Steering damper fluid......
- Thread starter delboy
- Start date
I think if you do a search you will find many threads on this subject. If I recall correctly most of these threads talked about the "feel" of the damper with different viscosity "oil" in there.
My understanding is the damper prevents, "tankslapping" if we change the viscosity because it "feels" better, do we affect the performance of this "sometimes" critical component? Possibly opening the door for tankslapper?
Obviously lots of aftermarket dampers that seem to work great for people. It would be interesting to see who gets tank slappers, and what modifications preceded them.
My understanding is the damper prevents, "tankslapping" if we change the viscosity because it "feels" better, do we affect the performance of this "sometimes" critical component? Possibly opening the door for tankslapper?
Obviously lots of aftermarket dampers that seem to work great for people. It would be interesting to see who gets tank slappers, and what modifications preceded them.
cipher5791
Registered
I put 90W gear oil in mine. 
If your not having any headshake problems I'd say 40 weight oil ought to do the trick. If it's wiggling you might try 80/90 weight gear lube. I've never had any problems with mine so I've never messed with it.
Hit the search, lotta threads on the subject in general.
Hit the search, lotta threads on the subject in general.
TXBusa05LE
Registered
30w
I put 40w in mine.
Great question!
The key word in your statement is "Prevents"!
Tank slappers on modern bikes are extremely rare. You have to do something really harsh to get your bike to enter a tank slapper (Not to be confused with head shake). Everyone gets a little wriggle or shake on odd occasions when the front tire leaves the pavement or most common when one has been playing with the suspensions ride height and ends up with to little trail. Or maybe the most common cause is use of the rear brake at the wrong time?
If you have ever experienced a stop to stop tank slapper, you most likely got your arse high sided. A bike doesn't get a tank slapper on it's own, it takes rider input to get the bike that fookered up. However, a good well tuned damper can help to "Prevent" the tank slapper before it gets out of hand. The key is well tuned. Most riders have a presumption that the stiffer the damper the better it works. No so! A damper set to stiff is less effective and more apt to compound the problem than a damper set to light. I find most riders and many racers have their aftermarket dampers set too stiff. There is a reason your stock damper has light weight oil. Any stock damper with 80/90 wt oil is much less effective than OEM oil.
There are exceptions. If you are doing rolling stoppies for instance, you need a very stiff damper. When I'm out practicing stoppies, I crank my ohlins damper up almost to it's limits on the stiff side. When you are balanced on the front tire, the last thing you want is the front tire to become the least bit unstable or you can quickly get pitched on your noggin!
My point is, if you are going to modify your stablizer, be sure you are making an improvement. Chances are you'll never need that damper unless you stunt or race, but if by chance you do, the difference in a damper that works or just feels good can mean the difference in going home to wash your skivies or getting a very expensive helicopter ride!
Thanks a million for the reply, I have read much about the "feel'. Nice to have some useful input on the all important "function" side of the issue.
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mike1180
Banned
I used 80W90.
I was concerned before I did it that it would be too thick.
No Way!
It works perfect. I wouldn't use a lesser weight.
It still steers extremely easy and is not tight at all.
One suggestion:
When I did mine, I wore latex gloves and got a large container and totally submersed the damper in the 80W90. (you can warm up the 80W90 by putting the container in warm water. That speeds it all up.)
As you work the rod in and out (with the fill hole upwards) the bubbles come out.
At the final stage, pump the rod in and out in a little movement of ¼ inch or so as you go through the whole range of the rod’s movement, fairly rapidly. That will get the last bit of air out.
I checked mine with the stock oil in it and also when I had first filled it and there was a gap in the movement of the piston, just like there was a small point where there was no fluid.
After redoing the fill I pumped that little movement and could feel the difference even when submerged – that gap went away.
Good luck!
I was concerned before I did it that it would be too thick.
No Way!
It works perfect. I wouldn't use a lesser weight.
