Curious to know what some of the aero experts’ thoughts are for comparing the following front wheels for being the “fastest”, “most aero”??
Parameters=
dont care about tubes or tires or widths, only the aspect of the wheel design itself
dont care about weight of the wheel
typical range of yaw angles found, say for a HIM and an IM
ride length of a HIM and an IM
WHEELS=
Zipp 1080
vs.
HED GT3
vs.
M5 2-spoke (see latest ST cover photo)
vs.
Zipp 808 (FC or non-FC, either way)
vs.
Xentis Mark 4tt or Mark 5tt
vs.
Zipp 404 (FC or non-FC, either way)
Curious because I saw a graph that said the 1080 was faster than a HED3 (but only at certain yaw). Then saw a graph that said 808FC was fastest of all, and so on, and so on, …
The two spoke wheel tests the fastest from what I’ve seen. As a mechanical engineer, I would tell you to stay away from it though. If you want to know why, just draw a force diagram of the wheel at a few different orientations… you’ll see why. Aside from that, the deeper wheel is virtually always going to be faster if you can handle it.
I have multiple depth Hed wheels but generally ride the GT3. I would be putting on your list the Pro tri spoke as well considering how much it is used in the pro peloton and race stage wins it is racking up.
The two spoke wheel tests the fastest from what I’ve seen. As a mechanical engineer, I would tell you to stay away from it though. If you want to know why, just draw a force diagram of the wheel at a few different orientations… you’ll see why. Aside from that, the deeper wheel is virtually always going to be faster if you can handle it.
I had a strong feeling that the M3 2-spoke wheel would “on paper” be the fastest. I don’t disagree with you on the down force load concern. But, I would hope that the company did some research and testing with this in mind. I know that if you hit a bump or curb while the wheel is at certain rotation, there is a greater chance of exceeding the load capacity. Again, I just hope the company took this into consideration.
What are your thoughts on the aero shape of the blades and leading edges of the blades, and the edge line closest to the hub? Would you prefer different airfoil shapes?
I have multiple depth Hed wheels but generally ride the GT3. I would be putting on your list the Pro tri spoke as well considering how much it is used in the pro peloton and race stage wins it is racking up.
I have had a HED 3c years ago, and felt it was fast. However I wasn’t impressed with the quality of the wheel. I like the Pro 3 spoke wheel, so it too could go on the possible fastest wheel list.
AOX 100 from AeroCoach is supposed to be pretty darn fast and it is designed for the TLR 23. Probably one of the better CdA/Crr combos out there. Other choices would be the Enve 7.8. HED 3+ with a Conti SS 20 looks scary fast and might be really good on a wide fork bike like the Speed Concept. Jet 9+ is also pretty fast with the TLR or Super Sonic regardless of frame.
You cannot separate this question from tire selection. You might not be able to separate it from frame selection depending on how precise you want to be.
That said, my money is on an H3+ with a narrow tire such as the Attack or 20mm SS.
AOX 100 from AeroCoach is supposed to be pretty darn fast and it is designed for the TLR 23. Probably one of the better CdA/Crr combos out there.
Just be warned that due to the construction of that wheel (aluminium rim with plastic rim covers which create the 100mm deepness), and the tightness of Corsa TLR sidewalls, which obviously creates a compression effect on the rim (not surprising actually, it has been observed with other shallow wheels and tight road tubeless tires as well), the plastic sidewalls of the wheel might bulge out to the point that it renders the wheel unusable.
When you mount a less tight tire (Turbo Cotton, for instance), you can ride just fine, I’ve already raced a couple of short TTs with that setup.
Aerocoach themselves didn’t offer any solution to this.
When Zipp discontinued the 1080 they released some data comparing the 1080 to the then new 808 FC. According to Zipp the new rim firecrest rim profile was a significant improvement but could not be executed in the 1080 depth because the rim would have been enormously wide and wouldn’t have fit into most bikes. This was of course before anyone was promoting really wide rims and bike manufactures limited frame clearance to narrow rims. In the modern era of discs I wonder if Zipp could revisit the 1080 but I digress. Overall the claim was that because of its toroidal profile the 808FC was faster than the 1080 so the 1080 was killed off.
I have seen graphs which show the 1080 as still being the fastest front wheel but my guess is this is very bike and tire dependent.
Yes, also AeroCoach seemed to be having some supply chain issues. Ordered an AEOX disc wheel for mid April delivery and they sent an email informing me that it would be delayed by a month…A month went by and still no further news so after several attempts managed to get an answer that it would be delayed by two weeks. Then was told it would be two weeks more. then by the end of June (two weeks out from ITU world champs) I had to pull the plug. Went with a HED jet and super happy with that.
On the positive side, they were quick with handling my refund.
