Bike Anti-Porn - When Things Go Wrong

mavic have been using that trick on Ksyriums for years now I think? Admittedly the non drive ¿side is laced 2x.

Which is not the same at all.

There are many reason, some may be conventional wisdom, but the gist is this; radial allow shorter spokes equal lighter.

anyone able to explain why they do that?

Mavic offer an explanation, and while it is basically right in principle, it is a justification for a design which could be dramatically improved to give an even greater effect on the relevant parameters by simply adding more spokes on the drive side. Equal numbers of spokes both sides is an archaic hangover from the days of dishless rear wheels, for a road wheel designed from scratch there is simply no excuse for anything other than 2:1 lacing.

Understood. I was asking because it was suggested that it was a bad idea to lace radially on the drive side specifically. That being the case it seemed odd for a manufacturer of mavics "renown" for lack of a more accurate word, to utilise that approach on a 500 quid pair of wheels if it was structurally suspect. But if having the non drive laced 2x compensates for the torsional loads on the hub (which 100% radial I'm guessing wouldnt cope well with) that makes more sense.

Understood. I was asking because it was suggested that it was a bad idea to lace radially on the drive side specifically.

Wait, you got it the wrong way round.

the non-driveside is radial, not the driveside.

On Ksyriums?

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ah yeah, got it wrong way round in my go.

as you were.

As ever, I bow before you technically gifted types. However, my Ksyrium SLs give every appearance of being indestructible, it's true they're not the lightest or most aero, but they ain't terrible and they are stiff. Why won't they die (or even go out of true)? The roads around here are shite and they've shrugged off the worst that Portugal, Thailand, Cuba, Slovenia (Strade Bianche central!) and Belgium can throw at them....

they're not the lightest or most aero, but they ain't terrible

Oh, but they are. Have you seen aero tests of Ksyriums? The only wheel which is actually worse is the R-Sys, and I think Mavic must have actually been going all out with that one to make it the worst wheel ever in any category. They're robust as long as you don't let any crap stay in the freewheel, but they're not fast.

Fair enough, I was thinking of a comparison with standard (probably archaic) 3 cross 32s or 36s on box section rims, not with modern carbon or anything specifically designed to be aero. Is there a comparison available? It's simply that after 10 years of heavyish use they won't die.

Is there a comparison available?

Not sure that anybody would bother to test Ksyriums against modern wheels, but the old Roues Artisanales test shows them as much slower than Aksiums or Shimano R500s

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I had a look at photos, it's hard to see as the spoke pattern they use isn't what I'm used to, looks like some unusual thing going on the Ksyrium DS. Don't forget that machine wheels cannot take all patterns either... (they can't cross under for example)

Radial on the NDS is always OK, in theory it makes for a stiffer wheel (shorter spokes, higher tension)

I think it looks fugly (assymetrical spoking can >>>>>) but no doubt there's a blurb about how good it is... or perhaps hard data. (a model somewhere came to the conclusion it didn't perse make for a wheel stiffer in all directions, I can dig that out if you want, hidden on wheel thread) :)

EDIT seems Tester has already explained it all.

http://road.cc/content/news/167898-go-faster-possibly-aero-hump-pocket-aerodynamic-cycling-jersey-upgrade

oh man oh man oh man

My fiancé wants me to wear something like that in bed to stop me sleeping on my back and keeping her awake all night with snoring.

Bloody hell, never seen that before! That's a lot more of an effect than I had thought. Just out of interest, where might a 32/32, box rim non-aero spoke build come on there?

Just out of interest, where might a 32/32, box rim non-aero spoke build come on there?

I've seen some aero tests which use 32 round spokes in Open Pro as a benchmark, IIRC they come out somewhere close to Ksyriums. Ksyriums with zicral spokes really suffer not only from the terrible rim shape but also from the fat spokes, so they're probably even worse on the road than they are in the tunnel due to needing loads of power to rotate.

That's a lot more of an effect than I had thought.

It's at 50km.h^-1, and only 20W between best and worst. It's significant for racing, but if you're just pottering around at 30km.h^-1 it's something you could measure but not notice. Since drag power is proportional to the cube of speed, a 20W difference at 50km.h^-1 is only about 4W at 30km.h^-1

Ah ha, I hadn't thought about it being a cube; that's not nearly as scary! Because I'm bad at maths/lazy, can you tell me what the drag would be from Ksyriums at 30km/h?

About 22% of what it is at 50km.h^-1. It's not quite that simple because the numbers in the table are a weighted average over a range of yaw angles appropriate to an elite TTer doing 50km.h^-1, the weighting would be different if you were only doing 30km.h^-1 because a given amount of crosswind would give a higher yaw angle.

I quite like it, have you seen that their Kickstarter, it was a success... https://www.kickstarter.com/projects/syncbicycles/sync-bicycles

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You are Mr Sync of Sync Bicycles AICMfreesyncbiek.

What's the retail on one of those?

It's basically just one of these but even uglier

http://www.contemporist.com/2015/10/13/you-ride-this-bike-lying-down-and-it-feels-like-youre-flying/?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+contemporist+%28CONTEMPORIST%29