Fork Springs - Orientation | GTAMotorcycle.com

Fork Springs - Orientation

oioioi

oioioi

Well-known member
Site Supporter
Can someone confirm the orientation of the Fork Springs for me?
Bike is 08 FZ6

I am working through my first fork seal replacement.
As I am taking the fork springs out I noticed the closer-wound coils were positioned at the top of the fork.

The Haynes manual says that the closer-wound coils should be at the bottom of the spring/fork.
I did not notice any mention of this in the Yamaha Service Manual.

The picture below is how there were assembled on the bike.

I am suspecting the a PO had the forks done and assembled the springs in reverse. That is if the Haynes manual is correct.

Thank you for the input
1592158688207.png
 
Doesn’t really matter the direction although most are installed with the smaller coils at the top.

A spring compresses at its softest point first, not from bottom to top.

I’d reinstall both with the same orientation.
 
Mad Mike said:
Doesn’t really matter the direction although most are installed with the smaller coils at the top.

a spring compresses at its softest point first, not from bottom to top.
Click to expand...

Interesting. Thank you for the input.

In that case I would think they are like this from factory and maybe not done before.

Judging by the oil that was in there, which can be seen in the top of the picture (vinegar bottle) they were probably never done before.
 
I will have to reread the manual. Unless I have a different one.
 
oioioi said:
I will have to reread the manual. Unless I have a different one.
Click to expand...

Apparently a lot of the times they come from the factory the other way around, but the manual says to put them like that so thats the way I did it, I posted this earlier with many other bikes this is the case also apparently
 
It only has a tight wound end and an open end because it's a progressive wound spring,
if you put a constant rate spring in there the coils would be consistent, wouldn't even have one end different ;)

as spring go they are either wound clockwise, or counter-clockwise.
in theory: tight up would reduce unsprung weight and tight down would keep your weight lower, but omg, surely the difference in minute or non existent.
 
Last edited:
Springs are 100% unsprung weight. Orientation doesn’t change that.
 
Mad Mike said:
Springs are 100% unsprung weight. Orientation doesn’t change that.
Click to expand...
I don't think so. A constant rate spring will be 50% unsprung weight. For a variable rate spring, if you put the tighter coils at the bottom, you would have more than 50% of the spring weight as unsprung, with the tight coils as the top you would have less than 50% as unsprung weight. That being said, I can't see this being a huge difference as we are talking about 40 or 60% of a couple pounds.
 
Sprung weight is anything that bears on a spring. Unsprung is anything beneath that, including the spring in its entirety.
 
Mad Mike said:
Sprung weight is anything that bears on a spring. Unsprung is anything beneath that, including the spring in its entirety.
Click to expand...
Not quite. The top of the spring is attached to the "sprung" part of the bike and moves as part of that mass. The bottom of the spring is attached to the hub and is entirely unsprung mass moving with the hub. Every part in between varies between those two points. Run the math an you will come up with 50% of spring weight is unsprung mass (assuming constant rate spring). I can't be bothered with calculus but I had to run that calculation in the past.
 
To clarify something with the above: The lower of the dual spring rates happens when there is space between all of the coils. When the spring compresses far enough that the more tightly-wound coils are collapsed against each other, there are now fewer active coils taking part in further compression, so that is when you get the higher spring rate.

When the tight coils are coil-bound against each other, that part of the spring is now acting like a solid lump of metal. If it's on the bottom of a fork leg, that's extra unsprung weight. If it's on the top of a fork leg, that's sprung weight.

Unsprung weight is A Bad Thing. If you're going to have a certain weight, it is better to have it as sprung weight than unsprung weight. Therefore ... tight coils to the top.
 
This whole thread is silly - unsprung weight is things like the wheels and brake rotors.
Sprung weight is everything hanging from the forks and shock(s).
Reducing unspring weight allows suspension components to react quicker, that's all.
It doesn't matter which way the fork springs are installed - they are going to be compressed equally from each end.
Just put them both in the same way unless there's some other reason not to - say if one end is tapered for instance.
 
Unsprung weight is also the coil-bound section of a dual-rate-wound spring, if it's at the bottom and the spring is partly compressed (i.e. normal ride height or any more than slightly into bump travel).

I will grant that it's a pretty small part of the total unsprung weight ... but installing it the right way 'round (tight coils to the top) is a FREE small reduction of unsprung weight.

I betcha the average person will not notice the difference.
 
Brian P said:
Unsprung weight is also the coil-bound section of a dual-rate-wound spring, if it's at the bottom and the spring is partly compressed (i.e. normal ride height or any more than slightly into bump travel).

I will grant that it's a pretty small part of the total unsprung weight ... but installing it the right way 'round (tight coils to the top) is a FREE small reduction of unsprung weight.

I betcha the average person will not notice the difference.
Click to expand...

I bet you're right.
 
Put it this way. The right way 'round is the tight coils to the top. But if I had just finished putting a fork leg together, and didn't remember which way I had put the spring in, I wouldn't bother with the 5 minute job of double checking unless it were a race bike. And if it were a race bike ... dual-rate springs are the wrong springs anyhow. LOL
 
I suppose I was trying to find the correct way as I was confused based on what was in the fork and what was on the paper (manual).
I didn't think that there really was a right or wrong way of doing it but I wanted to check just in case. Also, chances are that I wouldn't notice the difference between one or the other method. I'm no Mr. 46 here. :p
More after the "safe" way of doing it.
However, I knew for a fact that it was important to have the same orientation on both forks.

At least I or we learned more than we bargained for in the process of all of this.

Thank you to all that contributed. I am satisfied with the answers provided and can now make an educated decision.

If you wish to continue and prove your respective theories, please do so. I'm sure we can all learn more and be entertained at the same time.
lol
(y)?
 
My race bike - and many others - which has Ohlins damping cartridges retrofitted, has all compression damping in one fork leg and all rebound damping in the other one. (And it has a single brake disk and caliper - unsprung weight, not to mention the braking forces - only on one side!) If it functions with that much asymmetry - and it does, very well - I don't think you need to worry about having one spring right side up and the other one upside down!
 
Brian P said:
My race bike - and many others - which has Ohlins damping cartridges retrofitted, has all compression damping in one fork leg and all rebound damping in the other one. (And it has a single brake disk and caliper - unsprung weight, not to mention the braking forces - only on one side!) If it functions with that much asymmetry - and it does, very well - I don't think you need to worry about having one spring right side up and the other one upside down!
Click to expand...

You are right, I'm not going to argue that.
But my "attention to detail" (aka OCD) would just drive me crazy knowing that they are not the same. :ROFLMAO:
 
You must log in or register to reply here.

Back
Top Bottom