Accessory belt: 6PK 1067 vs 6PK 1065

[d00df00d]

One of the OE belts on my car is 6PK 1067. ContiTech's system says their equivalent product is 6PK 1065. Any thoughts on the discrepancy?

Reason for asking: I recently bought a bunch of parts to change all the tensioners, pulleys, and belts on my car. I did not verify any of the part numbers before ordering, and ended up with a 6PK 1065 belt. The vendor swears, and ContiTech seems to confirm, that that is the correct replacement for the OE 6PK 1067. I'm trying to decide whether to wait for them to ship me a 6PK 1067 or just throw on what they sent me.

Am I correct that the numbers indicate a 2mm difference in length? My engine uses automatic tensioners, so might a shorter belt theoretically end up with more tension on it? But even if so, I don't know how big a difference there'd be. Intuitively, less than 0.2% difference seems negligible, but I really am not in the mood to mess with this kind of thing on an 8400 RPM V8...

 

[drtyler]

I wouldn't worry about it. I doubt that 2mm is going to make any difference at all. The picture ECS shows for ContiTech equivalent for part 11287838200 is 6PK 1070. So I guess Continental has used slightly longer belts at times as well.

If it causes you to lose any sleep at all, looks like the dealer 6PK 1067 belt is less than $30.

The Continental "gatorback" belt for that application is 1067mm (actually 1066.8mm according to the website), so you could go that route for Continental 1067mm belt. Part number 4060420, which also has crosses to Ford Tempo and Aerostar applications, so your M3 could be in good company

 

[slacktide_bitog]

It's fine

I've seen them spec aftermarket belts shorter than OE by 10mm or more. 2mm is nothing

 

[d00df00d]

Thanks, guys!

 

[WyrTwister]

As long as the tensioner has enough travel to install the shorter belt , I would use it .

 

[d00df00d]

Tidbit from my meager research FWIW: Apparently, ContiTech's length tolerance for belts in this size range is ±6 mm!

Some back-of-the-envelope calculations for funsies: Assuming the stock system was designed for half that tolerance, and that all values in the range are equally probable, there's a roughly 60% chance that the 1065 will be within OE spec, let alone usable without issue. Based on that, I'm guessing the real probability is much higher and the two belts are functionally indistinguishable.