Aerodynamics / Aerodynamic Cost / Aero parts

That needs at least 27 more LOOK logos

That needs at least 27 more Hong Fu logos

ftfy

That's a Planet X with a load of non-structural fairings bonded on isn't it?

That's a Planet X with a load of non-structural fairings bonded on isn't it?

Yup.

Since the Stealth is up on blocks I should totally start gluing cardboard to it!

MOAR DOWNFARCE!!

The chap in the Tyres thread talking about putting a cheap tub on an old disc had me thinking: Has there been many/any improvements in disc aerodynamics over the last decade?

I'm using a cheap old HED track disc, shod with an expensive tyre for this TT season.
Apart from slightly better aero, crr and stability from a wider track, what can be improved?

Those bottles

No idea. I hope the gainz are massive having just bought a Zipp disc but I'm pretty sure, since the disc is covered so much by the bike, there's not going to be a great deal in it.

Are modern disk Wheels better suited to the modern trend for wider tyres?

Wider ones are. Doubt there's in it much though, probably depends on the frame. Cervelo T/P series shield the rear wheel so well that you're best off sticking a wider tub on a skinny disc.

I quite like the wider gluing area of a wider rim when using 25/28mm tubs. Doubt it really makes a difference. But definitely feels like everything fits better.

Yeah, most of the newer discs allow you to run fatter tyres. Does that translate to faster? Dunno.

Pro Tour teams like to plump for Lightweight discs - a disc that is not lenticular but conical (due to how it's made)- so presumably it is 'fast' because it's stiffness and really light weight trump its shape.
Lenticular is probably the best shape a disc could be if it were a separate body, but like @umop3pisdn says, if a frame shields the wheel well enough, it's shape matters less, and most modern frames shield them pretty well (if not as well as Cervelo).
The way it interacts with the frame is probably where the gains/losses are (and that's also why Zipp discs have [mostly] always been flat - see last paragraph:
http://www.zipp.com/technologies/aerodynamics/boundarylayer.php ).

Lenticular is probably the best shape a disc could be if it were a separate body

Depends on the yaw angle. Flat is likely to be better at ~0° simply because of the smaller projected area. Once you add a bit of crosswind, the lenticular ones can start acting as sails and generate enough lift to make the resultant force on the bicycle act forwards; it's not strictly a free lunch as the other component is a large sideways push which has to be resisted by some slip angle at the tyre, which adds rolling resistance, but that's likely to be worse with a flat disc too, as it will tend to stall much sooner.

You need to lose the ) from the end of your link.

Which lenticular discs will actually fit a T3 though? If you're not at zero yaw then you're not pedalling hard enough.

Pro Tour teams like to plump for Lightweight discs - a disc that is not lenticular but conical (due to how it's made)- so presumably it is 'fast' because it's stiffness and really light weight trump its shape.

I wouldn't rely on a lot of ProTour teams or riders to have much science to back that choice. 90% of riders in a TT stage treat it as a semi-rest day anyway.

Agreed, so most things considered, if I could only have one, I'd probably go lenticular.
Head-on shot of the Lightweight Conicalbahn (20mm at the brake track):

1 Attachment

Which lenticular discs will actually fit a T3 though?

Mavic Comete fits, but we were talking about an isolated wheel. In the back of a T3, flat seems to be at least as good.

Thanks, link corrected.

May as well just use disc covers and save yourself £1500. :)

I've heard quite a few of the local TT'rs complain that their oldish TT bike wont take fatter rear tyres. I assumed that was for training Comfort though.

Without buying and seeing if it fits should I go skinnier than 700x24 on my 808FC for short stuff? Anyone got any test data for an 808FC with diff. tyres fitted? Ta