Fork Uneven Height

[betoney]

7 hours ago, stumpy said:

you don't have to remove anything...with the bike on the center stand, loosen one side pinch bolts just enough that you can rotate and twist up the fork up to your desired height and then re-torque.  repeat on the other side.  it only takes about 10 mins to do this.

Agree with this, Ive even done this out on the trail on my dirt bike, lean it up against a tree, loosen a few bolts, twist up or twist down, tighten and you are done.

Edited July 22, 2019 by betoney

[BBB]

6 hours ago, stumpy said:

you don't have to remove anything...with the bike on the center stand, loosen one side pinch bolts just enough that you can rotate and twist up the fork up to your desired height and then re-torque.  repeat on the other side.  it only takes about 10 mins to do this.

That’s good to know. I did it the much more complicated way 🤪

[stumpy]

thats ok...just spreading some experience.  as long as you got it done thats all that matters..👍

[BrianG]

Another couple of things to note:

1.  You can easily change the ride height with the preload adjustment since that is actually all that preload adjustment affects. (unless the fork/shock is topped out, which it shoudn't be)  Moving the fork in the triple clamp is only necessary when the preload adjuster doesn't give you enough range.

2.  An important fork function consideration is a force called "stiction".  One way to get unwanted stiction is to have the fork springs unevenly loaded.  (one fork higher than the other)  The easy way to be certain that this isn't happening is to pass the front axle through the fork legs without the wheel.  Of course it should be a straight shot through the first fork leg and precisely home into the other.  Not all fork internals are precisely matched so it is sometimes necessary to adjust the location of one fork, in the triple clamp to accomplish this precise alignment.  This may leave one fork sitting a little different from the other in the triple clamp.

Edited April 10, 2020 by BrianG

[BBB]

2 hours ago, BrianG said:

  You can easily change the ride height with the preload adjustment since that is actually all that preload adjustment affects. 

You’re correct about ride height changing with preload, but it does also affect the way the spring responds.

Teach Me Suspension (Part 3): Motorcycle Suspension Preload

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Part 3 of our motorcycle suspension series takes a look at preload, what it...

 

[chitown]

It does... but only through a limited range of the available travel and thus not very effective. 

[BrianG]

8 hours ago, BBB said:

You’re correct about ride height changing with preload, but it does also affect the way the spring responds.

Teach Me Suspension (Part 3): Motorcycle Suspension Preload

---

Part 3 of our motorcycle suspension series takes a look at preload, what it...

 

This seems to be a common and persistent area of misconception.  The author of this article presents his arguement and then provides the diagram which accurately refutes his arguement.  His arguement is accurate for an unloaded spring system but the second and third pictures put the lie to his assertion when considering a loaded spring system. 

 

Specifically, you can see (in the second and third drawings) that the spring itself sits at exactly the same place and amount of compression when under the 50kg load regardless of the preload applied.  The only thing that is different is the location of the (top of the)internal cylinder. (which translates into ride height if that cylinder is clamped in the triple clamp).  The spring in both the second and third pictures are not different in any characteristic or action since they are both compressed exactly equally by the 50 kg load.

 

[piotrek]

14 hours ago, BrianG said:

You can easily change the ride height with the preload adjustment since that is actually all that preload adjustment affects.

Preload adjustment is not there to substantively alter ride height. Preload is meant (with the right springs) to optimize suspension travel (without bottoming out). Once you have suspension travel optimized, you can then move the forks up/down in the clamps to set desired ride height... or you could do these in reverse order. If your springs are correct, you will not need a lot of preload (I have one turn)... but might still need to alter your ride height.

Edited April 10, 2020 by piotrek

[BrianG]

45 minutes ago, piotrek said:

Preload adjustment is not there to substantively alter ride height. Preload is meant (with the right springs) to optimize suspension travel (without bottoming out). Once you have suspension travel optimized, you can then move the forks up/down in the clamps to set desired ride height... or you could do these in reverse order. If your springs are correct, you will not need a lot of preload (I have one turn)... but might still need to alter your ride height.

With the right springs the "preload" adjuster only adjusts the ride height to get the sag numbers (which are correct because of the spring rate) into the correct range of the total fork travel.  It is just a mis-named adjustable spring spacer.

Edited April 10, 2020 by BrianG

[betoney]

36 minutes ago, piotrek said:

 If your springs are correct, you will not need a lot of preload (I have one turn)... but might still need to alter your ride height.

A local suspension shop did a baseline setup on mine and it is very similar to yours, minimal fork preload for sag and forks raised 5mm in clamps but with an additional 5mm ride height on rear shock.

[piotrek]

1 hour ago, BrianG said:

With the right springs the "preload" adjuster only adjusts the ride height to get the sag numbers (which are correct because of the spring rate) into the correct range of the total fork travel.  It is just a mis-named adjustable spring spacer.

Right... but I suppose the point is that while the preload adjuster will alter the ride height to a small degree (spring spacer size is varied, as you rightly note), it is not there for this purpose. The shock in @betoney's photo is a good example in the rear, where the preload and ride height are independent adjustments.

[BrianG]

23 hours ago, piotrek said:

Right... but I suppose the point is that while the preload adjuster will alter the ride height to a small degree (spring spacer size is varied, as you rightly note), it is not there for this purpose. The shock in @betoney's photo is a good example in the rear, where the preload and ride height are independent adjustments.

Sorry, I can't find that post you referenced.

[peteinpa]

On 4/10/2020 at 2:24 AM, BrianG said:

 

2.  An important fork function consideration is a force called "stiction".  One way to get unwanted stiction is to have the fork springs unevenly loaded.  (one fork higher than the other)  The easy way to be certain that this isn't happening is to pass the front axle through the fork legs without the wheel.  Of course it should be a straight shot through the first fork leg and precisely home into the other.  Not all fork internals are precisely matched so it is sometimes necessary to adjust the location of one fork, in the triple clamp to accomplish this precise alignment.  This may leave one fork sitting a little different from the other in the triple clamp.

Just did this. Axle has zero stress going through both forks. top of fork tubes have about 2 to 3 mm difference. the bottom is what is important.

Also greased my seals per Dave Moss. Only had a slight improvement in stiction, not like in his video with the bottom tube held up by stiction.