Gear reduction

[seafurymike]

I need to gear down my drive motors and was looking at the PIE site.
http://www.piesau.com.au/

Now the AT5 units come in many sizes, so would I have to get a 36 tooth and a 12 tooth to give me the 3:1 reduction?

I would assume swinging pulleys larger than 50mm would become challenging?

/M

[rodm]

Yes it does give you a 3:1 ratio.
I don't see a problem using larger pulleys except for clearance around the the shaft or motor. The larger the pulley the more contact with the belt but not really an big issue with toothed belts anyway.