Try for a matched pair. Not buying a matched pair is probably why my replacements did not last long. Actually I also was not overly impressed with the continental belts even though they have a good reputation.

So I went to a full line auto parts store and selected a pair of sae utility belts that are a little thicker in cross section. They do not centre rub and have seemed to stand up very well so far. No initial stretch adjustment after a little use needed I noticed..

Time will tell but they have better traction I believe than the continentals did. They ride just a very small amount proud or above the pullies. We wil see how that works out when they eventually wear down a little.

Five dollars apiece here and probably less in the states. I just went out and checked they are 39 inches long with the first sae cross section larger than the continentals and there is now a slight amount of run in stretch.

Not enough to re adust the alternator tension yet by any means but it is there. It appears they have settled down in the pullies as well. They are now no longer proud of the pulley tops at all although it was a very small amount originally. At this point I am unlikely to go back to the specific metric belts.

That could change just unlikely to. Also a 39 inch belt of this type gives you a start position with a maximum alternator adjustment available down the road. The new continentals were centre area of the adjustment range on initial installation.

There is something to be said for serpentine belts with the tensioners used today. Vee belts will always need retensioning over time. Incidentally the car is a 1984 300d.