why do bikes and cycles have spokes which are angled and not perpendicular to the wheel........??

Answer 1

Complicated situation.

2 Basic reasons.
Both apply to each lacing pattern.
And the effects upon each pattern is Opposite in the 2 lacing styles.

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Straight Lace is much,much older---the Original spoke pattern going back to primitive times.

Cross-Laced was invented to overcome the Short Comings of Straight Laced.

Their properties are not "Opposite" by coincidence.
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Straight laced wheels remain subject to Dwell,,,
where Hub/Wheel are allowed to rotate independantly.
So they never actually get "Tight".

It's exact same effect as a Piston/Crankshaft experiences in the proximity of the end of the crank's stroke.
Crank rolls over several degrees of rotation ,,while Piston is Motionless.

Only way a Straight Laced wheel gets Tight enough to use,,is from extreme tension,,,and massive quantity of spokes.
The still does NOT eliminate the Geometry of the Dwell.
It only raises the level of Force required to enact it.

1st drawback is that everytime the Hub rotates inside the wheel,,,to take up that "slack" and begin applying tension to A Primary Spoke,,,
That Slack is passed on the all the succesive spokes in a sequence.
So as the wheel rotates,,,it perpetually is Loosening all the Other spokes.

The Load shifts in a quite wide dynamic range,
From Natural Tension>Rising Load>Peak Load>RELEASE of tension to Beneath Natural Tension>back to natural tension.
Spokes/Wheel/Hub all get literally HAMMERED,,,as the wheel merely rolls along.

Much like the Slide Hammer a Bodyman uses to jerk dents out of a car body "Too Far",,,then follows with a Body Hammer to pound it back IN to correct level.

Which brings us to 2nd drawback of Straight Lacing.
The Tension always pulls directly Outward from the hub.
It wants to pull the hub Apart,Radially.

Ever notice how SMALL the amount of Material is,at a Hub's Spoke Hole.
On the Outer Diameter,,,at Center of Spoke Hole?
SPOOKY small to be pulling directly against.

So,,Straight Lace Pattern has,
*DWELL,which creates a Wide Range Dynamic Loading acting upon All the components.
So wide in fact that it's force Dips Below assembled specs,,,which creates a "Self-Loosening" condition

*Radial Tension lines of force.
This trys to Pull HUB Apart,,,and at it's WEAKEST point.
And trys to Collapse Wheel,,,at It's weakest Point.
Very Little extra support is offered by ANY other spokes,,,
and only a FEW spokes offer any support at all.
And Those Few,,,are Only on ONE SIDE of the Primary Loaded Spoke

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Cross Laced patterns,,,

A)Eliminate the Dwell
They are laid along a tangental line of force.
Any load applied is Directly transfered to anchor points.
There is NO Lag while spoke swings back &forth across Dead Center.

Any Slack which allows Independant Rotation of Wheel &Hub is immediately distributed among Other Spokes.
Versus LOOSENING them,,,as the Straight Lace does.

That also has a BIG implication upon Reliability.
A Cross Laced wheel can Function with a STUPID number of Broken spokes.
3 or 4 times as many than would allow a Straight Laced wheel to collapse.

In even of Damage,,,a Cross Laced wheel Degrades extremely Slowly.
The Decay is intially based upon Material Strength,,,and only after MANY spokes are broken does the effect of Geometry begin to account for further decay,,or failure.

That's important because a SMALL Upgrade in material Specs or Sizing offers a Large jump in Durability,,,,and Safety Factor to accomodate a few broken spokes & remain functional

B)Cross Lacing eliminates Radial Tension

It creates Tangental Tension.

So Instead of pulling Hub APART,,,
it trys to pull Hub TOGETHER.

You'll see that statement almost Universally during any study/explanation of wire spoked wheels.

It sounds Odd,,,most folks just accept it because "The Expert" said so.
Some folks ponder it a bit,,,and get a grasp of it.
But Rare is any actual explanation offered
(*Frankly,,,I havent read any material on wheels in over 30 years....so Maybe Info has become more explicit/Better these days.
BICYCLE Sources have Always been the "Oracle" for Wheel Building Theories & Info.
Anyone who is interested in learning about WireSpokeWheels will find a Mind Boggling wealth of Info on the subject from the Bicycle Folks.
There are NO "Secrets",,regardless how anally Motorcycle people guard wheel building info trying to hold themselves out as "experts" .)

