Suspension oil?

[BIG TOOL]

Hi Guys,
I'm getting ready to change the oil in my shock, and forks. Its an '07 EC250 with the Sachs shock. LTR valved the forks, and the rear is stock. I was just wondering what weight oil to use for the job.

Thanks, 'TOOL

 

[GMP]

I send the shock back to Les for inspection/oil change.

For the forks what worked very well is a 50/50 mix of Honda 5w and 10w fork oil. Easy for me to get at the Honda dealer in town, but any good 7.5w should be OK if available.

 

[Dave]

You are going to need two different oils for the job.
I've used Bel Ray HVI 3wt and Spectro Ultra Light SPL in WP, Ohlins and KYB shocks with good success.
There are plenty of fork oils listed on this page:
http://www.gasgasrider.org/html/susp-oil.htm
Pick a fork oil with something around 20 to 30 cSt @ 40C viscosity and you'll be fine. If you get out in cold weather get one with a low pour point - your wrists will thank you for it.

 

[skid jackson]

I used motorex 7.5 weight which I believe is what the manual spec is. Saves mixing thing together. Motorex is swiss so it's gotta be good stuff!! btw 7.5 is not a common weight most shiops had 5 and 10 wt on the shelf. i just lucked into a local shop that had motorex

 

[Dave]

You can't trust the labeled "wt" of suspension oil as it often doesn't correspond to the actual viscosity. For example: Torco RFF Fork 7wt, Maxima Racing 7wt and Silkolene PRO RSF 7.5wt have viscosities of 16, 27 and 37 cSt @ 40C respectively.

 

[skid jackson]

so how do you find out what you really have???

 

[GMP]

You need the cst specs, or just relate what you have previously used and how it feels. Without even knowing the cst specs, I can tell you that the 50/50 mix works better than BelRay 7w, which seems too heavy(stiff) to me.

 

[Dave]

A weight (wt) is a range of viscosity not a specific viscosity. Here's a couple a charts, that don't completely agree by the way, that show how various wts compare with actual viscosity.

http://www.bgprod.com/blendr/pdfs/viscosityChart.pdf

http://www.powerstrokenation.com/forums/showthread.php?t=1503

When it comes to selecting an oil, decide on the range and pick one from the chart. The chart is sorted by viscosity at 40 C to make fork oil selection easy. Note that there are some shock oils in the list that don't make for good fork oils. BelRay HVIs are an example (they don't contain anti-foaming agents).

 

[GMP]

Well the Honda dealer in town no longer has the 10w SS8, so I got some Spectro 125/150 cartridge fork fluid that is very close in ct @ 40 deg C to the SS7/SS8 mix.