Most comon is around 45, but to get a real number you need at least to have the crown height for the fork you will need for the frame you have, and the headset you will run, and the head tube angle. Also, since it doesn't hurt anything to have more info, you may as well know the actual inflated diameter of the wheel and tyre you will run, though that starts to get picky unless a few similar small numbers get added up.
Wait a second, are you running the 650 on a 700 frame. Otherwise why aren't you just measuring the offset on your current fork. What kind of brakes are you moving to.
Your question isn't really a framebuilding one, unless you are planing to make a 650 fork that will fit properly in the place of the 700c.
I am, Im going to use a 650c fork with a 650cc rim in place of a 700c fork and 700cc rim.
Im just using my Apex brakes. If it doesnt fit i'll just get deeper brakes. But i need to find out how i would measure my offset? How would i know what is correct.
Im assuming 30mm. But thats just a guess. im prolbally going to get the 30mm anyways because it is a Oem factory in china with primer on top of carbon composite and im getting it shipped in from my uncle for free. He works for a cross sea boating company. But its not getting boated its fedex and no logistics check so it wont take 9 months.
But 30mm will do i think if not ill just spend another 30 to get a new one accomidating the offset before. I don't really care about toe bite. I just need my geo to be a little better.
Oh and CC is .. cubic centiliters a measure of volume , not distance .
Actually, cc = cubic centimetres. This is common measurement for displacement in engines or litres. There are actually 1000 cubic-centimetres in a litre or 10 cc per cubic centi-litre. So one cc = 0.1 cubic centi-litre.