Timing belt longevity

[Cozi]

Other than my Spider I have owned two other cars that had timing belts. An '89 Honda Prelude and a '95 Mazda Millenia. Both of them had timing belts that were good for 100k miles. I had thought that was a result of timing belt technology evolution and that it would carry over to the belts available today for the Spider. We're still stuck at 30k. Just wondering.....,what's up?

[So Cal Mark]

the belts that last 100k are of a different design than the Spiders' belt. If you look at the teeth on a Spider belt, they are square. Square-tooth belts tend to have the teeth shear off. More modern belts have round teeth that don't shear. Fiat was very conservative with belt life since most of their engines were interference motors.

[Cozi]

That sounds like an issue that could be overcome with cam-wheels etc. that are equipped with teeth that would interface with the new belts. Certainly there are belts out there that would fit. Mark?