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Discussion Starter · #1 ·
My wife has a 2008 Specialized Safire with f120 forks and she beleives to think that when she takes a sudden hit (like a curb or does a wheely) with them it feels like the frame is taking the hit more then the shock like it is bottoming out without actually bottoming out. If we just push up and down on the shock it is fine and I dont feel this problem when I ride it but she thinks it feels like a metal hitting possibly when she takes quick hard hits. I have the psi at 40 as she weighs 110 and sag is nice and rebound is 4 clicks from full open. Any suggestions are greatly appreciated....
 

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gigabyte772 said:
My wife has a 2008 Specialized Safire with f120 forks and she beleives to think that when she takes a sudden hit (like a curb or does a wheely) with them it feels like the frame is taking the hit more then the shock like it is bottoming out without actually bottoming out. If we just push up and down on the shock it is fine and I dont feel this problem when I ride it but she thinks it feels like a metal hitting possibly when she takes quick hard hits. I have the psi at 40 as she weighs 110 and sag is nice and rebound is 4 clicks from full open. Any suggestions are greatly appreciated....
The blue knob on the bottom of the right leg adjusts the threshold for the lock out. open it the whole way and make sure the lock out is off too.
 

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Discussion Starter · #3 ·
sorry this is a F120 RL I dont beleive I have this adjustment. Lockout is not on as I said if I compress it without hitting a bump or curb it seems fine...
 

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Hi Gig,

Does the fork have a sag indicator? On a square edge hit does the fork actually reach bottom out? The sag indicator would reach all the way to the top. You can use a zip tie if need be.

Sometimes for extreme lightweight riders to acheive appropriate initial sag very little air must be used in the air spring, on hits this weak air spring can result in the fork reaching bottom out too quickly.

I would bump up the air pressure a bit, use a little more compression damping, and/or check with Fox to see if they have a custom tune for lightweight riders.
 

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Has she always had this problem or is it something that's relatively recent?

When was the fork last serviced? If it's feeling harsh but not bottoming out it could have some stiction issues perhaps. If your wife is very light she might notice this more. Fox 32 forks have quite short service intervals.

http://www.mojo.co.uk/Website2010/html/setup3.html

Have you tried leaving the bike upside down overnight before a ride to let the suspension oil relubricate the bushings and foam washers?

You could also consider having the Fox fork custom valved eg:

http://www.mojo.co.uk/Website2010/html/foxservicing.html
 

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Discussion Starter · #6 ·
We have a zip tie for a sag indicator and it never comes close to fully bottom out. We never serviced the fork as it is 1 year old.... I will try the leaving the bike upside down tonight... on big bumps it is fine she thinks just not on quick small bumps, she says it started after us changing out the stem and originally the headset was loose and now its tight but she swears she feels a little harshness when hit a small quick bump... I think its fine but will keep looking into it...thx
 

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How many hours has the bike done? It does sound like the fork might need servicing. Try letting all the air pressure out of the fork and then moving the fork through its travel to see how smooth the fork travel feels with no air spring.

Are you sure the headset is adjusted properly? The aheadset top cap doesn't need to be tightened down much. If you snapped the bolt previously that's far too tight.:eekster:

The stem bolts need to be fully loose and then you lightly tighten the aheadset bolt to load the headset bearing. It's right when the headset turns freely but without any fore-aft play when you hold on the front brake and rock the bike backwards and forwards.

You then tighten the stem bolts down to keep the headset bearing adjustment. After the initial adjustment the aheadset bolt doesn't need tightening anymore. Once the stem bolts are tight you could even take the aheadset bolt out completely and it wouldn't matter.:)
 

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Biking Brazilian said:
How would I do this on an RL?
I think a heavier weight oil in the fork would add some more compression damping. Changing the oil weight affects a lot more than just the compression damping so you might be better off getting the fork custom valved at the same time. The 2008 F120 RL uses 7w fork oil as standard.

This thread is about motocross bikes but the principles are the same for a mountain bike:

http://www.thumpertalk.com/forum/archive/index.php/t-677009.html

It's not something you'd want to do for small bump compliance which seems to be the problem here.

Edit: Added model year of fork. The 2007-2009 F120 RL uses 7w suspension oil whilst the 2010 F120 RL uses 10w oil:

http://service.foxracingshox.com/consumers/Content/Service/oil_volumes.htm
 

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Discussion Starter · #10 ·
when all air is out it is smooth. I will try to add more air and test that out.... Might be too less air maybe...
 

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Her description could just be the best way that she can describe the common complaint of F120 and Float forks lack of travel usage and extreme progressiveness. The air chambers aren't very large so the pressure ramps up quickly making them very stiff after only about 3" of their 4.7" of availabe travel.

You can search this board and the Shock and Suspension board and you'll find a lot of info on this, and the very simple fix. I did the mod on my F120 and it helped a lot.
 

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Discussion Starter · #12 ·
Are you talking about removing some fluid from topcap or cutting the piston? The fluid thing I did already and dont feel comfortable cutting the piston...
 

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Cutting the piston rod. I know it sounds difficult, but it is surprisingly easy.

Removing some of the Float fluid helps, but not much.

Was you able to see a difference after removing some fluid? I think I gained about 8 mm travel after removing some of the fluid. I then cut the rod and got about 18-20 mm. I only removed 10 mm from my rod. If I had to do it over again, I'd probably do 15 or 20.

The hardest part is drilling the hole in the rights spot for the piston's roll pin, but that was fairly simple.
 

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Discussion Starter · #14 ·
If you have a detailed explanation and all tools and everything required I would try but might rather send to push for 200 but would rather do myself. Let me know...
 
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