Fork Oil capacity with Progressive Fork Springs

Discussion in 'General Tech Talk' started by Dean0, Sep 30, 2018.

  1. Dean0

    Dean0 .040 Over

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    Decided to upgrade the fork springs on my Roadster and with Progressive (the brand)

    What is the fork oil capacity?.. concidering the Progressive's have more coils than the standard type.
     
  2. 9Ball

    9Ball Supercharged

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    I have these on my Valkyrie...typical recommendation from Valk owners is 1 to 2 oz less oil than specs call for. Don’t go too far up on the viscosity...keep it near recommended weight or else the front end will be too stiff and the benefit of the progressive suspension will be minimized.

    My 2 cents...you can always call progressive technical service for best recommendation.
     
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  3. TURBO200R4

    TURBO200R4 stand up straight and grab the world by the a$$

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    I do not know touring
    but based on the small amount of oil that goes into the forks i would think that it would not be much less..
    measure the oil and see what i mean.
     
  4. Journeyman28778

    Journeyman28778 "And this one is just right" ~ Goldilocks

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    @Dean0 I'm about to put progressive springs in my Roadster and was also wondering the same thing. The Progressive springs will have more volume causing the resulting air space to be reduced if using the standard amount of oil. What did you find out?

    @BillB mentions this in a post here about an R3T (Touring progressive fork spring upgrade)

    "Book says air gap of 110mm. Instructions from Progressive sez nay. They say 140mm is absolute minimum air gap due to the spring design displacing more oil. I tend to think that the spring instructions over rule the manual in this case."

    The 30mm difference is about an inch, which seems pretty significant.

    I can't find anything on the Progressive site about this. Maybe it will be included with the springs when they come? If not, wondering if it's a different spec for the Roadster.
     
    Last edited: Nov 4, 2018
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  5. sonny

    sonny Living Legend

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    I have the progressive springs and filled the forks as recommended per manual. Even have the ridicules special tool recommended per manual for this job. IMG_0461 (2).JPG Running this for fork oil and have no complaints at all. Very smooth and responsive.:D:D:D:D:D
     
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  6. Journeyman28778

    Journeyman28778 "And this one is just right" ~ Goldilocks

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    Thanks @sonny. I was also thinking of going with 7W and will do so based on your recommendation.
     
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  7. sonny

    sonny Living Legend

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    I just used what others had recommended. :thumbsup::thumbsup::thumbsup::thumbsup::thumbsup::thumbsup:
     
  8. barbagris

    barbagris Mad Scientist

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    140mm airgap is the absolute maximum airgap independent of the spring. Any decent suspension guy CAN calculate this. But ime - even with the correct springs (to gain correct static and dynamic sag) 110 is too small.

    The stock springs are WEAK so you gain some air-spring by reducing to 110mm. But if you have the sag set correctly 125-130 seems about right. I run 120 at the moment with Maxton cartridges and springs - I have "lost" about 10mm of suspension travel. But I am happy to do so.
     
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  9. BillB

    BillB Turbocharged

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    I went ahead and followed the instructions that came with the springs and set the air gap to 140mm and it worked like a charm. Once the forks were back on and the springs were in the tubes the oil level was quite high in the tube. Another 30mm of oil would have had the tubes almost full with the springs in them. Based on my experience with the R3T I would go with the information that comes with the springs.
     
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  10. Dean0

    Dean0 .040 Over

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    I ended up using 10W with an air gap of 110mm on the roadster... stiffened up the front end nicely.

    As for the Touring, I went with the standard 10W and an air gap of 140mm as per instructions that came with the springs.
     
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