Much More Powerful Pie Now!!!

[Sundsvall]

The spokes were delivered by cycle9.com in the US. I’ve sent a request for new spokes and waiting for an answer. I’ll concentrate on my winter bike for now on and mount the CA and the rear tyre. As soon as I’ve got some data I’ll switch the controller to the new one and start experiment on different current limits to see if there’s possible to increase the power on a mini motor.

[Bikemad]

Here they have 3 3/4"

http://www.pitmotoparts.com/product_p/pmwh3.75.htm  Nice gauge too.  Not sure how it will go but you get these onto you rim and you will never have another problem.
]
Ohh and this item qualifies for free shipping.

"Set of 28 spokes with 90 degree Angle."

36 holes and 28 spokes does not match up so well, I think there would be a few gaps in it!

You'd have to buy 2 sets and have 20 spare spokes.

Alan
 

[Leslie]

Here they have 3 3/4"

http://www.pitmotoparts.com/product_p/pmwh3.75.htm  Nice gauge too.  Not sure how it will go but you get these onto you rim and you will never have another problem.
]
Ohh and this item qualifies for free shipping.

"Set of 28 spokes with 90 degree Angle."

36 holes and 28 spokes does not match up so well, I think there would be a few gaps in it!

You'd have to buy 2 sets and have 20 spare spokes.

Alan
 

Oh this is not GM's fault, my bad.  Forgive me again I'm just getting used to these problems.  Im sure GM Canada will supply the right job.

Yes of cause.

Two sets If Peter has problems with counting  ...  20 spares maybe a little overkill?  You can always do with a few spares.  Sometimes you slip a nipple or the thread isnt as tight.

I got 4 spares last time I did a rim, most handy.

Can any one find these fat spokes anywhere else cheaper and free shipping, go a head and post the linksy.  I for one want some spares.

Are these the same gauge GM use Alan?

[Sundsvall]

The problem with these spokes is that they are made for motorbikes and therefore probably is much thicker than bicycle spokes. The rim I intend to mount on the hub have eyelets for 14g spokes and the hub is for 13g spokes so the spokes I ordered are 13g/14g butted spokes. If I choose thicker spokes I have to drill the rim and take away the eyelets which will weaken the rim more than I can take benefit from thicker spokes.

I’ve recently learned that the English word for “eker” is “spoke”, and now I’ve used it extremely much in just a couple of meanings.

Peter

[Bikemad]

If I choose thicker spokes I have to drill the rim and take away the eyelets which will weaken the rim more than I can take benefit from thicker spokes.

Peter,

Take a look at this video, you may find it useful.

Alan
 

[Bikemad]

Are these the same gauge GM use Alan?

They don't give the gauge size, but I suspect they are probably thicker than the GM spokes.

I just took some measurements from the spokes on my kids motorbike:

and they appear to be 3mm diameter, whereas GM spokes are 2.55mm, and the diameter of the nipples that go through the rim are approx 5.8mm instead of GM's 4.5mm.

Alan
 

[Sundsvall]

Motorcycle spokes are from 3 ga to 10 ga (3,3 mm) and GM spokes are 13 ga (2,3 mm). The rim I intend to be a part of my wheel is for 14 ga (2,0 mm) spokes. The difference on the nipples should be similar which means I would have to file the eyelets 0,15 mm. The thickness of the eyelets sheets probably don’t exceed 0,5 mm. I think there would be risky to file on these but the questions are:
Is 2,0 mm spokes enough to handle the torque from the motor? 
Does the difference between 2,3 mm and 2,0 mm matter so much?

The questions will soon be answered as I’ll have my ordered spokes. Cycle9 apologize and make me new ones right away, no need to return the wrong ones. So if anyone is interested I now have 36pcs 197 mm 2,3/2,0 butted spokes.

Thank you Alan for the tips on the film. If I’d saw it earlier I maybe would have been in another opinion and filed the eyelets for straight 2,3 mm spokes.

A much happier Peter than yesterday.

[Bikemad]

Is 2,0 mm spokes enough to handle the torque from the motor?  
Does the difference between 2,3 mm and 2,0 mm matter so much?

