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What weight oil for progressive fork springs?

Posted: Tue May 26, 2020 9:03 pm
by grantimus
I have an 82 Interstate and have seals and the Progressive fork springs coming. My question is what weight oil would you recommend? I know that OE is 10wt but seeing that I'm a bigger guy, 6'2" and 290lbs and plan on doing some camping trips with it so would like it to better handle that additional weight as well. I'm thinking 15 or possibly even a 20w for me but not sure so i need your opinions on which? I don't like how bad the bike settles when I put my weight on it and do feel like the rear shocks will be the next to upgrade because they do bottom out on rough bumps, even with running the max recommendation of pressure in front and rear. Personally I don't care much for the air suspension am thinking of going with the non air 412s for the rear. Also, my hopes that if I upgrade to Progressive front and rear that it'll raise the height of the bike a bit since I'm taller anyway. Actually, I just came across a copy of Progressive's directions stating that 10w is good "ball park" starting point except for the following exceptions "GL1100 30w and GL1200 20w. Is that right, 30w for the GL1100 with Progressive fork springs? Any of you guys running that combo?

Re: What weight oil for progressive fork springs?

Posted: Tue May 26, 2020 9:31 pm
by bruce swaybill
I have an 83 interstate with progressive fork springs, Honda 10w fork oil and just below 20psi air, as well as the progressive 412 shocks set at preload of 4 (the GW part number is only HD springs). I’m 5-10 and 240# and It rides and handles like a dream. Solid with no wallowing in the curves. When I ride my other bike i find bumps in the road I didn’t know were there on the GW. While my Fitbit logs lots of “steps” when I ride the other bike, it logs nothing on the GW, like I’m sitting on the couch.
Hope this info helps!

Bruce S.

Re: What weight oil for progressive fork springs?

Posted: Thu May 28, 2020 10:58 am
by Oldewing
I run 20w with Progressives and no air, 412's out back. 6'2 270 lbs, well over 200K like that. 82 Interstate.

Re: What weight oil for progressive fork springs?

Posted: Thu May 28, 2020 2:37 pm
by grantimus
Thanks guys, I appreciate ya taking the time to share your setups. I'm thinking that I too will try 20w with no air. Once the fronts done then I'll be ordering a set of 412s too. Did running the Progressives in front and rear increase the height at all?