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 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...

 

[Houtman_imp]

How is the suspension on your Kawa 400 in comparison with the CB 1100 ?

 

[ozigoo]

I put Wilbers progressive springs in the Kawa forks which made a heap of difference, but the Kawa has 'Clubman' clip on style handlebars, so its a bit of a cafe racer. As such your leaning right over the tank so its a totally different riding experience. Its hard to compare the two bikes, its a bit chalk and cheese'ish. I prefer riding the Honda but the Kawa is a real buzz, no gutz being a 400, but its fun to ride. I am supose to be riding the Kawa on my restricted licence for a year, but I tend to take the Honda out alot more than I should...

 

[Tev62]

2017EX MY - I am 120Kg all clobbered up and found the bike a bit reluctant to go around corners on the factory settings, naturally so. My weight is raking the front end out.

I had mentioned before that I jacked the rear up to 4/5 on the rear and dropped one ring on the front from factory and had the bike handling very well. The spring rate on the front does seem very low though and it is easy to use up 50% static. I quickly gave up on the target of 30% rider SAG on the forks which was achievable on the rear.

After a change of tyres though I found the bike super sharp. I went from the OEM Dunlops to Bridgestone T31's which had a big impact on the handling. With new tread and possibly different tyre profiles there was an obvious extra nose down attitude to the bike which had me turning incredibly easy.

This allowed me to gain back a little front suspension preload in that I could wind the preload in completely and get perfectly acceptable handling. I settled on one notch less front preload for optimum handling in the end. Just shows what impact a change of tyre can make.

 

[the Ferret]

Yea I'm 76 kg (168 pounds). It's hard for manufacturers to set up bikes from the factory with their cost/benefits restraints that will be comfortable and handle well for both of us. Then they stick crappy tires on them and that throws a real wrench in the works.

I personally have never messed with sag. When I get a bike I ride a section of road at the factory settings. Then I put it on full soft and ride the same road. Is it better or worse? Then I stick it on full hard and ride the road. Is it better or worse? Then I have a basis for dialing it in. It usually ends up pretty close to the factory settings. I must be pretty close in weight to the median they shoot for.

 

[dave]

You need heavier springs.

 

[Tev62]

You need heavier springs.

Yes, I do at the front. With my Africa Twin it was the exact opposite, the rear spring rate was really low but the fronts were fine.

As the bike is only for day runs it is not worth the upgrade, I haven't managed to bottom them out yet but then that is because I ride fairly easily and the suspension is rarely tested hard.

 

[Whoops]

2017EX MY - I am 120Kg all clobbered up and found the bike a bit reluctant to go around corners on the factory settings, naturally so. My weight is raking the front end out.

I had mentioned before that I jacked the rear up to 4/5 on the rear and dropped one ring on the front from factory and had the bike handling very well. The spring rate on the front does seem very low though and it is easy to use up 50% static. I quickly gave up on the target of 30% rider SAG on the forks which was achievable on the rear.

After a change of tyres though I found the bike super sharp. I went from the OEM Dunlops to Bridgestone T31's which had a big impact on the handling. With new tread and possibly different tyre profiles there was an obvious extra nose down attitude to the bike which had me turning incredibly easy.

This allowed me to gain back a little front suspension preload in that I could wind the preload in completely and get perfectly acceptable handling. I settled on one notch less front preload for optimum handling in the end. Just shows what impact a change of tyre can make.

I am 122 kg and was just living with the suspension as is. Now you all make me realize that I am probably bottoming out quite a bit.

What do you have your front set to? I will try adjusting my bike to your settings as a starting point since my weight is very similar.

 

[Tev62]

2017EX MY - I am 120Kg all clobbered up and found the bike a bit reluctant to go around corners on the factory settings, naturally so. My weight is raking the front end out.

I had mentioned before that I jacked the rear up to 4/5 on the rear and dropped one ring on the front from factory and had the bike handling very well. The spring rate on the front does seem very low though and it is easy to use up 50% static. I quickly gave up on the target of 30% rider SAG on the forks which was achievable on the rear.

After a change of tyres though I found the bike super sharp. I went from the OEM Dunlops to Bridgestone T31's which had a big impact on the handling. With new tread and possibly different tyre profiles there was an obvious extra nose down attitude to the bike which had me turning incredibly easy.

This allowed me to gain back a little front suspension preload in that I could wind the preload in completely and get perfectly acceptable handling. I settled on one notch less front preload for optimum handling in the end. Just shows what impact a change of tyre can make.

I am 122 kg and was just living with the suspension as is. Now you all make me realize that I am probably bottoming out quite a bit.

What do you have your front set to? I will try adjusting my bike to your settings as a starting point since my weight is very similar.

I am 122 kg and was just living with the suspension as is. Now you all make me realize that I am probably bottoming out quite a bit.

What do you have your front set to? I will try adjusting my bike to your settings as a starting point since my weight is very similar.
The rear is easy and is on 4 out of 5 (+ve preload) which is a good place as it will allow you to add a little extra should you add a pile of luggage. SAG levels seem reasonable at the rear.

If I were you I would keep the maximum amount of preload you can on the front without harming the handling. Start with the front fully wound in, take a screwdriver with you on a test ride and adjust out one ring at a time until you feel the bike handles around corners best for you. Aim to have as much preload on the front as you can while maintaining good handling. Depending on your tyres you may find anywhere in the preload range but hopefully nearer the end with it fully wound in for max suspension travel.

 

[GoldOxide_imp]

I never bottomed out my CB1100 and it experienced some nasty potholes. For reference:

* Full tank ('14 CB1100 standard model)
* Rider 220 lbs
* Front dialed as "standard from dealership" (don't remember the factory settings)
* Rear was set to 4 of 5 preset
* Factory recommended tire pressures

In addition, I sometimes had a pillion (about +140 lbs), but we rarely struck potholes or speed bumps. Rock solid to 170 for 50 kms. Corners (~40 km/h) and U-turns (~15 km/h) were undramatic.

I am pretty sure sag exceeded 30% under many of these conditions.

I thought the CB was nice to control.

= = =

The few times I felt the CB was a wee unstable was on hot tar snakes and steel grate draw bridges. However, that could have been a function of the tires and not suspension.

 

[Tev62]

I never bottomed out my CB1100 and it experienced some nasty potholes. For reference:

* Full tank ('14 CB1100 standard model)
* Rider 220 lbs
* Front dialed as "standard from dealership" (don't remember the factory settings)
* Rear was set to 4 of 5 preset
* Factory recommended tire pressures

In addition, I sometimes had a pillion (about +140 lbs), but we rarely struck potholes or speed bumps. Rock solid to 170 for 50 kms. Corners (~40 km/h) and U-turns (~15 km/h) were undramatic.

I am pretty sure sag exceeded 30% under many of these conditions.

I thought the CB was nice to control.

= = =

The few times I felt the CB was a wee unstable was on hot tar snakes and steel grate draw bridges. However, that could have been a function of the tires and not suspension.

I think so, I found my OEM tyres didn't like those but the new T31's don't seem to mind them at all. They do run a little noisier mind.