Bike computer, magnet placement??

[Mozzy]

Being new I thought it would be fun to have a very basic wireless computer on the treadly. I got a Canyon one from Sainsburys which appears to work fine. I have it set for the correct size of wheel and all that but two questions remain unanswered despite having a search.

The magnet is the type that slots over a spoke and you then screw the small screw in the other side to lock it in place. This seems quite a weak idea and thus A turn too far wallops the thread. I need a new magnet now. Seems plenty to choose from; any particular type recommended?

The more important question, is does it make any difference where the magnet and sensor are placed? i.e. near the hub, or near the tyre edge or somewhere in the middle? I would hazard a guess someone will say it makes no difference as the wheel only goes round once with everything staying in the same place. I should have paid more attention at school some 50 years ago methinks.

Anyway, help from my peers would be most appreciated.

Mozzy

 

[HLaB]

It makes no difference where the magnet is placed, the computer only counts a revolution of the tyre and knows that one revolution is xxxx,mm of travel (you tell it that on setup); one revolution is one revolution regardless of where the magnet is placed.

Edit and is a magnet is just a magnet afaik but you may need to get a slightly different one if you have bladed spokes.

 

[Mozzy]

It makes no difference where the magnet is placed, the computer only counts a revolution of the tyre and knows that one revolution is xxxx,mm of travel (you tell it that on setup); one revolution is one revolution regardless of where the magnet is placed.

Edit and is a magnet is just a magnet afaik but you may need to get a slightly different one if you have bladed spokes.

Thank you, really appreciate your reply. No, spokes are just that … spokes, all normal and dandy like. I've set up according to the info which is a 2053mm wheel. Am I being dense again, is that just over two metres? My wheel is a 700c so deffo not two metres in diameter. That would be some seriously big wheel. I must be missing something

Mozzy

 

[Mozzy]

Oh I'm getting blonder. It is a wheel revolution that is measured not diameter of said wheel. Make a mark, roll the wheel forward then measure the distance travelled. Ahhh, it's all coming back now. Wonderful Maths teacher back in the 60's …. Mr Crunchfuttock.

Mozzy

 

[HLaB]

Thank you, really appreciate your reply. No, spokes are just that … spokes, all normal and dandy like. I've set up according to the info which is a 2053mm wheel. Am I being dense again, is that just over two metres? My wheel is a 700c so deffo not two metres in diameter. That would be some seriously big wheel. I must be missing something

Mozzy

Yip, that's 2.053m but you've worked it out anyway its the distance that your wheel covers in one revolution Circumference = Pi x diameter.

 

[Bayerd]

Oh I'm getting blonder. It is a wheel revolution that is measured not diameter of said wheel. Make a mark, roll the wheel forward then measure the distance travelled. Ahhh, it's all coming back now. Wonderful Maths teacher back in the 60's …. Mr Crunchfuttock.

Mozzy

Sorry Mozzy, I don't believe that his name was Crunchfuttock. I just did a search and it's the closest I've ever come to a Google whack.....

 

[snorri]

slots over a spoke and you then screw the small screw in the other side to lock it in place. This seems quite a weak idea and thus A turn too far wallops the thread. I need a new magnet now.

Do you really need a new magnet? If the screw thread is damaged you could try gluing the magnet to a spoke perhaps.

 

[Mozzy]

Do you really need a new magnet? If the screw thread is damaged you could try gluing the magnet to a spoke perhaps.

Two-pack epoxy coming out this morning or I may even have some metal weld somewhere. oh well, a good rummage round coming up.

@ Bayered. Not even close to a Google Whack on the name search it had three results, but did ask 'did you mean?'

Mozzy