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PostPosted: Tue Sep 17, 2013 10:19 am 
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Posts: 20
This seems odd, I've ridden both bikes and own a TMR01. i've tried a propel with mechanical dura ace. its a fine bike in every regard, it handles brakes and goes up hill and it also descends well. the Time machine for me is equally capable, and has in my view, better power transfer. straightline speed is pretty much the same on both. the Bmc has fantastic bump absorbtion as well and can really put the power down on bumpy roads, very well. the giant was a little more skittery, but i think that may well have been down to the tyres which were gatorskins !!!! yuk....

For what it is I have to say the BMC is mechanically complex ( the front brakes are a bit tricky to set up, and adjusting the saddle requires a spanner!). But once up and running, it’s a phenomenal bike. I run mine with dura ace C50's and ultegra, and it flies.


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Posted: Tue Sep 17, 2013 10:19 am 


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PostPosted: Tue Sep 17, 2013 2:06 pm 
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Quick question about the Wind Tunnel testing on those frames... the article doesn't give details, but were these done with or without a rider, and with or without rotating wheels? I'd be very hesitant to take the drag deltas as given without some kind of protocol, especially if these were riderless - maybe this is why BMC pulled their bike?


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PostPosted: Tue Sep 17, 2013 6:14 pm 
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Aero road helmets are already on the list. But no guarantees there, as it's a very complex test.

Protocol: no mannikin. Stock bikes, including all cables/housing/etc. Wheels are normalized, I think we ran a set of Enves in the last two rounds. Wheels are spinning. Saddles removed as that's an item that sees zero wind.

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PostPosted: Tue Sep 17, 2013 6:40 pm 
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So this isn't to discount the VN articles, and isn't intended to start a flame war.....but isn't any testing without a rider on the bike, for all intents and purposes, useless?

That's like F1 teams building a complete aero package and then testing it in the wind tunnel sans front wing. Without the front wing directing air to the rest of the "package" you have a disaster on your hands.

Is it reasonable to assume some manufacturers try to optimize aero in a rear world format (i.e. ya know, with a rider "riding" the bike") while others try to win magazine tests so they can use that in marketing? For the record, I don't own any of these bikes and have no horse in this race (In fact, I own an FM066SL, so I'm essentially a "free agent").

Just a thought.


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PostPosted: Tue Sep 17, 2013 7:44 pm 
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^No not really. If one rider gets on one bike, then gets on the other, and the positioning/setup is almost identical, the bike drag difference should be relative.

Some have done and tried that using a dummy on the bike and compared. We know about 80% of drag is caused by the rider, that is fairly constant, of course that is relative to rider position/setup also.

Also, wheels have an effect etc..so basically all the same components and setup would need to be the same without the rider to give a pretty reliable comparison.

It is absolute? Of course not, but it is something anyway.


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PostPosted: Tue Sep 17, 2013 7:48 pm 
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I'm with fa63 on those ideas. We already have seen and know the testing of the Venge/Foil and a few others.

Makes sense to do the New BMC TMR, Felt AR FRD, S5 and a few others that are widely available in the US. Even the Venge/Foil again.

Also, would like to see stiffness/torsion/rigidity done on the new frames also of the above first part of the latest iterations from Felt/BMC etc..

All that aero is useless if the frame is a noodle like the AR1 and previous aero models from the usual suspects.

Thanks


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PostPosted: Tue Sep 17, 2013 7:52 pm 
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Joined: Wed Aug 14, 2013 9:53 pm
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I have one other request. Would it be possible to post the actual data from A2? Maybe for a fee? Was there a control bike tested both times you went to A2? The gentlemen over at Aerodyne do a fantastic difference keeping the long term deltas to a minimum but with humidity changes in NC you cannot assume that the data from one test is directly comparable to another.


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PostPosted: Tue Sep 17, 2013 9:27 pm 
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Location: florida
VNTech wrote:
I think we'll test the new Felt, S3, BMC (new PR folks, maybe better luck), one other next year. I'm making those lists now. Requests?

