How to determine gear spec

[dago]

Hi to all

Newbie here, i m trying to find specs from gear i have to replace.
It is not as of now if i can have them from the manufacturer of my bike and if they can be availlable they will be around $150.00 each, i need 4.
So i m trying to find an other way to replace these gears but i m getting lost searching on the web.

Is there a way to to determine what are the specs of these gears so i could buy somewhere else or have them produce by someone else ?

Thank you

 

[francist]

Try here, good information and very recent.

The gears in my head don't mesh

I have a question. If I want to make 4 new gears but I only have the number of teeth of each gear, how do I calculate the OD's of the gear blanks if I have none other variables available? Because I am making new gears,I don't have any other variables. The gears are for my lathe and in the...

www.hobby-machinist.com

 

[dago]

Try here, good information and very recent.

The gears in my head don't mesh

I have a question. If I want to make 4 new gears but I only have the number of teeth of each gear, how do I calculate the OD's of the gear blanks if I have none other variables available? Because I am making new gears,I don't have any other variables. The gears are for my lathe and in the...

www.hobby-machinist.com

Thanks Francist for the lead, i have a lot of reading to do i guess, first i think i have to do is determine if it is a metric gear or not.