This chart was compiled as an example of different fork oil data as published by the respective manufacturers.
These figures came from the actual respective company's SDS / TDS sheets and are subject to change by them.
See the updated SDS / TDS information from each manuf. before trusting any charts on the internet.
You can also go to the Widman Calculators online and input your own information to print out a chart.
This helps with missing information not listed in the chart below.
Fork Oil | Nominal | Viscosity cSt | Viscosity cSt | Viscosity | Visual |
---|---|---|---|---|---|
Brand | Viscosity | @ 40°C (104°F) | @ 100°C (212°F) | Index | Color |
Harley Davidson | Type E 8) | 41.14 | 7.72 | 160 | |
Maxima9)(petro) | 5wt | 16.2 | 4.41 | 202 | Clear |
10wt | 37.4 | 7.72 | 182 | Clear | |
15wt | 47.1 | 8.49 | 151 | Clear | |
20wt | 71.1 | 11.28 | 151 | Clear | |
Lucas Oil (synth) | 5wt | 25.34 | 5.5 | 148 | Blue- Green |
10) 11) 12) 13) | 10wt | 42 | 7.6 | 153 | Blue- Green |
15wt | 49.2 | 8.6 | 154 | Blue- Green | |
20wt | 77.5 | 12.4 | 161 | Blue- Green | |
Red Line 14) (synth) | “Like Water” | 6.24 | 2.51 | 365 | Clear |
2.5wt | 8.96 | 4.16 | 507 | Light Blue | |
5wt | 15.87 | 7.35 | 512 | Yellow tint | |
10wt | 31.66 | 13.42 | 438 | Light Red | |
30wt | 69 | 17.5 | 275 | Orange tint | |
Belray 15) | 5wt | 17.4 | 4.2 | ||
7wt | 29.3 | 5.5 | |||
10wt | 36 | 6.6 | |||
15wt | 52.9 | 8 | |||
20wt | 77.1 | 10 | |||
30wt | 115.3 | 13.1 | |||
Amsoil Susp. Fluid 16) 17) (synth) | Light #5 | 15.9 | 4.4 | 209 | Green |
Med #10 | 31.8 | 7.3 | 206 | Blue | |
Motul 18) (synth) | 5wt | 18.1 | 4 | 119 | Amber |
10wt | 36.2 | 6.1 | 115 | ||
15wt | 57.2 | 8.4 | 119 | ||
20wt | 79.5 | 10.1 | 106 | ||
Motorex Racing Fork Oil 19) 20) (synth) | 2.5wt | 15.10 | 4.2 | 201 | Red |
5wt | 22.6 | 5.6 | 205 | ||
7.5wt | 35.9 | 7.7 | 192 | ||
10wt | |||||
Motorex FORK Oil 21)(petro) | SAE 10W/30 | 68 | Yellowish | ||
Castrol Fork Oil (petro)22) | 5wt | 15 | 3.8 | Clear & Bright | |
10wt | 32 | 6.3 | 150 | Red | |
15wt | 46 | Red | |||
20wt | 68 | 8.6 | Red | ||
32 | 32 | 5.6 | Light Yellow | ||
Castrol Fork Oil (synth) 23) | 2.5wt | 16.5 | 4 | Red | |
5wt | 28.1 | 5.7 | Red | ||
10wt | 42 | 7.5 | 150 | Red | |
Spectro fork oil 24) (petrol) | 5wt | 21.7 | |||
10wt | 33.3 | ||||
15wt | 47.2 | ||||
20wt | 72.7 | ||||
Spectro Golden Cartridge 25)(synth) | 5wt | 16.2 | 3.5 | 150 | |
7.5wt | 26 | 4.5 | 150 | ||
Spectro Platinum SX400 26)(synth) | 2.5wt | 9.2 | Clear |
PJ1 Fork Oil (petrol)27) (Highly refined mineral oil (C15-C50) is 70-99% weight) Synthetic anti-seal swell additive added. Says they are all of High Viscosity Index and Light Red in color. No viscosity weights are published however even in SDS. As a matter of fact PJ1 has the same SDS data sheet (for and that includes) 6 different weights although they publish that they have 8 different weights. Meets or exceeds OEM is published
Independent testing (not affiliated with Harley Davidson) was done on HD Type E fork oil. 28)
Based on the data from that testing, the chart below was created using the Widman "Graph your oils" web page.
The chart is a comparison of HD Type E, Red Line Medium, Red Line Heavy and the 75% RL Medium / 25% Red Line Heavy fork oils.
Temperatures from 0C / 32F to ~ 50C / 122F (the data on the web page goes up to 80C).
You can see clearly how the higher (442) viscosity Index of the Red Line Medium fork oil changes viscosity less at colder temp.
This should give a more consistent suspension at lower temps. Again, trust your own results / testing.