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Over torquing triple clamps affect forks?

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Don't know on the bushings. These forks are spares, been sitting around more than anything. They're not in bad shape.

I might mess with it some more but I've seen enough to confidently call B.S. on the guy in the first video.

 

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On The ktm shock body , if you even slightly over tighten the spring adjuster Perch ,you can feel it stop the piston going through smoothly

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4 hours ago, turbo dan said:

Don't know on the bushings. These forks are spares, been sitting around more than anything. They're not in bad shape.

I might mess with it some more but I've seen enough to confidently call B.S. on the guy in the first video.

 

What are you calling bullshit on? I don't get it, it is clear in his video. Do you think he is faking something?

You don't have the same clamp or the same forkleg even...

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Lets do this 2 times in the name of science. The missing ingredient is something to document the amount of pressure applied on the way to the bottom. Pushing it down with your body weight in the garage is a tad different then going through a set of sharp close whoops at high speed. Also when on the bike the forks are at a pitch and not straight up and down the pressure applied is not as simple as pushing it down and there is more of it in quick bursts. Straight up and down is easy, when the forks are a lever and a shock absorber is different in leagues. If they are overly tight while being used as the lever, because they are on a pitch, not straight up and down, the tube WILL flex and they WILL bind 100%. Tighten them with 700ftlbs and they will work straight up and down but probably snap in have and not budge when used as a lever.so....
Do this test, put a toothpick in a straw, set the straw at an angle like forks are, apply a bit of pressure and tell me what the toothpick does. And that, ladies and gentlemen is the difference nobody is talking about but what those torque specs are all about.

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Here’s to add to it a little. Anyone ever see how much the forks flex? Check out the second his rear tire touches back on the ground what the forks do. Interesting for sure.



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I think what this shows is that it is dependent on the specifications of the fork. If I had newer WP forks I'd test and be very careful about the torque specs I would use based on results not what the manual says. If I had a bike with older forks I probably wouldn't pay as  much attention to this as old forks are probably a little thicker with looser tolerances.  I do have a pair of 2006 SSS forks that I will eventually be revalving so I will test the torque specs at that time for increased stiction. I don't see this as a big problem as I would have already had to deal with it in the past on at least one of our bikes.

Edited by Budlite

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3 hours ago, AEES said:

What are you calling bullshit on? I don't get it, it is clear in his video. Do you think he is faking something?

You don't have the same clamp or the same forkleg even...

Pretty much.  If there are forks out there that are so easily distorted by 10 ft-lbs of torque on the pinch bolts I would hate to see how they would hold up to a big time overjump, slap down on the flat type of landing.

The fork I used is representative of the average fork you will find on many bikes.  Not brand new but in good condition.  The lower clamp diameter on every 48mm KYB I've ever seen in 59mm, so the tube thickness at the lower clamp is going to be the same.

2 hours ago, hondaman331 said:

Lets do this 2 times in the name of science. The missing ingredient is something to document the amount of pressure applied on the way to the bottom. Pushing it down with your body weight in the garage is a tad different then going through a set of sharp close whoops at high speed. Also when on the bike the forks are at a pitch and not straight up and down the pressure applied is not as simple as pushing it down and there is more of it in quick bursts. Straight up and down is easy, when the forks are a lever and a shock absorber is different in leagues. If they are overly tight while being used as the lever, because they are on a pitch, not straight up and down, the tube WILL flex and they WILL bind 100%. Tighten them with 700ftlbs and they will work straight up and down but probably snap in have and not budge when used as a lever.so....
Do this test, put a toothpick in a straw, set the straw at an angle like forks are, apply a bit of pressure and tell me what the toothpick does. And that, ladies and gentlemen is the difference nobody is talking about but what those torque specs are all about.

I applied no force to the upper, I simply let the upper drop and slide down under its own weight and the force of gravity.  I don't know what the upper tube and half of a triple clamp weighs but it's not much.

The tube will always flex, pinch bolt torque has nothing to do with that.  The original video shows a fork binding up from 10 ft-lbs of torque on the pinch bolts which is preposterous.

