In August this year, together with my friend Michael Shamash, I drove a Trabant from London to Weimar in Saxony, Germany, where it ground to a resounding halt. Our objective lay only 50 miles farther: Zwickau, where the Trabant was manufactured from the early 1950s until shortly after the fall of the Berlin Wall. This weird little car became the signature vehicle of communist East Germany: a sort of negative consumerist icon, epitomising the regime’s shabby-totalitarianism. Yet, for Michael, the brave little car, with its bizarre “Trabiplast” bodywork – a plastic compound developed by the DDR’s own chemists – has always been a harbinger perhaps not of a utopian future, but of a utopian present that ever shadows our own less than perfect moments.

Is it a coincidence that Michael is a person of restricted height? (This is a description he wouldn’t object to; small person is also acceptable; dwarf, just about. Midget never; it is the N-word of the restricted person’s vocabulary, and should be of yours as well.) No, of course it isn’t: Michael identifies with the car, not the repressive regime that spawned it. Besides, it’s hard to imagine how a British man of Jewish-Iraqi heritage, 60 next year, who, though extremely well-travelled, had never set foot in Germany before our trip, besides a coach ride in his school days, could possibly have contracted a savage case of ostalgie. But my own presence on Michael’s odyssey needs a bit more explanation.

Michael and I knew each other in childhood – he was on the school run with us when I was only in kindergarten and he at primary school. I remember him rolling around in the back of the car, giggling, quite at ease. Then, in his teens, he was fairly close friends with my brother, and I saw quite a bit of him. My impression of Michael during this period was that he was considerably more bitter – waking up more fully, with puberty, to the less-travelled road his disability meant he was embarked on. (Again: Michael accepts the semantic requirement for disabled, but doesn’t favour it. He’s none too sure about “differently abled”, either; while he and I both are engaged, although not necessarily enchanted, by the new empowering “superhuman” rhetoric that the Paralympics have spawned.)

In their ‘rotten-mushroom-coloured vehicle’. Photograph: Laurence Grissell

Then a hiatus, during which we didn’t see each other for 30 years. You might have thought that, as someone who knew a person of restricted height well in childhood, and who believes himself to be sensitive when it comes to disability, I would never make jokes about small people – and yet I have. Indeed, I think I should state for the record that I have a sort of obsession with the very small and the very large, and the distortions of scale they embody – my fictional work over the years amply attests to this. I am also, at 6ft 5in, almost exactly twice Michael’s height, a very – almost freakishly – large person myself. Yet I couldn’t absolve myself in this way, even if my dwarf jocosity had been in private – and it wasn’t, it was very public; on a short-lived BBC chatshow helmed by Johnny Vaughan, in fact.

It wasn’t the worst thing anyone’s said or done; arguably no worse than a lot of the weird images of small people Ricky Gervais and Warwick Davis have been bruiting about in recent years, but it was egregious enough to be the basis for a parliamentary question about the corporation’s tolerance of disability prejudice. What was it I said? Well, in the green room, I’d let on to Vaughan that I played a “game” when I was in the car with my children: if we spotted a small person in the street we’d sing out, “Child or dwarf?” and the others had to guess before we drove past. Of course I knew this was utterly crass, and would never have intentionally uttered it on live television, but Vaughan wrong-footed me on air, and out it came.

Once a person as small as Michael has been noticed, all human interactions acquire a different, more charged character

Was I mortified? Of course – sickened, and all the more so when I began seeing Michael around a few years later, falling into a pattern of regular dinners. When would the matter of my disgraceful behaviour come up? It was surely my responsibility to broach it. Eventually I did: of course, Michael had known – and why wouldn’t he? A writer, academic and prominent disability rights activist, at the time of my crime he was the chair of the Restricted Growth Association. Still more mortifying was the grace with which he forgave me: he’d been very bitterly disappointed, but I could rectify my actions by being a better example. “Have you ever noticed,” he said, “how peculiar it is that people of restricted height are now the only disabled people it’s still socially acceptable to mock?” I hope I have been a bit better over the past few years, but I fear not mocking small people hardly cuts it when it comes to a sensitive engagement with the problems they can face.

