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9 4 18 Volume Sag Calculator BikeCo

Fork Volume Spacing Calculator with Sag

We had a lot of click through, emails, chats, etc on the previous volume spacing calculator. We decided to produce second to help riders better understand tuning windows. Check out BikeCo’s Fork Volume Spacing Calculator with Sag.

Like the previous calculator this works best on a computer. It will work on a mobile device however the data will stack vertically. It is again based on the basic dimensions of a 160mm Fox 36 Float Grip 2 fork.

Expanding on the concepts in the earlier calculator this offers riders a chance to look at how adding or subtracting sag in correlation with volume spacing changes PSI. Use the calculator to gain a visual concept on how modifying volume spacing, sag or both will change a PSI ramp rate.

Enter a starting PSI (which will auto calculate to 20% sag) as well as the numbers of volume spacers you wish to compare.

Fork Volume Spacing Calculator with Sag

[supsystic-tables id=4]

Having an understanding of how ramp rate is effected by volume spacing and starting sag percentage will help you better tune your suspension.

Example of Use

For instance say we want to increase support in the mid stroke with the least amount of change to bottom out.

With this calculator you can compare a number of spacers in Col A versus another amount of spacers in Col B.

For this example lets compare 0 at 18% sag and 1 spacers at 20% sag, starting at 65 starting psi.

If our starting point is 0 spacers with 20% sag see the following develop:
40% sag = 84.93     60% sag = 100.31     80% sag = 122.49     100% bottom out = 157.55

Decreasing sag 2% (to 18% from full extension) without changing spacers results in:
40% sag = 86.08     60% sag = 101.67     80% sag = 124.15     100% bottom out = 159.69

Adding a volume spacer while remaining at 20% sag looks like:
40% sag = 86.19     60% sag = 102.98     80% sag = 127.90     100% bottom out = 169.05


Looking at this data we can see that lowering the sag 2% resulted in a more less dramatic change of pressures as the fork compresses. Essentially riders would see a 1.4% increase in PSI.

Decreasing the volume while staying at the same sag results in a higher ramp rate. Instead of the constant 1.4% without changing volume, changing the volume results from .12% at 40% to 5.9% at bottom out.

Since in this example we are looking at increasing mid stroke with minimal change to the bottom out reducing sag by 2% is a better place to start testing our setup.

Of course, other examples with different requirements produce different ideals.

Your Next Steps

So you’ve read this far – you’re into suspension tuning. And no one at BikeCo will blame you for that. There is SO much of a modern bike’s personality locked up in proper functioning suspension that getting your bike dialed in is a critical point in your setup.

Learn how compression circuits help fine tune your setup in the Suspension Compression Tuning Basics blog here.

Ready for the next level of performance? Check out BikeCo Pro Tune Suspension options for Fox forks and rear shocks. Our Pro Tune Suspension personalizes the component’s performance band to your specific size, riding disposition, ground speed, setup, experience and terrain.

Are you struggling to fine tune your suspension? When is the last time it was serviced? Aged oil compromised performance introducing additional friction, heat, etc which can create issues dialing in a bike. Contact our expert staff about how maximize your suspension’s performance.

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