Anyway,,,, The "Holds Hub Together" vs pulling it apart thing..

Easiest way to grasp that difference is to Visualize the comparison of Straight vs Crossed.

Let's use 1 each,,Rim,Hub,Spoke.
Let's assume that the HUB is the weakest link---it will break 1st of the 3 under a given load.

--Straight Laced
Hub is Hanging from Rim by a Spoke.
Rim's Spoke Hole is at 12:oo
Spoke is VERTICAL
Hub's spoke Hole is also at 12:oo

As we apply Load Down on the Hub's Axle,,,
It's easy to Imagine where it will Break.
It's already the Weakest Part in this example.
But ANY part will Break at it's Weakest POINT.

Hub's weak point is that Little,Tiny narrow band of material at the "Top" Outside Diameter of the Spoke Hole.
The Line of Force is pulling DIRECTLY against That.
It's Bound to be pulled apart under enough load.

Cross-laced:
Rim's spoke hole is at 12:oo
But Spoke is LONGER
So HUB's spoke Hole is Rotated OFF Centerline.
Hub's Spoke Hole is at 3:oo(exagerated for illustration)

Ok,,,You can see how the Tension against the Hub's Hole is now pulling almost "Sideways" against the Spoke Hole Flange.
And no longer pulling Directly Outward against the Hole.

It pulls ACROSS the Hub,,versus OUTWARD from the Hub.

Back to Straight Laced---Add some spokes to each side of Primary,Vertical one.
All they do is HELP PULL The Spoke Flange AWAY from the Hub.
Sure,,The LOAD is Split amongst them.
But they are not Only Helping Pull AWAY,,,they are also helping Pull AGAINST the Primary Spoke's Hole.

Picture One on each side of Hub's primary,vertical Hole.
They are pulling to spread Apart from "center",,while Center is being pulled OUTWARD.

CROSS-Laced,,,the Next Spoke is installed in OPPOSITE direction,,,and on OPPOSITE Side of Hub.

So it's 12:00 to 3:00 on Primary Spoke,,,,,,
and as odd as it sounds,,
the "Next Spoke" is at 6:oo on RIM and 9:00 on Hub.

(Wheels are Not physically assembled in that manner)

Every Spoke is installed in Opposite Direction,,,
and on Opposite side of spoke flange---ie; "Inner & Outer Spokes"

When you get back around to the Original "Primary" spoke we started at,,, the 12:oo to 3:oo one....

.....At the Hub ,,the spokes on EACH side of that one are installed Opposite.

They go Through the Spoke Flange in an Opposite Direction,,
and they are angled to the Wheel in Opposite Direction.

If you consider just 2 Spokes,,,next to each other at the Hub,,
They CROSS each other.
One goes Into the Hub from Outside,,,and is Angled UP to the Wheel.
The NEXT one goes thru Hub from Inside,,,and is angled DOWN to the Wheel

Spoke "A" runs from RIM 12:00 to HUB 3:00
Spoke "B" runs from HUB 2:00 to RIM 5:00

You can see that Proceding Clockwise,,,at the HUB Spoke "B" comes First and CROSSES spoke A as it points Downward in opposite direction.

That Crossing of spokes at the 2 adjacent spoke holes in the Flange pulls the Holes TOGETHER under load.

Much like a Cross-Laced SHOE.
Pull on the Shoes strings,,and the holes are drawn together.

Coupled with the more "sideways" pull of the angular spoke,,,this gives a tremendous increase in strength.

The Inner/Outer Stagger of the spoke installation is Also Self Supporting to LATERAL LOADING of the Hub's Spoke Flange.

When it trys to "fold the flange over",,,every-other alternating spoke is holding Back against the flange yielding in that direction.

Which is why most bikes use a radial Spoke Flange with Cross Drilled Holes and Angle-Headed Spokes,,,,rather than "old-fashioned" Cup Flanges with Radial-Drilled Holes and Nail-Headed straight pull spokes.

Cross-lacing has several variations,,,,mostcommon to motorcycles are named such as "CROSS-ONE",,Cross 2,Cross 4,,etc.

That Refers to how many OTHER Spokes each individual spoke Crosses.
More is Better.

