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Locutus
09-24-2008, 02:46 PM
Brad,

I've been giving this some thought and came to the conclusion that the Delta Runner might be the best platform for what I have in mind, but maybe the Load runner would be better, I'm not sure. What do you think?:

My idea is to mount two, or possibly two PAIRS of disc brakes on the rear axle, with one rear wheel driven by pedal power, and the other driven by a hub motor. The rear frame would need to be configured to mount all that, plus I'd need to mount three or four Optima yellow top batteries either on top or suspended underneath the rear frame (or both), just behind the seat but centered at or slightly forward of the axle, for balance and stability.

The extra braking power is, I believe, necessary for the additional weight of the batteries (perhaps in excess of 200 pounds). The positioning is important not only from a moving stability point of view, but also I wouldn't want the trike to lift the front wheel in the air in the absence of a rider.

So question one, I suppose, is: can the delta runner be easily modified without drastic design changes to accomodate these features? How would you place the electric and braking components if you were doing this?

Secondly, if 26-inch wheels are used, what combination of batteries/voltage and hub motor would be optimal to acheive at least a 35 mph (not kph) top speed, including moderate hill climbs, with a range of at least 30 miles? Would different batteries be better suited than the Optimas?

Third, with all that extra weight, should I use moped wheels and tires, moped brakes and moped-strength frame/axle component rather than those designed for bicycles? If bike components are used, I'm thinking that total rider/trike/battery/motor/etc. weight would be in excess of 400 pounds.

AtomicZombie
09-27-2008, 05:53 PM
I think the DeltaRunner would be the perfect platform for a city safe electric commuter. The frame is rubust enough the way it is to carry 100 extra pounds of battery weight and a motor. You might want to consider a motor like the 1.5HP 24volt scott motor if you plan to drive the rear axle. Running a hub motor through a BMX freehub is going to fail.

You might also consider going with 36 or 48 hole 20 inch wheels for strength, and a slightly lower center of gravity for the higher cornering speeds.

For the battery tray, place 4 foam pucks under the tray to avoid rattling the batteries too much. AGM batteries are not cool with constant jarring.

I now have the CycleBully electric trailer done and it is mounted to Kat's DeltaRunner. I will post photos and videos of the trike taking coners and such soon enough. I don't think I will be able to smoke around the corners at 45KM/Hr, but I think the trike will be fairly stable.

Brad




Brad,

I've been giving this some thought and came to the conclusion that the Delta Runner might be the best platform for what I have in mind, but maybe the Load runner would be better, I'm not sure. What do you think?:

My idea is to mount two, or possibly two PAIRS of disc brakes on the rear axle, with one rear wheel driven by pedal power, and the other driven by a hub motor. The rear frame would need to be configured to mount all that, plus I'd need to mount three or four Optima yellow top batteries either on top or suspended underneath the rear frame (or both), just behind the seat but centered at or slightly forward of the axle, for balance and stability.

The extra braking power is, I believe, necessary for the additional weight of the batteries (perhaps in excess of 200 pounds). The positioning is important not only from a moving stability point of view, but also I wouldn't want the trike to lift the front wheel in the air in the absence of a rider.

So question one, I suppose, is: can the delta runner be easily modified without drastic design changes to accomodate these features? How would you place the electric and braking components if you were doing this?

Secondly, if 26-inch wheels are used, what combination of batteries/voltage and hub motor would be optimal to acheive at least a 35 mph (not kph) top speed, including moderate hill climbs, with a range of at least 30 miles? Would different batteries be better suited than the Optimas?

Third, with all that extra weight, should I use moped wheels and tires, moped brakes and moped-strength frame/axle component rather than those designed for bicycles? If bike components are used, I'm thinking that total rider/trike/battery/motor/etc. weight would be in excess of 400 pounds.

Dave X10
09-27-2008, 07:00 PM
I now have the CycleBully electric trailer done and it is mounted to Kat's DeltaRunner. I will post photos and videos of the trike taking coners and such soon enough.

