Do you use an fairing or partial fairing on your ebike, emoped or BSM?

[ebike4healthandfitness]

By the way, I did experiment by using a smaller wheel and turning it around for a ton of trail with very little flop... it made things considerably worse!

Flipping your fork around will indeed increase trail but it will also massively increase flop

What size wheel did you go to and go from?

What fork offset and head tube angle do you have?

[BalorNG]

By the way, I did experiment by using a smaller wheel and turning it around for a ton of trail with very little flop... it made things considerably worse!

Flipping your fork around will indeed increase trail but it will also massively increase flop In fact, you trail to flop ratio probably stayed the same.

What size wheel did you go to and go from?

What fork offset and head tube angle do you have?

Currently I've increased trail (as in - slackened the angle), but not exactly 'on purpose' - I've had to to avoid crank conflict after I've lowered my bottom bracket, but I've had about 80 deg steering angle (give or take half a deg) with 45mm of fork offset with 24" 35mm tire.

Going for 20" wheel with 2.1 tire steepened the steering by about 1.5 deg and the trail actually went into slight negative - so I've had to turn the forks around for about 80mm of trail.

Obviously, my flop increased manyfold - BUT trail to flop ratio changed for the better of course and I still ended up with less flop than conventional road bike despite double amount of trail, so I should have great high speed stability, decent low-speed stability and be 'greatly resistant' to perturbations during riding... which would be the case unless those 'perturbations' comes in a form of sudden impulses of lateral force that directly translate into steering input by the trail lever arm (that increased an order of magnitude).

I welcome you to repeat the experiement, *I* have learned my lesson.

[BalorNG]

Only way to have a steering arrangement that would be immune to lateral force steering input yet provide great stability (without additional arrangement like steering dampers) is virtual pivot steering that has zero/near zero trail as conventionally defined - when 'looked from the side', but provide return to center force by actual inclination of virtual steering axis as steering is turned, resulting in grouth of level arm between contact patch and projection of the steering axis to the ground and return to center force that stem from combination of rolling resistance acting on the contact patch multiplied by that lever arm, but again - I do not expect you to understand what I'm talking about, but I'd be pleased to be proven wrong for once

P.S.
Btw, I do 'technically troll' you ATM, because it took me actual *years* to go from being as cluesless as you to actual understanding of virtual pivots and their application to bicycle steering and it took building a CAD 3d model, so in a way that would be not unlike dumping some sort of abstract higher math/quantum physics problem on a first grader, so yea, not understanding that is not by any means indication of a low intelligence or something. If you get it on the first try, you'll prove to be much smarter than me (which is also not entirely a heroic feat, I know my limitations)... though you already have all the information you need to - I've given you the link to Horn's recumbent motobike and you've read the Tom's paper on steering geometry.
But your pretentious strutting about reminds me of a Charlie Chaplin in a 'Great Dictator', so I just cannot stop from poking fun here and there

[E-HP]

But your pretentious strutting about reminds me of a Charlie Chaplin in a 'Great Dictator', so I just cannot stop from poking fun here and there

I admire folks that can click the submit button while providing their brutally honest perspective.

[ebike4healthandfitness]

Regarding ways to reduce the effect of crosswinds on a bike with a fairing I did this headset made by Cane Creek that also acts as a steering damper:

https://canecreek.com/product/viscoset/ (Comes in two tunes, mid and heavy)

https://bikepacking.com/gear/cane-creek ... et-review/ (A review of the mid tune)

[Chalo]

Regarding ways to reduce the effect of crosswinds on a bike with a fairing I did this headset made by Cane Creek that also acts as a steering damper:

https://canecreek.com/product/viscoset/ (Comes in two tunes, mid and heavy)

Wow. You so profoundly don't understand steering trail that you'll actively interfere with it on purpose. Props.

[SafeDiscDancing]

The guy with the recumbent is correct that things get a bit weird when you are so low to the ground as it relates to steering geometry.

And I've seen lot's of Electric Motorcycle builds where the builder somehow thinks they need to LOWER the batteries to get better handling but that is wrong.

The optimum location for the center of gravity of a conventional upright "cycle" is roughly along an imaginary line going from the center of the rear wheel to the middle of the headset.

Why?

Because a "cycle" actually counter steers to initiate lean angle and only after the lean is established does the front wheel switch back into the direction of lean. To get back up you need to reverse that but on a motorcycle you can drive the power through the rear to help pick it up.

Anyway the steering head angle without offset causes the front wheel to "fall into" the turn so to compensate you "offset" the front axle location forward which evens it out.

When an imaginary line through your head tube strikes the contact patch of the front tire that's "neutral" trail.