Only question remains: do we go with a mannikin or not. I'd prefer to, but we lose the ability to look back at previous tests and compare. Might have to just throw the Propel in again as a benchmark.


Please talk the powers that be into testing 5 bikes this time. The new boys on the block , BMC TMR01 and the Felt AR FRD. Then please bring back the Propel , the S5 and the Foil. I think everyone would love to see how those 5 stack up against each other in the tunnel using the same testing protocol. And yes please use a manikin when testing. Maybe Giant will allow you to borrow their moving version they have. Also I would like to see data with and without bottles. I mean really what do these numbers really mean with no bottles and cages. That's the problem choosing an aero bike using their wind tunnel data. The are all using different protocals. Some with no a manikin, some with a moving manikin, some using bottles, some without bottles, varied wheels, etc.

Those 5 bikes are considered the crème of the crop in the aero road game right now to most. Sure the Venge, the Noah Fast, the G6, etc. are all great bikes but they are a level below those 5 in the tunnel , the lab and on the road.


Last edited by theloper on Wed Sep 18, 2013 12:44 pm, edited 1 time in total.

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PostPosted: Tue Sep 17, 2013 10:25 pm 
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in the interest of not adding too much complication, I'd vote for a lower body mannequin which can generate the meaningful interactions between the legs and the frame. The upper body can't have that much interaction with the bike, and it would require a whole raft of fitting specifications, some of which might not be possible to meet on certain frames (i.e. saddle to stem drop) etc.


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PostPosted: Wed Sep 18, 2013 12:18 am 
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read german tour mag qtr 2013 english edition. they test with a pedaling manequin. their results contradict velo labs results.

control bike was a venge with zipp 808.

bh g6 with 1 watt of benchmark venge
trek 8 watt
bmctmro1 4 watt

the effect of water bottle mounted

bmc suffers the most 3.5 watt penalty
bh 2 watt
trek 1.2 watt

the effect of using a vuka sprint aero bar vs round bars is greater than difference in the tested frames !!

they also test position on the bike. surprising numbers. learn to ride low and gain more speed than spending $$$$$ on a frame

descending position ski 230 watts
in the drops 355 wats
low on the hoods 345 watts
high on the hoods 400 watts

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PostPosted: Wed Sep 18, 2013 3:03 am 
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The aero position seems quite interesting. I saw a test from Bicycling magazine that also confirms 'low on the hood' is a tad more aero than in the drop and I have seen many TT'er goes on break with that position. (Cancellara comes to mind) perhaps this is because when you are low on the hood, your arms are tugged in than in the drop creating less frontal area even though your head sits higher?


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PostPosted: Wed Sep 18, 2013 4:25 am 
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Location: Central USA
VNTech wrote:
Aero road helmets are already on the list. But no guarantees there, as it's a very complex test.

Protocol: no mannikin. Stock bikes, including all cables/housing/etc. Wheels are normalized, I think we ran a set of Enves in the last two rounds. Wheels are spinning. Saddles removed as that's an item that sees zero wind.



In my region, bikes ALWAYS roll along down the road with riders as standard practice.......why don't your wind tunnel tests?


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PostPosted: Wed Sep 18, 2013 9:40 am 
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Because without the rider you get a true appreciation for the differences between the frames. You're removing a massive variable (my body and position is different to yours is different to the next guy, etc) and getting a better reflection of how aero the frame is (or is not).

No need for snide replies tommasini :beerchug:

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PostPosted: Wed Sep 18, 2013 1:38 pm 
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I think the problem for me is that removing the rider shows the theoretical aero benefits that may OR MAY NOT exist in the real world when other factors are brought into the equation. Consequently the results can be highly misleading for someone looking for a faster bike.


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Posted: Wed Sep 18, 2013 1:38 pm 


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PostPosted: Wed Sep 18, 2013 2:13 pm 
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Only way for someone to conclusively answer that question is to take themselves and a pile of bikes and either conduct their own aero tests or get in to a wind tunnel.

As such, I don't see how that procedure is misleading.

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