Progressive Lowered Fork Oil Level

[gamorg02]

Quick question. When you lower your forks (1" or 2") with the progressive kit, you still measure the same distance from top of the fork tube (compressed) to the level of the oil right? I don't think the height of the bottom of the slider to the top of the fork tube when compressed changes right? nor should the oil level then?

much easier for me to measure that then 20.9 oz.

 

[4gasem]

Yes... I measured the same amount of oil as stock I believe. I used a tube measured to the correct length stuck into the fork and then sucked out the excess.

Worked great!

 

[gamorg02]

Yes... I measured the same amount of oil as stock I believe. I used a tube measured to the correct length stuck into the fork and then sucked out the excess.

Worked great!

thanks chris. picked up a $1.50 turkey baster. actually the lady did. she argued we already had one i said i didn't think she wanted fork oil on the turkey. she sighed and got it.

 

[one2dmax]

What's the measured level? I can't remember at the moment.

Sean

 

[gamorg02]

What's the measured level? I can't remember at the moment.

Sean

i'm 95% sure its 123mm for 93+ forks.

 

[satariel666]

Here ya go:

 

[gamorg02]

so i was right eh?

 

[satariel666]

Just like on the second picture.

"A" dimension so, 123mm from oil level to the top of the pipe.

621 cm3 of oil.


Its from the 2001 german v-max service manual.

 

[gamorg02]

Just like on the second picture.

"A" dimension so, 123mm from oil level to the top of the pipe.

621 cm3 of oil.


Its from the 2001 german v-max service manual.

i understand the 621 cm3 (20.9 oz) wouldnt' change, but just wanted to make sure my thoughts that the measured distance A wouldnt' change when the forks are set to be lowered. but cant' see how it does. it might be SLIGHTLY offset due to the fact there is another small spring in there.

 

[tugla]

smaller spring would just put in more oil garrett but you want that same air distance on the top for all the magic to work the same way. you just putting in the springs? got any valving going on in there? what you using for oil type/wt? just curious

 

[gamorg02]

smaller spring would just put in more oil garrett but you want that same air distance on the top for all the magic to work the same way. you just putting in the springs? got any valving going on in there? what you using for oil type/wt? just curious

right. the small spring is just the damper rod one since i'll have to have that in before i put the oil in. i'll jus tstick with the 123mm distance and not keep second guessing myself!

i'm dropping it 1" so i'm doing springs/seals/etc. i have the forks completely dismantled in the basement. the dust seals were so rusty along with the snaprings. glad i did it.

whatd ya mean 'valving'?

i'm use spectra 10wt. i know a lot of guys use a bit heavier but these mass roads are rediculous as they are. just ask rick or mike

 

[tugla]

the 10 wt will be good you'll like it, just wondering if you put in race tech emulators.

 

[gamorg02]

oh gotcha, nah. spent enough coin this year. i think i'll be impressed with the progressives as is.

 

[Nicki66]

So your putting in 15wt oil?

Did you lower the rear also? You might have to shorten your kickstand.

 

[gamorg02]

So your putting in 15wt oil?

Did you lower the rear also? You might have to shorten your kickstand.

10wt and rear has stock shocks. we'll see on the kickstand.

 

[tugla]

if ya end up needed a shorter stand garrett, i'm switching mine to stock height so could send you my shorter one.

 

[satariel666]

i understand the 621 cm3 (20.9 oz) wouldnt' change, but just wanted to make sure my thoughts that the measured distance A wouldnt' change when the forks are set to be lowered. but cant' see how it does. it might be SLIGHTLY offset due to the fact there is another small spring in there.

Gotcha.

IMO, with aftermarket springs you should fill the smaller amonut of oil, less exacltly how shorter the springs are.

For example: if the stock springs are 10" long and you want to install 9" long springs then, you need mesure the oil level exactly 1" less.


Hope that makes any sense :ummm:

 

[tugla]

as long as its just a height chg not spring diam. cant remember if its the exact same. Its volume in a cylinder so depends on how much it displaces to be real actuate. For sure you dont want too much fluid as it slows everything down but at the same time want enough for the shock not to over heat and break down the oil. i would think with a higher spring rate dont want to drop the oil level too much but i could be wrong here.

 

[DanQuin]

Essentially, adjusting the oil level in forks is a way of adjusting the "air spring" in telescopic tube forks. As the forks move through their travel, the space above the oil (air spring) will become compressed. This will slow the stroke of the suspension as the air pressure increases. (Thus all telescopic tube forks whether running progressive or straight springs, is actually progressive as it will take an increasing amount of pressure to increase fork compression).

There are problems on both ends of the spectrum when it comes to oil level changes: too little and it may affect damping, be subjected to greater amounts of cavitation and turbulence in the oil, and may not provide sufficient pressure to provide progressive resistance to bottoming; too much and you can hydraulically stop the suspension from using it's full stroke, and potentially blow out seals from the increased pressure.

When making changes, most recommend 5mm changes at a time.

Hope this helps.

 

[tugla]

good advise danquin +1 im sure this will help garrett scratch his head a little more hahaha.