So while I can’t claim to have jumped at the opportunity to realise Michael’s dream, I did welcome it: by travelling with him for several days, and hopefully being of assistance, I’d get a better insight, and with knowledge gain proper understanding. Driving the car, though – that proved quite a different matter. I had a background knowledge of the doughty little Trabi, the eastern Volkswagen. I knew it was crap. I knew it had a two-stroke engine that belches poisonous fumes and a top speed of bugger all. I knew it would have all the creature comforts of a tractor in a blizzard, and the legroom of a sock drawer, and I knew it handled so poorly it would be dangerous – quite possibly fatal on modern roads with high-speed vehicles whipping past us. Knew – but only in some locked compartment of my mind I didn’t trouble to open; not when I saw our rotten-mushroom-coloured vehicle for the first time. Not when I realised how soft the brakes and wonky the steering were – not even when I realised the seatbelts didn’t work properly and there were no wing mirrors. Yet my companion didn’t cavil at all as we grumbled through rainy central London and took the A2 for Dover.

‘Rumbling along in the stinky, rattling Trabi.’ Photograph: Laurence Grissell

I kvetched for England when it came to my own umbrella-like enfoldment in its rat trap of a driver’s seat, but Michael, despite the fact that his very short legs meant he couldn’t really sit on the passenger seat and only prop himself against it, never uttered so much as a murmur of complaint. We reached Dover with minutes to spare, and were waved aboard our ferry by a cheerful Romanian marshal, who had fond memories of his own Trabi – although he admitted he wouldn’t have swapped his current wheels, a Merc, for one. On board, we just about had time to reach the buffet, obtain battered fish so rigid you could have battered someone to death with it, eat it, and get back to our car.

I’d been about with Michael before – but not out in the way that requires stairs (or lifts, where available) and anything more than a couple of hundred yards’ walk. Michael’s walking pace is, I’d estimate, around one mile an hour, while I’m both long-legged and frenetic. Simply slowing down to accompany him began to teach me a little of the patience that must be essential if you’re a disabled person trying to negotiate an abled world.

On the ferry; in the Belgian motorway services where we stopped; at the hotel in Mechelen, just outside Brussels, where we stayed that evening; and in the restaurant where we had dinner: everywhere, in short, that people saw Michael, they reacted. These reactions may have been positive or negative – and the initial surprise of many was quickly and properly modulated, but nonetheless: the fact is that once a small person – and especially one as small as Michael – has been noticed, all human interactions acquire a different and more charged character. At the hotel, I’m sure Laurence (a radio producer and our photographer) and I asked if Michael needed any assistance; but it wasn’t until he himself pointed out the obvious obstacles that can easily arise, even in a modern and well-appointed hotel, that I seriously considered whether any of the following might be properly accessible: the hotel lift (many new ones require the insertion of a key card at a height above Michael’s head), the bed, the shower, the commode – and, indeed, the room itself, for the same reason as the lift. (And although Michael might be able to access a room, often the slot he had to insert his key card in to activate the electricity was again too high to reach.)

At the Trabant museum in Zwickau. Photograph: Laurence Grissell

Our objective was the old Trabant plant at Zwickau, which is now – fairly predictably – a museum. En route, we also stopped off to visit various Trabi-related spots. We were guided around a small museum of old DDR vehicles in the village of Sint-Katelijne-Waver, all in concourse condition, by Achiel Olbrechts, a Belgian Trabant obsessive who used to be an official dealer and now keeps the cars at his garage. His Trabis looked a great deal more roadworthy than our own. The same afternoon we reached Bonn, and were guided around its Museum of Contemporary German History by Dr Harald Biermann. I enjoyed myself (as I fear is my way) by twitting the amiable Dr Biermann about the oddities of contemporary German history. Michael, despite all the exertion involved, let alone the hours spent rumbling along the motorway in the stinky, fume-laden, rattling Trabi, remained in his element: querying and quipping, always chuckling.

In truth, I’d long since realised Michael is a glass-more-or-less-permanently-full kind of a guy, in stark contrast to my own less than sunny disposition. I once asked him about it, crassly assuming he’d reply, “If you had a disability as severe as mine, you’d have to remain philosophic”, but of course he said nothing of the sort, only ruminated for a while before answering: “Well, my mum’s a fairly optimistic sort of person, so I suppose she brought me up that way.” An answer with the ring of truth – at least for me, whose mother was often to be found lying upstairs in a Valium haze. What Michael was saying, of course, is that it is ridiculous to assume disabled people are solely their disability. Michael is a charismatic man – a good-looking one, and a charmer. No doubt he’d be all these things if writ still larger, but what I observed over the next couple of days is how brilliantly (and that really is the right word) he deploys these characteristics to pave his way in an often hostile world.

Stopping for Self to stretch his ‘horribly cramped’ legs. Photograph: Laurence Grissell

How hostile? On our last day together, we took the train from Zwickau, Michael heading for Leipzig airport and home, I en route to rendezvous with one of my sons in Berlin. The train was quite full, and while accessible for Michael from the platform, the carriage was awkwardly appointed, with high steps up to the seating. Eventually we settled, but turned out to be in the wrong class. When we pointed out to the conductor that it was difficult for us to move, she brazenly mimed picking up Michael and carrying him. In the ensuing conversation, Michael let fall a shocking story about how, in London’s Leicester Square, fairly recently, he became surrounded by people making all manner of comments – vocally, without apparent shame – about his appearance; they were, he said, perfectly ordinary people.