And this also makes me think that ebikes might get better handling if the battery is located more towards the middle of the frame triangle rather that being attached to the bottom tube region. I know the purpose is to preserve the "standard bike look" but from the standpoint of optimal handling it's not ideal.

[ebike4healthandfitness]

Another steering damper, the hopey gravity damper:

https://youtu.be/XIOX5xmKBkg

[calab]

Why would you need something like that crazy just inventing shit for the sake of inventing shit and seeing if it sticks to make a buck or what?

Another steering damper, the hopey gravity damper:

https://youtu.be/XIOX5xmKBkg

[BalorNG]

Regarding ways to reduce the effect of crosswinds on a bike with a fairing I did this headset made by Cane Creek that also acts as a steering damper:

https://canecreek.com/product/viscoset/ (Comes in two tunes, mid and heavy)

Wow. You so profoundly don't understand steering trail that you'll actively interfere with it on purpose. Props.

Well, for once I disagree with your and agree with eb4hf... to a point
Steering damping can replace trail - to a point, yea. The MEANING of trail is return to center force it create first and foremost (self-stability is mostly irrelevant except no-hands riding, and can be had by weight distribution as well). This force is all about controlling for *steering overshoot* - as described both in Patterson's paper (he's a helicopter pilot and pretty damn smart person) and Tom's article. This is not exactly well-known fact, but it certainly seems so because that is exactly what I did and adding a *STRONG* steering damper makes riding a bike with zero trail, even a flexy monstrocity of one, quite stable in comparison (which I did) - and this is why Python recumbents powered by negative flop are rideable despite having massive negative trail (you just cannot have high speed stability with them)

I've used a sheap, but really powerful moto damper from aliexpress - I've bought two, one of them promptly leaked, but I can buy like 10 for a price of one Ohlins Will eventually need to replace the seals and fix it...

Unfortunately, what it lacks is progressive increase in force with speed - which is what one of the streamliner makers did as far as I know to great effect - damping was controlled electronically. (So I really cannot claim that I came up with that idea by myself).
And what is even more interesting, *trail* is not optimal way of getting return to center force as well - because steering sensitity goes up with square of speed, but trail force rises linearly with speed (and flop is a constant fuction of steering geometry and load).

Which brings me to one of my ideas (and yea, *I* love inventing shit for sake of inventing shit and seeing what sticks ) - using a combination of some or other steering geometry and a control surface linked to steering that would provide 'aerodynamic trail' (return to center force that is *quadratically* speed dependant) and compensate for wind gusts by providing counter-torque.

Unfortunately, location of this 'control surface', size, shape, etc and which exactly steering geometry to choose to compliment it is a very hard problem to tackle without being an expert in aerodynamics and will likely have to be brute-forced by experimenting with different arrangements... rather unsafe experiments because effects will be apparent only at high speeds and at high crosswinds... but I'll get to it - eventually.

[BalorNG]

And yea, I totally wish ebike4healthandfitness good luck in his quest for knowledge and going anywhere it leads him - provided that he does not get fixated on first ramdom rambling from internet, internalise it as his own, develop an *illusion* of competence and than proceed to rabidly defend it using what amounts to a cargo cult of scientific method with great pomp. This is at best amusing, at worst sad and annoying... and no amount of theory, no matter how good it sounds to you, will do you good unless you bite the bullet and test your ideas by building prototypes, which is long, hard, messy, expencive and often depressive work because you simply cannot get things right all the time - getting them 1/10 of the time is actually a good results, que the famous quote from Edison

[Chalo]

Regarding ways to reduce the effect of crosswinds on a bike with a fairing I did this headset made by Cane Creek that also acts as a steering damper:

Wow. You so profoundly don't understand steering trail that you'll actively interfere with it on purpose. Props.

Well, for once I disagree with your and agree with eb4hf... to a point
Steering damping can replace trail - to a point, yea. The MEANING of trail is return to center force it create first and foremost (self-stability is mostl fronty irrelevant except no-hands riding, and can be had by weight distribution as well). This force is all about controlling for *steering overshoot* -

Yeah, I built a really comical tilting tadpole that does that, because the front axle is about 3 feet long but it steers in the center where a normal bike's front hub would be. After you make a steering correction, due to inertia it's well on its way to some other heading. But that's the fun of that objectively awful trike.

I think that by the time you need or want a steering damper, you are compensating for some more fundamental design mistake. My cargo bike used to headshake when there was a load in the box. It came down to the thing having too much trail, because the fork was made from a BMX fork with only 32mm offset.

IMG_20180924_021047.jpg (122.11 KiB) Viewed 331 times

While I could have installed a steering damper and taken away the resonant shaking, it would not have addressed the real problem. A real fix came from a fork with more appropriate 44mm offset. Now it doesn't shake under any conditions, and it carves through turns more steadily than any of my regular bikes.

