You are looking at your sag as a percentage of shock shaft travel. Ibis sets up using rear wheel sag not shock shaft. Don’t ever set that thing at 18.15mm shock shaft it will feel like arse.
Due to the leverage curve and progression of the V5 DW Link as a generalisation at around sag whatever you have as shaft travel if you double it that’s how much rear wheel sag you have. This number slightly increases as the suspension gets further into the stroke. It’s not exact but it’s that close it’s not worth worrying about.
As TanMan said 27.5% sag is the inside of the letters (DVO) on the shaft. You want to run your sag just to the bottom side of those letters. This will give you a fraction over 32% rear wheel sag. The Topaz in the Ripmo is a 210x55. If you do the sums you will see that the 14mm = 27.5% sag that Ibis recommends isn’t actually 27.5% of shock shaft travel. It’s 27.5% of rear wheel travel. This is due to the leverage ratio.
Just for reference I’m on an EXT Storia V3 now not the Topaz but after testing different spring rates and different sag settings my preference is to run exactly 16mm shaft travel for chunkier rough tracks. It’s the best all round setting and is really close to what I also settled on with the Topaz.
Thanks Ozibis!!!
I was wondering why my math was off.......probably guilty of not reading all the info out there. Great explanation. Its easier to just stick with the mm measurement than the percentage. It appears that the DVO print on the shaft is about 14mm away from the body, which is a great sag number to start with? Is your preference to set the sag at 16mm? Which is just on the outside of the DVO print?
Another round of tuning. I got to
main 245psi
bladder 200psi
two neg spacers 0pos
the climbing ability was starting to fall......flick back to middle and was great again
I decided to remove one of the two neg spacers......wow super plush......soft....didn't climb as well in open. I added 5 more pounds to 250psi climbed better but was real good in the middle. Sag was way past the DVO print....So now
main 250
bladder 200
one neg spacer 0pos
The down was nice.....I think I need to do something about the fork...its starting to not feel as nice now!!!!...
I did bottom out the shock....not harsh but I could feel it.....no jumps or drops....just smacking a big rock.....I stopped a few times on the way down and the o ring was way farther than it has ever been.....i'm thinking its a bit to soft.
I plan on going back on Wednesday for more tuning. Going to first remove the last neg spacer....I'm guessing that will make it even more soft than it already is....will require more air.....or........any suggestions?........Maybe that will make it too soft and will bottom out more.....which will then require a spacer in the positive ?
Is there a known reaction to adding or subtracting spacers? Will adding one to the neg result in "this"......while adding one to the positive with result in "this"? I was told by DVO to add a neg spacer when I needed to stop pedal strikes....I added one and it really helped the pedal strikes......it also made it pedal better.....so I always associated the neg spacer with firming up the beginning of the stroke. Am I way off?
thanks again for your help