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Old 10-19-05, 12:16 PM   #1
Steve Russell
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MX Comp Coil question

Does anyone know if the MX comp coil is supposed to make a clicking noise as you are riding over rough terrain? I just installed one on my bike and took it for it's maiden voyage last weekend. It sounded like a loose headset, I stopped several times to check it and the headset is tight. No leaks or other strange things with the fork, just the clicking noise. Is it normal? Thanks in advance.
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Old 10-19-05, 01:58 PM   #2
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How do you know you're not simply hearing the rough terrain????

There's no WAY I can isolate a click when I'm bombing over rocks.

Assuming you have super-human hearing and can tell the difference between a pebble clicking off your rims or frame, and the sound your fork is making - no, your fork is not supposed to click.
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Old 10-19-05, 05:22 PM   #3
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mine did that when new also. I lowered the air a smidge. problem solved.it was the rebound set too fast on the air side. later on I slowed the rebound down(pain in the rump on an 04 model) but not because of the clicking. it is long gone
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Old 10-19-05, 06:59 PM   #4
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Thanks for the info about the rebound setting. It wasn't rocky terrain, it was hardpack trails with lots of tree roots and stutter bumps so there were no rocks or pebbles bouncing off the rim.
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Old 10-19-05, 08:34 PM   #5
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this click could also be caused by the springs flexing out and hitting the sides of the stanction.
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Old 10-19-05, 09:38 PM   #6
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Quote:
Originally Posted by Steve Russell
It wasn't rocky terrain, it was hardpack trails with lots of tree roots and stutter bumps so there were no rocks or pebbles bouncing off the rim.
In that case, please excuse my presumptuousness!

(Your fork still shouldn't click, however.)
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Old 10-20-05, 05:43 AM   #7
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I just put a MX Pro on mine and it does the samething. I think it is just the spring bouncing around.
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Old 10-20-05, 06:13 PM   #8
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Quote:
Originally Posted by Steve Russell
Thanks for the info about the rebound setting. It wasn't rocky terrain, it was hardpack trails with lots of tree roots and stutter bumps so there were no rocks or pebbles bouncing off the rim.
mine made NO noise on big hits but roots, small bumps at high speed and stutter bumps were noisy. like said it could be the spring hitting( as mine was from a rapid reboound) do you have ETA?
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Old 10-21-05, 06:48 AM   #9
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No ETA on mine, just the basic fork. I slowed the rebound down a touch. I am also waiting for my firm springs to arrive so I can swap them out. Another question, how much air preload are you using. I noticed that they get very firm with very little air preload.
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Old 10-21-05, 07:39 AM   #10
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I use about 52 psi.
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Old 10-21-05, 09:48 AM   #11
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Is yours the coil fork or air fork? I was looking at the manual that came with mine and for the preload on the coil spring fork they recommend 0-15psi. 52psi seems like a lot of pressure for the preload. Also would like to find a pump with an accurate gauge that reads that low, it is a pain in the a** to try to read that low on the gauge on my shock pump.
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Old 10-21-05, 11:19 AM   #12
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Quote:
Originally Posted by Steve Russell
52psi seems like a lot of pressure for the preload.
It depends on the rider's weight, but 52 PSI is TOO MUCH - it needs to be between 0 - 15 PSI.

http://www.marzocchi.com/spa/mtb/pro...LN=UK&Sito=mtb

Marzocchi's chart (and manual) is confusing. The actual air pressure that you put in via your pump needs to be anywhere from 0 PSI to 15 PSI. Where the confusion lay is that the chart above shows you POSTIVE AIR PRESSURE - not the PSI you are supposed to inflate to. Postive air pressure is simply the weight that should be present on the fork by body weight, assuming you want ~20-25% of your total body weight to preload the fork. This corresponds to about 20-25% of your fork's total travel to be used up by preload (ie. just sitting static on your bike) - also known as sag.

So - long story short - add as much PSI between 0 and 15 to achieve about 20 % of your fork's total travel to be consumed by sag (just sitting on your bike).

Of course you can fine tune to your liking - it is not an exact science - but do NOT be mistaken in thinking that the chart above shows how much PSI to inflate to - it does not. Again, it only shows by rider weight, how much of your body weight is being used to preload the fork to roughly 25% sag.

I don't know why Marzocchi even needs to keep showing this misleading chart in their manual.

Again, for the MX Comp - the only thing you need to worry about is adding air between 0 - 15 PSI to give you roughly 20 - 25% sag.

Somebody oughta sticky this.

Last edited by shane45; 10-21-05 at 12:51 PM.
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Old 10-21-05, 12:43 PM   #13
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Quote:
Originally Posted by Feltup
I use about 52 psi.
WAAAAAYYYYY too much. See my post above. Does your fork even sag when you sit on it? There's no way you are using the full travel of your fork with that much air in it. I would suspect you have limited your fork to about an inch of travel.

