Quote:
Originally Posted by WhiteKnight
Read the bold print above. When you press on the spring (add more preload), you in effect shorten it, or compress it and vice versa. This in no way changes the length of the fork. It does, however, change the amount of distance the fork initially travels when the bike is hold it's own weight, and that of the rider, while the bike is at a stand still. Think of this the same way you set the preload on the rear shock. You are not changing the length of the shock. You are compressing or uncompressing the spring. The length of the shock remains the same, only the initial distance the shock shaft can travel changes.
i am not trying to argue, just making a point becauseit seems to me the ends of the fork are in a fixed position, the for cap being screwed to the upper part of the leg which is held in the upper triple tree, and an the bottom of the fok spring, which rests in the bottom of the fork leg.
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Not sure what point you are trying to make here:
The overall length of the fork is fixed, since it is a finite
maximum length, but the internal length of the fork varies with the distance the preload adjuster is screwed in.
When you screw in the preload you ARE making the fork longer -you are making the starting position of the fork further out towards the fully extended position.
When the forks are fully extended - for example on the centrestand with someone sat on the rear seat, the fork springs are under no, or virtually no compression forces. Yet when you allow the front wheel to drop to the floor they become compressed.
Since the forks at rest are neither fully compressed, nor fully extended, when you screw the adjuster in, you
shorten the internal length of the fork, and therefore the UPPER fork leg extends further out of the bottom fork leg.
When you screw the adjuster IN, you are not making the spring stronger, but simply taking up the slack in the spring and reducing the SAG in the fork due to the weight of the bike and rider.
Simple test.
Wind the preload adjusters fully out and either mark on the fork leg with a magic marker or a cable tie round the fork leg. Then screw the adjuster fully in and see that the fork leg will extend out from the bottom fork part.
The line or cable tie will attest to this.
You have, however, done NOTHING to alter how stiff the spring is...
This is exactly the reason most bikes do not have meaningful and properly functional adjustments on the suspension...most folk don't understand what they do..
Please note : this is not a dig at WhiteKnight, I simply disagree with his post somewhat.
JasonSmith : You have taken up the slop in the fork spring - that's all. That is what is meant by setting the SAG. Instead of the fork travelling 3" before the spring starts to be compressed, it now travels 1".
It still takes the same force to compress the fork to it's bottomed out position,no more, no less.
Furthermore, consider the FL-FP 750's - they had no preload adjuster on the fork, but the following FR-FV do. If you replace the fork cap from the earlier bike with one from the FR-FV then you would assuredly be able to feel a difference when you adjusted the preload with the new adjuster, but have you made the spring stronger?