Timing belt - when does it break on a Golf IV 1.9 TDI?

Re: Timing belt - when does it break on a Golf IV 1.9 TDI? (Falp)

I had my timing belt replaced at 59k miles. Only mod is the UP chip. And there were aleady small surface cracks in it.

Re: Timing belt - when does it break on a Golf IV 1.9 TDI? (Falp)

It makes absolutely no difference to the timing belt what state of tune the vehicle is in.
The power to the drive wheels doesn't go through the timing belt, so as far as the belt is concerned, it doesn't matter how much power is going to the drive wheels.
The load on the belt to operate the camshaft is the same no matter what the rest of the engine is doing.
The load on the belt to operate the injector pump might change a little bit but only under conditions where the "extra" power (over and above normal maximum power output) is being demanded, and even then, it is only a theoretical difference which in reality is likely to be insiginificant.
Previous advice still stands: do not go even ONE kilometre beyond the scheduled service interval for your particular vehicle, regardless of the state of tune. Preferably, do a thorough inspection at each oil change interval, and change it sooner if any abnormal conditions are observed. DO NOT use inspections as an excuse to extend the change interval ... do not go ONE kilometre beyond the scheduled service interval, no matter what else happens.