Idle Swing Arm Percentage

Ford SportTrac Forum

Help Support Ford SportTrac Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Not open for further replies.


Nov 3, 2019
Reaction score
Deer Park WA & St Croix, USVI
What engine do you have?
V6 engine
What year is your Sport Trac?
What Generation is your Sport Trac?
2n Gen Owner
Hi All a quick side question/poll. When your truck is running well, if you look at the top of your idler arm pulley, what percentage works for you?
0% swing does not working for me. Or with a smaller belt tensioning it 50% of the swing range does not work for me either?
Is just having the tensioner at about 10% of it's swing capacity the best?
Thanks Mattee (Maka)
It’s a spring. The more you pull( the direction to release tension on the belt) the more pressure it exerts on the belt. That said, the tensioner should live around the middle for 95% of the applications out there. You don’t want it close to either end of the spectrum as it will bottom out or lose tension.

Im sure this thread is directly related to your belt/acc drive issue… As I stated in that thread, I feel like something is still not correct. You shouldn’t need a shorter belt, unless you’ve change something.
Last edited:
Instead of starting another thread for the same issue or subject, please post in your original thread.

EDIT- Can't merge threads. This thread is locked. Please post in original "HELP!!! Serpentine Belt" thread.
Not open for further replies.