When I put on my UDP, I replaced my accessory belt. I tightened it to Chilton's spec of "no more than 1/2inch deflection at the longest span of the belt between pulleys". I think my belt is at the recommended tightness. I don't have a whine or a squeak. Which is better for reliability? To have the belt more loose or more tight?


Dave

 

An overtightened belt will wear the accessories quicker. For example, an overtightened serpentine belt will wear the AC compressor and PS pump quicker, possibly causing premature bearing failure.

A loose belt will slip, and make "squealing" noises. This slippage can cause premature wear on the belt itself.

Neither case, too loose or too tight, is good for the car. Since you already have the rough spec of 1/2" deflection under 10kg of pressure, why not adjust the tensioning bolts to achieve proper belt tension?

 

 

I'd say a loose belt would be safer. You will hear it being loose, or notice the air conditioner cutting out. Then you can just adjust the thing very easily. If you wear the belt, big deal, as its cheaper and easier to wear the belt then it is to replace the bearings in the components from overtightening.

 

I'm responding only because your Subject line calls me out. Eric L. gave good advice, and so did ericdwong.

A overly-loose belt is safer than an overly-tight belt. However, the best course of action is to make the belt tension "just right".