Traffic signal triggering magnets

[Rob Valdez 79 R65]

Thanks to Sue's link to K&J Magnetics for rare earth magnets here in the U.S., I am going to order some for my frame rails.

Here are the ones I am considering:

2" x 1/4" x 1/8" thick


2" x 1/2" x 1/8" thick

Click on the pictures for specifications.

I am considering 2 magnets on each frame rail.  To any doctors of magnetizim, do you think the 1/4" magnets will be enough, or do you think I will need the 1/2" wide version?
In 1/2" width, they also have 3 and 4 inch lengths available.

Thank you.

Yours in sensor triggering,

Rob

[Jon_P]

i use what is commonally called around these dairy farming parts as cow magnets. i get them from the local farm supply store. little super bond epoxy to the frame rails or to the center stand and i'm tripping lights all over. i have learned that finding the corner of the box helps and stopping there helps trip the signal also. if i have a tough light once and a great while i flip the center stand down or turn the bike off and start it. i would say 99% of the time i dont have a problem with lights when i have the cow magnets on the center stand rails

[nhmaf]

i think that those rare earth magnets are much stronger than the magnets that WhiteHorse Press
puts in the "traffic light trigger" gizmo, and those are smaller than what you'd have with (2) sets
of those quarter inch rare earth models.   I have a white horse press one, and while it has helped,
I can't say that it solves all the light issues either.   some problematic lights remain so with it.

Those cow magnets are very strong for non rare earth types, though I seem to recall that they are
certainly larger in size.   Price wise, they are probably alot cheaper, and available at any
real agricultural store.  But, where would you mount them so as not to interfere with centerstand, drain bolts,
and front cover ?

[Bob_Roller]

I've noticed in the Phoenix area, that road sensors are  going away, in favor of low resolution cameras mounted on the horizintal support tubes of overhead traffic lights. Flashing head lights and driving lights seem to help trigger these systems. I have found also, that if you deploy the center stand over one of those cuts in the pavement, it helps trigger that system as well. I need to find some cow magnets, as I have a few 'difficult' traffic lights to deal with on the weekend when there is no other traffic at 5:15 am to help you out.

[VaSteve]

Why do they call them "cow magnets"?

[NC Steve]

I had the same question and did a search.
Check it out: www.wikipedia.org/wiki/Cow_magnet
There's also a link on the page, under "what are cow magnets", to a seller/supply house. These things are pretty cheap too!

Who'd a thunk???  

[Justin B.]

They feed 'em to cows (4 legged, not two wheeled) so that metallic stuff they might eat will stick to the magnet instead of passing through and doing internal damage.  Hmmm, maybe "cow magnets" WOULD be appropriate for our machines!  

I have read these discussions on other forums and it seems like I remember most of the discussions heavily weighted in the "snake-oil" direction concerning any of the various megnetic signal light trigger hooti.  Am I getting the impression that this group thinks they actually work?  I have some of the very strong disc type Neodium (sp?) magnets laying around and may try them by placing a few on the cross-bar of the center stand...  I think there is one light around here that is not very MC friendly that I can test them on...

[airhead]

I tend to agree with the snake oil direction of thought with these things. Maybe the magnets will pick up nails before they can puncture the rear tyre though, which could be a good thing!!
The pick ups in the road are a large coil that has a magnetic field. The current drawn to maintain this magnetic field is constant (or quiessent) and only changes when a large metallic (not necessarily magnetic) object passes over it. This change in current draw is detected and triggers the lights.
I've found some lights are pigs with any vehicle, not just bikes, but that is their programming. In my whole time riding bikes, about 30 odd years, I've only had one problem light (and that was in the early days of these pickups) which was sorted by contacting the relevent traffic authority who boosted the sensitivity, and I no longer had any issues with it. I haven't had any problem lights since.
Having these magnets may only be a placebo thing, as some are still talking about non changing lights.
Save your money for something more useful, and save dragging extra weight around as well, or maybe stick it to the outside of the gearbox to catch the metal floating around in there before it gets to the bearings!!!

Bill.........................;-)