On Thu, 13 Jun 2019 14:28:46 -0700 (PDT), Tom Kunich
wrote:

On Monday, June 10, 2019 at 6:56:17 PM UTC-7, Ralph Barone wrote:
AMuzi wrote:
On 6/10/2019 7:55 PM, John B. wrote:
On Mon, 10 Jun 2019 18:02:05 -0500, AMuzi wrote:

On 6/10/2019 2:52 PM, Sir Ridesalot wrote:
On Monday, June 10, 2019 at 1:33:08 PM UTC-4, Tom Kunich wrote:
On Friday, June 7, 2019 at 10:01:07 PM UTC-7, John B. Slocomb wrote:
On Fri, 7 Jun 2019 11:09:59 -0700 (PDT), Tom Kunich
wrote:

On Thursday, June 6, 2019 at 4:31:13 PM UTC-7, John B. wrote:
On Thu, 6 Jun 2019 13:15:10 -0700 (PDT), Tom Kunich
wrote:

On Thursday, June 6, 2019 at 9:11:17 AM UTC-7, Sir Ridesalot wrote:
On Sunday, June 2, 2019 at 5:49:03 AM UTC-4, John B. Slocomb wrote:
See https://www.youtube.com/watch?v=-9gQ1KRhesM

In the narration he mentions that a 24 speed gear set, or even more,
would be perfectly feasible. No wires, no cables, either.
--

Cheers,

John B.

I can just imaging what road grit when it rains will do to those
exposed bearings and interface. Can we say RAPID wear?

Cheers

What exposed bearings? They are sealed ceramic bearings. But
again, the frame must be custom built for it. So there's no way
it would ever make it on the market.

Custom Frame? You mean like a MTB with fore and aft suspension? That
will never make it on the market?
--
cheers,

John B.

There is a very strong purpose for full suspension in racing and
people tend to copy racers. But ravers won't use drive shafts
because they are inherently very lossy. Hydraulic brakes and
electronic shifting are there just to increase the cost of a bike.

But the article about this "NEW" shaft drive system says that it is 1%
more efficient than a chain drive. You don't think that "racers" will
want a carbon fiber bike that will likely be as light as legal and 1%
more efficient?
--

Cheers,

John B.

Any testing they did must have been unloaded. You can make a lot of
things look quite efficient without a load on it.

IIRC the 98% efficiency of a derailleur system is reached ONLY when
the gear is equal to a one to one ratio. I might be wrong about that but my
understanding is that that 98% efficiency is ONLY reached with ONE
particular gear. Other gears are less efficient.

With the driveshaft system shown upthread I can't but wonder how it'd
wear and how soon the interface of the gears would get sloppy. Plus as
was also mentioned upthread, with that driveshaft it might not be too
easy to do an emergency wheel swap.

Cheers


Yes, there's that.
For bevel gears the stated '90~95%' is per set and you need
two so likely closer to 80%.

According to the Ceramicspeed site they tested the DrivEN system and
it is 99% efficient. The entire system.

With raised eyebrow I remain unconvinced of that.

Open crown/spur gear set (as opposed to wet gears in a rigid
case) 99%? Hell, every race car would use them if that were
true.



It’s not quite a regular crown/spur set. The spur gear “teeth” appear to be
made from ceramic ball bearing assemblies, so there’s minimal friction as
the “teeth” slide across each other.

The difference in rolling resistance between a ceramic bearing and a steel one is so slight that it requires VERY high RPM to detect. This is why adding ceramic bearings to your bike is economically silly.

Certainly adding ceramic bearings to "your" bike is likely not cost
effective but for a racing bike they may be worth the money as a
second could well be worth considerable money if it was the winning
margin in the TdeF :-)

--
cheers,

John B.