If you built a clamp that could handle 700 ft-lbs of torque it would surely crush the tube.  I apply 15-ft-lbs, which is only 2% of that.  It is 50% more torque than the guy in the video with his beer can fork tube, and yet I have no binding whatsoever.

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Inverted forks, as us old school gents call em, are very fragile by those triple clamps, and yeup, they can bind and distort, you gots to follow factory specs. Old school conventional forks sliders were thicker, hence higher torque values. When in doubt, check your shop manual. A side note, for more strength, I notice some after market folks selling trip clamps with 3 bolt pinch heads as vs. 2 bolters, Yeup..

 

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6 minutes ago, turbo dan said:

Pretty much.  If there are forks out there that are so easily distorted by 10 ft-lbs of torque on the pinch bolts I would hate to see how they would hold up to a big time overjump, slap down on the flat type of landing.

The fork I used is representative of the average fork you will find on many bikes.  Not brand new but in good condition.  The lower clamp diameter on every 48mm KYB I've ever seen in 59mm, so the tube thickness at the lower clamp is going to be the same.

I applied no force to the upper, I simply let the upper drop and slide down under its own weight and the force of gravity.  I don't know what the upper tube and half of a triple clamp weighs but it's not much.

The tube will always flex, pinch bolt torque has nothing to do with that.  The original video shows a fork binding up from 10 ft-lbs of torque on the pinch bolts which is preposterous.

If you built a clamp that could handle 700 ft-lbs of torque it would surely crush the tube.  I apply 15-ft-lbs, which is only 2% of that.  It is 50% more torque than the guy in the video with his beer can fork tube, and yet I have no binding whatsoever.

Diameter of the fork has nothing to do with it. It is the material, thickness and design of triple clamp.

Again, what in the video do you think he is faking? Has he mixsd with the torque wrench? Is he faking resistance when pushing the tube?

I'f you take a 2 or 3mm aluminum tube and push on it from side, it will give.

Making a round object oval with that thickness is not that hard, only need a very very small amount for the bushings to get screwed.

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I applied no force to the upper, I simply let the upper drop and slide down under its own weight and the force of gravity.  I don't know what the upper tube and half of a triple clamp weighs but it's not much.
The tube will always flex, pinch bolt torque has nothing to do with that.  The original video shows a fork binding up from 10 ft-lbs of torque on the pinch bolts which is preposterous.
If you built a clamp that could handle 700 ft-lbs of torque it would surely crush the tube.  I apply 15-ft-lbs, which is only 2% of that.  It is 50% more torque than the guy in the video with his beer can fork tube, and yet I have no binding whatsoever.
Here is what im saying, you are missing a dimensional force when doing your test. A fork does NOT go down only. The fork on a bike on the ground is actually like a board with the crown facing down. During the ride, the arc can be exceedingly large in different terrain and flexs at speed constantly. The inner cart, because it is bolted to the lug and held on the cap stays straight. If you over tighten the fork cant be loose enough to adjust for a straight rod to travel through a bent tube. If you would only put the toothpick in a straw and bend the straw you will understand that its a fools argument that says torque on the clamp is irrelevent. You seem to think the fork leg stays straight.... it certainly doesnt but the cartridge does. Over torquing the clamp make the fork tube more rigid and less likely to change in shape for the cartridge. What you are doing is putting a ball in a hole and saying it fits. Thats innaccurate. The xtrig test done horizontally is at least bringing some of the other dimensional force into play but it isnt even showing most of it. Straight up and down is something forks never see so i wouldnt accept any test in that way.
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1 hour ago, AEES said:

Diameter of the fork has nothing to do with it. It is the material, thickness and design of triple clamp.

Again, what in the video do you think he is faking? Has he mixsd with the torque wrench? Is he faking resistance when pushing the tube?

I'f you take a 2 or 3mm aluminum tube and push on it from side, it will give.

Making a round object oval with that thickness is not that hard, only need a very very small amount for the bushings to get screwed.

Diameter is directly related to tube thickness right?  So if the inner diameter is 49mm, outer diameter is 59mm, your tube thickness is 5mm.