It still steers extremely easy and is not tight at all.
One suggestion:
When I did mine, I wore latex gloves and got a large container and totally submersed the damper in the 80W90. (you can warm up the 80W90 by putting the container in warm water. That speeds it all up.)
As you work the rod in and out (with the fill hole upwards) the bubbles come out.
At the final stage, pump the rod in and out in a little movement of ¼ inch or so as you go through the whole range of the rod’s movement, fairly rapidly. That will get the last bit of air out.
I checked mine with the stock oil in it and also when I had first filled it and there was a gap in the movement of the piston, just like there was a small point where there was no fluid.
After redoing the fill I pumped that little movement and could feel the difference even when submerged – that gap went away.
Good luck!
The reason it's perfect is because you've never needed it!
However, before you can say it works perfect, you must give it a test!
If you truely believe you have the answer, pick the front tire up and carry it up to about 80 knots and set it down crossed up. If you survive unscathed, I'll be most happy to acknowledge you have a better mouse trap!
Oh, be sure to have a friend video tape the test ride just in case you are wrong.
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mike1180
Banned
The reason it's perfect is because you've never needed it!
However, before you can say it works perfect, you must give it a test!
If you truely believe you have the answer, pick the front tire up and carry it up to about 80 knots and set it down crossed up. If you survive unscathed, I'll be most happy to acknowledge you have a better mouse trap!
Oh, be sure to have a friend video tape the test ride just in case you are wrong.
I suppose I should check out my Arai helmet by getting off at 100 miles per hour too?
When I said it worked perfect I meant it steers perfectly.
The steering damper is like those other things that you hope you never need, but are designed to be there just in case; air bags, parachutes, life jackets, safety harness, leathers etc.
I didn't design the system, but thinking my way through it, if there are forces trying to wobble my steering, heavier oil would be better as it offers a little more resistance to those forces.
IMO
mike1180
Banned
I was told you went suppose to use dual weight oil like 80w90..
I can't see why it matters.
80W90 is 80 weight when cold and 90 weight when hot.
The difference between 80 and 90 weights is not much, and we don't ride when it is really cold, and it should never get really hot in use so I figure it sits about 85 weight anyway most of the time. The difference of 10 between the weights is something I can't feel form the bars.
If you are concerned you could use straight 80 or straight 90.
I haven't had any problems.
IMO
No Problem, I assumed you meant it functioned perfect.
Here is how your OEM damper works. It has a small orfice in which the oil passes through as you turn your steering. The oil is light and passes through very easily under normal steering.
If you get your bike into a tank slapper or even a head shake, the faster your bars go back and forth the faster the oil is forced through the orfice. The faster the oil is forced through this tiny little orfice the more resistance is created, thus damping the shake. Everything works exactly the way it was designed.
Now you take that light 10w oil out and replace it with 90w and you put the bike into a tank slapper. I need not remind you that a genuine tank slapper is extremely violent. I can vouch for that from personal experience. As the speed of the bars increases the heavy oil can no longer be force through the small orfice and the steering totally locks up. GAME OVER! Has the same effect if you have an aftermarket damper set to stiff.
As I said earlier, there is a reason those little guys in Japan designed your stock damper with light weight oil. It's not just to make your bike steer easily at slow speeds, it's designed to best manage the bike when it's most needed. Are there better dampers? Certainly.
If you are happy with your 90w damper, great! You'll most likely never need it anyway. I'm simply sharing my views (Food for thought) with those who are considering a damper modification.
+1 From me on the Physics side, this oil through an orifice in aircraft landing gear is called an "oleo". Damping, "Dampening" has more to do with frequency and not ,(so much with),force.
This "oleo" is "tuned" to dampen the front end, at the "resonant" frequency the manufacturing engineers have determined.
More Viscosity, might, might not, work as well, how critical is it?? Dont really want to test it to find out. On the positive side, lots of people seem to play with this, most are here to tell us about it.
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