Tell them you're taking out the Air conditioning - or changing a size...
Back when, the Belt length WAS measured in Inches.
Now it is measured by mm (millimeter) so they usually stock the belt as an indexed reference in Metric sizes to handle the aftermarket.
So say you have a your 97" belt, convert it to mm...
To Get mm = multiply inches by 25.4
X = 97 * 25.4
X = 2463.8 or just round up to 2464...
Now, they may have this in stock but it's listed as (Brand) 3K - 246 - 4
They used Centimeter and the oddball (4) as the last digit is the offset length Perimeter to Interior - K can be the reference to the Rib/Composition - V X 4 structure
On certain websites, that all they use is the mm or Metric equivalent - so as long as you can convert to mm or Centimeters (divide mm result by 10 to get the cm size as you see above) you should be good to go.
One word of caution - they usually "skip" specific sizing - because; say you need an Alternator Belt to fit but don't have A/C? I've seen 3650 (365.0cm) or 360 CM but not 3624 mm - they'd have in 3600 (mm) or 3650 (mm) so you'd need to buy the size LOWER then what you originally have measured - at least within 50mm or 5cm - so go with the 3600 mm size and then you can tension/adjust tensioner as needed.
- Using the above 50 mm increment - as you go into LONGER sizes - the sizing issue becomes more moot because of the sheer lengths needed to run the serpentine thru all those pulleys and then the tensioner assembly becomes less critical - so if you're pulley is a smaller diameter - this means they use a smaller pulley to "spin up" the shaft of that alternator to provide more power in the charging system for slower RPM vehicles that use a modified Automatic CVT transmission where the engine can run just above idle throughout most of the in-city driving speed ranges and barely crack 2,000 RPM if accelerating and back down to about 1,100 RPM as they cruise.
- So they "spin up" so that usually then indicates the adage of LOWERING the distance the belt travels to make the circumference of the pulley attain one revolution. (Spin up - same speed, same distance, but Pulley attains more torque and speed to convert to rotation. So again - use the smaller - shorter size - to achieve this.
Below is Inch reference but Metric may be easier for the store clerk to go get it for you.
[ATTACH=full]37662[/ATTACH]
