Are FLO wheels really this slow...??

[tiltmaniac]

As for trying, at least they're cheap

I have a box/packet already, actually, I'm just too "lazy" to swap wheels and try them.

They have enough stiction that I don't think they flutter much, at least when new. OTOH, because they don't have a hard-stop, they also can't provide (much) lift (which requires side forces to translate sideways force to forward).

 

[benphyr]

...They have enough stiction that I don't think they flutter much, at least when new. OTOH, because they don't have a hard-stop, they also can't provide (much) lift (which requires side forces to translate sideways force to forward).

Good to know about the low flutter.

If the spoke fins are bilaterally symetric then they would not be providing lift but would be causing least drag but if they are providing lift then they are going to produce more drag it seems to me.

 

[bladderhead]

Last milennium I was on my Claud Butler going downhill and a big lorry overtook. The type that has a container and another container on a trailer. Ground wave? You have no IDEA! Big steer on the front wheel. I was between the lorry and the trailer. Somehow I stayed upright and did not use the brakes and steered off to the side. Scariest thing that ever happened to me. Thought I saw the Grim Reaper sitting on the towbar. When did they invent disk wheels? Had I had a disk wheel I would have been his.

 

[ed72]

I had a British Made touring bike from the 70's and toured all over that Island. The Lorries and cars seem to come very close to you over there or at least that was my memory. The confidence of youth, I remember riding in the rain with big truck tires seemingly right at my right ear. I beat the following into my head, "Stay left, look right" especially on those double roundabouts.

 

[bladderhead]

I have never ridden in those places where they go on the wrong side of the road. Must be scary. If I go on a biking holiday it will be to Australia.

 

[Balor]

When did they invent disk wheels?

I'm reasonably sure that first wheels were actually disk wheels:

But I daresay aerodynamics was not a goal

 

[bladderhead]

No ground wave from a horse and cart.

 

[ed72]

Weather is horrible and I caught my better halve's cold, so, no more testing for now.

I am reluctant to put data out there because the error bars are high. For example, the Giro Vanquish helmet is faster for me than the Bell Star but more importantly, it cools my head better.

No ground wave from a horse and cart.

I had an Amish farmer race me with his horse(s) and buggy. I think one of the horses was breaking some serious wind.

 

[ed72]

It may not be interesting but I did a 10 mile up and 10 mile down along the river one day on 125 watts using my Giro Vanquish helmet, fast wheels and 23mm Continential Supersonic tires, and a race cut jersey. The next day (similar temps. and humidty) I used my Bell Star helmet with big mirror, a club fit jersey, older 404 wheels with puffy 25mm GP4000sii tires. Almost the identical speed took me 160 watts. Wind was light but different direction both days but up and back along a curved route should somewhat average the effect. The difference from one day to the next was very noticeable. I stopped to check if I was getting a flat or if the brake was rubbing.

I had also performed an up and down the river on the FLO60 front and then the 2-Spoke front. There was no wind an very low traffic, the 2-spoke was a little faster but nothing to get too excited about. On the next day, there was a mild crosswind up and down with more traffic. I used the same kit. The only difference was using the 2-spoke front wheel. It only took me 116 watts to average 21.5 mph in one direction (down) and 128 watts for 21.1 the other direction (up), which I partially attribute to the sail effect on the rear covered wheel and the 2-spoke front. These are by a good amount the lowest power levels that I have needed for those speeds on that route. It really felt like I was floating. I do this route at least 10 times per week and sometimes 6x in one day.

I guess that Mr. Hambini is onto something with his turbulent wind tunnel testing; however, it is pretty hard to duplicate or measure on the road despite having one up and back along my 10 mile river stretch that was my lowest power to date by far. In perspective, it means only 6-7 watts less to go 21.3 mph average but imputed to Time Trial Speeds, it is about 0.88 mph or 20 watts. This isn't quite as bad as Hambini's results but his testing was at 50km/h and I was only doing 47km/h on my TTs. My other data point suggesting he is correct WRT FLO is my personal best 10 mile TT on the FLO front is 20:43. I did a 20:44 using the 2-spoke with a slower rear wheel and a basic normal jersey and no arm coverings on a much cooler and drier day (power difference was only 1 watt lower with the 2-spoke....I'd call it a tie) Chung field testing also showed the 2-spoke to be faster.

I am 100% convinced (for me) the 2-spoke is faster than the FLO60 but I am also convinced that the advantage varies considerably due to external wind conditions.

If I were in the market for a spoked set of wheels, I'd probably look at the Yoeleo or Zipps given his testing results showing they are 30-35 watts faster than the FLO60 at 50km/h. I suspect he is close to being correct but can't be conclusive.

I know which wheel is going with me to Borrego Springs.

 

[bladderhead]

I think one of the horses was breaking some serious wind

Worse than rolling coal.

 

[ed72]

Worse than rolling coal.

He gave me a pretty good race. I dropped him but he almost got me on the climb. The PA amish country is rolling

 

[bladderhead]

Maybe if the horses had rocked from side to side they would have got more power. Can you put a power meter on a horse?