Last edited by shane45; 10-21-05 at 02:28 PM.
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Old 10-21-05, 01:57 PM   #14
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I thought that sounded like too much, my fork starts getting stiff even with 15psi preload in it. Thanks for the info about preload vs. sag, that helps.
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Old 10-21-05, 02:01 PM   #15
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It's the least I can do, considering I sounded a bit like a jerk in my first post in your thread.
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Old 10-21-05, 02:33 PM   #16
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what year fork are yall speaking of? Ive got an 04 ad it says for people my weight I should be using 45-52PSI. I keep it down at about 40 for plushness but anything below that and Im very squishy and cant climb worth a turd, even with the ETA engaged. its a 120mm with ETA
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Old 10-21-05, 02:38 PM   #17
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Quote:
Originally Posted by iamthetas
I should be using 45-52PSI.
Read my post above. I bet you what you are reading does NOT say PSI - it says Lbs. There's a difference.

The chart in my link above is for 2005 models, but I don't believe there was any difference on the '04's - you need to put 0 - 15 PSI in your fork in order to have 45-52 pounds (not PSI) of weight on your fork to preload it.

If you are not using close to the full amount of your 120mm travel on moderate to bumpy terrain, you have too much air in it.

It's simple really - add enough (or take out!) air in order to have 20 - 25 % of your fork's total travel used up just by sitting motionless on your bike (sag).

Last edited by shane45; 10-21-05 at 04:14 PM.
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Old 10-21-05, 05:45 PM   #18
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You all are smoking CRACK! Do you even know what PSI stands for? There is no other way to measure air pressure besides PSI(unless you use the metric scale). You are confused by your pump gauge. The gauge says LB/in2 which is pounds per square inch. 52 psi correct.

Last edited by Feltup; 10-21-05 at 06:20 PM.
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Old 10-21-05, 06:53 PM   #19
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There is a difference between positive and preload pressure. The MX Pro only has positive which needs anywhere between 30-65psi or lbs. It is easier to look at the bar scale which is betweeb 0-4,50. 1bar is close to 15psi that is what the manual says to put in the MX comp coil an the MX pro coil, nether have ETA and they have air on both legs. For positive it says to put 2,90-3,80 bar(42-52psi or lbs). This is for the MX comp air, MX comp with ETA, MX Pro air and the MX Pro with ETA. This is in both legs unless it is ETA.

I was wrong because the MX comp coil only has preload air and it only needs 0-15psi.
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Old 10-21-05, 07:35 PM   #20
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Quote:
Originally Posted by shane45
Read my post above. I bet you what you are reading does NOT say PSI - it says Lbs. There's a difference.

The chart in my link above is for 2005 models, but I don't believe there was any difference on the '04's - you need to put 0 - 15 PSI in your fork in order to have 45-52 pounds (not PSI) of weight on your fork to preload it.

Shane, you are most definitely confusing this issue for everyone reading, my friend.

Their coil forks use 0 to 15 psi (that's air pressure) for their preload. That's an indication read directly off the face of the pump guage. This is based on rider preference and not directly tied to weight.

The air forks use 25 to 65 psi (again, air pressure) for main chamber pressure (positive pressure, they call it). Again, that's an indication directly from the guage. This is based on rider weight and should be set to achieve the desired amount of sag (typically 20 to 30%).
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Old 10-21-05, 08:08 PM   #21
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No my friends - call Marzocchi and find out for yourself.
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Old 10-21-05, 08:10 PM   #22
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Quote:
Originally Posted by Speedub.Nate
The air forks use 25 to 65 psi (again, air pressure) for main chamber pressure (positive pressure, they call it). Again, that's an indication directly from the guage. This is based on rider weight and should be set to achieve the desired amount of sag (typically 20 to 30%).
No way is anyone going to get 20 - 30% sag with 65 PSI.

Remember, I am talking about MX COMP forks here - not Marzocchi's entire line. The thread is about MX Comp - and nothing more.
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Old 10-21-05, 10:42 PM   #23
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Quote:
Originally Posted by shane45
No way is anyone going to get 20 - 30% sag with 65 PSI.

Remember, I am talking about MX COMP forks here - not Marzocchi's entire line. The thread is about MX Comp - and nothing more.

Do you not understand the difference between postive air adjustment and preload air adjustment? First you said that pounds and PSI were two different things. Some Comp forks have positive which requires more pressure and some only have preload which requires low pressure. You really need to go back the middle school and learn some basic math skills. Here is the page from the manual, I hope you can read.
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Old 10-21-05, 10:50 PM   #24
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Here is the page.
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Old 10-21-05, 11:15 PM   #25
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For positive it says to put 2,90-3,80 bar(42-52psi or lbs). This is for the MX comp air, MX comp with ETA, MX Pro air and the MX Pro with ETA. This is in both legs unless it is ETA.
thank you for clearing that up. I thought it was PSI(pounds per square inch) as positive air and not preload.
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