Mystery magnet wheel accessory
 

This doodad was on the hub of a 1990s wheelset I got recently. It's a magnetic ring inside a plastic retainer clipped to the spokes.

The magnetic ring is rubbery and under it is a circlip type ring, presumably to provide a little more retention for the magnetic ring.

I'm guessing it was part of a speed or distance sensor. I didn't notice it until later so I didn't ask the seller.
https://cimg1.ibsrv.net/gimg/bikefor...63e95aef0.jpeg
Outer surface.
https://cimg2.ibsrv.net/gimg/bikefor...203b25e2e.jpeg
Inner surface, clipped to spokes.

Looks like the one from an Avocet bike computer.

Yep, oldschool exciter ring. :50:

Back To The....Well You Know?
 

Flux Capacitor for Bicycle.

(Never really took off because still needed to reach 88 mph to take off.)

I know that part. The ring would not zip tie to my hi flange hub when I got my Avocet back in the 80s. So I pulled out the magnet and glued it to the hub. It’s still there…

https://cimg5.ibsrv.net/gimg/bikefor...2036896a5.jpeg

Yes, that's a magnet ring for Avocet (I think it worked with model 20, 30 and 40) bike computers from the 80's.
They actually came with different mounting prong locations to work with either 36 or 32 hole front hubs.
A time. pickup sensor for it is mounted just above the fork dropout with a small zip tie. A very clean design for the time.
The Avocet model 20 I bought for my Peugeot PSV back in 1984, is still on the bike and still works!

Thanks, all!

I won't use it, but now I'm curious to see what those older sensors looked like. I'll Google around later.

I've got Avocet speedometers of this style on three bikes. They have their quirks, but I like them. A couple of photos of them in use...

https://live.staticflickr.com/65535/...5e56e0_c_d.jpg

https://live.staticflickr.com/8022/2...fda518_c_d.jpg

Steve in Peoria

+1 on old Avocets steelbikeguy

Finally had to give up on them because temps below 40 degrees would scramble their brains, even with new batteries.

Boy, I haven't had mine in the cold weather for a long time... mine are on my shiny bikes that just get ridden on nice days. The bikes that get used and abused are fitted with more modern Cateyes, and they've tolerated all sorts of horrors.

Some LCDs don't handle freezing temperatures, and will get very sluggish. I've also had problems with one or two Avocets where the electrical contacts to the LCD were held in place by the two halves of the housing. When it got older and the plastic "relaxed" a bit, the pressure on the contacts was reduced and the display segments would fade and disappear. A rubber band around the housing often fixed this, but it wasn't a great solution.

Avocet was a great innovation, but other companies with more experience and resources eventually produced products without the chronic issues of the Avocets. I don't think any of them ended up being as inconspicuous and unobtrusive as the Avocet, though.

Steve in Peoria

Yup, that’s the hub flange-mounted transmitter for an Avocet Cyclometer. Here’s a scan from the Cyclometer 20 owner's manual showing the part and how to mount it.

EDITED TO ADD: I think this is from a later model (30 and up?). The transmitter for the model 20 was made of black plastic and the mounting tabs and slots were offset (see image below).

https://cimg0.ibsrv.net/gimg/bikefor...05afdbc4a0.jpg

Partial threadjacking: steelbikeguy How are you routing the wire down your fork leg? I don’t see any zip ties.

I use clear packing tape to stick it to the inboard side of the fork blade. It's a low-tech way of doing it, but it works much better than it has a right to. Here's a cropped photo of the Raleigh International that (sort of) shows the wire routing and the tape:


https://cimg0.ibsrv.net/gimg/bikefor...a7295e28bc.jpg

Steve in Peoria

Looks like one of the rings in a Turbo Ecabulator

Clever! I’ll have to try that with helicopter tape.

When I mounted my Avocet model 20 Cyclometer on my PSV back in 1984, I routed the sensor wires through the top and bottom brazing vent holes on the right fork leg so the wires are not visible below the fork crown and down the fork leg, making for a very clean looking installation. I remember using a thread sucked from the top hole down and through the bottom hole using a vacuum cleaner, to fish the wires through the fork leg.