Sorry, that is for the other forum.

 

[LarryOz]

If I were in the market for a spoked set of wheels, I'd probably look at the Yoeleo or Zipps given his testing results showing they are 30-35 watts faster than the FLO60 at 50km/h. I suspect he is close to being correct but can't be conclusive.

Wow 30-35 watts is a lot of power (to either gain or loose). I have a set of FLO's that I am just mounting tubeless tires on. I will have to test them out against my Boyd set, and my Rolf set and see what I can find.

 

[ed72]

1 HP = 750 watts on horse 1

2 horses but the second one was named, Jimmy, and he was anemic.

I had the aero on them but that little buggy was fast up the hill. I kept looking in my mirror.....those poor beasts were getting a good flogging

 

[ed72]

Wow 30-35 watts is a lot of power (to either gain or loose). I have a set of FLO's that I am just mounting tubeless tires on. I will have to test them out against my Boyd set, and my Rolf set and see what I can find.

The theoretical difference is mindblowing. Is it real? How to measure? It was only 5-6 watts at 30km/h per Hambini but that is still significant. What is interesting is the Enve 7.8 performance near the best of the best. In low yaw, static wind tunnel conditions, the Enve does not do that great but many riders hold it in high esteem and one of the Triathalon mags tested it against the 2spoke. Anyway, Hambini's results for the Enve matched rider's opinion of the wheel. Another reason I think he is onto something is how Zipp has been moving away from wide rims and getting narrower. They have not said why.

My limited testing between the FLO 60 and 2 spoke wheel was only changing the front wheel but everything else was constant. I was going to buy the Zipp 858 NSW with the shark fin trailing edges but it was a lot of money and it had mixed reviews. The 2-spoke has a NACA foil profile design and I could at least find rider reports on it. I don't think it will be sufficient to get me from 20:43 to below 20 minutes but I suspect it is at least 30 seconds quicker under the right conditions (say....65-80 seconds on a 40km TT). I am mostly looking for better stability in rolling, windy terrain like in Brittany, France. High yaw conditions. Being a big guy, I get going very fast in rolling terrain and wind throws me. I could downgrade my rim depth and that is certainly an option.

I am skeptical of Hambini's results but it sort of makes sense if you think of the laminar flow across the rim and how it can become detached with disturbances, especially if a rider moves the front wheel around a lot and vehicular traffic is high. A wind tunnel or Chung field testing does not simulate these conditions. My 10 mile up and down the river might be a good test if I have the discipline to do it. Maybe 10 or 20 runs with each set of wheels with identical gear and kit. Just the difference in wheels. Same tires. Try to hold a steady modest wattage for each run, say 180 watts.

I am thinking of selling my FLO60 carbon wheelset but am not quite to that point, yet. The final proof for me will be TT times.

30 watts is huge. I am still gobsmacked not sure what to make of it.

 

[Balor]

I am very confused as to why wind should "throw" you more at *your* high speeds - its speed is unchanged after all!
... unless, of course, it is really "negative aeroynamic trail" at work.
Here comes one of my crazier ideas - do you, by chance, have a disk or a high-profile front wheel you can fit into your bent with fork reversed for negative offset?
Of course it would be not be an "apples to apples" comparison - you'll get massively increased trail and flop, but if you do a few comparative tests with a low-profile and high profile rims in that configuration, you may may glean some potentialdy useful insights - like, say, eventually ordering a custom carbon bent with custom (disk, of course) forks and steering angle close to 90 deg.

 

[ed72]

I got all my slippery Sunday go to meetin full kit clothes on and did up and down the river trials. I planned to do 6 x20 hard but after the first effort, it was clear that I am still sick. So, I putzed up and down comparing two different front wheels with no other changes. I held the same position and only moved my hands off to drink. Wheel A vs Wheel B. The one that made the whosh whosh turbine noise seemed to have a motor on it. I kept looking behind me to see if a buddy was pushin me. Wicked bizarre to soft pedal at 19 mph. I must have a broke power meter or somethin.

 

[ed72]

I am very confused as to why wind should "throw" you more at *your* high speeds - its speed is unchanged after all!
... unless, of course, it is really "negative aeroynamic trail" at work.
Here comes one of my crazier ideas - do you, by chance, have a disk or a high-profile front wheel you can fit into your bent with fork reversed for negative offset?
Of course it would be not be an "apples to apples" comparison - you'll get massively increased trail and flop, but if you do a few comparative tests with a low-profile and high profile rims in that configuration, you may may glean some potentialdy useful insights - like, say, eventually ordering a custom carbon bent with custom (disk, of course) forks and steering angle close to 90 deg.

I am not going to pretend to have a degree in aeronautics and fluid mechanics stuff was a long, long time ago.

