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What are good bladed spokes besides sapim for mtb use? What is the name of the bladed wheelsmith spokes? Thanks.
Bladed spokes help.
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Blades
I just built up a pair of disc wheels with Wheelsmith XE-14 elliptical spokes. They are made from a 14/16 butted spoke and they weigh a tiny bit more than CX-rays and a tiny bit less than DT Supercomps. I got them from oddsandendos.com for a good price-basically around half what the CX-rays cost. I have not ridden them yet as I am still waiting on the arrival of my new frame.
I just built up a pair of disc wheels with Wheelsmith XE-14 elliptical spokes. They are made from a 14/16 butted spoke and they weigh a tiny bit more than CX-rays and a tiny bit less than DT Supercomps. I got them from oddsandendos.com for a good price-basically around half what the CX-rays cost. I have not ridden them yet as I am still waiting on the arrival of my new frame.
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So the wheelsmiths are not comparable at all? Id love to use cxrays but my shop does not carry sapim products. I'd really prefer to have the shop build my wheels. What do the aerolites cost per spoke?bhsavery said:
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Why bladed spokes? They do look very cool, but don't they live behind the tire and rim (aerodynamically) and are therefor already in "dirty air" (disturbed air)? Meaning no real benefit.
Also, cant double butted spokes be just as thin?
I'm not raggin, I've just been thinking about these issues and curious about your thoughts.
Mr. P
Also, cant double butted spokes be just as thin?
I'm not raggin, I've just been thinking about these issues and curious about your thoughts.
Mr. P
Blades
Personally I love building with bladed spokes because you can easily see the exact amount of spoke windup you are getting, and then compensate for it. It is very easy to end up with a wheel with no windup built in. Conventional wisdom states that Bladed spokes are stronger than round spokes of equal original dimensions (bladed spokes start life as round spokes) because of the additional cold working used to form the blade section. DT aerolites and Sapim CX-Rays seem very similar in price and weight. It seems like they both originate as 14-17-14 spokes (revos in the DT's case). Is it really true that CX-rays are stronger and/or stiffer than Wheelsmith XE-14s (which start out as a 14-16-14 round spoke). Is Sapims SS alloy better? Or are The CX-Rays perceived to be better because of the higher price.
Personally I love building with bladed spokes because you can easily see the exact amount of spoke windup you are getting, and then compensate for it. It is very easy to end up with a wheel with no windup built in. Conventional wisdom states that Bladed spokes are stronger than round spokes of equal original dimensions (bladed spokes start life as round spokes) because of the additional cold working used to form the blade section. DT aerolites and Sapim CX-Rays seem very similar in price and weight. It seems like they both originate as 14-17-14 spokes (revos in the DT's case). Is it really true that CX-rays are stronger and/or stiffer than Wheelsmith XE-14s (which start out as a 14-16-14 round spoke). Is Sapims SS alloy better? Or are The CX-Rays perceived to be better because of the higher price.
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SAVE your $$, Stay round Yo!
At the speeds that we go on Mountain bikes ~15-20mph, aerodynamics of bladed spokes plays a marginially small roll in the net force resisting foward motion of the bike. Time trial at road bike speed, then we can discuss aero spokes. Not on mtn bikes though.
Thinner spokes will not decrease drag force greatly either as drag on wires is more depentant on speed than any other. OT, but this is one of the reasons why biplanes with wires are a thing of the past, the guy wires had a huge inpact on drag. Only with the advent of Al substructures were planes able to have one wing with internal spares and ribs...I digress.
Drag force increased with the Square on velocity.
Drag Force= 1/2*rho*A*Cd*V^2
Power=~Drag Force* V
Where ,
Rho= air density
Cd= Coeffient of Drag
V= Velocity of moving fluid
A=Cross Sectional Area Normal to fluid velocity
You will get marginal gains at the speed mortals bike at. Along the length of the spoke there is a diminishing return of the impact of a bladded spokes, as you move toward the hub the relative Velocity motion of the spoke in the air is less.
But by all means get them and tell your buddys that they add 10hp to you bike.
EPO
At the speeds that we go on Mountain bikes ~15-20mph, aerodynamics of bladed spokes plays a marginially small roll in the net force resisting foward motion of the bike. Time trial at road bike speed, then we can discuss aero spokes. Not on mtn bikes though.
Thinner spokes will not decrease drag force greatly either as drag on wires is more depentant on speed than any other. OT, but this is one of the reasons why biplanes with wires are a thing of the past, the guy wires had a huge inpact on drag. Only with the advent of Al substructures were planes able to have one wing with internal spares and ribs...I digress.
Drag force increased with the Square on velocity.
Drag Force= 1/2*rho*A*Cd*V^2
Power=~Drag Force* V
Where ,
Rho= air density
Cd= Coeffient of Drag
V= Velocity of moving fluid
A=Cross Sectional Area Normal to fluid velocity
You will get marginal gains at the speed mortals bike at. Along the length of the spoke there is a diminishing return of the impact of a bladded spokes, as you move toward the hub the relative Velocity motion of the spoke in the air is less.
But by all means get them and tell your buddys that they add 10hp to you bike.
EPO
Mr.P said:
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160 Posts
I like your idea of keeping track of wind up, but for double the price I'll use tape.
As for cold working you are right, but all butted spokes are cold worked. But say even if the cold working that creates the blade section strengthens the spoke. It the cold worked section does not extend the weakest part of the spoke, the J bend, were all spokes break.
Keep em round,
EPO
As for cold working you are right, but all butted spokes are cold worked. But say even if the cold working that creates the blade section strengthens the spoke. It the cold worked section does not extend the weakest part of the spoke, the J bend, were all spokes break.
Keep em round,
EPO
barrows said:
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160 Posts
Mechinics of Materials 101
Bladed spokes have the same strength in relation to their total weight. I think you have a misunderstanding of material properies. Unless the spoke is using a different material, heat treatment or secondary material treatement for the specific strength and specific modulus will be the same. If lower elongation of a spoke is needed in the design of the spoke(i.e. wind up), there are to things that can be done: change material properties, or geometery. If the design is using the same material( Round vs Bladed) the only way to increase the strength of the spoke is to add cross sectional area...which is mass.
Deflection Axailly= Force*(Spoke Length)/( Cross Sectional Area * Modulous of Elasticity)
Stress= Force/Area
Stay Round,
EPO
This
Bladed spokes have the same strength in relation to their total weight. I think you have a misunderstanding of material properies. Unless the spoke is using a different material, heat treatment or secondary material treatement for the specific strength and specific modulus will be the same. If lower elongation of a spoke is needed in the design of the spoke(i.e. wind up), there are to things that can be done: change material properties, or geometery. If the design is using the same material( Round vs Bladed) the only way to increase the strength of the spoke is to add cross sectional area...which is mass.
Deflection Axailly= Force*(Spoke Length)/( Cross Sectional Area * Modulous of Elasticity)
Stress= Force/Area
Stay Round,
EPO
This
Leadghost said:
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