Fork oil for 1100

[vambo]

Hi
Anyone who knows what grade the stock oil is on the 1100 ?

Leif

[Richard]

10W20 according to this link

[vambo]

Thanks

Leif

[Freddy]

Now all you have to do is try and source 10W20 fork oil......

[Richard]

Why? Or is it hard to get at your place maybe?

[Freddy]

Why? Or is it hard to get at your place maybe?

To my knowledge (or at least in this part of the world) no one sells multi grade 10W20 fork oil. That's what those numbers mean, and oil that behaves like a very thin oil at low temperatures, yet like a reasonably thick one when the temperatures are hot. All fork oil is sold these days as single weight e.g 5, 10, 15, 20. So really a 10W20 specifications sort of says any of these oil weights will be fine, depending on the operating temperature.

Next problem, unlike motor oil, there is no universal standard as to what a 15 weight fork oil is. One manufacturers 15 weigh oil may be about the same as another's 20 weigh oil. While the numbers give some indication, all they really tell you is how that weight compares to other weights in that same manufacturers product line.

Even in the bike, the 'correct' weight oil is going to be a compromise. Put in an oil that is thick enough to give you the rebound damping you want, and you may find it gives excessive high-speed (fork movement not bike speed) compression damping.

Bottom line: It's more trial and error than science.

[vambo]

Thank you Freddy..
I also noticed that they don´t sell multigrade fork oils living in Norway i guess a 10 grade will be fine

Leif

[Freddy]

Thank you Freddy..
I also noticed that they don´t sell multigrade fork oils living in Norway i guess a 10 grade will be fine

Leif

Yep a 10 or 15 should be fine. I'd start with the 10 and see what you think. The 15 is probably going to give a more appropriate rebound (even a 20) ...... but (there's always a but).... you start introducing the potential for a serious problem. And that problem is 'hydraulic lock'.

If your not familiar with how the damping in these basic forks works, it's juts a tube with some small fixed size holes in it. Oil getting pushed through these fixed size holes is how the basic damping works. There a set of holes for compression damping, and another set for rebound damping. It's the compression damping side that presents the potential problem. Hit something hard enough that compresses the forks really fast, and the fork oil can't get driven through these tiny holes fast enough, causing the front end to 'lock'. People generally think the suspension bottomed. It didn't, just locked up somewhere in its stroke. The thicker the oil you are running the more prone the forks will be to this problem. It's certainly an issue on a 750 and no matter how light an oil I used couldn't totally eliminate the problem. But lighter oils certainly reduce the likelihood. I've completely rectified the issue by modifying the forks with cartridge emulators.

So again, another compromise and why i think a 10 would be a good starting point.

[Richard]

I see...
Well I checked what I ordered way back in time for my previous bike:

Castrol FORK OIL MINERAL 10W 500ML
Mineral oil Fork oils of Castrol represent a high standard in the fork oil technology. The products are designed for use in all chassis components and provide good performance characteristics. To obtain the optimum viscosity for vehicle and operating conditions this fork oils are also mixable.

- Good damping properties at all temperatures
- Good air release
- Wear protection for extended service life of the fork components
- Protection against corrosion of internal components

Content: 0.5 liter tin

Thanks Freddy for all good info again