When to Use Double Rib Belts？

So after buying a new replacement belt for 2.4l we realized that the one from zzp only had ribs on one side where the wheels on our engine have grooves for the ribs on both sides. The previous belt also had ribs on both sides. After looking around a little bit I couldn't find any double sided 703 5 rib belts. That is what we think we need. So if anyone knows anything about this that would be great. I am assuming it is not a good idea to put on the zzp belt that is not ribbed on both sides. I doubt you'll find a 703 belt. If memory serves (at least for Duralast at Autozone) the number is inches divided by 10. So 703 would be 70.3 inches. I think they usually come in 0.5" increments. Pretty sure on my supercharged 2.2 I'm running a 705 (70.5"). I'll check tomorrow morning.

Can't speak to the double sided as I'm not sure how your belt routing is setup I think you're overthinking this. The ribs run against the crank pulley, A/C compressor (if applicable), and alternator. The tensioner pulley is smooth and runs along the backside of the belt, so ribs don't matter on the backside.

I think you're overthinking this. The ribs run against the crank pulley, A/C compressor (if applicable), and alternator. The tensioner pulley is smooth and runs along the backside of the belt, so ribs don't matter on the backside.

He is running an add on supercharger so that might be why he needs a double-sided belt. I’m assuming the SC just makes the belt run like it does on the LSJ. Easiest way to tell if it should be smooth or ribbed as it routes around a pulley is if the pulley is smooth or ribbed. Also posting a picture.

If it’s routed like the LSJ, I’m assuming everything is almost identical.


LSJ Serpentine belt replacement part number is , rock auto has them and they are also 70.2”

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I doubt you'll find a 703 belt. If memory serves (at least for Duralast at Autozone) the number is inches divided by 10. So 703 would be 70.3 inches. I think they usually come in 0.5" increments. Pretty sure on my supercharged 2.2 I'm running a 705 (70.5"). I'll check tomorrow morning.

Can't speak to the double sided as I'm not sure how your belt routing is setup

Yeah, its how I thought it was - 0.5" increments. K5 meaning 5 rib.

I'm curious about the belt routing now, because a DIY supercharger add on using LSJ bits would make sense to use a double sided belt. The ZZP kit doesn't need a double sided belt, as jirwin and BAR-AIR have indicated based on prior posts/pics

AleX1/9's City Goblin - 07 SS/SC donor - Chassis #18 - WA registered

Good Evening, Just took a quick walk around my car looking for places that I might have added tabs or threaded lugs if I could have before powder coating (some of these are just to get you thinking). Hope this helps, Bruce Big help! Thanks BAR, will take all this into account before... Looking at the last picture here http://dfkitcar.com/forum/index.php?threads/kingchucks-and-friends-street-goblin-435-06-lt-manual-aftermarket-supercharger./post- it at least sort of looks like his belt runs on one side on the supercharger and then the other on the alternator. The LSJ setup has a 6 rib double sided belt and a one-way clutch on the alternator. NA conversions use a 5 rib belt and spin the stock (solid pulley) alternator in the opposite direction of an LSJ. That's why LSJ builds have to keep the AC compressor (for the pulley), and why the belt has to be double sided.

The LSJ setup has a 6 rib double sided belt and a one-way clutch on the alternator. NA conversions use a 5 rib belt and spin the stock (solid pulley) alternator in the opposite direction of an LSJ. That's why LSJ builds have to keep the AC compressor (for the pulley), and why the belt has to be double sided.

Right, but OP has a converted 2.4L that had a double sided belt with 5 ribs. His whole donor confuses me tbh, because a Cobalt LT would have been fitted with a Gen 1 L61, but he's got a LE5 which makes sense for a Cobalt SS/NA. I guess that makes sense if an LSJ tensioner and idler were swapped on and the L61/LE5 tensioner was removed. Key indication should be a 5 rib belt running on a 6 rib tensioner pulley.

I'm content to let OP chime back in before I continue speculating lol Sorry I havent been responsive, been a long week.

Anyway, here is what I just bought. Thank you for all the insight on this but I just didn't want to have to deal with extracting the bolt from the wheel so I just bought the whole assembly new. The rubber things were wearing out anyway so it probably needed replacing soon. As for the belt it is a 6 rib double sided 70" belt. Thank you for pointing that out Rauq, I was about to order 7 for some reason. I am 90% sure these will work but I will update when they arrive.

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