Just Wondering

Chuck T

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My bike is a Boomebike Zeegr S1 dual motor dual battery. Have had this bike about 2 months. I normanlly ride 20 to 50 miles a day. Live in Jacksonville, Florida, I am 83 years old. I ride 4th gear 29.8 mph most of the time. Have had the bike at 36.6 mph in 5th gear on GPS level ground. Asked Addertooth about switching front and rear wheels complete. He asked Why? LOL. At times I get the feeling the front motor has a lot more power then the rear motor. By switching I could find out. Just a feeling. Anybody else opinon welcomed. Would like to find out how fast it would go. If anyone knows how to hack display or controllers let me know.
Oh! Addertooth,Changed rear shock to 750 Pounds. Still to stiff for me. I only weigh 160 pounds. Going to change to street tires to.

Chuck
 
The front and rear motors are both 1Kw. The front motor has less weight over it, and can be more likely to "peel out" under heavy acceleration. This may lead some people to think it is more powerful, but it is not. It is an issue of less weight on the front wheel, which is why on soft surfaces it can spin under heavy throttle. Both motors are equally powerful. If you lean forward over the handlebars, you will see the front wheel-spin is dramatically reduced.

One other factor is that a motor "power rating" (such as 1Kw) is how much Power can be applied to the motor without it becoming too hot (or damaged). If you put a 5kw motor on your bike, it will likely not become any faster. What would make it faster would either be a higher battery voltage, OR, having the motor controller unit (Controller) feed more power to your existing motors. On a stock Zeegr bike, 2Kw (total power both wheels combined) equates to 40 amps of current being pulled from your single battery). This is near the upper limit that battery can safely provide.

Your bike currently has a 48V battery. Generally speaking, getting 32 to 36 MPH out of a "geared hub motor" bike with a 48V battery is considered doing pretty good.

What your bike has in spades, is Torque. With both motors at full throttle, you are producing almost 170 Newton Meters (about 120 foot pounds) of torque. This is much higher than most eBikes. This torque figure is higher than most of the well-known speed bikes (such as the Wired Freedom, eCells, Motor Goat v3). This allows the bike to accelerate more quickly to 30ish MPH than most eBikes. But, there is more to top speed, than simply torque. Torque simply gives you more "grunt" when accelerating. With your high torque, the eBike can run through dry sand or mud at a higher speed than lower torque bikes, you can climb hills with greater ease.

I wrote a small article about changing out the shock. And yes, I started at 750 pounds, but then went to a lighter 650 pounds. I am a bit over 200 pounds. I also suggested a 550 pound spring for riders who were even lighter. What you are shooting for is about 20 percent compression of the spring when you sit on the bike while stationary. The spring stiffness value is NOT 1 to 1 with the weight of the rider and bike. It has a cantilever mechanism which applies pressure to the rear shock. This cantilever mechanism has a "mechanical leverage" to the force applied to the spring. This is why my bike (with a 200ish pound rider) works best with a 650 pound spring. You don't want too soft of a spring, which can "bottom out" when going over a bump. When a spring bottoms out, it can have a "hammer effect" on the pivot joints in the rear suspension. After enough "hammerings" it can cause damage at the pivot joints of the cantilever mechanism.

If you are willing to have a bit less torque, but want more speed, my suggestion is one of the "speed bikes" I mentioned earlier. All three of those bikes will take you to about 40 MPH (The Motor Goat v3 will hit about 45 MPH with a rider of your weight). I have a Goat on order, because (like you) I like the ability to have more speed. However, I know it will have less torque (110 Newton-Meter "Nm" of torque on the Goat).

This answer is fairly authoritative, as I own the same bike as you, and have worked as an engineer for over 4 decades. The key differences between our two bikes are some minor version changes, where your controllers are set a bit hotter than mine.
 

All comments pertain to my bike and what I found out about my bike and equipment.

Ride to stiff, shock only using half of it's stroke. Dealer says it's 1200 pound shock. Order 750 pound shock and installed. 750 shock softer but still only using half of it's stroke. Remove shock and raise and lower rear wheel. Wait a minute this is not good ! Raising the rear wheel it hits the the black plastic case of the back controlller before it uses the full stroke of the shock. I wouldn't worry about the hammer effect on pivot joints over damage to the rear controller. It maybe the lesser of two evils.

