TTA Serpentine Belt number?

[Steve Wood]

I woke up and thought it might be getting time to change the belt on my cars...

I like the shorter replacement belt that was put out for the TTA's   GM 12399983 which had the numbers 6pk 1605 on them

think that meant it was 1605 mm long.  The original belts seemed to be a bit too long and would often allow the idler to hit the ac compressor pulley when the engine revved.

What are you guys using for new belts these days?

[SuperSix]

I search for 635K6, I use Gatorbacks mostly. the Gatorback PN is 4060635

http://www.amazon.com/Goodyear-4060635-Gatorback-Poly-V-Belts/dp/B000C32J6I

They work fine for me. I guess if you want to shave 1/2" off, you could get the 63".
http://www.amazon.com/Goodyear-4060630-Gatorback-Poly-V-Belts/dp/B000C34KR4

[Steve Wood]

if I recall, the 63 is a little short....the 64 is too long and the 63 5/8 would be better if it was a hair shorter

[SuperSix]

if I recall, the 63 is a little short....the 64 is too long and the 63 5/8 would be better if it was a hair shorter

The 4060635 is 63.5, not 63 5/8.. I have always used that length. I believe the TTA belt is 64"

[Steve Wood]

no..the TTA was the same and then the replacment I cited was a bit shorter

Ordered two Goodyears on close out from Rock....they will fit the T...not sure on the GN due to the overdrive pulley on the waterpump

[Steve Wood]

also ordered a Gates K060630 which Gates says is the replacement for the GM number above....stran ge the description says 63 5/8"...Hopefully it will fit the GN

[Steve Wood]

Okay, I ordered a couple of the 635s and when they arrived, they also had 1605 stamped on them just like the TTA belt from GM.  I looked at them and thought that is going to be too long for the GN with the overdrive pulley so I went to the Gates cross index and saw that they listed the TTA belt as a 630 so I ordered one of them as well.

Originally, the T had the TTA belt on it and had about 1" clearance between the idler and the compressor clutch pulley.  As the Gates 630 was shorter than the 635, I saved it for the GN and put one of the 635's on the T.  It gave me the same 1" clearance as did the factory TTA belt. 

On the GN, I could not see any numbers on it, but, I had about 1/4" clearance on it which meant I only had about 1/8" tension on the idler.  I popped it off and put the 630 from Gates on it that was also listed for a TTA tho it did not have 1605 stamped on it. Magically, it was a perfect fit and I now had 1" clearance on it which is about right to center the tension on the idler.  I was one happy camper tho I was tentless.

Both were cracked to heck and I was running on borrowed time.

The numbers stamped on the belts are approximate outside diameters but it does not mean one can compare one brand to the other as they are made to fit a range of lengths and companies don't seem to compare their numbers with one another.  On Rock Auto, the Goodyear 635 is listed as 63 5/8" but the same belt number may vary a bit from brand to brand.

Looks like the Goodyear 635 that Mark proposed above is a perfect fit for a car with stock sized pulleys and it looks to be the same length as the TTA replacement belt that we used to use.  Sure is easy to change the belt on the front mount car!

here are a couple of pics to show how much difference there is between a 630 and a 635 on the GN...original appears to the 635 and the last is the 630

[SuperSix]

Sweet! I actually helped the infamous Steve Wood! 

[Steve Wood]

yep, the belt you suggested is the same length as the old TTA replacement belt which had 1605 stamped on it...

strangely, the belt I used on the other car which needed a shorter belt is listed as being the replacement for the TTA belt as well...but it is definitely shorter...I guess the moral is to use what fits and ignore the numbers