Safety of taking a bicycle to a country where they drive on the other side of the road?

Bicycles are made so that when making a turn signal, one can brake on the hand not occupied making the turn signal with the primary brake, BUT with incorrect assumption what the primary brake is.

The incorrect assumption is that the primary brake is the rear brake. Thus on the right driving countries, the rear brake is on the right (because you make left-turn signal in these countries so the right hand is free), and on the left driving countries, the rear brake is on the left (because you make a right-turn signal in these countries).

My opinion is that this doesn't matter much for one-handed braking. Braking one handed either brake will do, as you can't brake hard with only one brake on the handlebars. Braking two handed, you probably want to use the primary front brake with your primary hand. Most of us are right-handed so that means the front brake should be on the right.

So, the safest option (assuming you are right handed) is to ensure your right brake is the front brake and use that setup always no matter where you ride the bike. On most of the countries, this means the brakes should be reversed.

There may be legal requirements for the default configuration of new bicycles sold, but a friendly bicycle shop will reverse the brakes on request, and you can always do whatever you want with your bike. Nobody is going to arrest you if you have two working brakes in the reverse configuration.

Note that some brakes such as V brakes have different parts for right-front and left-front setups. The right-front V brake has 135 degree noodle and the left-front V brake has 90 degree noodle. The 135 degree noodle allows for a slightly better cable setup for the right-front configuration, but this actually doesn't matter. A long time ago, I set up a V brake bicycle to have the right-front brake lever configuration, and the 90 degree noodle worked just perfectly.

In some countries there are very strong rules (or maybe even laws) about which brake lever handles which brake.
In other countries it is up to the bike factory or bike shop.

This has resulted in my mother having the brakes reversed on her (then) new bike and the bike shop did switch them as soon as asked.

When I bought a new bike I asked the bike shop to switch the brakes as I did not use the rear brake enough to keep the cable going. Again the people in the bike shop had no problem with switching the brakes.

I see no reason not to bring the bike you are used to unless the cost is high. (In which case I might ask for the brakes to be swapped if it is not as you are used to now.
Just realize that learning to ride on the other side of the road is not natural and you should give yourself time to adjust, by riding on safe paths and low traffic roads.

I am British living in Spain, and I ride my British bike here, so have some experience. I agree with others that you are probably best advised to ride the bike you are used to. If there are any regulations, I have not seen any signs of their enforcement in over 10 years of cycling here.

I just wanted to add that the hardest things to master are looking over your (other) shoulder (if you use a mirror, you might want to change it to the other side) and roundabouts. Riding on the other side of a lane is not such a big deal, and moving to the side where you want to turn to is quite natural, but going round roundabouts the "other" way is just weird. I imagine it would be easier to cope with these novelties on a bike which you're used to.

Personally, I miss some questions that I would consider first:

• Will your own bike be the only one that you ride, and you the only rider of your bike, or will you borrow local bikes resp. lend yours to locals?
• Do you plan to stay for a longer period of time, or is it likely that you will move back before you get accustomed to the "reversed" brake sides?
• How important is brake layout to you, in terms of safe braking?

If you choose to reverse sides, it might be a good idea to dedicate some time to get accustomed to the new situation, e. g. do some emergency brake training, and start every ride with an emergency brake for the first few weeks. Depending on your riding style and the traffic situation, you might want to train anyway, as you need to look over the correct shoulder and in the correct directions in different crossing situations, as was pointed out before.

While I live in the "right side driving" Europe, I have been in Japan 3 different times, once when I lived there for a semester, twice while I was there on a cycling vacation.

The first time I bought a BSO locally, the second time I took along my bike from Europe, the third time I rented a bike on the spot.

The most confusing part is to start on the opposite side of the road on day 1, but past that there is no big difference. I don't even remember I had to get used to a different braking arrangement when I used the locally sourced bikes.