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Speed sensor for spokeless bikes (indoor velodrome)

hi,

How can I measure a speed when I use a baton (trispoke carbon) on front wheel such as HED3 and a carbon disc on my rear?
I cannot attach the speed sensor to the any of hubs.
is the only option is to use a magnetic sensor and glue it to the disc?

If so., are you recommending the origin one? And then what magnet? The original one is for spoke attaching.

Thanks,
Bart

0 philipshambrook over 8 years ago

We've just taped one of the original magnets to one of the tri-spokes on a HED. Works well. You can easily find neodymium magnets to stick to the spoke too if you need a bit more grunt.

0 bartek. over 8 years ago

by "taped" you meant to use a tape? like a duct tape?

0 khartung over 6 years ago

Sometimes we just have to think outside the box. You can attach one of the new magnetless speed sensors to one of the tri spokes, or even insert it into the valve stem cutout (which I guess would be thinking inside the box in this case!) :-) It works, despite what the specs or the mounting instructions of the sensors suggest.

0 tmk2 over 6 years ago

If it's a fixed-gear bike (like most bikes on a velodrome) then you can attach the magnet-less sensor to the crank arm, although setting the correct wheel size will require some testing, unless you know the cadence - to - wheel-rpm ratio.

0 khartung over 6 years ago

Interesting, so attach the speed sensor to the crank arm? I suppose if it can track speed attached to a spoke or in a valve stem reset, then it can track on a crank. I will try that. I believe you can manually set the wheel size in most bike computers, so that would be the work-around.

0 tmk2 over 6 years ago

I believe you can manually set the wheel size in most bike computers, so that would be the work-around.

Yes, but the trick is to find the correct wheel size. The real wheel size of the bike won't do, obviously, as it rotates differently than the crank arm. But the good news is that in a fixed-gear bike the ratio is constant.

0 ScottEyler over 4 years ago in reply to khartung

Do you have any images of this?

0 ScottEyler over 4 years ago

With A HED Tri Spoke wheel, can you use the Bike Speed sensor in any way, or do you need to go to the 2-piece, magnet on spoke and sensor mounted on rear triangle? Thanks

0 GooseRider_ over 2 years ago

Have the same issue. I can put a neodymium magnet inside the valve cavity of the rear disc wheel. However, what Ant+ speed sensor should I use with this magnet? I also need it to work with my Power2max power meter which will provide power and cadence.

So basic question is in 2022, what Ant+ speed sensor works with external magnet?

Thanks,

Morten

0 Scillonian over 2 years ago in reply to GooseRider_

This speed and cadence sensor from Coospo may be adaptable to your requirements:

https://www.coospo.com/product-item/coospo-bk8/

https://smile.amazon.co.uk/CooSpo-Bluetooth-Wireless-Compatible-Runtastic/dp/B09B2FMB4S/ref=rvi_2/261-6187656-4649869?pd_rd_w=Bk7oS&pf_rd_p=febd3956-4d60-4288-b8f2-cb468eb6674d&pf_rd_r=YRX30F57G3ME6GT31A90&pd_rd_r=64c5e178-9b4d-4226-bb5e-8b8a877dfeb2&pd_rd_wg=sbIC4&pd_rd_i=B09B2FMB4S&psc=1