It is important that the distance is consistent, otherwise you will get some noise in the RPM data. Other than that the dimensions are min/max type dimensions. 

 The dimensions of theets in photo mustn't be followed with extreme precisione correct? 

Looks great!

For automatic brake. It's only to polished.

Hi jostein, what do you think about this wheel? 28 thoots. 

The issue with many wheels is that the distance between the teeth is too small. To fix this, you remove every other tooth. Then the distance between the teeth will double. You can remove the rim too, but it is probably not necessary.

Do you mean to remove the rim circled? Or the thoots of wheel?

Sorry but I can not understand which other thoots i should remove

Do you mean to remove the rim circled? Or the thoots of wheel?

Sorry but I can not understand which other thoots i should remove

Thanks 

Eric

Sure! You just take an angle grinder and remove every other tooth. It can be done by hand, no problem.

Sorry, can you explain me wich other tooths are to grind off?

You are very patient and kind

This should work if you grind off every other tooth: 

https://uk.rs-online.com/web/p/timing-belt-pulleys/0183619/

Ok, is necessary that wheel Follow the spec in photo. I think it is so difficult find a wheel that Follow these spec. Could you suggest me any website to buy the wheel?

Thanks 

Hi,

The trigger wheel in your link looks too to be 5mm wide, does it not? Make sure it follows this spec:  http://yourdyno.com/the-trigger-wheel/

It does not look like it will follow the spec from the photos. But it was very cheap!!

You can go down to as low as 20 pulses per second and still have good auto brake performance. 200 pulses per second is really only needed for inertia dynos, or if you insist on having 100 RPM updates per second. It's a bit overkill! 

I Will make dyno with automatic brake control. Im going to buy a Steel timing belt pulley. I have found one with 68 tooths and 5mm pitch, look The link below, in your opinion this pulley can work with your rpm sensor? 

pitch.  https://m.ebay.it/itm/Pulegge-dentate-per-cinghie-positive-XL-037-Passo-1-5-5-08mm-in-acciaio/142668151387?hash=item2137af3a5b:m:m9bF-Rbm0BLbej_U7InaVZg&varId=441651973554

Thanks aalot

Eric