make your own db aero spokes

[jb]

we'd have a bike that the CTC old guard would be proud of - having cost nowt but blisters.

[mattsccm]

I doubt Brucey is advocating it for all occasions. It will work and shoddy workmanship shouldn't be taken into account. Good idea for reproducing the odd spoke if need be.

[AndyK]

we'd have a bike that the CTC old guard would be proud of - having cost nowt but blisters.

I rather think the CTC old guard would be scathing about "aero" spokes however they're created.

[scottg]

I doubt Brucey is advocating it for all occasions. It will work and shoddy workmanship shouldn't be taken into account. Good idea for reproducing the odd spoke if need be.

You just need a quality spokeshave, to make consistent spokes.


https://www.lie-nielsen.com/products/1- ... &node=4091

Factory aero spokes are overpriced fancy rubbish.

[Brucey]

....Ir may well end up light, but won't be (as) strong

it doesn't need to be, away from the joints, so there is plenty of weight to be saved in most PG frames. Tubes very rarely break in the middle which is where DB frames are made thin.
My argument would be that if you thought you had a machining technique that might be up to it, why would you not give it a go?

[LWaB]

The drawing or forging processes that are commonly used for double-butted spokes have advantages with regards to grain structure, particularly for fatigue resistance.

I worry that grinding or filing away metal to make PG spokes into DB spokes might have a similar effect as CNCing vs. forging. Remember all those ‘90s CNCed Al cranks that would break while similar weight forged cranks just kept going? Machined hubs tend to break flanges compared with forged hub shells too.

[cyclop]

Remember the "Smash" adverts?"I took a spoke out ,flattened it with a hammer It was then too long so I cut it and rethreaded it Then I decided to do the whole front wheel, Then I did the back wheel, .What happened to "Smash"by the way?Can you still get it?

[rjb]

Is it worth the effort and risk?. Just replace your broken spoke with any one of the correct length you have available. Don't think the marginal loss in performance will be noticed by the readers of this forum.

[ANTONISH]

I wonder what the most aerodynamic spoke cross section would be ?

[rareposter]

I wonder what the most aerodynamic spoke cross section would be ?

There are loads of studies (of varying accuracy / repeatability) around the place. Consideration of aero in wheels seems to have started around about the Moser Hour Record time (1984) and then the '84 Olympics but it was mostly based on guesswork.

Wind tunnel set-up and design plus how the wheel is measured (alone/as a pair, on/off the ground / rolling/stationary, mounted in a bike or not, does the bike have a rider on it, frame/fork design, yaw angle, tyre width and pressure) will all give wildly varying results.

Computational Fluid Dynamics can do away with a lot of the variables and is cheaper since you don't have to make physical versions of every wheel permutation.

But it's also dependent on rim depth and shape, hub shape and (to a certain extent) how the spokes are mounted in both hub and rim plus number of spokes and spoking pattern.

I worry that grinding or filing away metal to make PG spokes into DB spokes might have a similar effect as CNCing vs. forging.

Oh yeah, you'd wreck the structural integrity of the spokes. Aero spokes are made by pressing round (drawn / extruded) spokes in a die to achieve the required shape (cold-forging), that preserves the grain.

I still suspect that Brucey does actually know all this and is just on a wind-up mission. Mostly because I cant quite believe that anyone would be catastrophically stupid enough to think it's a good idea.

[jb]

I wonder what the most aerodynamic spoke cross section would be ?

Simple, you get a 48 spoke wheel and beat out all the spokes on an anvil until they meet one another thus forming a solid wheel, the perfect aerodynamic shape...

[Brucey]

...., you'd wreck the structural integrity of the spokes.......
I still suspect that Brucey does actually know all this....

yes I do know all that [hence my earlier comment] and no, it isn't a wind up; It is in fact possible to do precision work with an AG, it just takes correct wheel selection and a a bit of practice. For example to my surprise I found that, after some practice, it was possible to consistently remove about 5um from some parts, whilst preserving their flatness and parallelism.
It isn't at all difficult to improve on the drag of boring old round spokes and far from being 'wrecked', the strength reduction should be [at worst] commensurate with the reduction in cross-section.

[KM2]

When an aero spoke is formed, isn’t it manipulated into that shape causing more alignment of crystals and therefore stronger than the round shape it was created from? Would this mean that the thin manipulated material would be stronger than the simple round filed shape of the same dimensions.

[Brucey]

When an aero spoke is formed, isn’t it manipulated into that shape causing more alignment of crystals and therefore stronger than the round shape it was created from? Would this mean that the thin manipulated material would be stronger than the simple round filed shape of the same dimensions.

yes, hence the comments in my original post.

[Cyclothesist]

Lol. It's one of those - just because it's possible doesn't mean it's desirable or even a good idea. It is an hilarious notion though. Someone surely has to make a video of this ideally using a hairdryer drafted diy forge with some judicious beating of a glowing spoke using a claw hammer and a sledgehammer pressed into service as a makeshift anvil. That would realign the grain structure...but likely not the spoke