The forces on the front wheel and tire at 30-35 mph is quite a lot different than at 20 mph. The effective yaw angles are significantly different, too. At higher speed, the yaw angles are always lower than at lower speeds with the same wind (obviously). When the laminar flow on each side of the rim has a detachment at one side, one side is at a higher pressure and the other at a lower pressure. The delta between one side of the rim and is much higher at higher speeds during flow detachment. This delta creates a torque on the wheel and into the bars. It is not that air flow does not detach over the wheels at slow speed, in fact it is more likely, it is just that the force differential is much higher at higher speed.

When the flow over and around the front wheel detaches, the lateral force felt into the handlebars is like an order of magnitude higher at 30-35 mph than at 20 mph as my feeble minded brain tried to reason out. Reminds me of messing around as a kid sticking my hand out the car window and taking it from.... a knife shape and looping it around on the highway but not really the best way to explain. On the slow side roads, the level of excitement just wasn;t there

 

[Balor]

It is not that air flow does not detach over the wheels at slow speed, in fact it is more likely, it is just that the force differential is much higher at higher speed.

Well, but why? Obviously, due to wheel offset, otherwise you'll be getting uniform pressure.
One way to do it is to center the wheel's CoP along it's steering axis - zero offset. Quite doable with steering angle of about 80 and has it's own merits( minimised steering inertia, for instance).
But with small-ish negative offset you will be getting steering input, but the input is going to return the bars into 'straight ahead' position instead of vice versa. I've ridden about in 15 mph side wind with a front 700c disk just for the purpose of testing (no very high speeds of yet, unfortunately) and only time I've felt steering input is when I've hit an amplified wind gust directly from the size (gap between two buildigns), and it wasn't bad at all... and felt like the input was INTO the wind inspite of negative offset - but it might have to do that CoP of MBB bikes is already quite a bit ahead of steering axis due to legs + transmission sticking out, so I might have been worse off without it actually.

I suspect that my nose cone project (CFD show that it cuts drag roughly by half, fact corroborated by a few data points of evidence concerning Zziper fairings) will be much more well-behaved with a front wheel disk.

 

[ed72]

Air will detach at 10-15 degrees yaw depending upon the wheel rim and tire and also fork design because it is really all one system. Lower bike speeds into the same wind vector will give higher yaw angles than the same wind vector at higher bike speeds. If the tire is larger than the rim, detachment is at lower angles than with a more smooth transition between tire and rim. The best transition is to have a rim slightly wider rim than the tire from an aero perspective anyway. Realize none of this applies to 20-25 km/h for Jan fanboys.

GL with the cone project. I forget if I wrote but my little handlebar bag for randonneuring on my upright lowered my drag. I would not go too big but I am sure you know what to do.

Do you know anything about sailing or sail effects? I am struggling to understand why I seemingly needed so little power at 19 mph with the 2-spoke when going into a cross/headwind. I barely needed to pedal or so it seemed. I was wearing the clothing and wheels intended for the 12H Borrego Springs UMCA Worlds in later October. So, everything was already very low drag and low frictional losses. My best tires, etc. The only other explanation is a wonky power meter but on say 0.5% downhills, I did feel like I was not putting any force into the pedals and on completely flat, it felt like I was soft pedaling. When I turned around to go back down the river and with a tailwind, the power levels were "normal" to my eyes and legs......this is the only reason I am not sure if this observed effect is a power meter issue.

If you look at the efficiency chart in the attached link, Bram is showing an unusual test. He seems to have the wheels spun to a certain RPM. Then he applies a 90 degree cross wind. He counts the ramp time. I am not sure I understand his test. But. The disc wheel is 8 seconds better than the standard 36 hole round spoke wheel; however, the 2-spoke is 32 seconds better than the standard wheel. Thus, the 2-spoke is 4 times better than the disc. We know that disc wheels can provide forward thrust in side winds due to the sailing effect. This seems to show the 2-spoke provides 4 times the thrust of a disc in the right conditions. My Crr was very low due to good pavement and good tires and I had a skinsuit on to test everything that I have optimized (position, gear, etc), so, my CdA was very, very low. I was trying to practice handling and bike control. I may not explain properly but at high speed (say 35 mph), turbulent air from trucks or going thru bluffs (cliff areas) can require attention unlike at 20 mph, one can almost sleep.

Let's say I was applying 40-50 watts to the pedals, this should get me around 13 mph or something. But let's say the sail effect was 15 watts at that ground speed. This push then gets me to say 15 mph but then the sail effect at 15 mph further pushes me to 17 mph and so on. If my "hull" is small and narrow, the sail effect is greatly magnified until an equilibrium is reached.

It has to be a wonky PM. I'll figure it out. One thing is for sure from multiple road and field tests, the FLO6) is only a little slower in calm winds or in head or downwind conditions (say 5-6 watts....no speed mentioned...LOL) but it is slower in crosswinds than the 2-spoke.....for certain.

http://www.2-spoke.com/speed/

Some basic yaw, handling, and sail effect background by Cannonwhale.

https://www.slowtwitch.com/Tech/Yaw_Angles_in_Cycling_Part_2_6162.html