Hi I'm about to rebuild my front forks on the Vfr what oil is the best to use what grade etc

Believe OEM fork oil for cartridge NC30 forks to be Showa SS-7 which has an ISO viscosity index of 16. ISO index is considered to be a much better indicator than SAE weight. SAE weight for fork oils can be all over the place, one manufacturer's SAE 15 can be the equivalent of SAE 20 for another manufacturer.

The original sticky label on the forks says to use Honda Ultra Cushion Oil 10 (10 weight fork oil)



I'm using the Honda brand of oil at the moment but i've never had any issues before using various other brands (Castrol etc) 10 weight fork oil before.

While it's true that the ISO measuring system has less tolerance in it for the viscosity of the oil compared with the older SAE system so in theory all ISO grade oils of the same number will be a lot more similar, the suspension is adjustable. Therefor oil grade alone is not the only deciding factor in setup.

To get maximum performance from suspension it needs to be in good condition and adjusted properly, a different brand of oil might throw your suspension settings out based on a different brand of oil, but after a strip and rebuild it'd be wise to re-tune anyhow.

For road-use especially I don't think the tolerance of 10w fork-oil makes that much difference, as long as it's 10 grade you can play with the suspension settings.

Also i'm curious to where you came across this Showa SS-7?

After many hours of internet searching I came across a web page that claimed SS-7 (5wt) as the OEM oil. Given the coincidence that NC30 forks are Showa, I thought it was as good a choice as any as a starting point.

Honda Ultra Cushion #10 is the oil type from the HRC manual but I cannot find any info regarding its ISO rating or availability.

Yes ultimately fork oil weight is a personal choice however IMO sticking to one brand and one type within that brand is the best option, simply to maintain consistency, or use the ISO rating.

magg wrote:After many hours of internet searching I came across a web page that claimed SS-7 (5wt) as the OEM oil. Given the coincidence that NC30 forks are Showa, I thought it was as good a choice as any as a starting point.

Honda Ultra Cushion #10 is the oil type from the HRC manual but I cannot find any info regarding its ISO rating or availability.

Yes ultimately fork oil weight is a personal choice however IMO sticking to one brand and one type within that brand is the best option, simply to maintain consistency, or use the ISO rating.

I have a can of it here.. it's 10 weight. Not sure if there is an ISO rating on it though, but i'll have a look on the can for you :)

It's commonly available in Japan but i'm not sure if it's available world-wide.