Yes, most beadlocks only hold the outside lip. As I mentioned before the inner bead area is designed differently and much wider which makes it much harder to debead.
This picture shows what I am talking about. The left side would be the outer lip and the right side the inner lip. If you look on the left/outer lip area outlined in red that is where the outer tire bead sits on. That is only as wide as the tire bead and you don't have to push the tire very far to knock it off the rim lip. If you look on the right side/inner lip area outlined in red that is where the inner tire bead sits on. Basically you have to push the tire a lot more to knock if off the wheel lip. If you have never mounted or dismounted a set of tires there is a reason you always take them on and off from the left/outer lip of the wheel. It's nearly impossible, or at least extremely difficult, to mount or dismount the tires by going over the left/inner lip because of this.
The second reason is that in the majority of conditions there is much more force pushing against the outer lip of the tire. It's simple vehicle dynamics. For example if the machine is leaned over to the left with the driver's side in a deep rut most of the forces are pushing against the outside edge of the tire inwards and will pop it off the bead.
From personal experience of off-roading various vehicles for 20+ years it is very rare to debead the inner portion of the tire, beadlocks or not. I have personally debeaded the inner one time and maybe have seen this 1 or 2 other times on different vehicles. However I have debeaded the outer numerous times on the same vehicle (prior to running beadlocks) and have seen it dozens of times on other vehicles.
And I will say it again.......you CAN debead the inner tire, it's just not nearly as likely to happen for the reasons stated above.
*disclaimers
- There are "reverse backspace" wheels where the inner and outer lips designs of the wheel are reversed between inner and outer....same concept as above but you mount the tires from the inner lip now. There are are some design reasons for doing this to get a really "deep dish" wheel, but they do work well in off-road vehicles if you don't have beadlocks because now the outer bead of the tire is sitting on the wide part of the wheel lip.