Brad

Looking forward to seeing those pics!

Locutus
10-01-2008, 03:43 PM
Brad,

I'm not sure I understand why a hub motor wouldn't work well on a rear wheel. I was thinking that If I just attached the hub motor to a fixed axle, that the motor would then force the wheel to spin. Since there would be two rear axles (one for the deraileur and the other for the hub motor), one could spin while the other is fixed. But perhaps I'm missing some important details in my mind?

Perhaps a better idea would be to build the rear as designed, and put a hub motor on the front wheel instead?

I still think I should put at least two disc brakes on the rear axle, though.

I would consider the smaller BMX wheels if I could still achieve the 35 MPH top speed with them. Might be difficult if I use a hub motor. I was thinking that I'd need both the larger diameter wheels and over-volting of the motor to do this. Maybe I could fabricate custom hubs that are both wider and have more spoke holes, and do the same to the wheel rims. That should add lateral strength to the larger diameter wheels. I don't plan to take corners at high speed anyway. My speed requirement is for the straightaways, and I'll be more conservative on the sharper turns.

My latest battery configuration idea is to mount one or two batteries behind the pilot seat, and two under or alongside the seat. This way I could add a passenger-rider seat and footrests as part of the structure holding the batteries in place. The passenger would sit above the battery behind the pilot seat, and rest his feet above the two batteries ajacent to the pilot. This would also have the advantage of moving the center of gravity slightly lower and forward, compared to mounting all the batteries behind the pilot seat, and when there is a passenger riding, he would be able to see over the head of the pilot. All in all a very compact and efficient arrangement, and would still be amenable to adding a weather/aerodynamic shell later.

Thoughts?

TheKid
10-01-2008, 04:38 PM
How would you mount the hub motor to a fixed axle? I could see how it would work with a Lightfoot type of rear, which has dropouts to accomodate normal bike wheels. The answer to the location question is yes, mount the motor on the front wheel. All you have to do is bolt it on the front fork. It's a natural for delta trikes.

AtomicZombie
10-01-2008, 06:11 PM
I think he is talking about this setup...

http://clevercycles.com/blog/nahbs07/nahbs07-Images/1.jpg

The problem is, now the freehub pawls on the hubmotor have to deal with 4 times (or more) constant torque than they were designed for.

If you could only find a decent sprag clutch to somehow mount to the threads, it would be a good idea. The smallest sprag clutch I could locate was almost a thousand bucks.

Brad

darnthedog
10-05-2008, 02:16 AM
The hub motor will not work with a rotating axle. It is meant to be mounted to replace a fixed axle on a bike while spinning the hub. The hub motor would mount to the front wheel but not the rotating axle. For the axle you may want to just mount a separate gear on the other axle and mount a motor with a chain. The motor will free wheel so no free hub is required.
You can see some separate motors on www.evparts.com should you desire to spin the axle instead of mounting the hub motor to the front wheel.

I take part in an electric vehicle discussion board and was going to build an electric car. But due to cost and heath related issues have moved to biking.

Also be aware there may be local regulations on speed limits on bicycles with motors. In some states motorize cycle are not permitted on bicycle paths or roads. Check with your local police department to verify speed limits and such. Electric assist is ok but when you get going over 25 mph some police start to worry. So your 30 to 35 mph may violate the local laws.

Locutus
10-07-2008, 02:16 PM
Since the AZ trikes are non-leaning designs, I've been thinking that bike tires with a flat road-contact cross section, like those used in Worksman tricycles, might be better suited than standard round cross section. This would give the tires a larger contact patch in the upright position. Better for traction and handling if the tires won't be leaning into corners. What are your (AZ Krew) thoughts on this?

jimFPU
10-07-2008, 03:16 PM
The downside is larger contact patch=more friction=more rolling resistance=more work.

