Suspension Static Sag

[ozigoo]

Ok so I pulled my forks apart, new seals and oil plus PD valve and back together.
It was a relatively straight forward job. I banged the collar and seals back in with the ol' plastic pipe and clamp trick, (Delboys video) which worked a treat.

So Ive never set up the static sag before and after watching a number of videos went through the process as explained simply below.

https://racetech.com/articles/SuspensionAndSprings.htm

I weigh about 90kg

The only way I could achieve the desired 30mm of sag both front and rear with me on the bike was to dial everything to its maximum. Also after a normal casual ride the zip ties on the front forks move 90mm which suggest the forks are bottoming out at some stage on the ride.

I'm interested if others have done their static sag settings? and zip tie experiment?

I might try playing around with oil levels in the front forks to see what difference that makes, but looks like I will probably need 'heavier guage' springs to stop the bottoming out.

Also the bumps are more noticable with everything dialed up which is not good either.

I didnt really notice it before but now that my attention is focused on the suspension when Im riding and evaluating every bump, my opinion of the stock suspension has decreased dramatically.

[Cormanus]

Did you see [url=http://cb1100forum.com/forum/showthread.php?tid=2902]this thread ozigoo?

[ozigoo]

I did, its a great post but no-one posted up any of their numbers for comparison..
It would be interesting to see how different peoples bikes are set up.

FRONT

1. weight of rider (kg)
2. Front fork preload 1- 5 IN (5 being max preload, screwed right in)
3. Sag number in mm
4. Zip tie front, take for a ride, measure from top of seal to zip tie

REAR

5. Preload setting 1 - 5 (5 being max.)
6. Just the sag number



For me
1. 90kg
2. 1 Line in (about 4 turns in from 0 preload) ...For comparison I also did MAX in (5)
3. 40mm (Max in 30mm) sag
4. 90mm (total front fork travel)

5. 5
6. 32mm sag

Any takers? cheers

[max]

Ozigoo since it was raining mostly today here's my numbers;
2010 cb1100, measured with some string substituted for a cable tie.

Front;

1, 86.3 kg
2. 5, all in max preload
3. 40 mm. ( from wheel lifted to end travel then me sitting on the bike 40 mm. difference. ).
4. 95 mm. from there 55mm. to nearest travel mark of dust seal ( the clean part ) so 40 + 55 = 95 mm.

rear;

5, 0 ( min preload, lowest seat position )
6. 30 mm. sag ( measured from rear-most adjustment screw straight up to tie-down bolt and me sitting static. ).

And thanks for the pictures and explanation, no hands-off head-shake here either,cheers.

[treedoc_imp]

I went through this process a few months ago.

Im 88kg and my rear preload is one click from max, my front is also one line from max.

I found adjusting the front preload made stuff all difference to anything

I am sure the suspension could be better, but the more I thought about it the less satisfied I was with it.

Suspension upgrades are expensive so now I just forget about it and ride, and its fine!

But I am interested in your assessment of the valve.

[ozigoo]

Cheers guys, great effort.. Like you treedoc , the more I think about it and focus in on the little bumps the more dissatisfied I have become...and yes its bloody expensive to upgrade with no guarentee of satisfaction.. maybe some 'stronger' springs in the forks,, Wilbers arn't too expensive.

Max, that 95mm of travel is pretty good, given that mine is 90mm + 30mm = 120mm all up...Im interested now to see what it is without the PD valves, I thought they would have reduced the travel not increase it.

As for the valves, TBH I cant tell any difference. Im going to buy one of those long grabber things to poke into the forks and take out the valves ,in situ, put the old spacers in and do some tests with and without valves..Its so subjective, how do you rate a bump?

Treedoc any chance you can put a ziptie on your forks and measure the travel after a ride?

Cheers again guys, it helps to know what other bikes are doing so we can assess potential issues.

[Aussieflyer]

Hey Ozigoo,
the front suspension must have been designed for a 60Kg Honda test rider! I recall that someone on the forum tested the original springs to determine they were near enough to 0.75Kg/mm which is barely enough to hold up the weight of the bike ... no wonder you need all of the preload yet still bottoming out. Further, they are progressive rate springs so they will always have a lot of initial sag. For your weight and that of our heavy bike you might consider 0.90 or 0.95 kg/mm springs - these would go nicely with your new valving. From memory the rear wasn't too bad so you could leave that end alone and just wind up the preload a little to get the 30-35mm of sag. One additional point that i noticed when changing fork seals was that the new seals created quite a lot of stiction ... where they have friction which affects their static resting position. Mine took a while to 'wear' in so in the meantime you might want to measure the average sag, i.e. the middle of where it settles from both unloaded down to resting position and from compressed back up to resting position.
Good luck with it all. Once you've worked it out and found pre-load and damping settings to suit you the ride will be much better.

[Bheezy27403_imp]

The Honda's I've been on have very soft front ends from the factory. It's amazing that a company that puts out such quality products undersprings the front end so badly. I remember when I took the CB out in the technical mountain stuff for the first time I had to pull over and adjust the forks after the very first section. My little CBR is unbelievably soft for a so called "sport bike" to the point of being dangerous.

[max]

Just as a subjective comparison my cb900 hornet is a plusher ride,
even with everything softened out, the new cb1000r has adjustable preload, rebound and damping showa forks but does not feel any better than the cb1100 in the absorbing bumps department at normal speeds.

It becomes a different story when the bikes are doing 140 km/hr, the suspension feels as if the bumps disappear and the bike hovers above the road as a separate unit as if on tracks, not easy to explain but that is how it feels to me.

Most of my rides are country roads, winding and somewhere from 60 to 80 km/h just rolling and smiling with a little excitement thrown in when it feels right.

So what is your expectation for the changes, what's the endgoal ozigoo?

[ozigoo]

Initially I was just changing the fork oil , and hadnt thought about the suspension as I have had the bike only a relatively short time. When I pulled the forks out I noticed the dust seals were a little perished so I thought, 'what the heck' Ill change all the seals. Then a mate sugested PD valves while I was waiting for the seals and after a little research thought, 'what the heck' only $150 may as well. After more research I focused in on the suspension and opened a can of worms in my brain, static sag etc....Now seeing the front forks probably bottoming out makes me think I need "stiffer" springs as Aussie flyer suggested (thanks for the infor Aussie much appreciated)..My end goal is to just have reasonabley good suspension for my weight, and nothing bottoming out. I dont want to spend alot of money so small tweeks, like valves and springs are probably all I need...