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Suspension Oil Comparison: WPL vs. Fox and RockShox

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Posted By: Shopify API

Jan 9, 2020


Before you begin reading make sure if you haven’t already, read this post and watch this video . Those will inform you of everything you need to know about Oils, Viscosity Index, cSt, Lubricity and much more.

We get several emails asking how to determine what suspension oil weight you need for your bike. We wanted to clear this up and show you a couple charts that will help you decide which oil you need, by showing the characteristics of each variation of our oils, biking OEM (original equipment manufacturer) brands, and a popular aftermarket brand in biking. This way, you can compare the numbers of our oil to what else is commonly used, and then correctly choose the right oil for your needs.

The “weight” system is a bit confusing when it comes to identifying oils because it’s not a real unit of measurement. It is terminology used to describe certain oils, but is non-standardized. This means that a 5 weight oil could also be something like a 2.5 or a 3 weight oil from a different brand. The important details such as the kinematic viscosity in units of centistokes isn’t usually talked about first. We’ve made it much easier for you to determine what oil you need by creating these charts below that show each weight, the viscosity for each weight at 40 degrees celcius and 100 degrees celsius and also the Viscosity index.

Using these charts you can determine what oil you need for your suspension. For example, if you’re using a 15 wt(weight) Rockshox oil you’d want to use our ShockBoost 20 wt oil because the Viscosity at 40 and 100 degrees celsius are similar to each other. With Maxima’s 5wt and 3wt you can use our ShockBoost 2.5 wt because the viscosity at 40 and 100 degrees celsius and the Viscosity Index are similar. You could of course use our 5wt oil as well if you want a slightly thicker oil. Suspension tuning is an art form.

ShockBoost Viscosities
ShockBoost Suspension Oil Viscosity @ 40°C (cSt) Viscosity @ 100°C (cSt) Viscosity Index
2.5wt 16.5 5.40 320
5wt 20.8 6.34 290
7wt 24.6 7.1 280
10wt 35.1 8.9 250
20wt 69.1 11.0 152
Maxima Racing Oil Viscosities
Maxima Suspension Oil Viscosity @ 40°C (cSt) Viscosity @ 100°C (cSt) Viscosity Index
3wt 14 5.2 370
5wt 15.9 3.51 150
7wt 21 7.30 349
10wt 29 9.4 334
15wt 46 8.48 154
20wt 65 12.9 201
RockShox Viscosities
Rockshox Suspension Oil Viscosity @ 40°C (cSt) Viscosity @ 100°C (cSt) Viscosity Index
2.5wt 10.75 4 325
5wt 16.10 5.05 285
10wt 33 8.4 240
15wt 42.80 10.4 250
Fox Racing Oil Viscosities
Fox Racing Oil Viscosity @ 40°C (cSt) Viscosity @ 100°C (cSt) Viscosity Index
5wt 15.8 4.07 168.2
10wt 47.36 13.69 302.7
20wt 98.9 13.6 137.9

All of these stats can be found here and here.