I have a standard walmart ordered Huffy Cranbrook. I upgraded to a spring tension which I love. Now I want to upgrade my sprocket. I was told to get a 40 tooth adapter. But some sites ask me what 'diameter' I want ect. ect. Could you guys link me to a good site to purchase one and the right specs to maintain. I'm not spending $80 just to have to send it back. Thank you! much love to this forum community. Making my first build a wonderful experience.