On 7/2/2020 10:44 AM, Frank Krygowski wrote:
On 7/2/2020 12:46 PM, Jeff Liebermann wrote:
On Thu, 2 Jul 2020 11:23:43 -0400, Frank Krygowski
wrote:

On 7/1/2020 11:33 PM, Jeff Liebermann wrote:
On Wed, 1 Jul 2020 10:57:13 -0700 (PDT), Lou Holtman
wrote:

Fits into the hollow axes of the GRX crankset and is held by a magnet:

https://photos.app.goo.gl/hJcKwKxXXKRo6eyS9
https://photos.app.goo.gl/sSganYNLo3a5R3SG6

Lou

Nice:
https://www.allinmultitool.com
https://www.singletracks.com/mtb-gear/multitool-fits-inside-crank-spindle-adds-bike-chain-breaker/

68 Euros.

I admit it's cute. But it seems like you can get a multi-tool that's
even more effective for half the price if you're willing to keep it in a
gasp! bike bag.

Yep, truly horrible.Â* Think of the aerodynamic drag and added grams of
weight caused by the bag.Â* Mounted to the frame, it might affect the
glossy finish required to maintain laminar air flow.Â* However, none of
that is as serious as the lack of security for the tool.Â* There's
nothing to keep anyone from walking by, seeing the unique logo, and
simply pulling on the cover to remove a 68 Euro tool held in only by
magnets.Â* If locking proves difficult, perhaps the "pro" model will
include a pepper spray in your face dispenser?

And the bike bag version won't slow you down with eddy current losses
due to the cute one's magnets.Â*Â*Â* ;-)

Ummm... the retention magnets rotate along with the steel spindle.
Everything else is aluminum, carbon fiber, or wood, none of which are
affected by magnetic fields.Â* Actually, you can use eddy currents
through an aluminum disc for magnetic braking but it takes a much
larger magnet:
https://en.wikipedia.org/wiki/Eddy_current_brake

Well, as a cute science demo for a young physics major who was visiting,
I took a high strength magnet about 5mm diameter by 15mm long and
dropped it down an aluminum tube about 10mm ID and a meter long. It fell
very, very slowly. (Try it. It's fun!)

Her father is a very smart electrical engineer, but neither of them
understood what was happening.

My point? Eddy currents work well with aluminum. (I don't know about
carbon fiber.) If you have an aluminum frame and this toolkit, your only
hope is that the steel spindle will shield the magnetic fields from the
aluminum.

Doesn't the spindle completely shield everything outside the spindle
from the magnetic fields? (Serious question, but I thought it did.)
Mark J.