[Closed] These valve caps? Why yes, yes they are

For those moments where every watt counts.

In which direction is the rounding?

just cut the valves down to the rim after you've pumped them up FFS - Its what the pros do

just cut the valves down to the rim after you’ve pumped them up FFS – Its what the pros do

I had a tubeless valve sort of do that all by itself as the metal bits detached company with the rubber bits as I was trying to re-inflate an annoying slow leak.

The result might have been more aero but it did give my mates a laugh as I stood there with the bare valve stem in my hand in a puddle of sealant.

0.7W at 45kmph - but remember that the top of the wheel is travelling at twice the speed of the bike and air resistance will go up as a square as I recall - so that’s really equivalent to a 300W boost to your hulk-like thigh power.

Proof that People are stupid....

Although... in terms of £ per watt saved, even at the expensive (for a valve cap) price of £14 a pair it's probably not the worst idea.

Wrong way round in pic?
You could make it with gorilla tape.

would it help if there were some spring loaded flaps on them so when the valve had reached the point in its rotation when it was moving backwards relative to the hub - the wings pop out and "paddle" the bike forward?

would it help if there were some spring loaded flaps on them so when the valve had reached the point in its rotation when it was moving backwards relative to the hub – the wings pop out and “paddle” the bike forward?

At the bottom of it's travel the forward motion at the rim is essentially zero doesn't actually ever travel backwards, so no need for this.

Gorilla tape and a bit of folded cardboard however would achieve pretty much identical results aerodynamically.

I've just realised - my habit of leaving the valve caps off (usually because I've lost them) is an aero AND rotating mass saving !

tragic

I'm guessing the market for these is niche. Given wattshop is run by Dan Brigham - who knows more about aero than most* I'm guessing there's something in it though if you are at the pointy end of competition.

*Coached/helped riders to world records and championships. Took on national teams with huub watt bike. Coached the Danish team to victory and a world record after being shunned by BC too.

I’m guessing there’s something in it

0.7W apparently : )

I'd run these on my DJ bike for extra pumping speed. Or I could swap my jeans for tights.

If only they'd have simply fitted 5000TL instead of the TT, they wouldn't have wasted 1.6W per tyre...

Or I could swap my jeans for tights

But something smooth, not your usual fishnets, right?

Fishnets for disrupted airflow, golf ball dimples effect. Worth 2W at 15kph.

There's a tangible benefit to it, unlike tanwall tyres etc

Tanwalls do have a benefit. They identify 'those guys' at a distance.

Heh

What's the rule on aero?

If we're on marginal gains - why no aero bar plugs? Why are saddles not aero underside?

spring loaded flaps

Fnaar.

Don't get me started on £1000 mech arms that save 1w when clean and new. I guess it's no different to weight weenies of the 90s

as I stood there with the bare valve stem in my hand in a puddle of sealant.

Badger?

So, on my Jeffsy, bimbling along at around 12mph, it's probably not worth it?😀

as I stood there with the bare valve stem in my hand in a puddle of sealant

Best double entendre of the thread. 👌

Tanwalls do have a benefit. They identify ‘those guys’ at a distance.

The heros among men?

If only they’d have simply fitted 5000TL instead of the TT, they wouldn’t have wasted 1.6W per tyre…

Or they could have fitted the 5000 clincher with a latex tube and saved 1.2W over the TL... 😉

Or just go tubular?

Do they do a GP5000 tub. The aeroness of the tyre was down to the small amounts of tread they put on. Acts as a trip strip.

At one point the GP4000 clincher found its way onto the front wheel at pro level TTs.

The only way you'll really know how effective the valve caps are is by waiting to see if the UCI ban them.