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Re: Aerobar questions Watts Faster [boing] [ In reply to ]
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boing wrote:
Grill wrote:
Ex-cyclist wrote:
Grill wrote:
Ex-cyclist wrote:
General rule of thumb is 60mm above the base bar for good separation.


Interesting rule of thumb as I haven't found this at all.


Care to expand on this? This was pushed out by Felt when they were doing a ton of testing at LSWT.

What have you found and how have you tested it?


I've found that the frame makes a difference, but ultimately rider position trumps all. Testing-wise, I've done many hours with AeroCoach. When I had to replace my Plasma 3 TT (with 30mm spacers), I specifically chose a larger P5 so I could run my pads directly on the basebars (yes I have a lower CdA now, obviously not entirely due to frame/bar selection, but by how much was surprising considering how much time I'd spent getting dialled on the Plasma).

https://www.instagram.com/p/BZiwcNml9MC/


That's interesting I currently ride a Plasma 3 small, with my missile evo extensions at their longest position. Similar to your self to ensure 3cm compliance I went out and brought a 54 P5 to get a bit of extra reach the got a tririg one for it. Because i have invested in 2 Newport sessions in the Plasma I have stuck with it though it is a bit battle scared. As a 172cm short arse I expect really a 51 P5 would be the frame I should be on, but have wondered if stack height via a larger frame is more aero than stack height via an aerobar.

I am hoping I can at least replicate my Plasma fit on the 54 so I can use it for training as the Plasma is set up as 1x which isn't always helpful for longer training rides in the TT position. Otherwise I will have to sell it and try and find a 51 P5 or P3.

Worth asking Xav what he thinks. I picked out the P5 in a 56 for 3cm compliance and got to right around the same CdA as my medium Plasma 3 in a single session. Came out ahead in the second session on the P5, and in the third, where I was no longer limited by 3cm, was way ahead. I suspect that the P2/3/5 performs best with no stack (and the right bars), and there are enough of the team on them to at least have it as a known quantity. If I could do it over, I'd probably only have gone for the P5 in a 54 if there was a compelling reason to run a different bar than the Tulas (as it stands I already struggle to get enough reach out of the 56).
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Re: Aerobar questions Watts Faster [LAI] [ In reply to ]
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LAI wrote:
Grill wrote:
Shambolic wrote:
Well aerodynamically you are better a short frame, low base bar and a tall stack height. Then you have to find the aerobar that accommodates that.

Except I'm not. And I know many people with very low CdAs that aren't either. I don't know where that statement has come from, and I'd argue that guidance akin to fitting a penny farthing isn't where anyone should concentrate their efforts.

To add another point on larger frame less pad spacers: during his time with Felt, Dave Koesel seemed to always recommend the largest frame one could fit on. To me this makes sense, not that aero has to, but the larger and properly shaped bits of the frame seem like they would handle airflow better than a set of spacers.
I'd love to test this, but it seems a little impracticable. Also, reach becomes an issue when adjusting for frame size; especially, if one is trying to make up for 60cm of spacers. However, a flexible bar would allow one to accommodate this issue. Anyone want to loan me their 58 Da?

Careful to overly paraphrase, a UCI legal frame may not be the best option to "buy large" vs. a non-compliant frame. I was on a 54cm DA until the flat stem was available and then swapped to a 56cm with 7cm of pad stack. I'm certain that the 56cm is the faster option vs. a 58cm and ~5cm stack.

-SD
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Re: Aerobar questions Watts Faster [Ex-cyclist] [ In reply to ]
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So I currently have no spacers on my bar with 20mm of headtube spacers on a 80mm -6 deg stem. I feel too upright when climbing but comfortable in the aero position

-17deg 70mm stem would get me into the same position with 4mm less reach with 30mm bar spacers and 5mm of tube spacer

But, the same stem slammed with a 60mm spacer would bring my position up by 25mm.

Would it be more aero or less aero being in a higher position using 60mm spacers? (Generally)I use a 3T Brezza and the pads already have a stack of
30mm from the base bar
Last edited by: MrStealYoKOMs: Apr 15, 19 20:49
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Re: Aerobar questions Watts Faster [ In reply to ]
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take 2 riders, a high yaw and low yaw rider with exact fit coordinates

The high yaw rider may want a "larger frame" (if it's well designed) to help them sail better while the faster rider may want a smaller frame to get more pedestaling between the base bar & elbow pads.

Brian Stover USAT LII
Accelerate3 Coaching
Insta

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Re: Aerobar questions Watts Faster [Ex-cyclist] [ In reply to ]
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As per Heath, general trend with riders I have worked with is extensions slammed to base bar or *lots* of pad stack/separation. If you can't get the 60mm separation, you're better off raising the base bar to make the gap as small as possible.

Tech writer/support on this here site. FIST school instructor and certified bike fitter. Formerly at Diamondback Bikes, LeMond Fitness, FSA, TiCycles, etc.
Coaching and bike fit - http://source-e.net/ Cyclocross blog - https://crosssports.net/ BJJ instruction - https://ballardbjj.com/
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