In preparation for installing the HD screamin Eagle adjustable forks on my 2013 XL1200C I was looking at which Red Line fork oil would match HD Type E.
Information on the web seemed to be all over the place on fork oils in general.
The "weight" the manufacturers specified sometimes didn't match the actual viscosity.
I contacted Dave at Red Line, his recommendation was to mix 75% RL Medium with 25% RL Heavy to approximate HD Type E at 40 C / 100 F.
I sent a sample of HD Type E to Blackstone for a VOA and requested the viscosity at 40 C / 100 F.
Here is the VOA Data:
(I calculated the Viscosity Index using the Widman Calculators online
https://widman.biz/English/Calculato...isc-index.html )
(works in FireFox but not Chrome)
Code:
+-----------------+-------------+
| Oil Brand | HD fork oil |
+-----------------+-------------+
| Weight | Type E |
| | |
| ALUMINUM | 0 |
| CHROMIUM | 0 |
| IRON | 0 |
| COPPER | 0 |
| LEAD | 0 |
| TIN | 0 |
| MOLYBDENUM | 0 |
| NICKEL | 0 |
| MANGANESE | 0 |
| SILVER | 0 |
| TITANIUM | 0 |
| POTASSIUM | 0 |
| BORON | 92 |
| SILICON | 1 |
| SODIUM | 2 |
| CALCIUM | 35 |
| MAGNESIUM | 3 |
| PHOSPHORUS | 208 |
| ZINC | 9 |
| BARIUM | 0 |
| | |
| SUS @ 210F | 51.5 |
| cSt @ 100C | 7.72 |
| cSt @ 40C | 41.14 |
| Viscosity Index | 160 |
| Flashpoint F | 435 |
| Fuel % | 0 |
| Antifreeze % | 0 |
| Water % | 0 |
| Insolubles % | 0 |
+-----------------+-------------+
The VOA looks very similar to a VOA of Castrol Multi Vehicle AFT I had done several years ago as far as viscosity and additives.
Mentioned because some people say to use ATF in HD forks.
I used the Widman "Graph your oils" web page (
https://widman.biz/English/Calculators/Graph.html )to create this comparison of HD Type, Red Line Medium, Red Line Heavy
and the 75% RL Medium / 25% Red Line Heavy fork oils at temperatures from 0 C 32F to ~ 50C / 122F (the data on the web page goes up to 80C but isn't in the screen shot.
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
Here is some data I assembled from web sites on different fork oils-
(may not be 100% accurate

)
Spectro Viscosity at 40C didn't seem to match the listed SDS Viscosity Index.
http://www.spectro-oils.com/wp-conte...Data-Chart.pdf
Code:
+----------------------------------+--------+-----------+-----------+-------+
| PRODUCT | WEIGHT | @ 100° C | @ 40° C | Index |
+----------------------------------+--------+-----------+-----------+-------+
| Redline Like Water | | 2.30 | 5.30 | 397 |
| Lucas S1 Suspension fluid | 2.5 wt | 3.50 | 11.00 | 230 |
| RL Extralight | 2.5 wt | 4.00 | 8.30 | 539 |
| Amsoil light 5w | 5 wt | 4.40 | 15.90 | 209 |
| Harley Type B | 10wt | 5.51 | | |
| Lucas S2 Suspension fluid | 5 wt | 6.10 | 18.60 | 321 |
| Amsoil Medium 10w | 10wt | 7.30 | 31.80 | 206 |
| RL Lightweight | 5 wt | 7.50 | 16.00 | 519 |
| Harley Type E | 20wt | 7.95 | 46.00 | 145 |
| Harley Type E VOA Blackstone | | 7.72 | 41.14 | 160 |
| Screaming Eagle Type Heavy | 20wt | 8.60 | | |
| Spectro Type E | 20wt | 8.90 | 64.9 ??? | 385 |
| RL Medium | 10wt | 13.60 | 32.00 | 442 |
| RL Medium SDS | | 13.30 | 31.70 | |
| Spectro Type Heavy | 40wt | 14.10 | 141.2 ??? | 400 |
| RL 75% med and 25% Heavy | ~20wt | 14.35 | 38.50 | ~397 |
| RL Heavyweight | 30wt | 16.90 | 69.00 | 262 |
| Screaming Eagle Type Extra Heavy | 60wt | 24.49 | | |
+----------------------------------+--------+-----------+-----------+-------+