Honda CR-E vs. Alta Redshift

[Rix]

Hmmm, Weight distribution is one thing but I do think a normal ICE (Crank, Counterweight, Shaft, piston, gearbox...) have a very different Gyroscopic physical effect than the electric motor/ reduction gearbox has). I have been involved in a project where we got a bike with too good CG (centre of gravity) and it did feel really weird to ride

Did if feel weird to ride because it was so different than other bikes, or did it feel weird to ride because it sucked? I remember putting some saddle time on a 2009 husaberg 570 with its canted cylinder and centralize motor. It handled way better than any other big bore thumper at the time. turned way easier too. Took some time to get used too, but once I did, I could fly on it.

 

[ElectricMoto]

Did if feel weird to ride because it was so different than other bikes, or did it feel weird to ride because it sucked? I remember putting some saddle time on a 2009 husaberg 570 with its canted cylinder and centralize motor. It handled way better than any other big bore thumper at the time. turned way easier too. Took some time to get used too, but once I did, I could fly on it.

I have owned a Husaberg FE 450 with that motor and it was a great Motorcycle. No this prototype with super-centralized CG was actually too flickable when cornering and felt strange when jumping, like if you been riding Dirt bikes all your life and suddenly ride a Downhill bike when the lack of counterweight makes you feel very unsafe when jumping

 

[Tuner]

Hmmm, Weight distribution is one thing but I do think a normal ICE (Crank, Counterweight, Shaft, piston, gearbox...) have a very different Gyroscopic physical effect than the electric motor/ reduction gearbox has). I have been involved in a project where we got a bike with too good CG (centre of gravity) and it did feel really weird to ride

Low and centralized mass encourages the front and rear wheels to rotate around the mass center prompting the for and aft rocking. Most off-road motorcycles are rear weight biased, where the Alta is near neutral, particularly while standing on the pegs. "Lack of significant rotating motor mass also allows for more pitching as a result of rapid motor rpm deviations during limited and / or inconsistent traction".

 

[Rix]

I have owned a Husaberg FE 450 with that motor and it was a great Motorcycle. No this prototype with super-centralized CG was actually too flickable when cornering and felt strange when jumping, like if you been riding Dirt bikes all your life and suddenly ride a Downhill bike when the lack of counterweight makes you feel very unsafe when jumping

Okay, I can grasp what you are saying with the DH Bike VS MX analogy. Still, it would seem, that once you got used to the character traits of a "super-centralized CG" it would be easier to rid with less rider input, I guess thats not the case.

 

[Philip]

Honda explains that their silly shorty twin pipe 4-strokes have a better "mass centralization". I guess they would have to add a long and heavy single pipe on their CR-Electric for a better "mass decentralization".

 

[Mark911]

The location of the center of gravity (and therefore the weight distribution) is one of the biggest compromises in vehicle dynamics. Front to back determines the static weight distribution and the height determines the dynamic distribution due to weight transfer during acceleration and braking. For example, if the assumption is that the bike/track will generate good traction you'd generally want a lower CG to reduce excessive wheelieing (both accel and nose wheelies). If traction is assumed to be limited you'd want a higher CG in order to generate greater weight transfer (front and rear) to help traction during accel and braking. Of course there's everything in between as well. CG height also influences how easily the bike leans (Roll) into a corner. Front to back distribution affects the cornering and straight line balance of the bike. Does the bike oversteer or understeer, have a "light" front end etc. The ease by which a bike rotates about the CG (pitches, yaws, rolls) has more to do with how the weight is distributed about (the distance from) the CG than the exact CG location. The more weight that can be "located" closer to the CG the easier it is to pitch/yaw/roll. This isn't always desirable as some Yamaha critics will claim that the "mass centralization" went too far and that's why that bike (the 450YZF) tends to endo far too easily as the front pitches down. The CG also affects how the rear suspension "squats" or "jacks" due to chain torque and chassis kinematics. Both being dynamic phenomenon and largely influenced again by the bikes power and available traction. This is one area of vehicle dynamics where the Alta is very different from an ICE bike. The Alta's power (and related traction) is smooth, continuous and seamless without the huge swings in torque/traction that an ICE bike generates at every shift. Therefore, the Alta should be much more "settled" in the rear (establishing a relatively stable attitude) during acceleration everything else being equal (which we know is never the case). Just some food for thought.

 

[wwmotors]

Most MX / SX motorcycles feature roughly a 60 RR / 40 FT weight bias. The long wheel base also encourages pitching though that is something that most modern single shock chassis's must also contend with. Long, tall with low centralized mass = a rocking couple.

The hight of the center of mass must be exactly as high, that the bike in full acceleration does not wheely, but also has a nearly 100% weighttransfer to the rear. So a low center of mass is not the goal. Spoken exactly: Center of mass belongs also to the power of the engine and the momentary grip level! So You would need different settings of wheelbase for different maps! So thanks god, it is good, that we have a driver on the bike, who can change that with his body position!