IMG_20200924_203630860~2.jpg (937.22 KiB) Viewed 331 times

When I look at your LWB recumbent, I see a bike that would probably have much better steering qualities with a more normal head angle (even if it needs near zero trail to tolerate crosswinds).]

[ebike4healthandfitness]

Another function for fairings would be a place to mount a flexible solar panel.

Apparently this has even been done for bicycle wheels as well.

Notice the second to last picture claims 40W for the single wheel.

[BalorNG]

Yeah, I built a really comical tilting tadpole that does that, because the front axle is about 3 feet long but it steers in the center where a normal bike's front hub would be. After you make a steering correction, due to inertia it's well on its way to some other heading. But that's the fun of that objectively awful trike.

I think that by the time you need or want a steering damper, you are compensating for some more fundamental design mistake. My cargo bike used to headshake when there was a load in the box. It came down to the thing having too much trail, because the fork was made from a BMX fork with only 32mm offset.

While I could have installed a steering damper and taken away the resonant shaking, it would not have addressed the real problem. A real fix came from a fork with more appropriate 44mm offset. Now it doesn't shake under any conditions, and it carves through turns more steadily than any of my regular bikes.

When I look at your LWB recumbent, I see a bike that would probably have much better steering qualities with a more normal head angle (even if it needs near zero trail to tolerate crosswinds).]

A 'mistake' is an suboptimal choice, usually accidental.
Using way less trail than usual on something with large lateral area and compensating for it with... something else is not a 'mistake', but a deliberate design choice of the 'least evil'.
If you could just go ahead and install a small, light fairing on any bike and have it add a ton of speed and not interfere with anything - everyone would be using them by now, and screw the UCI... it obviously is not the case, because their are indeed either marginally effective or even entirely ineffective or bulky and crosswind sensitive... quite often both.

Which brings me to my pet peeve - when 'mountain bikes' were "invented", it was UCI that had to follow the trends and basically invent some MTB disciplines to suit them... and if recumbents were indeed as great as some more ardent bent evangelists suggest, all benefits - we'd ride recumbents anyway, and UCI will be forced to adopt them, just like they did with eMTB - and I mean, what can be more abhorrent to UCI than e-assisted bikes if you think about it?

Unfortunately, recumbent designs that have clear advantages over 'upright bikes' in both speed and comfort (best example - highly reclined lowracers) have no less great demerits when it comes to control, not even a tiny shred of 'offroadability', impared vision and visibility and, in absolute most cases, significant penalty to raw power output that gets greater when you need it most - climbing.

I think this problem can be solved, or at least minimized while retaining the benefits - but so far most bent manufacturers seem oblivious that it even exist (or at least pretend it does not), yet alone make steps to remedy the situation - with Cruzbike being one of rare exceptions, but they have their own share of foibles...
Same with fairings - and combination of recumbent position and fairings IS a way to go - velomobiles, that can ride 40 mph on pedal power alone with a rider that is fit, but far, far from olympic champion (230-250watt, laughable watts from perspectives of this board - Toecutter is a great example what can be achieved with fully faired recumbent).

But combination of singletrack dynamics and full fairings (a streamliner) while have even more raw potential - but even more potential for disaster. One thing is for certain - you need to think way outside the box if you want to make some new advances on this problem...

[ebike4healthandfitness]

Some power saving estimates for disc wheels:

https://www.trainingpeaks.com/blog/what ... odynamics/

"A standard front wheel costs about 30-40 watts at 20 mph, while a good aero 3-4 spoke wheel will only cost 15-25 watts, and a full disc wheel will cost you just 5-10 watts."

That is pretty significant reduction in power that would only grow as speed increases.

Of course, crosswinds will be an issue to think about.

[ebike4healthandfitness]

If you could just go ahead and install a small, light fairing on any bike and have it add a ton of speed and not interfere with anything - everyone would be using them by now, and screw the UCI... it obviously is not the case, because their are indeed either marginally effective or even entirely ineffective or bulky and crosswind sensitive... quite often both.

We've already had two people in this thread report using the small zipper fairing and both confirmed that it does work as well as claimed in the OP (and possibly even better). So the performance claim is definitely not in question.

[SafeDiscDancing]

Motorcycle Road Racing went through this whole aerodynamic issue and arrived at a set of rules that seem to have calmed any anxiety about cross winds.

For decades the simple rule was "no fairing ahead of the front axle" and "no fairing beyond the end of the rear wheel".

That worked.

These days in MotoGP they are focused on down force and things like ride height adjustment to limit the tendency to wheelie which is not anything that ebikes or bicycles worry about. And in that they seem to have allowed some deviation, but it's still pretty much the same cross wind scenario despite all the winglets being added.

