque is a stationairy force Nm. The amount of force that's needed to move an object is power in J or W (or HP so you will).

By changing the gearing you change the amount of HP per revolution of the rear wheel by changing the Torque part of the Formula. HP = Torque × RPM / 7023. Change the Torque at the rear wheel at the same wheelspeed (actually what you do when changing gearing) and you have increased/decreased HP.

NM is torque, J is Energy, W is power.

 

[Erwin P]

No, the top of the HP is always near the End of the usable rpm. At a certain point te torque curve drops faster than the rpm rises. That is the point of max HP. With the Stark the HP does not turn down, as it is downregulated from max HP by the electronics (I assume the maximum possible HP of the Stark engine at 120HP, and there you would probably see a max HP). And it is near the end of the usable rpm with other bikes. Because the torque curve is always qwite flate over the range. Completely Flat on a Stark.

HP does not matter at all at low speed. It is more useful to determine the topspeed of a bike. And HP is most useless on elecrical vehicles. All the effects you describe are due to higher torque. Nothing else.

The torque curve isn't flat on the Stark. Dyno's have shown a curve in rear wheel torque and power. But true enough much flatter than ICE's.
There is a big distinction between wheel HP/speed and motor HP/speed that you seem to mis out of all of this.

Here is the proof HP per wheelspeed changes with gearing:

The top HP will indeed remain near the top of usable engine speed. Lets put that at 80 HP at 14000 rpm (motor speed) and 100 km/h (wheel speed) for this example.
If you were do 1/2 the gearing it would still do 80 HP at 14000 rpm, but now it will be at 50 km/h.
If we assume a straight line power ''curve'' for this bike.
50 km/h - 40 hp / 25 km/h - 20 hp / 12,5 km/h - 10 hp.
Were you to 1/2 the gearing it would look like:
50 km/h - 80 hp / 25 km/h - 40 hp / 12,5 km/h - 20 hp.

Power is what moves you, torque is stationairy.
I actually have a simple real world example for you. At 35HP the Stark has a serious amount of torque. Yet from a standstill in deep sucking mud it has much trouble start the rear wheel turning. There is roughly the highest amount of torque you will ever get from it in 35HP, but still it's not moving. As soon as the rear wheel turns just a tiny little bit (by you paddling or whatever so the motor makes actual rotations) it all of a suddon has little problem with getting unstuck and spin the wheel to absurd speeds.
On an ICE this is solved by pulling the clutch, building revs (torque x rpm = power) and dump the clutch to release that power. If that ICE would have top torque at 4000 rpm and top power at 8000 rpm there is a serious change it will stall releasing it at 4000 rpm while if you release it at 8000 rpm it will probably power onwards.

Here is actually a good video on it:

 

[vic321]

The torque curve is not flat on the stark, but the electronic turns down max HP to 80 HP, so the HP curve stays constant. You found a way to enlarge HP on a vehicle by changing the gear? Try to get a patent. That will be worth billions in the car industry.

 

[Erwin P]

Just read the last post again

The HP per wheelspeed. That's what the car industry has been doing for over a century and it's actually what gearing does.

The horsepower curve is also not flat. It is an actual curve. Just look up that dyno i posted not that long ago.

Edit: Here it is:


The top ond is the 80hp, wich you can see collide with the 60 and 70hp near the end.

 

[vic321]

Torque is also relative to wheelspeed. On a EV the torque kurve goes down softly from its max at 0rpm. And your measured HP curve is as flat as the regulation of the electronics allow. But much flatter than in an ICE engine.

 

[Erwin P]

Torque is also relative to wheelspeed. On a EV the torque kurve goes down softly from its max at 0rpm. And your measured HP curve is as flat as the regulation of the electronics allow. But much flatter than in an ICE engine.

Sure it is relative to the wheelspeed, but is dictated by what the motor delivers and further modified by gearing. That is not something we were discussing was it?

The curve is very smooth, but far from flat. The lower ones are quite flat sure, but the top one is most certainly an curve. Stretched out over a way longer speed range than any ICE, but again that was not something we were discussing.

You can also clearly see the 80 hp collide with the 60 and 70 hp. That's where you see there surely no longer is any regulation on the output as it is just the maximum it can do. I am actually pretty sure the 80hp output is the max of the motor, or at least it will be after some laps. Power clearly drops after some use on 80hp.
My guess is the flatting instead of hyperboleing in the middle is due to limitations of the battery pack. That's also the area where we most often have the most noticeable powerdrops in SM.

 

[vic321]

HP is also dictated by what the motor delivers. And by the gearing. HP is independent from the gearing of the motor. Therefore it is so useful to characterize an engine. Just one single number.