 

[Tuner]

The location of the center of gravity (and therefore the weight distribution) is one of the biggest compromises in vehicle dynamics. Front to back determines the static weight distribution and the height determines the dynamic distribution due to weight transfer during acceleration and braking. For example, if the assumption is that the bike/track will generate good traction you'd generally want a lower CG to reduce excessive wheelieing (both accel and nose wheelies). If traction is assumed to be limited you'd want a higher CG in order to generate greater weight transfer (front and rear) to help traction during accel and braking. Of course there's everything in between as well. CG height also influences how easily the bike leans (Roll) into a corner. Front to back distribution affects the cornering and straight line balance of the bike. Does the bike oversteer or understeer, have a "light" front end etc. The ease by which a bike rotates about the CG (pitches, yaws, rolls) has more to do with how the weight is distributed about (the distance from) the CG than the exact CG location. The more weight that can be "located" closer to the CG the easier it is to pitch/yaw/roll. This isn't always desirable as some Yamaha critics will claim that the "mass centralization" went too far and that's why that bike (the 450YZF) tends to endo far too easily as the front pitches down. The CG also affects how the rear suspension "squats" or "jacks" due to chain torque and chassis kinematics. Both being dynamic phenomenon and largely influenced again by the bikes power and available traction. This is one area of vehicle dynamics where the Alta is very different from an ICE bike. "The Alta's power (and related traction) is smooth, continuous and seamless without the huge swings in torque/traction" that an ICE bike generates at every shift. Therefore, the Alta should be much more "settled" in the rear (establishing a relatively stable attitude) during acceleration everything else being equal (which we know is never the case). Just some food for thought.

The above statement in bold is not 100% accurate. "Huge Swings In Traction" is indeed a stumbling block regarding the Alta. The lack of rotating mass as compared to that of a gas motorcycle is often cause for huge traction swings in less than perfect traction conditions (aka off-road). These traction variations can and often do upset the chassis.
FYI: Back to back testing with various combinations of rotating mass netted a 4% reduction in lap times @ Glen Helen. In addition, the constant torque below 6500 motor rpm,
and the near constant power output above the 6500 rpm threshold, strongly influences optimum overall gear reduction and map selection. Like most anything else, the Alta as delivered is a compromise that can and should be fine tuned for the application.

 

[Philip]

The disruptions of traction due to shifting on the ICE bike happen 1-3 times on each straightaway and last split seconds. In contrast, every time the rear wheel of the Redshift lifts from the ground, it speeds up way faster than the ICE bike's rear wheel. When it lands, it throws a lot of roost, but it does not propel the bike much because the rear wheel's inertia is wasted on throwing the roost, but there is no flywheel whose inertia would add more instantaneous engine torque to launch the bike forward once it regains traction.

I think this is exactly what makes the Redshift so much more predictable and easier to ride.

FYI: Back to back testing with various combinations of rotating mass netted a 4% reduction in lap times @ Glen Helen.

You you mean I can shave off 6 seconds of a lap at Gen Helen with a bigger flywheel?!! How much heavier does it have to be?

 

[Tuner]

The disruptions of traction due to shifting on the ICE bike happen 1-3 times on each straightaway and last split seconds. In contrast, every time the rear wheel of the Redshift lifts from the ground, it speeds up way faster than the ICE bike's rear wheel. When it lands, it throws a lot of roost, but it does not propel the bike much because the rear wheel's inertia is wasted on throwing roost, but there is no flywheel whose inertia would add more instantaneous engine torque to launch the bike forward once it regains traction.

I think this is exactly what makes the Redshift so much more predictable and easier to ride.


You you mean I can shave off 6 seconds of a lap at Gen Helen with a bigger flywheel?!! How much heavier does it have to be?

It's not that simple.
Track conditions, rider preference, rider style, and a host of other variables, including steering geometry and suspension settings all influence what is the "best" setting for the day.
This particular day of testing was with Darryn Durham and it was wet. We did numerous back to backs with multiple Alta's and a 2018 KTM SXF 450. Rotating mass was the only Alta variable. A third party data aquisition system was transferred between motorcycles to insure accuracy.

 

[Tuner]

I should point out that my opinions are primarily based on testing. Often times what made sense in theory failed to apply. It took me the better part of two years with Alta to truly get a handle on how to properly setup and tune our particular electric off-road motorcycle. That said, I was still very much learning at my four year mark just prior to our closing. The truth is, we just barely scratched the surface regarding true potential and understanding.

 

[VINSANITY]

I should point out that my opinions are primarily based on testing. Often times what made sense in theory failed to apply. It took me the better part of two years with Alta to truly get a handle on how to properly setup and tune our particular electric off-road motorcycle. That said, I was still very much learning at my four year mark just prior to our closing. The truth is, we just barely scratched the surface regarding true potential and understanding.

Please keep sharing your experience to me it is very interesting trying to dial in new technology - Alta’s are kind of like late 1970’s motocrossers when they were trying to find the right configurations etc.

 

[ElectricMoto]

I should point out that my opinions are primarily based on testing. Often times what made sense in theory failed to apply. .

Copy that we were in the same position, what looked good in theory sometimes was not the case in reality ( when riding)

 

[Redwolf]

...what looked good in theory sometimes was not the case in reality )

This is true in R&D in any industry. And almost everywhere else in life too.

 

[Butch]

Good stuff. Thanx kids...