Bicycle Mechanics - Bicycle Computer Question

I just bought a Specialized Team Wireless and have a quesiton that has been bothering me all day. In the manual it does not say where to mount it on the fork.

So basically my question is, if the mount is towards the bottom and the magnet is closer to the hub, won't the speed read a bit faster since it is spinning faster. Where as, if it was mounted at the top, you would get a slower reading?

My theroy on how it works is that since it is wireless, if judges the distance bewteen the computer and the fork and does all these calulations to produce the speed. Correct me if i am wrong and i am sure i am wrong.

I would love to get an accurate reading so if anyone has any experience I would really appreciate it.

Thanks

So basically my question is, if the mount is towards the bottom and the magnet is closer to the hub, won't the speed read a bit faster since it is spinning faster. Where as, if it was mounted at the top, you would get a slower reading?

The computer measures the time it takes for the magnet to make one revolution, not the distance it travels around, so it reads the same no matter where you put it. Think of it this way - the spoke end at the hub takes the same amount of time to make one revolution as it's opposite end at the rim.

I've got mine mounted near the hub - less distance for the magnet to travel = less likely to fall off.

55/Rad

it doesnt matter where you mount it on the fork because the spoke goes through just as fast. the way it calculates speed is by obtaining rpms. it takes your tire size (which you input) and calculates how far/fast etc. you are going.

Think of it this way - the spoke end at the hub takes the same amount of time to make one revolution as it's opposite end at the rim.


This is what i am having trouble understanding.


Ohh wait i jsut got it! Ohh man boy and i stupid! This is all starting to make sense! Thanks for the reply!

it doesnt matter where you mount it on the fork because the spoke goes through just as fast. the way it calculates speed is by obtaining rpms. it takes your tire size (which you input) and calculates how far/fast etc. you are going.

Actually, even though the RPMs are the same, the magnet goes much faster out by the rim. Some sensors have trouble picking up the magnet when it's out by the rim and is going at a much higher linear speed. The solution in this case is to put the sensor and magnet much closer to the hub.

Actually, even though the RPMs are the same, the magnet goes much faster out by the rim. Some sensors have trouble picking up the magnet when it's out by the rim and is going at a much higher linear speed. The solution in this case is to put the sensor and magnet much closer to the hub.

hmm the range from the handle bar to the hub is not within the optimal tranmission range. I was thinking of putting it near the middle of the fork but realized it is very dangerous for the sensor so I went with mounting it near the brake post. In case of a fall, my brakes would be more likely to take the damage.

Mount the pickup as close to the computer as you can. You will save yourself lot of headache caused by intermitency. The location of the pickup with respect to the calculated speed and distance is immaterial, because the circumference of the wheel doesn't change with the position of the pickup. The computer just uses the pre-programmed wheel circumference and pulses from the pickup to calculate everything else it outputs.

To some extent, the location of the magnet is governed by the width of the wheel, i.e. the distance of the spokes from the fork.

I mount the wireless units as close to the computer as the wheel/fork spacing will allow. It gives better transmission.

To some extent, the location of the magnet is governed by the width of the wheel, i.e. the distance of the spokes from the fork.

Yes, but depending on the sensor band design, you may be able to compensate by rotating the sensor inwards so as to maintain the proper magnet-sensor gap.

On the Team wireless I run the transmitter unit at near the bottom of my fork, the magnet in towards the hub and the computer on my bars without any problems whatsoever in a few hundred miles of abuse.