I've made several short excursions with three of the following QRP rigs (except for the Currahee, which I just received today) and am considering which of the four to carry with me on longer trips like the TAT and various BDR's.

Conditions would be: Bumpy riding, likely to fall (I hate riding in deep sand!), exposure to heat and humidity.

I operate only CW and would like to activate parks (and possibly SOTA summits) on the way, usually only on 15, 20 and 40 meters.

The antenna in all cases would be a 5m (17-ft) telescoping whip attached to a mount on the bike, a loading coil for 40 meters, two radials and with an antenna tuner. The latter is a must to compensate for variations from one set-up to the next.

Power would come from the bike's 7.4AH lead-acid battery. 

These are the radios I'm considering: 

The least expensive of all my options, mine is a 15-40m version. I would have to carry a dedicated battery (3S LiPo) in order to not exceed the radio's input voltage limitation and a dedicated charger as well. (Evidently not anymore - see comment from KL7MJ below!) And a manual tuner like the ZM-2.

A work-around to the manual tuner is to shut off the radio's high-SWR protection circuitry and use an auto-tuner but this carries a degree of risk.

Along with the Currahee, the QMX is the smallest and most physically rugged and offers a lot of versatility in a tiny package, however this comes at the cost of electronic fragility due to the input DC limitations, especially if the antenna is not well-matched.

This is a knock-off of the original mcHF, which is no longer available. Covers 10-80 meters with about 8-10 watts out. Has a built-in speaker but requires an antenna tuner. Probably rugged enough - certainly cheap enough to replace (though I doubt I would) if I damage it.

This radio offers a lot of bang for the buck and I like it a lot but, depending on the seller, quality can be hit or miss. I was lucky in getting a good one and won't provide a link to any specific seller since they vary so much in reliability.

This is a Steve Weber KD1JV design which means that it has a low-noise receiver with great selectivity and that it is compact and rugged enough to be suitable for motorcycle travel. Its three bands are exactly the three that I use the most.

No need to carry paddles as they are built in - but they do take some getting used to. 

I would need to carry a tuner, patch cable and either earphones or a tiny (powered) speaker. Power would come from the bike's battery.

This is the most rugged radio of the bunch and I may very well carry it as an second radio, if not the primary. 

This is the most expensive, yet most complete, radio of the bunch. Battery and ATU are built-in and the motorcycle's 7.4AH lead-acid battery can either power the KX2 or charge its internal 2.6AH battery. More about that here.

The integration of battery and ATU make this the fastest rig to get on the air and the one with the least amount of other items that take up space and need to be attached, kept track of, etc. I can be calling CQ in less that 10 minutes after stopping at a site.

I've taken the KX2 on an off-road 400 mile motorcycle ride in Colorado and there were no issues at all despite the radio not being anyone's definition of rugged. I kept it rolled (burrito-like) in a sheet of foam which was carried in my tank bag.

This is my current favorite for the trip. 

I own the 4 radios mentioned above. One that I don't own and that is no longer obtainable that would be a worthy consideration is the Xiegu X5105.

All bands, built-in ATU, built-in battery. This rig tries to be a KX2 and if they were still in production, I'd definitely consider taking it as I would cry less if I damaged it than I would for a KX2.

I suppose it was superseded by the X6100/6200 - a radio I have owned and don't like due to the clumsy implementation of CW memories. 

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