The two spoke wheel tests the fastest from what I’ve seen. As a mechanical engineer, I would tell you to stay away from it though. If you want to know why, just draw a force diagram of the wheel at a few different orientations… you’ll see why. Aside from that, the deeper wheel is virtually always going to be faster if you can handle it.
I had a strong feeling that the M3 2-spoke wheel would “on paper” be the fastest. I don’t disagree with you on the down force load concern. But, I would hope that the company did some research and testing with this in mind. I know that if you hit a bump or curb while the wheel is at certain rotation, there is a greater chance of exceeding the load capacity. Again, I just hope the company took this into consideration.
What are your thoughts on the aero shape of the blades and leading edges of the blades, and the edge line closest to the hub? Would you prefer different airfoil shapes?
Thanks for the input.
Thanks an interesting question. We know the exact velocity difference between different points of the spoke/blade relative to other parts, but I think that if you wanted to tune the width and shape you’d need to do fluid flow analysis.
On a side note, I always think it’s funny when people always mention the wind tunnel when it comes to testing bikes and wheels without a rider. Fluid flow analysis via Solidworks or ANSYS is always going to be more accurate. (And cheaper)
When you say fluid flow I assume you mean computational fluid dynamics? Solidworks is definitely not something I would use for that!! Ansys, sure, but $$$$$. Or OpenFOAM, which is free, is what I use!
I wouldn’t go so far as to say cfd will always be more accurate than wind tunnel testing. The models are approximations so there are errors, just like there are measurement and fixturing errors in a tunnel. But it is a great tool to reduce the number of hardware iterations and tunnel time by a whole lot.
The two spoke wheel tests the fastest from what I’ve seen. As a mechanical engineer, I would tell you to stay away from it though. If you want to know why, just draw a force diagram of the wheel at a few different orientations… you’ll see why. Aside from that, the deeper wheel is virtually always going to be faster if you can handle it.
I had a strong feeling that the M3 2-spoke wheel would “on paper” be the fastest. I don’t disagree with you on the down force load concern. But, I would hope that the company did some research and testing with this in mind. I know that if you hit a bump or curb while the wheel is at certain rotation, there is a greater chance of exceeding the load capacity. Again, I just hope the company took this into consideration.
What are your thoughts on the aero shape of the blades and leading edges of the blades, and the edge line closest to the hub? Would you prefer different airfoil shapes?
Thanks for the input.
Thanks an interesting question. We know the exact velocity difference between different points of the spoke/blade relative to other parts, but I think that if you wanted to tune the width and shape you’d need to do fluid flow analysis.
On a side note, I always think it’s funny when people always mention the wind tunnel when it comes to testing bikes and wheels without a rider. Fluid flow analysis via Solidworks or ANSYS is always going to be more accurate. (And cheaper)
You can never claim computer modelling is more accurate than windtunnel testing. Computer modelling provides a way of estimating not measuring a value. The only way to gauge the quality of the modelling estimate is to compare it against real world measurements i.e. windtunnel test data. Modelling may give more reproducible and/or consistent results but the results may also be completely wrong. In summary modelling data always needs to be validated in the tunnel which is why tunnel testing is such a big deal.
The two spoke wheel tests the fastest from what I’ve seen. As a mechanical engineer, I would tell you to stay away from it though. If you want to know why, just draw a force diagram of the wheel at a few different orientations… you’ll see why. Aside from that, the deeper wheel is virtually always going to be faster if you can handle it.
I had a strong feeling that the M3 2-spoke wheel would “on paper” be the fastest. I don’t disagree with you on the down force load concern. But, I would hope that the company did some research and testing with this in mind. I know that if you hit a bump or curb while the wheel is at certain rotation, there is a greater chance of exceeding the load capacity. Again, I just hope the company took this into consideration.
What are your thoughts on the aero shape of the blades and leading edges of the blades, and the edge line closest to the hub? Would you prefer different airfoil shapes?
Thanks for the input.
Thanks an interesting question. We know the exact velocity difference between different points of the spoke/blade relative to other parts, but I think that if you wanted to tune the width and shape you’d need to do fluid flow analysis.
On a side note, I always think it’s funny when people always mention the wind tunnel when it comes to testing bikes and wheels without a rider. Fluid flow analysis via Solidworks or ANSYS is always going to be more accurate. (And cheaper)
You can never claim computer modelling is more accurate than windtunnel testing. Computer modelling provides a way of estimating not measuring a value. The only way to gauge the quality of the modelling estimate is to compare it against real world measurements i.e. windtunnel test data. Modelling may give more reproducible and/or consistent results but the results may also be completely wrong. In summary modelling data always needs to be validated in the tunnel which is why tunnel testing is such a big deal.
A wind tunnel is a means of estimating too. In both cases you’re assuming variables and conditions. Computers run algorithms in both cases. I’m not going to argue with you that it should be validated via a wind tunnel. The more ways you can validate data the better. And I’ve never seen an instance were fluid flow analysis is “completely wrongâ€.
