iPhone sat-nav apps tested: On your bike

All the sat-navs offered many of the same features, and we had no trouble plotting a route between two postcodes in London. All offered the choice between landscape and portrait views, which you can't get from most dedicated sat-navs.

Unfortunately, all had many of the same drawbacks too. Support for cycle routes was very poor, although Sygic was the best of a bad bunch. All of them directed us on to busy A roads, even where a bike route was nearby.

All the sat-navs also struggled with their GPS connections. Although the iPhone in our tests always had a direct line of sight to the sky, all the software struggled when we were surrounded by tall buildings -- which means most of the City of London was a failure zone. They also ate battery, with all three draining around 30 per cent during our 5-mile, 40-minute test.

Audible directions were almost universally useless, with demands to turn coming far too late to be useful or safe. When we went off-piste and took an alternative route, none of the sat-navs we tested did a good job of adapting. Most of the time, they either kept fruitlessly directing us the same route, or just asked us to "turn around when possible".

We also disliked all the sat-nav user interfaces, none of which followed the usual iPhone standards. Instead, each walked its own path of oddly grouped functions, shifting button locations, and unclear results -- although TomTom had the nicest-looking system, and CoPilot had the best use of multi-touch zoom.

Google Maps

Until the iPhone's GPS improves, we'll be sticking with Google Maps. It has a clear user interface that takes advantage of the iPhone's keyboard and multi-touch zoom, comes up with decent routes, does a great job searching for specific locations, and best of all it's free. It doesn't have many of the premium features the sat-navs boast, such as TomTom's IQ routes, but since many of those features don't work well on the iPhone, we don't think they're worth paying extra for. Unfortunately, it doesn't specifically support cycle routes, but its walking routes are often a good alternative.

The main advantage of sat-navs is they offer turn-by-turn navigation and all maps live on your phone, so you don't need a data connection to download maps as you go, like on Google Maps. In our tests, the turn-by-turn help was almost useless, so we'd only recommend an iPhone sat-nav app if you're likely to be travelling where you can't get data, or it's too expensive to roam abroad.

If money's no object, we think despite its flaws, TomTom edges out the competition. TomTom tells us when the hardware dock comes out it will significantly improve the app's performance -- but of course, that's even more money to lay out.

Both CoPilot and Sygic fight it out for last place, but they're much cheaper. Go with CoPilot if you like a smoother interface and social-networking features. Choose Sygic if you want to be able to browse the map Google-Maps-style when you're not following a route.