Even Number of Spokes bad???
- Thread starter Mischief7m
- Start date
Yeah strength, rigidity and mass moment of inertia matters and that is basically it for a wheel.
On a related topic, I should try to dig up some pictures of casting defects in OEM and Aftermarket one-piece cast wheels. Only way to avoid such defects completely is to use a 2 (or more) piece construction. The size of the defects in some wheels would make the eyes drop out of your head. They are internal, so you'd never know unless they failed (which they sometimes do!)
On a related topic, I should try to dig up some pictures of casting defects in OEM and Aftermarket one-piece cast wheels. Only way to avoid such defects completely is to use a 2 (or more) piece construction. The size of the defects in some wheels would make the eyes drop out of your head. They are internal, so you'd never know unless they failed (which they sometimes do!)
DeSloth;1021368 said:
thats the nature of casting....especially those from china.
unfortunately, the price of most wheels doesn't allow for radiography or ultrasonic inspection.
adampecush;1021418 said:
Yeah it is an inherent casting issue, but wheels are a particular problem due to the narrow junction where the 'spokes' meet the rim. This junction restricts material flow during solidification and bam - massive internal flaw.
I wouldn't single out any particular country - it can and has happened on OEM wheels from reputable companies manufactured all around the world. Careful modelling and analysis reduces the problem, but you'd never know unless you do as you say and check each and every wheel.
Anyway - sorry to bore everyone with this. I guess it's just something to keep in mind next time you consider bolting cheap wheels onto a car like a supra. Good wheels are expensive for a reason, unfortunately :icon_mad:
DeSloth;1023986 said:
This is probably true....although I have a bit of a bias based upon the work I do (metallurgical failure analysis)
It does sound a bit far fetched, if it did make a difference it would be negligible.
That being said, 5-spokes look a lot better on a Supra than 6-spokes. :icon_bigg
That being said, 5-spokes look a lot better on a Supra than 6-spokes. :icon_bigg
I've never heard that before. A lot of cars in Grand touring ride on multispoke wheels. I don't see how how having an odd or even number of spokes would make a real difference in the perfromance of the car.
theoretically having an odd number of spokes increases strength and longevity of a wheel. i believe this makes sense for someone like us who drive street cars, but a rim constructed of a lightweight alloy with any even number of spokes may be more likely to get dented or damaged
The only thing I can come up with (this is just my spur-of-the-moment theory) is that having spokes directly opposite one another could contribute to flexing and hinder even distribution of loads....but not much. I would be MUCH more concerned with build quality and thorough testing, along with looks. :biglaugh:
In my mind, there's something about NOT having no two spokes parallel to each other that seems like it could be stronger in certain situations.
For example; I'm imagining a four-spoke wheel on a car going around a corner, if you freeze what's going on when all spokes are either perfectly horizontal or perfectly vertical and look at the forces on the rim/wheel on the side of the car facing the outside of the corner, you have the ground pushing the bottom lip of the rim toward the car and the inside of the turn, see the red arrow. Since the lip of the rim is a strong cylinder it will distribute forces to all the other spokes which then transfer force to the axle, holding the car.
Looking from the back of the car in 2-d, shown in the bottom of my picture, the axle serves as a sort of fulcrum ((star)), where the bottom spoke is being pushed toward the car and the rim bends the top spoke(s) outward, away from the car. Its easy to see this on toy cars with loose wheels. push the bottom in, the top will come out a bit. (Don't even factor in suspension we're just looking at the wheel, hub, and road)
Dont laugh, its a quick drawing
Looking at the top circles that represent the view of the outer face of rims with four and five spokes, i colored them to roughly resemble how i see lateral forces being distributed. The red is force toward the car, green is pushing away from it. brighter represents more force.
Neglecting all other forces besides the lateral ones, the 4 spoke rim relies on the top and bottom spokes to hold all the loads, leaving the horizontal spokes to do nothing. In the 5 spoke rim you have more distribution, and no single spoke has to hold 1/2 of the forces being applied and no spoke is left to do nothing.
So in my comparison, i was only comparing 4 and 5-spoke rims. 6 would be better, 10, even more, and so on and so forth.... I dont even know about three...but at the moment I dont think i've ever liked any true 3-spoke designs anyway.
In the general scheme of things though, (I don't have any real idea, remember I'm speculating) I'd say that two rims manufactured to the same standards using similar materials will be similarly strong. comparing them exactly seems like comparing apples and oranges unless the rim with more spokes also has thinner spokes....in which case you're still testing how well forces are distributed. More spokes would be better, even or odd. The only case that might be weaker seems to be 4-spoke rims and that probably isn't an issue unless they're made poorly....in which case it wouldnt matter how many spokes you have.
In my mind, there's something about NOT having no two spokes parallel to each other that seems like it could be stronger in certain situations.
For example; I'm imagining a four-spoke wheel on a car going around a corner, if you freeze what's going on when all spokes are either perfectly horizontal or perfectly vertical and look at the forces on the rim/wheel on the side of the car facing the outside of the corner, you have the ground pushing the bottom lip of the rim toward the car and the inside of the turn, see the red arrow. Since the lip of the rim is a strong cylinder it will distribute forces to all the other spokes which then transfer force to the axle, holding the car.
Looking from the back of the car in 2-d, shown in the bottom of my picture, the axle serves as a sort of fulcrum ((star)), where the bottom spoke is being pushed toward the car and the rim bends the top spoke(s) outward, away from the car. Its easy to see this on toy cars with loose wheels. push the bottom in, the top will come out a bit. (Don't even factor in suspension we're just looking at the wheel, hub, and road)
Dont laugh, its a quick drawing
Looking at the top circles that represent the view of the outer face of rims with four and five spokes, i colored them to roughly resemble how i see lateral forces being distributed. The red is force toward the car, green is pushing away from it. brighter represents more force.
Neglecting all other forces besides the lateral ones, the 4 spoke rim relies on the top and bottom spokes to hold all the loads, leaving the horizontal spokes to do nothing. In the 5 spoke rim you have more distribution, and no single spoke has to hold 1/2 of the forces being applied and no spoke is left to do nothing.
So in my comparison, i was only comparing 4 and 5-spoke rims. 6 would be better, 10, even more, and so on and so forth.... I dont even know about three...but at the moment I dont think i've ever liked any true 3-spoke designs anyway.
In the general scheme of things though, (I don't have any real idea, remember I'm speculating) I'd say that two rims manufactured to the same standards using similar materials will be similarly strong. comparing them exactly seems like comparing apples and oranges unless the rim with more spokes also has thinner spokes....in which case you're still testing how well forces are distributed. More spokes would be better, even or odd. The only case that might be weaker seems to be 4-spoke rims and that probably isn't an issue unless they're made poorly....in which case it wouldnt matter how many spokes you have.
IJ.;1025021 said:LOL nice theory Fig but how would it provide a "performance advantage" ??
It wouldn't?
no...i was just bored and wanted to throw out a theory for the only comprehensible and slightly reasonable reason for anyone to say odd spokes are better. no performance advantage. never thought there could be unless one is more aerodynamic than the next.