What is everyone using? I've seen the Ural version and various military grade cans used as well. I'd like to be able to lock it to the bike and lock the cap if possible.
I use a 15L fuel can to top off as-needed. When it's empty, I fill it. I also have a few 1L bottles and Wolfman bottle holders that I carry on a long trip, though only once so far because, in Vietnam, if you're near civilization, there's a gas station coming up soon. As you can see, the can is locked in place by the spare tire. Yes, it could be stolen, though I'm not worried. The cap cannot be removed unless the can can be, too.
Do you want to maintain an aesthetic look (i.e. have a jerry can)? If not, rotopax has worked well for me. Quick easy on/off, nice mounting brackets, and lockable. Lighter too, since its not made of metal.
Having more fuel just means you're gonna be twice as far from home when you break down Best to play it safe and putt yer Ural round the town .
Every rig that I've looked at that carries spare fuel uses the OEM 10L jerry can, or a RotopaX fuel container. I've seen a pic or two of the small RotopaXs mounted inside the trunk, although that's not something I'd personally recommend doing. Locking caps aren't anything that I've seen, though.
I think I would like to maintain the aesthetic look if there is a mount and can that work well. I am familiar with the rotopax having used them on other vehicles. The rotapax has a locking mount now as well.
We have used the SC mounting area for a 5 gal or the 2.5 gal plastic red container. Would suggest a thick carpet as a none abrasive cover over the sidecar's outside step where many dogs step first. Now anyone needing a ride must step over any container strapped down. This location will better help in quicker right turns as well. This is only used when out & about. In city, no need.
I carry a Rotopax gasflask in the truck, it's never leaked, and it's vapor tight so there's never been any sell of gas in the trunk. IMO, from personal experience it's safer and more secure than an external jerry can.
RotopaX containers are indeed robust, but nothing is immune to failure. I'd rather trade a bit of security for safety, as it concerns the possible loss of a few liters of fuel on the Ural.
Part of my experience is when someone tampered with the jerry can on my Patrol, undoing the latch on the cap. I noticed a strong smell of gas, and found it after loosing half the cans worth of gas while riding. I also know others who have had fuel cans stolen. I've never had any fuel container fail, so I'm simply balancing actual problems against remote possibilities.
I'm sorry to read about the tampering that you experienced. I'd be fibbing if I said I wasn't worried about the possibility of vandalism, as you mention, and vis-à-vis carrying fuel inside the rig's trunk. If I didn't have the spare tire providing some degree of security for the jerry can, I might not carry the latter. So the idea of having a RotopaX secreted in the sidecar is something I'd consider as a fallback position here.
My Jerry was used as decoration only...didn't want the weight of 8lbs a gallon DE conforming the sheet metal Luckily there's all kinds of ways to carry fuel.....When I'm off road exploring I carry 4 of the 30oz MSR bottles with me Much easier to pour without making a mess and you don't have to wrestle a bunch of weight when your arms are noodles from riding hard I came up with a little saying along time ago to help remind me that .............. "When you take a break top off the tank" These little bottles make that task super easy .
I've had 2 2 gallon rotopax's's mounted inside my 'hannigan classic' for a few years now with no issues at all. One in the footwell under the carpet and the other behind the seatback using the trunk wall.
I have several of those exact MSR fuel bottles, and the Wolfman bottle holders that are also pictured. They're performing yeoman's duty on my Suzuki dual sport. ...although, since I've installed the supertanker Acerbis fuel tank on the Suzuki, I could reassign the MSR bottles, etc. to Ready Reserve for the Ural.
Check Amazon for Round external fuel tanks. They have aluminum cylindrical fuel tanks from 1 to 5 gallon. Sent from my SM-G955U using Tapatalk
How much "extra" fuel you need will determine what your options are. How often you will use the extra fuel may help you determine how much you want to spend and how you could mount it.
You could also just do what I do and run a bike cable lock through the molded in handles on the rotopax (or the ones on a jerry can) and through the side rack it's mounted on. Won't stop someone from opening it but will prevent / deter and quick theft. Also can uncoil the lock and run it through your jacket and hemlet so you can leave your jacket and helmet on the bike worry free