Cycle computer help please ?

[deano69]

I bought 2 bikes for my boys and also a cycle computer each but on installing them it says in the instructions the top of the sensor and the computer unit should be 70cm apart ??? it simply isn't possible 70cm from the unit to the sensor top would mean the sensor would have to be set on or near the wheel axle.

Its just the way it reads but its working fine where it is I think they meant no more than 70cm away from each other for the wireless signal to be picked up, also if I move the sensor higher or lower on fork and move magnet to suit will it still register accurately ? or should the magnet be in a particular place on spokes ...at present its about 50mm down from wheel rim much how the instruction pic shows it or can it be set anywhere /.

I have set in the the wheel size but wondered does the magnet pass the sensor closer to the hub faster after one full revolution or at the top near rim or would it be exactly the same silly question I know but it looks to be faster when closer to hub but thinking about it would prob be same.... the instructions are pretty useless and not worded correctly to understand the procedure.

Cheers,

Deano

 

[snorri]

I think they meant no more than 70cm away from each other

I have set in the the wheel size but wondered does the magnet pass the sensor closer to the hub or at the top near rim or would it be same silly question but the instructions are pretty useless and not worded correctly to understand the procedure.

I think you are right, the distance between sensor and comp. should be not more than 70cm.
The magnet position on the spoke is not critical, mine are usually about half way along the spoke.

 

[deano69]

Cheers, I have had computers in the past and the one on my bike is pretty accurate when tested against my gps phone app and my magnet is about 2" down from wheel rim

 

[steveindenmark]

My magnet goes as close to the rim as I can get it. Your instructions should give a diagram where it is to be placed.

Steve

 

[L14M]

Mine just says the magnet should be 5cm apart from the sensor.

 

[Broadside]

I have set in the the wheel size but wondered does the magnet pass the sensor closer to the hub faster after one full revolution or at the top near rim or would it be exactly the same silly question I know but it looks to be faster when closer to hub but thinking about it would prob be same....

You are over thinking it :-)

The sensor counts how many times the magnet passes in a given time frame to work out how many times the wheel is rotating and therefore can determine the speed of the wheel, it does not scan the speed of the magnet passing. You are right that the rotation speed at the hub is far slower than at the rim but that is not what the sensor is measuring. Therefore the magnet can be at any position on the spoke so long as it is within range of the sensor, most specify something like a 5mm gap.

 

[Octet]

+1 to what Broadside has said.

Because of this, the most important thing in determining an accurate speed/miles is your measurement of the wheel.

 

[steve52]

yep its a minimum distance