Ok to use lithium AA batteries in GXT1050's or MS355R's?

I am considering purchasing either Midland’s GXT1000’s or Motorola’s MS355R’s for use in a week long cycling trip called RAGBRAI (old, famous U.S. bike tour across IA with about 15k to 30k ppl per day).

Background on usage:
My wife and I want two-way radios with headsets for communicating when we get apart because mobile phone service goes down due to overloading (the ride is across mostly rural areas of IA). Both of the GMRS radios seem like solid choices, and include detachable mics with PTT for one-handed use while on the bike.

My question is:
Whether or not it is ok to use high powered lithium AA batteries (such as Energizer’s Ultimate Lithium line) in these units? The Energizer’s quote 1.5V’s on the package, but I know they can run over that (1.6V or even 1.65, or so I’ve heard). Will this possibly damage the radios? I would prefer to use a high capacity lithium because we may transmit quite a bit on the ride, which I figure will drain the batteries quite quickly if using the high power mode on either of those handsets, and we are trying to avoid carrying very large numbers of batteries or attempting to recharge daily using the included NiMH battery packs. Obviously the Midlands probably have better overall battery life (per installed set) due to their 4 AA capacity vs. Motorola’s 3 AA’s.

Alternatively, if you feel that it would be better to simply use good quality alkalines, I would appreciate the advice.

Thanks for any information.

Those batteries will be fine. They are totally compatible with standard AA cells.

Where people run into problems is using the 3.5 volt “AA size” rechargeable lithium ion batteries. They may e the right size; but have twice the voltage.