What angle to check caster no X factor?

[Skip Fix]

I've seen some different conflicting angle to turn the front wheels to to not need a multiplication factor to get the caster 15 and 20 degrees. Whcih is correct?

[Gratefuldiver]

Per Marc at SC&C its 15

[Skip Fix]

Thanks I thought 15 was correct but someone else said 20 is also.

[David Pozzi]

At 15 degrees turn in and out, you multiply by 2.
Here is a great reference: http://www.smartracingproducts.com/smartcamber/SmartCamber%20Instructions_2014_final_update.pdf