It would be great to have an UNLIMITED CLASS for human bicycle racing which had no limits on what you raced meaning that if a recumbent could win they would win.

[spinningmagnets]

The MotoGP companies have a lot of R&D money, so I wish they allowed fairings from an inch in front of yhe front tire to a foot behind the rear wheel to see what they come up with...

[SafeDiscDancing]

Note the winglets.

[ebike4healthandfitness]

In the opening post it lists velomobile at 30 watts for 35 kph, but this must be for a super specilized velomobile because a Milan SL (shown below) has a much greater power consumption of either 145 watt or 160 watt at 50 kph.

If 145 watt or 160 watt at 50 kph then certainly power consumption will be much more than 30 watt at 35 kph. My estimate for Milan SL at 35 kph would be at least 71.5 watts or 79 watts.

[ebike4healthandfitness]

So if a road bike with the small fairing riding on the handlebar tops is 157 watts at 35 kph....what is the wattage of a road bike with the small fairing riding on the drops? How about the wattage of a road bike with the small fairing riding in the drops and using the solar panel disk wheels? (See the two posts 6 and 8 spots above this one). Is it possible a road bike properly equipped and designed can get within striking distance of a sleek three wheel like the Milan SL velomobile?

[BalorNG]

In the opening post it lists velomobile at 30 watts for 35 kph, but this must be for a super specilized velomobile because a Milan SL (shown below) has a much greater power consumption of either 145 watt or 160 watt at 50 kph.

If 145 watt or 160 watt at 50 kph then certainly power consumption will be much more than 30 watt at 35 kph. My estimate for Milan SL at 35 kph would be at least 71.5 watts or 79 watts.

I think that meant air drag only, and it sounds reasonable, but rolling resistance on a trike (even a highly specialized racing trike) is usually close to a factor of two compared to a bike, and this has nothing to do with number of wheels per se, but the combantion of camber/toe-in and small wheels that have higher rolling resistance everything else being equal - not by much, but it adds up.

All in all, a small, light, silent and practical fairing that 'adds more than it takes away' (provided you want speed, not just reduction in windchill) will likely never happen - unless you mold a RIDER to a fairing and think way, way outside the box - que that motorcycle with a venturi tunnel:

https://www.advrider.com/behold-the-wmc ... ri-tunnel/
https://newatlas.com/motorcycles/wmc-2w ... cle-v-air/

This is something I wanted to test for some time, I don't mind being beaten to it It is likely my implementation would have been not extreme enough anyway.

[BalorNG]

Motorcycle Road Racing went through this whole aerodynamic issue and arrived at a set of rules that seem to have calmed any anxiety about cross winds.

For decades the simple rule was "no fairing ahead of the front axle" and "no fairing beyond the end of the rear wheel".

That worked.

These days in MotoGP they are focused on down force and things like ride height adjustment to limit the tendency to wheelie which is not anything that ebikes or bicycles worry about. And in that they seem to have allowed some deviation, but it's still pretty much the same cross wind scenario despite all the winglets being added.

It would be great to have an UNLIMITED CLASS for human bicycle racing which had no limits on what you raced meaning that if a recumbent could win they would win.

Well, 'that worked' in a way that prevented any fairing designe that is more or less effective, ehehe.

True, above mentioned venturi tunnel *sort of* works as a longer nose and longer tail, but turned inside out This is still suboptimal compared to a true full fairing - best HPV racing streamliners boast Cd of about 0.05 - but this is likely a lot better when it comes to crosswind sensitivity, though the tunnel would still produce interesting effects I wager...

Again, I have an even crazier idea (this is one of few things I do not find lacking - crazy ideas) - an air intake that looks kinda like nostrils and that channel the ingested air to the same side of the fairing, producing counter-lateral-lift using coanda effect - this should drastically reduce side wind sensititvity at the cost of lost of side wind propulsive force and extra drag, but a fairing that is practical enoug to be used even if suboptimal is much better than an effective one that sits unused because it is too dangrerous to operate.

Unfortunately, that will not work with 'truck bow waves' as much as I understand...

[tomjasz]

Fairings on pedal bikes cause engine overheating.

Fairings on motorbikes can increase rider comfort, or decrease drag, but are not so likely to do both. The large fairings I used on my motorcycles increased overall drag (judging by measured MPG) as a consequence of making a nice generous bubble for me to inhabit.

Making a great Minnesnowta add on for winter trike? Hmmmm

[tomjasz]

Re directing the air above your chest, yes please. Re directing to the top of your chest, no thanks. Same wind, but you now catch it concentrated in your face.

Yup. Same with Vespa mid screen but a add on product of the same material, can’t remember the name, pushed the air over my helmet and I didn’t have to look through another layer. Both the mid and full screens increased mileage.