Peter,

My Magic Pie has 12 gauge spokes with 13 gauge nipples, but thinner gauge spokes will be more than strong enough to handle the torque from the motor, they will also be more flexible and able to absorb more road shock than a thicker gauge spoke. I would actually prefer to have the thinner spokes for this very reason.

Check out this post for further information.

Bicycle maker Paolo Salvagione discusses how bicycle wheels get their strength.

It's easy to think of the spokes as columns supporting the wheel and helping it retain its shape. But, the "support" that the wheel receives is created by pulling the spokes towards the center of the wheel (tension) rather than pushing out from the center (compression). If you've had the occasion to hold a spoke that was removed from a wheel, you've probably noticed how flimsy it is. You could bend one in half without too much effort. However, if you tried to pull one apart you would not be able to. The "pulling" of the spokes toward the center of the hub is what gives the bicycle wheel its strength.

So just how strong are bicycle wheels?
"Wheels, from what I remember, can hold about 400 times their own weight on a regular basis and they won't collapse until roughly 700 times their own weight, which makes them one of the strongest man-made structures on the planet," explained bicycle maker Paolo Salvagione.

This relates to standard bicycle wheels, so don't expect a heavier hub motor equipped wheel to support 400 times its own weight!

Alan
 

[Sundsvall]

You have a very good point there Alan. If I stop my ordinary bike with disc brakes in a emergency situation the torque on the spokes would probably be higher than the torque made by the motor in acceleration. Correct adjusted spokes are much stronger than we often believe.

I was in a motorcycle accident a couple of years ago, where both the car and the mc had to be towed away. The mc repairman changed the frame, the front fork, the front mudguard, the exhaust-pipe and the handlebar, but the front wheel hadn’t deformed at all. We became amazed on how strong these spoked wheels are.

Peter

[Spacey]

I took my egg shaped wheel to the bike shop to have the Magic Pie put into the rim the original bike came with. They couldn't do it but did say that the spokes need to be crossed rather than vertical if you are putting a lot of power through the wheel.

I've had a few loose spokes already so will be using Loctite on the threads to see if that stops it.

Also my modded (well over 50amps on pull away) GM Controller is still going strong? I think the key is to have the air running over the heatsink. I've done 200 miles on it so far and abused it so much.

[o00scorpion00o]

Hi All,

Yesterday Pat and I went for a long spin, As expected, I left him behind on acceleration and hills, and he left me behind on long level ground. Actually there was around a 2 mile stretch with a slight descent, so naturally he had the advantage! I used just just over 1.2 amps less than Pat. That was over around 16 miles! 

Hills though, no chance!

So, maybe next summer I will do as Leslie suggested, buy a 24 volt 20 amp ping. That will give me between 72-76 volts. I would imagine that would give me close to 40 mph!  I also have the extra space and weight to consider, as I don't like so much weight on the rear rack!

I'm not sure what that will do to efficiency, I expect it to be worse, of course, considering wind resistance! But from reading the sphere forums, I think the Pie motor is most efficient at 48 volts!


Mark

[Bikemad]

Spacey,

If you have the latest Pie, the spokes are not vertical, in a 26" rim they are angled at approx 9 degrees, which is probably 2 times greater than a standard wheel, to take far more torque than even your modded Pie can supply! But I definitely agree that radial spoking (vertical) would not suitable for transmitting large amounts of torque through the wheel. The maximum drive torque that can be transmitted through the wheel would be limited by the front wheel lifting off the ground. If the motor was powerful enough to do this, the new spoke layout should still be able to handle it.



See my original post for more details

On a new wheel, the spokes will generally loosen as they settle themselves in.  If you simply re-tighten them correctly, they should eventually reach a the stage where they are completely settled in, and should then remain correctly tensioned for a long time.

Alan
 

[Spacey]

That's a releif to know. So how tight is tight on these spokes?

I do have about 5mm oscillation in the wheel which. You can feel at high speed.

[MonkeyMagic]

<< Is thanking himself for only ever buying and running cast/solid wheels

bit heavy tho

[Leslie]

I asked the bike shop man to lace a rim with those eyelets and he made me drill em there at the shop. I totaled his rim before I even bought it..

I insisted I use a round file and work them slowly.  Oh well he knew better..  Anyway I found the y pedal video here..  Well it would of worked.