# Fox 40 Spring Discussion



## jurichar (Aug 19, 2009)

For those of you that run the 40, Im curious how closely you follow fox's guidelines for spring rate. My body weight is about 185 so about 190+ with gear. According to Fox I should be running the Green (+1 from factory blue spring) for guys 180-200. I've been running the green on my 2011 demo for the last few months with about 1.5 inches of sag (0 preload - as preload is dumb and removes small bump compliance from your fork while giving you nothing in return except a different sag number). I digress...I typically run very little compression 3-5 clicks (from fully open) as anything higher than this feels like a turd stick. With the above settings I really cant bottom out the fork ever even on bigger stuff. I did bottom it out on 9ft to flat-ish high speed drop, but thats to be expected regardless of spring. 

So i decided to drop down to the Blue spring (weight rating 160-180) which is not even close to the reccomendation for my weight. I only rode it for a single day, but it felt surprisingly better. i got right around 2 inches of sag, and it allows my compression damper to have more of a useful range, im now running about 5-8 clicks from full closed. Its got a very different feel, but i think it feels better.

Im interested to see if anyone with some suspension knowledge has any light to shed on this. Am i being an idiot and immediately need to replace the green spring. Or is there a bit of merit to this opinion?? Is there any reason why fox's guidelines would be off?!?


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## kenbentit (Jan 2, 2003)

I had the opposite situation with my fork. Same body weight but I was running the Blue spring. I had trouble getting the suspension to feel balanced with that spring installed. It was especially noticeable at speed thru rocky sections, I felt like I really had to lean back to keep from hanging up. I kept increasing my Comp settings to the point where things started feeling a bit harsh. After swapping to he green spring things were immediately better. I was able to bump back down to minimal Comp and had greatly improved control overall. Sensitivity on the slower stuff isn't as plush as the blue spring but it feels much better at speed. I'm still able to get full travel on mine even with the green spring...


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## illnotsick (Mar 28, 2011)

I weigh 120-130 and I use the purple spring ~2" sag. I get full travel, only fully bottom out in sketchy situations. The blue was too stiff, never had a chance to try the black but I wouldn't want to go any softer than what I have now.


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## jasevr4 (Feb 23, 2005)

I weigh around 160lbs and have trouble using all of my travel and getting full sag out of my 40. Currently using the Medium spring. Considering going to the Soft but not sure if it's worth it.


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## illnotsick (Mar 28, 2011)

jasevr4 said:


> I weigh around 160lbs and have trouble using all of my travel and getting full sag out of my 40. Currently using the Medium spring. Considering going to the Soft but not sure if it's worth it.


Try backing off the preload. How much travel are you using? The hydraulic bottom out on the 40's isn't easy to get all the way through, it's there to save your ass when you need it.


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## waterdogs (Jun 18, 2010)

I am a bit heavier about at 200 w/o gear. I originally had the green in and when down to the blue as I wasn't using all the travel. Going back to green now, as I think it's too plush and doesn't pop enough for some of the jumps. Also, knowing that I am not nearly as fast as those on the UCI circuit, I've noticed from reading over the net, most of the guys whom weight less than I are running the green.


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## gladegp (Aug 21, 2007)

I'm 170 lbs and should be on the blue spring, but I'm only getting 15-20% sag with zero preload. Seriously considering trying the purple spring. Then I could run more compression damping, currently running a few clicks in from zero just to have some but I really want it more plush


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## azdog (Nov 16, 2004)

I'm 175lbs and run the purple spring. The blue was too stiff for my taste even with compression and preload all the way out. I also adjusted the internal bottom out all the way out as well which made a huge difference. Even when I called Fox they said I may want to try the purple spring even though it was not recommended per the guide for my weight.

@gladegp-I would try it based on your weight.


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## chris_d (Apr 5, 2008)

I am about 190 and run the blue spring with zero preload. I had the Fox tech at the GRT go through it last season including setting the sag and he would have said go to the green if the sag was off or thought it was under sprung for me. It's a little soft but I stop the brake dive with a little more LS.


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## jasevr4 (Feb 23, 2005)

illnotsick said:


> Try backing off the preload. How much travel are you using? The hydraulic bottom out on the 40's isn't easy to get all the way through, it's there to save your ass when you need it.


No preload, even ridden it with 0 clicks high speed, 0 low speed.

