Do some brand of Serpentine belts work better than others?

[unforgiven]

I've been reading about changing the serpentine belts and when I go out to look at what to purchase, some reviews for some brands seem to say the belt doesn't fit but may not be CX-9 specific. So my question are:

1. Looking at all the brands, AC Delco, Continental, Bando, Gates, etc. Are there some that are well known to not have good fitment and to stay away from as well as which ones are known to fit best?

2. Are the aftermarket tensioners ok to use? The AC Delco one with belts is much cheaper than the Mazda OEM.

3. I'm sure OEM is some name brand. Do we know who made the belts and tensioners on the 2008 models?

Thanks!

 

[table5511]

I can't answer your questions, but can add that these 2 belts are low cost. I bought oem belts online. Maybe 30 bucks? BTW the only way I got the stretch belt on was to use many zip ties on the power steering pulley and rotate crankshaft and pull stretch belt over pulley. The belt is next to the frame rail so a belt tool won't work.

 

[Bronco Boy]

1. Looking at all the brands, AC Delco, Continental, Bando, Gates, etc. Are there some that are well known to not have good fitment and to stay away from as well as which ones are known to fit best?

Name brands are good; Delco, Gates, Dayco, Goodyear etc.

2. Are the aftermarket tensioners ok to use? The AC Delco one with belts is much cheaper than the Mazda OEM.

Yes. Again, name brands are good. Stay away from cheap offshore brands. Delco is cheaper because that is GM's aftermarket division, and they make tons of parts for tons of vehicles. Mazda makes parts for Mazda only, so the cost will be higher.

And if you buy a quality belt and it doesn't fit, it most likely is wrong for the application.

 

[Rubbertoe]

I just replaced my serpentine belt last night. I used a Gates serpentine belt. My CX-9 is 2013 with 60K. The reason I replaced it was because I have heard a few times a squeal in the mornings when I start the car. I believe it is when I have the A/C on. I checked the Stretch Mark and mine was very close to the Max Stretch(about 1 mm away). So I decided to change it. The belt had no cracks and in good condition(just slightly stretched i guess).
The problem I found was that the Tool I borrowed from O'Reillys to pull the Tensioner was too long and didn't allow me to pull the tensioner farther. So I ended up having to cut off some of it to make it shorter. I then asked my neighbor to help me pull it while i was installing it through the Wheel bay. It really was easy. However I spent most of my time trying to use the long tool which ended up being pretty long.
I checked the Stretch mark after installation and it was close to the minimal. After driving a few miles, I found that the stretch mark indicator is moving towards the nominal.