Anyone who runs a Citroën on 165x400 Michelins will know the empty-wallet feeling you get when the tyres need replacing. You just about have to pawn the car to buy the tyres, as they are nearly NZ$500 each. The rear tyres on my car are cross-ply retreads with plenty of life left in them; the Michelins on the front were worn out. The new tyres option was not an option at all; the two new tyres would be worth about as much as the car. So I cast around, looking for cheap options.

Someone had some half-worn second hand tyres at a half-worn pro-rata price. Certainly an option, but they would have given only half the life. Someone else had some cross-ply retreads in good condition, on rims, for a very reasonable price. I tried them on the front for a day, but couldn't keep the car on the road: it was very inquisitive, didn't want to go where I pointed it and kept wanting to investigate what was on the side of the road or what was over the yellow line. So back went the retreads. For me they are fine on the rear, where all they have to do is hold the back of the car off the ground, but not on the front.

Then a friend suggested the radical option, which he developed as a solution to this problem on his son's old D runabout. Get a pair of 400mm Citroën rims and a pair of 15" rims (Volkswagen ones are probably the easiest to find). Take them to a specialist wheel engineering shop. Cajole them into doing what they consider to be a horrible job quickly. The horrible job is to cut out the centre of the rims and weld the Citroën centres onto the Volkswagen rims. All this costs about $100 per wheel, by the time you pay for the Volkswagen rims (assuming you provide the Citroën wheels yourself), cleaning, cutting, welding and painting, and a few dollars to cover my friend's expenses in organising this for you (which seems mainly to involve hassling the wheel people to get on with it). Don't laugh, there's more to this cajoling caper than you think: I had to wait about a month for mine, and they were wheels my friend had given them to do several months previously, so he could have a couple on hand!

Now comes the best part. You go to a tyre retailer (just about any one will do) and you buy a couple of ordinary 165x15 tyres. Brand new, NZ-made, steel belted radials for about $100 each. And when they have worn out, the next lot of tyres is just as cheap.

This was such a radical option it had to be the answer. The D is such a radical car I'm sure it would approve. There are some problems, however, all connected with the smaller diameter rims. Because I have converted only the front wheels I have two different tyre sizes on the car and only one spare. So if I have a puncture on a front tyre I would have to get it repaired quickly. It would not be good to have two different sized tyres on the front of the car for long. Secondly, the Citroën hub caps no longer fit on the smaller diameter rim. Hub caps from the 15 inch wheels on later D models seem to fit though, and look similar to the original ones. Alternatively, my friend suggests getting those little GS caps that clip on the centre of the wheel, and drilling holes in the wheel so the clips hold. Also, the steering ball-joints foul the smaller diameter rims, so you have to file a bit off the ball joint (but not much though).

The most interesting problem is that the slightly smaller diameter wheels change the gearing of the car. I calculate that it lowers the gearing by about 5%, so at a given road speed the engine is spinning 5% faster and the speedo says you are going 5% faster than you really are. In my case this is a benefit, not a problem, because the tired old motor needs all the help it can get. Quicker acceleration and more comfortable cruising, because the worn little 1.9L engine is not struggling as hard to move that great lump of metal around. It still cruises just as fast, maybe faster (although it might just be wishful thinking!). The falsely high speedo reading also provides cheap insurance around the speed cameras. You could use 185x15 tyres instead, and these would be a few per cent faster than the 165x400s, but that size is not made in NZ, so you would have to buy Michelins, which cost over $200, somewhat defeating the purpose of setting yourself up to run on cheaper tyres.

So all the problems are surmountable. After over a year's running on the new front tyres I am very pleased with the result. And grateful to my friend for his advice and assistance. Contact me if you want a rave.