Michael will accept disabled assistance at airports and rail terminuses, but says the standard of care and general efficiency varies widely; he has the resources (and there is a subsidy) to take cabs. He could have driven, but would have required a specially adapted vehicle. The world, seen through my partial Michael’s eye view, was full of long and quite tedious walks, obstacles that might well require physical help to be overcome, and the ever-present possibility of negative and even outright hostile responses to the very fact of your existence.

Perhaps every able-bodied person should go on a road trip with a differently abled companion, as a rite of passage

Michael tells me that when he travels with his partner, who is averagely sized, she has got occasionally hostile and sometimes insulting remarks. And yet when I texted Michael to ask him to look over this piece for any further solecisms, he and Helen were in Vancouver. The secret of his way-finding came to me, as did another less pleasant epiphany, on a night walk up towards Wartburg Castle, outside the Saxon town of Eisenach, where, on our third night, we were staying at the hotel Kaiserhof. I had arranged to meet Michael for supper in the woody nook of the hotel dining room – a bizarre simulacrum of a Saxon hunting lodge – and gone out for some fresh air and to stretch my horribly cramped legs.

But up there on the wooded hillside, looking towards the castle – which gave its name to another, and still more unlovely, car built in the old DDR – I was gripped by fear: our last meeting that afternoon had been with Beate Dittmar, a teacher who grew up with Trabi-driving parents. We had met her at Point Alpha, above the Fulda Gap, the pass between the wooded hills of Thuringia where the west expected the Soviet hordes to invade. Michael had been his usual charming self, but on the final 30km leg to Eisenach, negotiating winding and hilly roads, I became horribly aware of our Trabi’s terrible vulnerability: the brakes were mush, the handling appalling, and I was beginning to have trouble with the dash-mounted gear stick. It crystallised in a horrible image: if anything came on to the carriageway unexpectedly, even 100 yards ahead, I’d be unable to stop the Trabi from hitting it in time, and while the DDR chemists may have had great faith in the rigidity of their Trabiplast, I didn’t. Moreover, there was Michael, propped up against the passenger seat, the completely inadequate seatbelt somewhere down round his thighs.

At the Trabant museum in Hottelstedt village. Photograph: Laurence Grissell

Back at the Kaiserhof, I confronted Michael with this potentially fatal state of affairs – one we’d remained wilfully oblivious of for the past 500 miles. Should we go on? Michael was in no doubt: we’d come this far – and of course, he’d come a lot farther. There’s a rather Zen quality about Michael – a function, I think, not of a lack of concern for his personal safety, but a consuming desire to seize the day. It’s this that enables him, a small person, to bestride the wide world; this, and a willingess to always engage with people, whoever they might be. Time and again I observed shocked responses to Michael, and how he used them to his advantage, deploying his formidable charm to seize control of the situation. Jean Cocteau observed that charm is the quality that enables someone to solicit the answer yes before they’ve even posed the question – and Michael has it in abundance.

The Trabi, its mushy gearbox finally disintegrating, conked out the next morning near Weimar, about 30 miles short of our destination; we caught the train for the final leg. Michael wasn’t too disappointed – we had the delights of the old Trabant plant to look forward to. But when I parted from him the following day, it wasn’t our automotivational trek that stayed with me, but the sense I had of having been graced by the experience of travelling with Michael. I stress: graced, not shriven. My guilt at retailing crass and hurtful sentiments in the past was still there – and rightly so; but being with Michael had forced me to slow down. A lot. Slow down, and engage with the world in a more sensitive and patient manner. There’s an awful lot of well-meaning public information that urges us to consider the predicament of the differently abled in our society but, as ever, it’s the doing rather than the telling that can really shift attitudes. Perhaps every able-bodied person should go on a similar road trip, with a differently abled companion, simply as a rite of passage – perhaps then we can finally realise Michael’s own ostalgic vision.

As for Michael himself, as we took our leave he pronounced me forgiven, which was just as well: I wasn’t sure I could cope with much more penitential motoring. His enthusiasm for travel was, however, undiminished, and his affection for Germany cemented by five days of close contact with the Trabant, a car he continues to adore.

• Will Self and Michael Shamash’s road trip, Self Drives: The Trabant, is on BBC Radio 4 at 1.45pm every day from 28 November to 2 December.