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Fox forks oil weights?


quickdraw
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I have serviced my Fox 32 F100 RLC (2007) twice before and used fox 7wt fork oil. When checking trough the online service guide I noticed that they now specify fox green 10wt - anybody know why or have they just rebranded the oils?

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This is news to me too. I take it this is for the damper, not the left leg?

 

Yep, the oil volume specs sheet now has 10wt green specc'ed for both damper and right (spring) side? There is also apparently a 10wt red?

 

I do know that it specified 7wt before? The pre 2007 X series still has 7wt specc'ed.

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Using the same oil in both legs is good news for the DIY fork mechanic. It means he/she only has to keep two bottles of oil in the garage instead of three. The air piston probably still requires a thick oil such as 80W90

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The air piston oil wt is still the same. It seems strange that they changed the oil wt for the damper.

 

Oh, well I still have enough 7wt to last me a while.

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Fox rebrands its fork oil.

The important thing to remember here is that the "weight" labelled on the the oil bottle does not mean it has the same viscosity as an oil of the same labelled "weight" by another manufacturer.

There are tables available comparing the actual viscosities of oils in Centistoke (Cst), usually at a standardized temp. of 40 degrees.

The "old" Fox 7wt is rebranded Torco RSF "Medium" with a viscosity of 31.82 Cst at 40 degrees Celsius.

 

The "new" Fox ten weight oils(yes there are two!) are probably Silkolene PRO RSF 10wt "RED" and Silkolene 10wt "GREEN"

The Silkolene/Fox "GREEN" apparently has a similar viscosity to the Torco RSF medium/Fox "old" 7 wt.

The Silkolene/Fox "RED" has a higher viscosity than the "old" Torco/Fox 7wt. It follows that you can use the Fox 10wt "GREEN" in both legs on pre "FIT" damper forks.

The FIT damper oil is the higher viscosity Silkolene/Fox "RED" and the bath oil the lower viscosity Silkolene/Fox "GREEN". This is according to Fox's master oil volume chart.

Fox always used the 7wt for damper and bath oil because of their open bath design,but with their new FIT dampers, they went with the heavier oil in the damper but stuck with the 7wt equivalent for bath oil.

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Fox rebrands its fork oil.

The important thing to remember here is that the "weight" labelled on the the oil bottle does not mean it has the same viscosity as an oil of the same labelled "weight" by another manufacturer.

There are tables available comparing the actual viscosities of oils in Centistoke (Cst), usually at a standardized temp. of 40 degrees.

The "old" Fox 7wt is rebranded Torco RSF "Medium" with a viscosity of 31.82 Cst at 40 degrees Celsius.

 

The "new" Fox ten weight oils(yes there are two!) are probably Silkolene PRO RSF 10wt "RED" and Silkolene 10wt "GREEN"

The Silkolene/Fox "GREEN" apparently has a similar viscosity to the Torco RSF medium/Fox "old" 7 wt.

The Silkolene/Fox "RED" has a higher viscosity than the "old" Torco/Fox 7wt. It follows that you can use the Fox 10wt "GREEN" in both legs on pre "FIT" damper forks.

The FIT damper oil is the higher viscosity Silkolene/Fox "RED" and the bath oil the lower viscosity Silkolene/Fox "GREEN". This is according to Fox's master oil volume chart.

Fox always used the 7wt for damper and bath oil because of their open bath design,but with their new FIT dampers, they went with the heavier oil in the damper but stuck with the 7wt equivalent for bath oil.

 

Goatman, welcome to The Hub.

 

We've discussed this topic here often and it is nice to see a new perspective.

 

My experience is that the colour of the oil is not an indication of its OEM and I think Fox has changed the colour of its oil to distinguish between old and new. Nevertheless, they've made changes in suppliers and changes in the colour, but kept the viscosity of the oil required for legacy forks the same, but labelled it 10WT instead of 7WT. We know these numbers are arbritrary so why not just stick with callit it 7? Or am I missing something.

 

Tell us more about FIT please.

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Goatman, welcome to The Hub.

 

We've discussed this topic here often and it is nice to see a new perspective.

 

My experience is that the colour of the oil is not an indication of its OEM and I think Fox has changed the colour of its oil to distinguish between old and new. Nevertheless, they've made changes in suppliers and changes in the colour, but kept the viscosity of the oil required for legacy forks the same, but labelled it 10WT instead of 7WT. We know these numbers are arbritrary so why not just stick with callit it 7? Or am I missing something.

 

Tell us more about FIT please.

 

Thanks Johan,

 

I agree 100% re colour change.

I have a hunch that the Fox 10 weight GREEN is Silkolene "Maintain" 10 weight which is very similar in viscosity to the old Fox 7wt/Torco RSF.

Why Fox has decided to relabel two different viscosity oils as 10wt now is something only their marketing department would have an answer for.....

The 2011 Fox oil volumes manual has so many colours in it now it almost resembles a rainbow:

http://www.foxracingshox.com/fox_tech_center/owners_manuals/011/index.html

 

The Fox Isolated Technology aka FIT damper has been around for a number of years in the FOX 36 forks and a few others I believe.

It has now found its way into the latest generation of Fox 32mm forks.

It basically isolates the damping oil from the bath oil inside a rubber bladder.

Apparently this reduces the chance of cavitation (fluid aeration) in the oil as well as reducing the weight(yippee like 71g or something ridiculous)as you need less oil volume in the new damper.

This is what Fox has to say: http://www.foxracingshox.com/1429/

I looked at the service instructions on "Fox Help" and the FIT damper is not an easy beast to overhaul, especially compared to the open bath damper forks.

I am wary of this "innovation" as other fork manufacturers like Marzocchi have used it before, even DT Swiss has a pressurized rubber bladder in some of their forks.

Whether there will be a marked damping improvement out on the trail I do not know....but I have read reports of some of these FIT damper forks having increased stiction issues even after lengthy "breaking in" periods.

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