Originally Posted by Boraxo

We have done that but everything has to go right, specifically:

• No delays from PVR (check recent arrivals for track record)
• Arrival at T-6 customs (add 15 minutes if you have to walk from TBIT to UA gates in Terminal 7-8)
• Global Entry (even then we find CBP is always the worst at LAX - seems to go out of their way to hassle you
• No checked baggage (always takes forever to arrive at LAX)
• Clear membership (TSA precheck line can be long)

Without checked bags it is easily doable if your flight is on time. Very risky with checked bags. Better to take the longer connection (if possible) and then try to jump on the earlier one if you can make it. We've done this repeatedly.