does tightneing spokes increase air gap & reduce efficiency?

[monster]

does tightneing spokes increase air gap & reduce efficiency?

i noticed that when i take the side plates off my X5 you can't get them back on again untill you loosen the spokes. the out side part streches when the spokes are tight!

 

[Drunkskunk]

the ring is a cast and machined part. its flexability is near zero before it would crack. I doubt the pressre of spokes could stretch the ring uniformly by enough to effect the efficancy.

But if the ring had a hairline crack, it might expand. Or if the spokes were putting tension on the ring unevenly, it might oval, causing it to pinch against the stator.

 

[nathan_jones]

hi mattew,

speaking from working in a cast iron and aluminium foundry for five plus years, attatives are added to cast metal to increase ductility, silica if i remember correctly however. im taking about buildings with structural members spanning in meters not milimeters so IMO its possible, but i design buildings not swiss clocks so mm doesnt count to me

 

[monster]

well i know for a fact that, when i take the side plates off my X5, i can't get them back on again untill i loosen the spokes. the bolt holes just don't line up with the bolts when its under spoke tension.

 

[ElectricEd]

I can accept that. In my experience Crystalyte aluminium castings are a bit like plasticine. I screwed the threaded boss off the sidecover of my 408 by using granny gear. When looking closely at the sheared surfaces, you could see how ductile the material was by the nature of the tearing.
In your case, you can easily get a combined force of 100s of Kgs pulling outward on the flanges of the hub. It is actually the sidecover bolts that do the job of retaining these forces.
The trouble with all of this bike stuff is that it is a fine line between being strong enough for the job and being too damned heavy. Imagine the problems that aircraft designers must have.

 

[Miles]

Whether they are like plasticene or glass, that won't affect the tensile modulus, though.

 

[ElectricEd]

Whether they are like plasticene or glass, that won't affect the tensile modulus, though.

Hmm, but the type of alloy does. Who knows what type of cheapcrapium is alloyed with the aluminium? :wink:

 

[Miles]

Whether they are like plasticene or glass, that won't affect the tensile modulus, though.

Hmm, but the type of alloy does. Who knows what type of cheapcrapium is alloyed with the aluminium? :wink:

True, usually only by a very small amount, though. But, as you say, who knows.....?

 

[michaelplogue]

Would the use of a heat gun on the covers (or just throwing them into the oven beforehand) be sufficienct enough to cause them to expand enough to get the holes to align correctly?

 

[monster]

the holes are out of alignment by about 2-3mm across the diameter of the hub.

 

[michaelplogue]

That seems to be an awful lot. Are all of the holes off by that much?

 

[Drunkskunk]

the holes are out of alignment by about 2-3mm across the diameter of the hub.

3mm off would be a 1 cm diffrence in diameter. That much stretch in the magnet ring, you would think you would have the glue cracking off the ring and dropping magnets. you certianly would probably see gaps and/or cracks opening up between the magnets.

That realy seems like a Lot. I suspect if you don't have a problem with the magnets, then there is something else going on here.

I've been working on, around, or with cast parts for 20 years. Engine blocks, patio furniture, pump housings, tools. the advantage of cast parts is they don't flex, stretch, or deform when compared to other forms of the same base metal, and can be used for things were presision matters.

 

[Mathurin]

Are tires on? Pumping them brick hard makes spokes ping on a wheel that's just been trued.

 

[monster]

my motor and wheel are fine. this is how i thought all X5's were like? this is just an observation from stripping it and working on it about 5 times. if you take both side plates off and then try to put them back on without loosening the spokes. do up a bolt on one side of the plate and the bolt holes on the opposite side will be out of alignment by about 2-3mm. it will only be possible to put two bolts in on the same side, any more you attempt to put in will be at funny angles or not fit.

 

[el_walto]

I made the mistake of not marking my x5 cover before removing it. It needs to be placed back in exactly the same place or the holes will not line up as they are not symmetrical.