I'll be replacing sc and multi belts and sc tensioner, and all idler pulleys this weekend.
Question on the main belt tensioner pulley - I see the Gates 38015 is a poly replacement, also the Dayco 89017 poly, and the Dayco 89007 steel pulley. The 89007 is listed on the Advance Auto website as the correct pulley,but everyone else shows the 89017. The steel pulley is 31mm wide, the poly is 25mm.
Overall diameter and bearing diameter are the same for all three.

So, will any of them work? Just concerned about the extra width of the steel pulley.

Any of them will work. Some folks prefer the plastic or steel over the other. Personally I see things as it'* the bearing that goes bad and they use the same bearing in both.

That means when the bearing locks you can burn the plastic pulley and toss the belt or you can lock the steel pulley and burn up the belt then toss it. Either way if we ignore the noise the bearings usually make, we are buying a pulley and belt instead of pulley only.

Thanks! I'll just stick with the OE-type poly.

Advance Auto only had the steel pulley.

I don't ever want to replace those belts/tensioner/pulleys again. What a PIA! Most of the pulleys had ridges on each side from wear. Hopefully good for a few years at least.

They should last for a good long time.

Probably get another 14 years!

I just replaced mine at 177,000 miles. (Maybe you saw my other thread.)

Pulley started squealing on Saturday night, sounded god-awful by Monday morning as I drove to a job interview. Though my drive belt didn't snap from wear and tear, the one around my waist did… how odd.

I went for the $18 steel one at Advance. Bought it online and saved 20%. Wasn't even aware that they made plastic ones.