Does 5+10 = 7.5?

[Kevin Daly]

I know this is definately a NERPT ready project but I was at the bike shop today looking to get some 7 weight fork oil for my forks (incase you didnt figure that out) and they didnt have 7 wt. just a clear 5 wt and that redish colored 10 Wt.

The guy at the parts counter said "od dude just use 10 wt. you cant tell any difference." I said Na...I'm looking for 7 wt. (knowing full well that this was a very different viscosity for a fork). So I am turning to leave and the manager said "dude just mix the 5 and 10 wts. together and that gives you 7 wt oil. I laughed and said "no i dont think so, that would be 7 1/2" and walked out.

But ok I could see mixing two of the same product line with different weights and getting the average, but two completely different types of oil? does anyone really do this?

 

[FJRay]

I wouldn't. I was also told by the gurus at GP not to use the silkolene brand because it will oxidize and cause things to stick. I found out the hard way. went with 7.5 Bellray.

 

[Kevin Daly]

I wouldn't. I was also told by the gurus at GP not to use the silkolene brand because it will oxidize and cause things to stick. I found out the hard way. went with 7.5 Bellray.

I have used Maxima, which you cant buy in town but I wanted to get this done before my next ride so I ran in thinking yama or honda made something i could use.

 

[Geezer]

I would have no qualms about mixing two different viscosities of the same fork oil. Be aware that the viscosity ratings are not standardized for suspension oils and does vary considerably across brands. This chart by Peter Verdone is very informative.

 

[dsmack]

Linky no workee!

 

[Geezer]

Linky no workee!

Sorry about that. It works fine for me. This is the link: https://www.peterverdonedesigns.com/lowspeed.htm

 

[FJRBluesman]

I've hard you should not mix different viscosity oils. If I were to do it, just to get me back home, or finish a ride (whether one day, one week, a month) it wouldn't really matter. But to have it as a permanent mix for the duration of a maintenance schedule, I would say no.

 

[charismaticmegafauna]

But ok I could see mixing two of the same product line with different weights and getting the average, but two completely different types of oil? does anyone really do this?

If the two fluids are completly miscible it could be possible. If you have a nearby independent oil-lab with a Brookfield viscometer, they could give you the specs of your hybrid-fork-oil and you could compare it with the chart linked by 'Geezer'.

Yes, I enjoy mixing-up a 'witches-brew' of fork oil -- but, am fully cognizant that it might not be optimum...! :blink:

Anyway..., with multiple damping adjusters -- why adjust the medium (fork-oil viscosity)? Are you at the end of adjustment?

 

[Anthony]

According to Verdone's chart, viscosities are not even standardized with some brands.

Maxima seems to be standardized as far as I can tell.

 

[SFZX]

Kevin,

I did just exactly what you are asking after talking with the tech at Race Tech Suspensions. I have a ZX11 Kawasaki that I did a total front and rear conversion to race tech suspension on. Including hard anodizing the friction surfaces. The front forks are adjusted partialy by using different viscosity oil. I'm sure your familiar with gold valves, for simple damping rod shocks. Be sure the brand of the two your mixing is identical. You can definitely tell the difference between 5, 10, and an equal mix of the two. I actually did try all three before I got settled on the mix of 5 and 10. Hope this helps. But I have to wonder why this would be necessary with a fork as easily adjustable as the FJR's for compression and rebound.