The simple solution is measure what you have now, and just repeat.

Far enough that you can slip a credit card all the way around. You don't want a pebble or anything getting jammed in there, but a credit card at the highest point is usually okay. I believe that is the UCI minimum for the P3, but I don't think the rear wheel cutout on the Blade has the internal curvature of the P3 cutout (i.e. the P3 cutout wraps around the wheel looking at the bike sideways, and also around the tire looking from the back), so you might want to go like two credit cards for your Blade.

Herbet is at Eurobike, but I am sure Litespeed tech support answers email.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

This always make for a good chuckle

Think about the air your cutout hits ... , your front brake and cable, fork, headtube, legs, water bottle (if used) all hit this still air first

The air is so turbulent when it hits your seattube, in my eyes, it seems that it matters little, if at all, if you have 3 or 15 cm of spacing

Are you jealous that you can't adjust the spacing relative to the cutout on your Arcole? :)

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

Well, 15cm might make SOME difference, if only because then the wheel would be out of the dropouts. :)

-C

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Any run that doesn't include pooping in someone's front yard is a win.

My problem is that the old tires were 700x20 so the wheel was all the way forward and let me 4 mm from the cutout... now when I changed for michelins 700x23 I had to adjust.

Good tip from the credit card thanks !!!

I was afraid that if for some reason ( bumps for example, torsion ) the tire gets contact with the frame...

Thanks !!!

Luiz

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Luiz Eng

Hey Gary,

Yes the flow is turbulent after it has crossed the first part of your body, but there is always the possibility of "re-attaching" some part of the flow and reducing the size of the low pressure zone aft of the rider.

There are many studies in aeronautics and fluid mechanics dedicated to the theory of flow re-attachment. Look at wing fences and vortex generators on aircraft, all designed to re-energize the flow.

Now how much the cutout of the P3 helps in terms of aerodynamics over a triathlon course, I wouldn't like to speculate. I would suggest that the ability to stay in the aero position longer has a much greater effect. However, the turbulence created by the rotating leading edge of a wheel does have a big effect... one that is reduced by creating a laminar flow over the seat tube that is not as disrupted by the leading edge of the tire. In order to get this effect, you have to get the tire as close to the seat tube as possible.

Gains in minutes? Maybe not... but when you can miss a world championship win or a Kona slot by seconds, I'd say there was an advantage worth taking.

oops, I meant MM

The Arcole has 8 or 9 mm of clearance, so the difference is maybe 6mm of spacing between the Arcole and the P3

I guess I will never win the world championships unless I get that P3

:)

my new Barolo has the same spacing, 8mm

Not jealous, the P3 is OK, but Javelins are much cooler in my opinion - hot rods

its the motor that makes the difference

- gary

Motor makes the difference... I hear ya... :)

I'm not a P3 owner and probably never will be... I figure I have to lose some weight, gain some speed and train a lot harder before it's worth it. I was just trying to say that there is some aerodynamic effect to the cutout... but I promise I'll get off my soapbox...

And the javelin... definitely a hot rod... I'll just sit here drooling and dreaming shall I? :)

If I wanted to get a P3C, I would get one tomorrow

Nice frame, not my kind of geometry

Carbon is nice, and the Barolo has a carbon rear, but I like the "bulletproof" feeling the Arcole gives

It is a bad ass frame, wicked fast and built like a jet fighter

Hello,

Thats an off repeated myth (that because the air is dirty aero doesn't matter). Think about it this way in dirty air the tube still has to push aside air molecules, they are just moving in random directions, but they still must be moved and that takes energy. An aero tube will have to move less molecules a shorter distance. It is true that "still air" takes more energy to move, but its certainly not enough less that it nullifies aero properties. Now of course we can argue the magnitude of benefit from aerotubing in the first place.



Styrrell

I dont think the issue is aero tubing, but space between the cutout

Does 6mm closer to the seattube make the P3 faster than the Arcole?

Who knows, probably makes no difference really.

Hello, How close is a question which probably can't be answered without a windtunnel and a powermeter setup. I remember when the first frames with cutouts came out. At the time the prevailing wisdo was that too close was bad because the wheel would try to pull air inthe space and without room to exit friction would result. Now everyone seems to believe that closer is better.



Styrrell

I doubt you could measure the cutout in a wind tunnel with a powermeter, highly doubtful there is even a detectable difference

When a rider punches a hole through the air, most of that air is moved around the rider, e.g. look at smoke and how it displaces and moves around the sides of the rider, now how much of that smoke actually hits the settube - and then how much does 6mm of a gap matter?

Like I said its a small difference in any. One thing you have to realise is that the smoke in a WT is indicative of how much air is being displaced and moved. When you see the smoke part and stay continuous thats good. When you see the smoke become disrupted, thats bad. In both cases every part of the bike still is cutting through air, just because the smoke is parted before the seat tube doesn't mean that the seatube isn't cutting through air just as dense as the air that was being marked with the smoke. My guess is that from 0 - 10 mm you loose very little aero benefit. I'm still curious if moving to close, without any rubbing causes some power loses.

Styrrell

One reason I am not a fan of horizontal dropouts is the wheel change issue

Many people do not know this, but the Barolo has an option for horizontal dropouts - but why bother, only 6mm closer to the tube, which may or may not increase friction as is

Like shaving your arms, can it be measurably faster?

How could that cause power losses if there's no rubbing?

Personally, I put the wheel on my P3 a little further out than credit card distance. A lot of things flex under power. Even if a wheel doesn't rub on the stand, it may still rub on the road when you're weighting and powering it.

As far as the aerodynamics go, I think the only one around here who has actually tested it in a wind tunnel is Gerard. And I believe he claimed a while back that the wheel needs to be very close.



-- Jens

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Styrrell

Unless you are riding at speeds in excess of 25mph, you should not worry about it.

I know ... And definately I'm not a 25mph guy... but I paid a good amount of money on the frame so I want to take all from it...even if it is 0.0001mph....

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Luiz Eng

Hello, Actually the slower you go the more time you save with a lower CdA.



Styrrell

how about 28 mph

[reply]Hello, Actually the slower you go the more time you save with a lower CdA.



Styrrell[/reply]

Supporting data or opinion?

Hello,



Its neither opinion nor really needs any testing, just simple math equations. I don't have exact numbers at hand but basically a slower rider spends more time riding a certain distance say 112 miles. So if a fast rider and a slow rider both lower their drag an equal amount the slow rider will save more time than the fast rider.



Styrrell

Like LENG I've got the 2005 Blade as well. On Sunday I was riding in some pretty stormy conditions with my racing wheels. Before I left the house , when I was putting on the wheels , I was lining up the back wheel and also decided it would be a wise idea to try to get as close to the frame as possible. I was probably about 3 or 4 c/cards away.

I don't have enough time on the bike and the wheels and in that type of stormy climate to be able to say whether or not the gap had a major effect or not.

One definite observation though , was that the HEDH3Carbons that I was riding on had a dramatic effect in the winds , crosswinds and water on the road.

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