The big question now is where do I go from here ? And Ideas welcomed! Chuck
 
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I went with an external coil spring shock. This allowed me to replace the spring with a lighter 650 pound spring when the 750 pound stock spring proved to be stiffer than I liked. As I said earlier, you may prefer a 550 pound spring (just guessing). The 750 pound model is "DNM DV22AR". I bought a cheap shock with a 650 pound donor spring (both 165mm shocks). The donor shock was less than 20 bucks. The original shock was almost $55, but it is a quality shock.

The shock had adjustable compression and rebound. Which gives better opportunities for tuning them for the best performance.

I just walked to my bike and pressed down hard (impulse force) on the seat. The rear wheel was never near the controller box on the downtube from the seat. This is with a 200 plus pound male rider, and a 650 pound mechanical spring. I examined my controller box for any scuffs on the surface. There are none.

I am running 26X4 Innova Hybrid (higher pressure tires which reduce rolling resistance). These are 30 PSI tires, which handle and corner much better than the stock knobby tires. Their profile appears to be the same height as the original tires.

My factory tires were also 26X4 tires, (Chao Yang). I didn't like them. They were 20 PSI. They roared going down the road, and cornering was poor.

Not all shocks are created equal. I dislike "internal spring shocks" for good reason. They lack adjustability for compression. You are stuck with the factory settings. With external coil springs, you can adjust the "pre load" on the spring and make it stiffer or softer, within reasonable limits.

Below is a picture of the shock on the bike. I had to shorten the bushing which shipped with the shock for fitment.
5 On the bike.jpg
 
My bike is a Boomebike Zeegr S1 dual motor dual battery. Have had this bike about 2 months. I normanlly ride 20 to 50 miles a day. Live in Jacksonville, Florida, I am 83 years old. I ride 4th gear 29.8 mph most of the time. Have had the bike at 36.6 mph in 5th gear on GPS level ground. Asked Addertooth about switching front and rear wheels complete. He asked Why? LOL. At times I get the feeling the front motor has a lot more power then the rear motor. By switching I could find out. Just a feeling. Anybody else opinon welcomed. Would like to find out how fast it would go. If anyone knows how to hack display or controllers let me know.
Oh! Addertooth,Changed rear shock to 750 Pounds. Still to stiff for me. I only weigh 160 pounds. Going to change to street tires to.

Chuck
Holy smokes.....83 yrs old and ridin 36mph.....impressive.....I am 71.....I ride in PA 1 for exercise......don't like going over 10mph.....if I want to go any faster.....I drive my RAM truck with a 5.7 Hemi......that sucker can move!
 
Thanks Jerry;

Ex motorcycle drag racer. Late 70's and 80's ran NHRA-IDBA-Dragbike format. Ran the circuit in all three at the same time. 1982 Dragbike and IDBA National champian. Have held over 30 world records during my run. All in gasoline powered bikes. Chuck
 
LOL. Now you know where the purple color comes from !

Picture shows the tire hard up against the controller box. The shock has traveled 1.575 in. below mounting hole. that leaves approx., .101 in. travel to go in the shock. Shock has approx. 1.675 in. total travel.
As you can see in picture ziptie around shaft of shock I'm only getting .675 in. travel on the shock. Either the shock is to stiff or something is stopping the shock from having more travel.
I'm not a engineer, but some thing is stopping the shocks movement.
Ohh., The drag picture is from a 1/8 mile strip not a 1/4 mile.
 

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LOL. Now you know where the purple color comes from !

Picture shows the tire hard up against the controller box. The shock has traveled 1.575 in. below mounting hole. that leaves approx., .101 in. travel to go in the shock. Shock has approx. 1.675 in. total travel.
As you can see in picture ziptie around shaft of shock I'm only getting .675 in. travel on the shock. Either the shock is to stiff or something is stopping the shock from having more travel.
I'm not a engineer, but some thing is stopping the shocks movement.
Ohh., The drag picture is from a 1/8 mile strip not a 1/4 mile.
The Eye to Eye distance on the shock absorber looks a bit short, and I am not talking about due to compression. Even with compression, it should not be that short. You didn't get a 155mm eye to eye length shock did you? These bikes seem to work best with 165 to 170 length.

Odd, your shock has 165mm printed on it, but I would feel tempted to measure it in spite of that sticker.
My picture, above your set is a measured 165mm under no load. Look at the angle of my cantilever system.

EDIT: My bad, I didn't realize you had disconnected the bottom of the shock. I was so focused on the angle of the cantilever arm.
 
Yes, with an internal spring, you can never know when you are hitting spring binding, which will always limit maximum compression.
 
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