I don't know what is wrong with this guy's rig.  I did not duplicate the binding despite applying more torque to the pinch bolts.  I used a production KYB fork in good working condition, representative of an average guy's suspension.

You are welcome to try to duplicate the result.  If you do find forks that bind up with 10 ft-lbs applied to the pinch bolts please let me know what type of fork it is so I can make sure to never ride them.

Forks flex all the time, if they are so poorly designed that minimal tube distortion causes significant binding there is something wrong with them.  That is not normal.

Edited by turbo dan
dont spel gud
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36 minutes ago, hondaman331 said:
1 hour ago, turbo dan said:
I applied no force to the upper, I simply let the upper drop and slide down under its own weight and the force of gravity.  I don't know what the upper tube and half of a triple clamp weighs but it's not much.
The tube will always flex, pinch bolt torque has nothing to do with that.  The original video shows a fork binding up from 10 ft-lbs of torque on the pinch bolts which is preposterous.
If you built a clamp that could handle 700 ft-lbs of torque it would surely crush the tube.  I apply 15-ft-lbs, which is only 2% of that.  It is 50% more torque than the guy in the video with his beer can fork tube, and yet I have no binding whatsoever.

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Here is what im saying, you are missing a dimensional force when doing your test. A fork does NOT go down only. The fork on a bike on the ground is actually like a board with the crown facing down. During the ride, the arc can be exceedingly large in different terrain and flexs at speed constantly. The inner cart, because it is bolted to the lug and held on the cap stays straight. If you over tighten the fork cant be loose enough to adjust for a straight rod to travel through a bent tube. If you would only put the toothpick in a straw and bend the straw you will understand that its a fools argument that says torque on the clamp is irrelevent. You seem to think the fork leg stays straight.... it certainly doesnt but the cartridge does. Over torquing the clamp make the fork tube more rigid and less likely to change in shape for the cartridge. What you are doing is putting a ball in a hole and saying it fits. Thats innaccurate. The xtrig test done horizontally is at least bringing some of the other dimensional force into play but it isnt even showing most of it. Straight up and down is something forks never see so i wouldnt accept any test in that way.

Yeah man, I'm dumb.  I had no idea that forks experience loads not directly paralell to the direction of travel.  This is all breaking news to me.  I can't argue with the rest of your post because it is almost completely incomprehensible. 

What you are missing is that in the video in the original post, there is no load on the fork leg whatsoever.  The horizontal orientation of the fork is completely irrelevant.  The binding is purported to be caused by tube distortion at the triple clamp, which I was not able to replicate and I have never seen in practice.

Edited by turbo dan
stil cannt spel

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3 hours ago, cdf450 said:

Here’s to add to it a little. Anyone ever see how much the forks flex? Check out the second his rear tire touches back on the ground what the forks do. Interesting for sure.


 

That's why the fork tubes are machined with a specific taper.  The amount of flex built in is a large component of how they feel.

With this understanding in mind, you can see how big of a problem it would be if your forks would bind up with the slightest amount of tube distortion, as the first video seems to show.

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7 hours ago, mog said:

On The ktm shock body , if you even slightly over tighten the spring adjuster Perch ,you can feel it stop the piston going through smoothly

Honestly that just seems like a bad design.

The shock body could be a little thicker.  Another case of KTM going a bit too far to shave weight.

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Honestly that just seems like a bad design.
The shock body could be a little thicker.  Another case of KTM going a bit too far to shave weight.
More the clamp system ,kyb etc use apposed force on the lock nut ,no pressure on the shock body
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That's what I mean.  They should have accounted for the clamp system in the design of the shock body.  A thicker body would resist distortion and would be less sensitive to the clamp being a little too tight.

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That's what I mean.  They should have accounted for the clamp system in the design of the shock body.  A thicker body would resist distortion and would be less sensitive to the clamp being a little too tight.
Agreed , mine was way tight from new ,maybe why some testers don't like the shock and others do? Too much variance on production?

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Hey turbo, can you repeat the test horizontally, match the specs and steps ? Your setup is the average persons situation.

In that xtrig vid, if you look closely the stroke still slows on their own clamps.

 

 

 

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