Aerodynamics / Aerodynamic Cost / Aero parts

Isn't there a minimum handlebar width UCI rule though?

Oddly, no.
"1.3.009 The bicycle should have handlebars which allow it to be ridden and manoeuvred in any circumstances and in complete safety."

there is for TT base bars

Still no, if you're under UCI regulation. For CTT, it's 35cm regardless of what kind of bars you have.

35mm U shaped carbon wheels (2130g with GP4000s and latex tubes)

or

20mm box section carbon climbing wheels (1520g with Vittoria Cronos)

for Haytor Vale on Sunday? 5.8km @ 6% with a 23kph cross / head wind.

https://veloviewer.com/segment/1618327?referrer=Embed_blog.veloviewer.com

You riding Tester? Also, is there a good online calculator for this kind of thing?

Don't think so, Jan Willem van Schip has been racing on super narrow bars for quite a while.

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You riding Tester?

lol

Also, is there a good online calculator for this kind of thing?

This is as good a first order approximation as anything else. What you don't know is how much C_d.A and C_rr you're adding with the light wheels. However, the gravity bit is easy, and 20km.h^-1 up a 6% gradient takes about 3W.kg^-1, meaning your 610g weight saving is worth just 2W. I don't know the climb, but it's autumn and hill climbs are usually on quiet roads, so the surface could be strewn with whatever the rain drags off the surrounding terrain. I'd stick with GP4000s to be more confident of actually getting to the top with air in the tyres.

It's a road that is fairly sheltered from cross/headwinds up to approximately the 3.3km marker on that link, then the stone wall drops away and you are onto the more exposed moor. The final 1.5km is properly brutal when the when blows, as the shape of the moor funnels the wind straight at you.

It won't be that quiet, especially on a nice day as it's one of two roads onto the Moor. Cattlegrid after the farmshop isn't flush with road, and is on a gradient kick up.

mywindsock is quite good for this -

https://mywindsock.com/segment/1618327/#forecast=1569142800

Looks like 0.5kg difference is worth around 5s and to get that back in aero requires a CDA 0.01 lower or a CRR lower by 0.0005

Nice. Thanks for the data and tips. It’s your club isn’t it Tester? Gonna me marshalling the National HC?

So the 600g is worth 2w or 5s. Does the hive mind think that 35mm wheels and bladed spokes are worth more than that? Tester’s point about durability is making me lean towards the GPs anyway. Might be able to borrow some GP5000s actually... even lower Crr

You're confusing Mid-Devon with Maidenhead & District

Yes. Yes I am.

Yes I am.

You're far from being the first to make that mistake

Regarding the narrow bar setup wouldn't it fail this rule?:

ARTICLE 1.3.008“The rider shall normally assume a sitting position on the bicycle. This position requires that the only points of support are the following: the feet on the pedals, the hands on the handlebars and the seat on the saddle.

So Jan Willem van Schip above ok, the gcn video setup not ok because of forearm contact.

(Not that it seems to be enforced)

http://cyclingtips.com/2019/10/bumpy-frame-smooth-air-the-next-big-thing-in-bike-aerodynamics/

I like the sneaky use at 2016 olympics. The bumps only give benefits at yaw, so I guess on a track bike that would be the only place that works. The moving legs create crosswinds.

I'd bet that sawtooth seat post has more to do with avoiding slip (by engaging with a corresponding detent on the clamp, possibly as simple as using the clamp bolt as a cross pin) at the very high loads experienced on a sprint bike. Last corner can be entered at 70km>h^-1+ sitting down, with a 90kg+ rider. It's hard to get an aero post to stick at the best of times, as Cervelo owners will attest 😐

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or both! or psy-ops....

psy-ops

Yeah, that too. Plenty of history of one of the big nations trying something, finding nothing, but deploying it anyway to force everybody else to waste time checking if there's anything there.

Wouldnt that force them to only be able to change the seatpost height in 1cm increments?

They could use clamping bits with different offsets to get finer resolution. Fiddly but doable.

change the seatpost height in 1cm increments?

You could get around that with some clever mechanism, or you could just accept that 1cm is fine enough resolution given that the rider's height will change by that much from morning to evening.
I always wonder whether people who dial in their tribar reach in 2mm increments ever take the time to have separate 5AM and 7PM set ups 😁

Sawtooths’ses eh? I’ve only ever seen them on the trailing edges to help control the air leaving the surface.

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I’ve only ever seen them on the trailing edges

I think the shape and function are very different between leading edge and trailing edge. Also, all bets are off with F1, half the aero weirdness is about fucking the following car rather than helping your own.

I've also seen them as vortex generators on underbodies to try and seal off the low pressure area under the car. I was all ready to try some on my race car, but the rules got changed to outlaw underbody appendages. I drafted the new rules, so I've only myself to blame.

edit: vortex generator is probably the incorrect term. Turbulence generator, perhaps.

vortex generator is probably the incorrect term. Turbulence generator, perhaps

As far as I understand it, vortex generator is the correct term in the case of trying to create air fences to constrain streamline flows.
If you're trying to delay boundary layer separation, a simple turbulence generator can help (e.g. rough surface texture), but it looks like a vortex generator may be more efficient in this instance too, as it can achieve the same boundary layer extension with less increase in skin drag.

Air fences was definitely the aim. They would particularly have helped on my car, which had rounded sides which virtually begged the air to come in through the side and into the undercar area.

A friend of mine tried them, and claimed that it decreased lift at the rear of the car, although TBH I'm not sure his testing methodology and hardware were accurate enough to repeatedly measure improvements of that magnitude. Anyway, they got banned after I came up with a double diffuser-ish design which was legal at the time, undoubtedly effective and resulted in the much tighter flat floor rules being introduced.