New Member, New Project ... would love advice, input, help, encouragement

[3Vz9Ycvx]

Hi everyone. My name is Brett. I live in Los Angeles.

I'm about to embark on a custom, DIY electric bicycle project.

Based on my research so far, I feel fairly confident that Golden Motor products will fill the bill for my project.

I'm going to customize my existing bike to be an eBike.

The bike I have is a GMC Topkick Dual-Suspension Mountain Bike from Amazon.com. More info and specs here: http://www.amazon.com/GMC-Topkick-Dual-Suspension-Mountain-Bike/dp/B000BT4W2C/ref=sr_1_2?ie=UTF8&s=sporting-goods&qid=1264624386&sr=8-2

Basic specs:

    *  Frame: 26-inch full-suspension aluminum MTB frame
    * Fork: Zoom CH-386 suspension fork, 65mm travel
    * Shocks: Kind Shock, adjustable to 650 pounds
    * Chain: KMC Z51
    * Crankset: Alloy ISA 335P, 28/38/48, L170mm
    * Front derailleur: Falcon MF 31 T
    * Rear derailleur: Shimano RD-TZ30GS SIS, 7 speed
    * Shifters: Microshift TS-50 ADII index L3/R7
    * Brake levers: GP 30 AP aluminum
    * Brakes: LCHI DSK-320 disc brakes, 160mm
    * Rims: Alloy black 26 x 1.5 inches
    * Tires: Kenda black with yellow band 700 x 25C
    * Stem: A-head TDS63K-8, EXT: 100mm, 15D
    * Handlebar: HL-MTB 153, W: 600mm, R: 30mm
    * Saddle: Velo, black padded
    * Seat post: Alloy micro-adjust 27.2 x 300mm with quick-release

I'm looking at the Golden Motor Magic Pie kit to do a real-wheel electric motor addition to my bike.

My intended purpose for this project is an eBike I can use for my daily commute to work - 1.2 miles one-way (2.4 miles round trip) - and to commute to the beach - 3.6 miles one-way (7.2 miles round trip).

Based on what I'm learned so far, the General Motor Magic Pie with a decent Lithium Ion battery pack should do the trick.

The GM Magic Pie also appears to be compatible with my bike based on the specs I've seen.

My only initial concern is fitting the Magic Pie to the back wheel with a 7 gear setup. Does anyone know if I'm going to face any problems on that front?

Looks like my existing disc brake plate is compatible with the Magic Pie motor.

Is there anything else I should be considering at this point?

What battery pack should I be considering for my purpose? I want to be able to comfortably do the 7.2 mile round-trip trip to and from the beach.

Thanks for your help, insight, suggestions, encouragement and everything!

Best,

- Brett

[Hardcore]

get the rear Magic Pie kit with 48v 12ah
rack 002
and for the shifter problem, you could also trow another few bucks to get a smaller one.
i can do with alot of winds about 20km easely that's 12,5 miles, should be sufficient enough
for the roundtrips you want to make.

kevin, also check out at goldenmotor the first pic, that's my fully susp. ebike

[3Vz9Ycvx]

Hi Kevin,

Thanks for the advice. Now I gotta dip into the bank account and come up with some $$.

That setup you have is sweet! Nice ride.

For anyone: I've seen many eBikes with the motor mounted on the front wheel.

Is there any difference between a front mounted motor vs. a rear mounted motor? Why would someone choose a front vs. a rear mounted motor?

[Hardcore]

the power can sometimes bent the front fork or rip it off the bike

[3Vz9Ycvx]

Hi Hardcore,

Thanks for the info.

What about a front and rear motor together? Any concern about bent forks or wheels flying off?

[RWD]

I'll speak up for front hubs.

I personally prefer front hub. I like the balance and handling better. Some suggest regen could affect the handling but I have not experienced that at all. But Hardcore is right. The biggest concern is the strength of the front fork dropouts. I'd only consider a front hub if you have some method of strengthing it. Front forks are simply not made for the kind of torque a gm motor produces. My two front hub bikes I chose bikes with solid steel forks and welded reinforced plates. The wheel axle is captured by 1/2" (12mm) thick plates. In fact on my bikes the front wheel nuts can come completely off and the bike will continue to run fine and safe.

The other thing I'm not sure about in your case is a suspension fork. I kind of wonder how a front hub system wlll do since you are introducing torque in a different direction than what the fork was designed.

If interested, here's one of my front hub bike conversions:

http://www.evalbum.com/popupimg.php?16152

[3Vz9Ycvx]

Much thanks for the excellent info on front mounted motors RWD.

Your ride is beautiful, very stylish. Did you do the front end reinforcement work yourself, have someone else do it or did the bike come that way?

[RWD]

Yes, I did the work myself.

What I did was weld a 1/4" plate on each fork dropout with a slot pointed down (like a fork dropout). Then created a smaller size 1/4" plate with a slot upward that screws to that welded plate. The mp washer with the tab rests in this outer plate slot (pointing up). The result is the mp axle is captured on a 1/2" (12mm) surface.

http://www.evalbum.com/popupimg.php?16174

If you don't have access to the equipment to perform this reinforcement and still want a front hub motor, then you can look into some support arms. They look like a coaster brake arm and keep the axle from rotating in the dropout.

[Bikemad]

The biggest concern is the strength of the front fork dropouts. I'd only consider a front hub if you have some method of strengthing it. Front forks are simply not made for the kind of torque a gm motor produces.

The drop-outs on most front forks are not usually subjected to any twisting torque whatsoever from a non-motorised hub, even with disc brakes the braking force is applied through the calliper, not the axle, which is simply used as a pivot. This is why they are prone to failure under the turning force applied directly by the axle due to motor power and regenerative braking.

On a 26" wheel, the force trying to spread the dropouts wide open is around 33 times greater than the pulling/regen braking forces at the tyre. Having measured a stall force of 17.5Kg at the rim of my Magic Pie, I would estimate the actual force applied through the axle trying to spread the dropouts would be at least 500Kg (1100lbs) if the wheel nuts were loose! and that's without the additional forces caused by mechanical braking etc.

I'd expect the total force applied to the the rear lug of the front fork dropout during heavy braking to be pretty big!
So it's no wonder they can't cope.

The other thing I'm not sure about in your case is a suspension fork. I kind of wonder how a front hub system wlll do since you are introducing torque in a different direction than what the fork was designed.

Most suspension forks (especially the type fitted with disc brakes) should be more than capable of taking all forces generated by the motor or regen in addition to their normal loads, but unfortunately, the dropouts may not!

Alan
 

[Hardcore]

one word re-inforce it with whatever you got, welding or whatever just get what you want