What length belt?

[TerminatoRS]

Current belt is 25-080774 which is 78.25” long I believe. Just swapped a bunch of pulleys and now it seems a c-hair too short. Here’s the new setup:
3” blower
1 90mm idler
3 100mm idlers
2lb lower
J2fab alternator pulley which is 69mm I think
Thump tensioner and 76mm pulley (same as stock)

I think another half inch will probably do it, but I figured it’d be better to consult the experts first.



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[TerminatoRS]

Thought I had it all squared away. Smooth and quiet, nothing rubs...etc. Now I’m thinking this belt is a shade too long based on where the stopper on the tensioner is. Should I go a notch shorter?

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[TerminatoRS]

Bueller?

 

[CobraBob]

I'm not Bueller, but I'll try to help. LOL.

You could check out the belt length recommendations chart and related info on my website. Your configuration is more custom, so the "string method" might work best for you. Anyway, here's the link. Belt Length Chart

 

[01yellercobra]

If that's about halfway on the tensioner travel I'd say you're good.

 

[TerminatoRS]

I looked over the belt guides several times and couldn't come to a clear conclusion so I bought two different lengths right out of the gates. lol The one I put on first is the longer of the two. If it weren't winter, I'd just take her out and test for slippage with some load on it, but unfortunately all I can do for now is tug the throttle cable while watching it. It doesn't slip, but that stopper on the tensioner rotates counterclockwise towards the rest (or whatever it's called) a bit which is why I'm concerned. Once there's actually some load on the system, I don't want it smacking up against the rest and squealing like a banshee.

 

[roy_1031]

I thought the 08 stood for 8 rib and the last 4 were the length. So your belt is actually 77.4” which would be a little shy of that 78” you were looking for.

Edit-
Gates says it’s 77.81” for part 080774.

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[TerminatoRS]

The 774 is what was on there before I swapped the pulleys and tensioner. I ordered two new ones (776 and 780) and currently have the 780 on the car which puts the tensioner at it's current travel pictured above. I may just change to the 776 and see what happens.

 

[olympic]

I have a Thump tensioner as well and you can't get much more gap between stop and the rest than what you have in the picture. There comes a point where a shorter belt just won't go on. But if the 780 went on faily easy then give the 776 a shot.

 

[TerminatoRS]

Copy that. Maybe I'll give a go tonight. Thanks for the input, gents!