I NEED A LOAN FOR NEW TOY!

[EasTexRIII]

The cog count

The cog count is determined by the circumference of the cogs, which is 2Pir. So just for arguments sake, lets say that the smallest diameter used is 4cm and each gear increases the diameter by one centimeter, then the difference in the ratios will be 4/5 (or the other way around if you like, it won't affect the results). By the time you move to the outermost ratio with his 13 speeds the ratio will be 15/16 - which is a much closer ratio. If you were to add another 4 gears then they would all be lower gears and even closer together.

This is a regular bicycle rear cog set.
Say the smallest is a 12 & next one 13, 14, 15, and on..... you can change those out to a first gear 11, then 13, 15, 17, 19, ect..... of course then you would, with the same number of cogs, end up with a larger last cog (lower gears) on the same size 11 speed cassette

 

[EasTexRIII]

Interesting but not quite as claimed. The ceramic drive bearing races enter and exit the driven plate tangentially just like a gear set. Thus sliding friction is present because of a changing contact radii, just like a hypoid gear set or a chain drive but worse in this design. The smaller the driven member diameter (fewer teeth) the worse the problem. So, I want to know the efficiency in each ratio and then at minimum and maximum input torques. I suspect the 1% is all hype and reality far different.

It has few parts externally which is nice but the electronic position monitoring and gear changing could be quite complicated.

A CVT with adjustable sheaves and a simple steel belt (band) likely has better efficiency.

Blain, you mind works at a much higher level than mine (nothing to brag about) But I think that this setup works because these high end bike are only going to benefit pro racers who don’t pay for equipment, their teams sponsors do so they are going to be using these light weight aluminum rear cogs for a few races then replace them after they wear.
Also the watts put out to the rear wheel by the human motor will not stress the parts out like a real motor would.
Not sure if this has anything to do with what you said, that goes over my noggin

 

[Speedy]

Oh quite contrare! When the rider puts his full weight, say 170 lbs, on a pedal with a 6" crank arm, he is putting 85 lb/ft of torque into the drive member. This is more torque than the majority of motorcycle engines produce. The power (or watts) are low only because of the slow rate (rpm) at which we pedal.

The "rear cog" as you call it will also see a lot of side load which must be dealt with. Therefore, it most likely won't be light weight aluminum. This drive obviously turns the rear wheel. So how much advantage does it really have? Anybody can say anything on the internet. "Show me the numbers" or it is no more than snake oil.

 

[Ishrub]

Absolutely brilliant concept. As an ex cyclist (old Pro - Trackie) I get amazed at what I see in bikes now but this is just a leap ahead and I want one

You never cease to amaze! Pre-lycra days when you rode in lightweight hessian or was that canvas?

My cousin in Canada, Phil White, co-started and has now sold Cervelo which started making Olympic rule testing 'Barrachi' track bikes using the design cues he had from an Aero Engineering degree, going on to full Tour de France team sponsorship etc.

History - cervelo.com


Cervélo Cycles was created in 1995 when two engineers, Phil White and Gérard Vroomen, decided to market their work developing faster time-trial bikes. Having been involved in bicycle and human-powered vehicle design since 1986, they started a bike design from scratch when a top-ranked Italian pro cyclist approached Gérard to design the fastest possible time-trial bike for him.

 

[barbagris]

A CVT with adjustable sheaves and a simple steel belt (band) likely has better efficiency.

But can sound like fingernails on a blackboard.

 

[Ishrub]

Not so - The gears change wirelessly. It's only when you want to change overall ratios that you need to stop and swap the shaft.
As for flexing a good start would be a proper CV joint in the swingarm pivot rather than a universal but precise positioning would be a must. BUT - materials selection for a 200ft-lb power feed would be crucial.

I'll have to watch the vid now I suppose if it has updates. I read about it on NewAtlas.com dateline:July 10th, 2018; when I posted that Brazilian aero engined rimless custom a couple of weeks ago.

Good source of weird and wonderful stuff emailed to you regularly if you 'free subscribe' to NewAtlas.
"World’s most efficient" bicycle drivetrain unveiled at Eurobike
"In its current form, DrivEn can't shift between gears, although BikeRadarreports that this could conceivably be managed using a wireless servo to move the rear bearing mechanism fore and aft relative to the cassette."

Of all the items currently on display at this year's Eurobike show in Germany, one of the most attention-getting is CeramicSpeed's DrivEn pinion-style shaft-drive system. According to its designers, it creates 49 percent less friction than the high-end Shimano Dura Ace chain-and-derailleur setup.