The Limitation to the number of "Crosses" is the physical dimensions of the Hub & Rim.

Old Vintage Road Race bikes used HUGE Ceriani ,Fontana,etc Drum Brakes
8"~9" Brake Drum Diameters,,,and THEN the Spoke flange outside of that.
That made for VERY Short Spokes in a 17"~ 18" rim.
Also made it Impossible to angle the spokes as necessary to achieve the Stronger Cross 3~Cross 4 Lacing patterns.

If You ever look at Old Road Race Bikes with the huge front Drum Brakes,,,notice the Spokes/Lacing.
Looks like "something is missing"...like,,,SPOKES.
That's an Illusion bnecause they necessarily have the Least complex Cross pattern,,,,giving the wheel assy a very Thin,Sparse look as far as spokes.
But,,same actual number as any bike,,,and are usually the Largest spokes available,,wire gauge wise.
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There's lots more to the matter.
It's VERY Logical,,,but also complex at same time.
The reassignment of loadings and interactions is quite ingenious.

A Straight Laced wheel will destroy itself in "no time" unless Built "perfect" and highly maintained.
Even Then it's abilities are very limited.
Any Damage,,,and it comes down like a house of cards.

Cross Laced wheels are so strong & "mutually supporting",,,
I've ridden literally 100's of bikes over the years with Spokes LOOSER than when I Intially install spokes on a new-build,,,before Tightening them.

And Owner had BEEN riding them that way.

I've seen 1000's with 2~3~4 spokes Broken,,
A quite a few with 10~12 Spokes broken out of a 36spoke wheel.

Anybody who's worked in a shop any length of time has seen same sort of situations regularly.
It's quite common,,,Especially on small dirt bikes.

As much a testament to Dangerous Poor Maintenance and Stoopidity as that is,,,,
It underscores how much Strength and structural integrity that a Cross Laced wheel has.

Even a Cross-Laced "Blown-Up Garbage"Wheel can still roll down the road.
It will SCARE You off the bike before it collapses.

Try that with a Straight Laced wheel,,,
and Disaster WILL come Sudden and Certain.

The Maner in which each Type fails is roughly comparable to the difference between a Tire Blow-Out vs a Slow Leak.

A Straight Laced wheel is BEAUTIFUL.
It's very elegant and actually becomes a part of aesthetic design.
It can even be a Focal Point.
Especially with a BUNCH of spokes,,they'll catch practically ANYBODY's attention.
They're Premeire in that aspect.
But...that's about the END of their short List of "Pro's",,
while their "CON's" list is an encyclopedia of "everything Bad about Wire Spoke Wheels".

Cross-Lacing yields Strength ,Rigidity,,Durability and all those obvious thing,,reduced maintenance,etc

But it also adds an exponential increase in Safety Factor,,,
particularly in event of external damage.
They are just next to impossible to Collapse even after suffering a severely bent or dented rim.

NOT a full & complete answer,,but I hope it gives an idea of the basics.

*** I'm NOT condemning Straight laced wheels as "Bad" or Dangerous.
Some people actually Ride on them.
I understand the appeal.
If I built a Custom thing,,I'd surely consider them.
But at Least an Awareness of their structural properties is in order,,if not an actual caution of their useage limitations.

Answer 2

There are some ones with straight perpendicular spokes, but they need a lot more spokes to hold up. The angled spokes are better at transmitting power or braking from the hub to the rim of the wheel, because they "pull on" the rim.

Answer 3

I've seen radial spokes before. They make a much stiffer wheel which may not be desirable. Generally, a radially spoked wheel is only going to be in the front. The reason for this and the reason they are not used is probably that they are less effective at countering the torsional affects of acceleration provided by a rear wheel (thus delayed acceleration and loss of energy, perhaps synonymous with turbo lag if you're familiar with sports car engines)..

Answer 4

It's similar to a suspension bridge!

The spokes at the top of the wheel support the axle, it might make more sense knowing this.

The spokes are angled so the weight is distributed ove multiple spokes, instead of one or 2.

Answer 5

in any structure a triangle gives the most strength the spokes at an angle give the wheel a degree or rigidity when at an angle using less material therefore they are lighter

Answer 6

Cross hatching Wire wheels make them stonger! straight lines tend bend! the "X" has wider force area to take shock...