Do We Need Our Own Custom CHINERTOWN Road Frameset ?

[Dareios]

The Zenith's big advantage is that it's basically the only bike Tour ever tested that fully committed to the round bottle. The lower half of the down tube is wide and shaped to direct air around a bottle (and the included very integrated bottle cage that it was also tested with). The bottle mounting section is also recessed to bring the bottle closer to the tube https://www.instagram.com/p/DVso5W7jBjL/. Almost every other bike ever made either ignores the aerodynamic contribution (detriment) of a round bottle, or acknowledges its existence but only half does something about it. In the past I would've been completely for doing it this way, but with the recent proliferation of aero bottles, it's become a slightly harder decision.

Another small thing is that it was tested with padding on the drops of the handlebars. This improves comfort while riding in the drops, but with the right shape, it can also improve aero performance, at least in the tunnel.

I think the Morpheus reppit shares a similar philosophy when it comes to the downtube being shaped around round bottles.

[Dareios]

It's interesting how the Baldiso Zenith, which looks fairly normal aside from certain wonky areas, tested fastest in the tunnel when, from the front profile it looks much wider than the Stromm Raktt (formerly the fastest aero road bike). Weird how aerodynamics works I guess. Wonder if super deep fork and seat tube is unnecessary for good aero performance too, given how well the Zenith performed.

I do think that there is a point of diminishing returns. Also, if only the fork is super deep and the rest of the bike has rather narrow tubes (from a lateral view) I do wonder if it makes the front wheel/fork more vulnerable to crosswinds.
In the rear you have more weight to stabilize the bike more in the wind + if only the fork is really deep crosswinds have also more area to push the bike around at the front vs the whole bike.

But I guess that might also be the effect of getting fork rake/trail wrong (see Factor One and what I've heared also the Winspace M6).

[toxin]

I think the Morpheus reppit shares a similar philosophy when it comes to the downtube being shaped around round bottles.

More than most, but not quite to the same degree as the Zenith. Most bikes with a deep bottom bracket junction and wide down tube have the DT transition almost directly into the BB. This often results in the DT profile being cut off at the widest part of the virtual airfoil where the tangent of the edge of the tube is parallel to the longitudinal axis.
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Where the the Zenith is somewhat unique in that the down tube is wider than the bottom bracket and the tangents of the rear edge point inwards. If you drew the profile for a whole unkammed section of the DT, the bottle would probably be contained fully inside it.
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I do think that there is a point of diminishing returns. Also, if only the fork is super deep and the rest of the bike has rather narrow tubes (from a lateral view) I do wonder if it makes the front wheel/fork more vulnerable to crosswinds.
In the rear you have more weight to stabilize the bike more in the wind + if only the fork is really deep crosswinds have also more area to push the bike around at the front vs the whole bike.

But I guess that might also be the effect of getting fork rake/trail wrong (see Factor One and what I've heared also the Winspace M6).

The theory here could be similar as deep rim vs disc on the rear where putting a disc on the rear increases the total side force on the bike, but it also moves the center of pressure rearward behind the steering axis, reducing wind-induced steering moments and improving steering stability.

This could be taken a step further with the Factor One in particular, where the forward offset fork places virtually all of the fork's side area far in front of the steering axis. This could mean the local center of pressure on the fork is moved further forward from the steering axis, giving the same wind-induced side force greater leverage and producing greater steering moments.

This is why my fork has that slightly SL8-esque curve in the leading edge of the upper part of the fork. It's an attempt to move some side area away from the front.

[halflight]

Didn't think that the wide bottle shielding on the Zenith would produce that much watts savings. That's impressive. I still think designing an aero bike around regular round bottles would be better than aero bottles, since it seems most people, even the pros, still use round bottles. They are much more common and cheaper. That's why I partly like the design of the Raktt. Even though it uses bayonet fork, looks very TT-like, the assembly process is pretty standard (BSA, standard handlebars, easy Di2 battery location, etc.).

[toxin]

Well, it's not the whole reason for that result. I'm sure it's still be a very fast bike without that detail, it's just the edge that ekes out the top spot under tour protocol.

Yeah if the goal was the fastest bike for every day use just focus on round bottles. If you're an amateur racer though, you'll be using your own bottles more often than not and aero bottles are some of the best price-to-performance equipment choices.

[Dareios]

The theory here could be similar as deep rim vs disc on the rear where putting a disc on the rear increases the total side force on the bike, but it also moves the center of pressure rearward behind the steering axis, reducing wind-induced steering moments and improving steering stability.

This could be taken a step further with the Factor One in particular, where the forward offset fork places virtually all of the fork's side area far in front of the steering axis. This could mean the local center of pressure on the fork is moved further forward from the steering axis, giving the same wind-induced side force greater leverage and producing greater steering moments.

This is why my fork has that slightly SL8-esque curve in the leading edge of the upper part of the fork. It's an attempt to move some side area away from the front.

Yes, to me this sounds logical. I do wonder if the Stromm Raktt is more balanced than the Factor One when it comes to crosswinds. Yes, there is a deep fork and a not so deep downtube, but compared to the Factor One the fork clearly less far ahead of the steering axis. + the really deep upper part of the seattube might balance things out, more total side force, but more rearward center of pressure.