Towing a SMART
Here goes nothing!
I've been researching this subject for weeks. I've heard all the horror stories from Merc about the seals blowing on the gearbox. Dreadful wear on the gearbox itself, etc. etc. But, to cut a long story short (and it is a VERY long story), the SMART does not have a conventional automatic gearbox (which would get damaged if towed). The best description I've heard is that it's a software controlled manual box. This means that when you put it in neutral, that's exactly what you get. No problems. Because I'm a suspicious individual I didn't take all this without checking around, so when the Caravan Club held it's annual rally in my back garden (Burghley Park) a couple of weeks ago, I took a ramble around and found people who were towing SMARTS on A frames. I asked each of them what their experiences were and not one of them had ever had a single problem. Then I asked the dealer that I bought my RV from. They said the same thing: Both they and several of their customers have been towing SMARTS for years without any adverse effects. Pretty convincing evidence. However, one thing worth bearing in mind is that sur le continent, several member states are not too keen on A frames. They have to tolerate them as apparently, the ruling is that the law which applies is that of the country of origin, i.e. if you arrive from the UK towing with an A frame, there's not much they can do about it if you stand your ground. However (again), the Dept of Transport is currently reviewing and updating the UK rules on towed vehicles and no-one seems very certain as to what the revised definitions will be. It could be that they will come into line with other EU states and make A frames 'illegal'. Whether this will apply retrospectively is anyones guess.
Bottom line: For more or less the price of a braked A frame, you can go to Woodford Trailers and get a very nice, fully braked trailer that will take all four wheels of your SMART off the ground. As far as I know, no-one (not even the French) object to that and as a bonus, you only wear out two tyres instead of four.
So after weeks of convincing myself that an A frame was the answer. I went out and bought a trailer today.