AtomicZombie
10-07-2008, 05:13 PM
Wider tires also have less traction.

Brad

John Lewis
10-08-2008, 09:08 PM
I notice the Greenspeed Scorcher trike tyres seem to be flat across the bottom. They are supposed to hve low rolling resistance.

That said, when I wear down the rear tyre to a flat section on the tadpole trike there is noticably more rolling resistance. Obvious when I change the tyre out. Of course there could be other reasons for that.

John Lewis

steamboatm
10-12-2008, 11:19 AM
Wider tires also have less traction.

Brad
Can you elaborate on that I am new this, I thought that wider was better!
Regards,
Gerald

savarin
10-12-2008, 09:53 PM
Can you elaborate on that I am new this, I thought that wider was better!
Regards,
Gerald

The wider the tyre the larger the contact patch.
The total weight of the machine is now spread over a larger area therefore each square inch of contact exerts less pressure on the ground.
Imaging 48 lbs of bike set on 2 skinny tyres, each contact patch is approx 2 square inches so thats 4 square inches total. Each square inch now exerts 12 lbs. of pressure
Now make the wheels bigger say 8"wide, this will give a contact patch of approx 16 square inches, times 2 wheels = 32 square inches.
48 divided by 32 = 1.5 lbs of pressure exerted by each square inch .
The larger the contact patch the more the total weight is spread out allowing the vehicle to almost float over the ground thus lowering the grip.
A skinny wheel in sand grips like hell, a fat wheel in sand floats over the top. (assuming you dont up the revs and wheel spin.)
The opposite is also true, a woman (or man) in stiletto heels exerts a pressure of some tons on that tiny contact patch.

SirJoey
10-12-2008, 09:58 PM
Hmmmm...

Maybe they should use skinny bicycle tires on Funny Cars... :D

http://img185.imageshack.us/img185/9206/signaturehalloweenvr0.jpg

AtomicZombie
10-13-2008, 12:36 AM
I think the idea there is to heat the larger contact surface up and cause more grip as the rubber melts?

I guess if a burn out was not part of the start, a skinny tire would be better if it could take all that force. The traction would certainly be better from a dead stop.


Brad



Hmmmm...

Maybe they should use skinny bicycle tires on Funny Cars... :D

http://img185.imageshack.us/img185/9206/signaturehalloweenvr0.jpg

savarin
10-13-2008, 04:27 AM
The problem with this argument is the large number of variables.
The variables that have to work together are, torque, surface speed of tyre, friction of surface, friction of tyre against surface, pressure per sq" on surface, rolling resistance, weight of vehicle etc etc. All these play a part so unfortunately there is not a straight corelation.
Another large problem is when the surface is loose or slippery.
A small contact patch has less resistance pushing through the soft/slippery stuff, the large contact patch has an enourmouse amount of resistance to overcome to get through this surface to find actual grip which is why car tyres aquaplane on water above a certain speed.
However, a very heavy vehicle will push even a wide tyre through this layer easier.

greenevegiebeast
10-13-2008, 07:07 PM
Hmmmm...

Maybe they should use skinny bicycle tires on Funny Cars... :D

http://img185.imageshack.us/img185/9206/signaturehalloweenvr0.jpg

If you watch a grag race with topfuel dragsters, the tires start off short and wide, uppon exceleration the tire expands it becomes taller and thiner, split seconds after the driver hit the throtle.

ditz
10-16-2008, 07:45 PM
Top Fuel cars run slicks and the tires do get tall and thinner during the burnout and at speed. The faster the tires turn, the larger the dia. of the tire because of centrifical force. The slicks only get large at the starting line if the tires spin. No spin, no centrifical force, so the dia does not increase until the speed of the car increases.

just my thoughts

TheKid
10-16-2008, 07:51 PM
Yes. Slicks are made of very soft rubber, inflated to a low psi when cold. As they spin, the heat expands the air, resulting in the tire inflating higher and narrower, while the psi increases.