At the heart of the prototype drivetrain is a cylindrical carbon fiber shaft, that reaches from the single chainring in front to a flat 13-speed cassette on the rear wheel.

Mounted on either end of that shaft are sets of very-low-friction ceramic bearings (there are a total of 21 of them), which engage the teeth on the chainring and the cassette cogs. As the rider pedals, the bearings transfer torque from the chainring through the shaft and into the rear wheel, turning it.

In its current form, DrivEn can't shift between gears, although BikeRadarreports that this could conceivably be managed using a wireless servo to move the rear bearing mechanism fore and aft relative to the cassette.

BikeRadarreports that this could conceivably be managed using a wireless servo to move the rear bearing mechanism fore and aft relative to the cassette.

"CeramicSpeed has proudly accomplished what many have said couldn't be done," says company CTO Jason Smith. "We achieved a 99-percent efficient multi-speed drivetrain while eliminating the chain and complex rear derailleur."

That efficiency is reportedly achieved due to the fact that the system does away with the eight points of sliding friction that are present in a regular drivetrain, where the chain articulates while passing through the chainring, cassette and derailleur.

DrivEn was developed in partnership with the Mechanical Engineering Department at the University of Colorado, and has just received the 2018 Eurobike Award. There's currently no word on commercialization.

And for another take on the shaft-drive bicycle idea, check out the
Alpha Bike concept.
Source: CeramicSpeed via VeloNews

 

[EasTexRIII]

Oh quite contrare! When the rider puts his full weight, say 170 lbs, on a pedal with a 6" crank arm, he is putting 85 lb/ft of torque into the drive member. This is more torque than the majority of motorcycle engines produce. The power (or watts) are low only because of the slow rate (rpm) at which we pedal.

The "rear cog" as you call it will also see a lot of side load which must be dealt with. Therefore, it most likely won't be light weight aluminum. This drive obviously turns the rear wheel. So how much advantage does it really have? Anybody can say anything on the internet. "Show me the numbers" or it is no more than snake oil.

Well the rider is not putting anywhere near his full weight on the pedals since he is mostly sitting. When he does stand up on the pedals he still has a lot of his weight on his arms at the handlebars too.
The power is actually not from the amount of weight on the pedals, but from his muscle strength and V02 max (maximum oxygen the lungs can procees) and RPM’s (usually 80-115 RPM’s) & then factor in his power to weight ratio (weight as in the pounds he has to pull along, or I guess gravity? on a flat, or especially an incline) - not weight on the pedals.

Now your side load point is something I didn’t think about. Since I know for a fact some racers are using aluminum cassettes, but the chain gives a top load I guess they don’t wear as fast as this side load setup. And really the bikes they are riding on race day have the aluminum cassettes but the ones they train on are steel. Remember they are not paying for components they use.
I only said this bike had aluminum cassette because it just looks like it in the video, maybe it’s not?????

But brother, you do have me looking at this differently (not that I’m going to buy one of these- God knows I can’t afford one) just that it’s intriguing to me.
So what I say is only based on experience of what I’ve seen in cycling over the past 30 years, & this is a horse of a different color, so you’re thinking outside the box n I’m not
Thanks for your insight

 

[EasTexRIII]

You never cease to amaze! Pre-lycra days when you rode in lightweight hessian or was that canvas?

My cousin in Canada, Phil White, co-started and has now sold Cervelo which started making Olympic rule testing 'Barrachi' track bikes using the design cues he had from an Aero Engineering degree, going on to full Tour de France team sponsorship etc.

History - cervelo.com


Cervélo Cycles was created in 1995 when two engineers, Phil White and Gérard Vroomen, decided to market their work developing faster time-trial bikes. Having been involved in bicycle and human-powered vehicle design since 1986, they started a bike design from scratch when a top-ranked Italian pro cyclist approached Gérard to design the fastest possible time-trial bike for him.

Wow Pete! He’s your cousin?
Cervelo is an awesome bicycle company. I know some people here who own some of those bikes

 

[Ishrub]

Wow Pete! He’s your cousin?
Cervelo is an awesome bicycle company. I know some people here who own some of those bikes

Yeah, I'm real close to cycling royalty. I have met him once when I was 8/9 and he was 5/6

I'm almost closer to Kevin Bacon

His sister, BinL and nephew live here in Canberra too, though by complete happenstance and we see them often.

 

[EasTexRIII]

Yeah, I'm real close to cycling royalty. I have met him once when I was 8/9 and he was 5/6

I'm almost closer to Kevin Bacon

His sister, BinL and nephew live here in Canberra too, though by complete happenstance and we see them often.

Well that’s still purty cool. Awesome bike design