Andrew Ferres wrote on Monday, March 28, 2011 - 11:40 pm:I'm not sure if you are understanding the 2 different locking mechanism's of seat belts.
There is Inertia Reel, and Momentum Reel.
Inertia Reel locks up when the centrifugal force inside the belt reel reaches a certain amount (like a centrifugal clutch), hence they lock up when you yank them hard.
Momentum Reel locks up when the belt reel is not at rest and horizontal (notice how when cars are parked on an angle/hill the seat belts can be annoying?). Hitting the b-pillar while pulling the belt simulates the car braking suddenly, or being hit, etc, as the locking mechanism inside the reel is activated.
JDM belts are only Momentum.
ADR approved belts are Momentum and Inertia.
Both belts *should* lock up in the event of an accident, however the ADR ones have a back up of sorts (which also makes its extremely annoying when you go to lean forward to change the radio station and they lock up!).
That said, the original belts in the Celsior are now over 20 years old, so its probably a good idea to replace them as part of preventative maintenance.