I'm replacing the lower sliders on my 15 RGS. I see Harley offers three different types of fork oil? Which one should I use and why?

 

Ask someone at the shop where you're going to buy it.

 

I put some of the heavy Harley brand fork oil in my 11 Road King. I put in the same amount that I got out so I know didn't over fill it. Man it was harsh, I ended up draining about half of that out and adding some of the lighter weight oil to soften it up and it was much better.

If I remember right there are 3 different weights of oil Harley sells but they don't say what weight they are. I'm thinking they are 5, 10 & 15 wt.

I think I would stay away from the heaviest oil.

 

This is what I run in my '04 Road King, and it's what a local dealer recommended. The forks feel a lot better than they did with the original fork oil.
http://www.harley-davidson.com/store...eagle-fork-oil

 

I use the same fork oil in my 2012 Heritage. I began using it when I installed my chrome front end kit. I like it better than the stock fork oil since I get less brake dive with it.

 

You can certainly mix different viscosities to create a custom blend if needed.
Don't want your forks to "dive" during braking? Add spring.

 

I agree. I only changed to a heavier oil to help with dampening, not to reduce brake dive. It was just something I noticed with the heavier oil.

 

Depends on your load...how heavy is the load on the bike , if you weigh 300 lbs 2 up soaking wet then the heavy oil might be too harsh for you..compared to 450 lbs like us...I like about 10wt, last time I mixed bel ray 7 and SE racing fork oils, it was perfect.

 

Thats a good point. I'm 165# wife is 110# thats probably why the heavy weight oil was harsh for us.

 

I get noticeable braking dive, was going to order springs but my dealer said try SE oil first because it will produce a noticeable difference. I haven't done it yet, but I was impressed that they were trying to save me some $.