peteinpa Posted December 18, 2020 Share Posted December 18, 2020 I've done the searches, found 1 thread that worked but can't find it back. Right now I have stock suspension on my 2015 FJ-09. Between the front and rear the front is way worse to me than the rear. I'm 340 lbs and want to put in 1.0 Race Tech fork springs (the highest available easily). The factory fork oil is 5 wt. what oil should I go with? I'm not doing any other fork changes. The left fork has a set rebound and compression damping built in right? Or does it do nothing but lube the spring? The right is adjustable. I'm interested in different weight oils left to right, I will be setting height at 130 mm or higher to assist against bottoming out. I'll be using Maxima fork oil, and don't mind mixing 2 to get the weight I want. Just for the record the 2015 FZ-07 stock suspension is WAY worse than the FJ-09 and it took me a couple years to improve it. I know I may want a new rear shock once I improve the front. Link to comment Share on other sites More sharing options...
Supporting Member betoney Posted December 18, 2020 Supporting Member Share Posted December 18, 2020 52 minutes ago, peteinpa said: I've done the searches, found 1 thread that worked but can't find it back. Right now I have stock suspension on my 2015 FJ-09. Between the front and rear the front is way worse to me than the rear. I'm 340 lbs and want to put in 1.0 Race Tech fork springs (the highest available easily). The factory fork oil is 5 wt. what oil should I go with? I'm not doing any other fork changes. The left fork has a set rebound and compression damping built in right? Or does it do nothing but lube the spring? The right is adjustable. I'm interested in different weight oils left to right, I will be setting height at 130 mm or higher to assist against bottoming out. I'll be using Maxima fork oil, and don't mind mixing 2 to get the weight I want. I don't think you will need to set a higher oil level if you have correct springs, are you bottoming out currently? The more oil you add the less air gap you have - potentially less plush, too much oil and you might not get the full travel of the fork. How does the current rebound and compression damping feel to you? Higher viscosity (thicker) oil will give you more damping effect, like closing the adjusters. Ideally you want a lighter/lower viscosity and set the feel with the adjusters but fork oil is cheap enough to experiment and fine tune the feel. Not all oil viscosity is equal between different brands, find one brand that is readily available to you, (maybe Bel Ray or Maxima?) and experiment with that same brand for consistency. If it were me, I would start 5w and go higher only if you need to. Good Luck. ***2015 Candy Red FJ-09*** Link to comment Share on other sites More sharing options...
Supporting Member piotrek Posted January 7, 2021 Supporting Member Share Posted January 7, 2021 On 12/18/2020 at 9:52 AM, betoney said: Not all oil viscosity is equal between different brands... Perfect segue to my recent experience with marketed weight and actual viscosity... Torco discontinued their 10.75 cSt@40C oil (marketed as Torco RFF 5) about 5 years ago, and simply shifted higher cSt@40 oils in the series down the "weight" rating... so the new Torco RFF 5 is now16 cSt@40. A difference that would certainly affect performance. Torco RFF 5 is mentioned on this forum and others as having low cSt@40 (equivalent to RockShox 2.5w), which is no longer true. Link to comment Share on other sites More sharing options...
whisperquiet Posted January 7, 2021 Share Posted January 7, 2021 All you ever wanted to know about fork oil.... Suspension Fluid - Pvdwiki Link to comment Share on other sites More sharing options...
Supporting Member piotrek Posted January 7, 2021 Supporting Member Share Posted January 7, 2021 18 minutes ago, whisperquiet said: All you ever wanted to know about fork oil.... Suspension Fluid - Pvdwiki Viscosity table is out of date a bit, but yes... otherwise a great reference site for all things suspension. Link to comment Share on other sites More sharing options...
peteinpa Posted January 7, 2021 Author Share Posted January 7, 2021 Thanks. Looks like it'll be Maxima 5 wt. set at 140mm. I hope the springs are drop in. Link to comment Share on other sites More sharing options...
Supporting Member betoney Posted January 7, 2021 Supporting Member Share Posted January 7, 2021 1 hour ago, piotrek said: Perfect segue to my recent experience with marketed weight and actual viscosity... Torco discontinued their 10.75 cSt@40C oil (marketed as Torco RFF 5) about 5 years ago, and simply shifted higher cSt@40 oils in the series down the "weight" rating... so the new Torco RFF 5 is now16 cSt@40. A difference that would certainly affect performance. Torco RFF 5 is mentioned on this forum and others as having low cSt@40 (equivalent to RockShox 2.5w), which is no longer true. 43 minutes ago, whisperquiet said: All you ever wanted to know about fork oil.... Suspension Fluid - Pvdwiki 22 minutes ago, piotrek said: Viscosity table is out of date a bit, but yes... otherwise a great reference site for all things suspension. 17 minutes ago, peteinpa said: Thanks. Looks like it'll be Maxima 5 wt. set at 140mm. I hope the springs are drop in. I'm not sure how up to date this list is, but this was compiled by Matt Patton. Oil Viscosity - Forks-by-Matt ***2015 Candy Red FJ-09*** Link to comment Share on other sites More sharing options...
Supporting Member piotrek Posted March 20, 2021 Supporting Member Share Posted March 20, 2021 Thought I would share a tool that I used to blend different viscosity oils to tweak non-adjustable compression damping on my FJ-09 fork. I used this calculator to get my ~13cSt@40, which still allows me to work with the rebound damping adjuster. Link to comment Share on other sites More sharing options...
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