Absolute furthest I've ever got the thing was about 6.5 inches after a really sketchy landing. Usually after a day on the mountain it will be around the 6" mark.


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## davec113 (May 31, 2006)

I'm 200 lbs w/o gear and the stock spring seems to be just right even though I should use a heavier spring. Both hs and ls comp is about 1/2 way in. It's not that plush but feels great hitting big stuff at high speeds... the faster I go the better this fork performs. Seems like Fox spring recommendations are for WC riders, everyone else probably needs a softer spring than Fox recommends.


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## ebxtreme (Jan 6, 2004)

160 lbs. and I ride the blue spring which is about perfect for me.

My wife is about 130 and she rocks the purple spring....also good for her.

EB


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## nmfly (Sep 28, 2007)

I bought a used bike which came with a green spring - seemed harsh especially on small bump compliance, Switched to blue but it was still harsh, then changed oil to Red Line 10wt. What a difference that made - the fork is now plush on small hits with no bottoming issues on big hits. At 170# I'm now very happy with the blue spring.

Lesson learned - use the right oil.


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## motobutane (Sep 23, 2008)

I switched to the green, but I need a Ti green spring. I've got a blue-Ti and a purple steel I need to sell or trade.....anybody?????? bueller....bueller.


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## Hobblyjig (Jun 28, 2011)

I got a new Fox 40 this weekend. I've got almost 0 sag even regardless of preload setting. I assume this is because its brand new and needs to be broken in. How many hours of riding am I looking at to break it in all the way before I can even think about whether I have the right spring or not?


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## tuumbaq (Oct 6, 2005)

Hobblyjig said:


> I got a new Fox 40 this weekend. I've got almost 0 sag even regardless of preload setting. I assume this is because its brand new and needs to be broken in. How many hours of riding am I looking at to break it in all the way before I can even think about whether I have the right spring or not?


Even with brand new fork you should still be able to achieve the right sag... Tight seals and bushings will mostly give you poor small bump compliances and it shouldnt affect your sag that much.

How you are measuring your sag would have a greater effect on it :thumbsup:Try flipping the bike upside down, cycle the fork a few times and measure your sag again.Make sure to STAND on the bike with your body weight to the front...


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## kamikazee ideki (Jul 2, 2007)

I must be the odd one out in all this. I'm 170lbs and running a green spring in my 40 and a 500lbs spring on the dhx4. (riding an 09 Glory) I get pretty close to correct sag with this setup, and the bike rides amazing.


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## Got-Bike!! (Nov 9, 2010)

chris_d said:


> I am about 190 and run the blue spring with zero preload. I had the Fox tech at the GRT go through it last season including setting the sag and he would have said go to the green if the sag was off or thought it was under sprung for me. It's a little soft but I stop the brake dive with a little more LS.


I'm 204 and have the blue also. Same result as you after Fox Tech set me up at the US Open! Never bottoms out and is super plush. After the set up on the fork and my shock it gave me a false sense of security! I wish I could take him to all my races!


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## ak pura vida (Dec 15, 2008)

i have been running the green spring this year but i'm not quite getting enough sag (i'm 200+ geared up) so i'm going to try the blue spring. with the green running zero high and low spring comp seemed better than when i had them set in the middle but still not convinced it is set up as good as it could be. i'm really trying to learn how to set up my suspension better, and how the different changes effect the feel of the ride. sure wish i could spend some time with someone that was really competent with suspension setup. think it would do wonders for me.

i also need to service it. the oil seal is just starting to leak an RCH, and i need to change the oil. so fox recommends their 10wt oil, what makes the red line oil better? i run red line in my sled during the winter and really like it, but what difference did you notice when you went to the red line oil over the fox oil?

pv


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## techfersure (Dec 17, 2010)

I'm at 185 without gear too and thought the green was to stiff.was doing shuttle runs with Neko Mually and got to talkin about spring rates and set up,we weigh in the same and he helped me set mine up to mimic his,dude,night and day woke it up to it's full potential,he told me once there set up it's set and forget.


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## jurichar (Aug 19, 2009)

Which spring did you go with?? And just out of curiosity what other settings.



techfersure said:


> I'm at 185 without gear too and thought the green was to stiff.was doing shuttle runs with Neko Mually and got to talkin about spring rates and set up,we weigh in the same and he helped me set mine up to mimic his,dude,night and day woke it up to it's full potential,he told me once there set up it's set and forget.


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## techfersure (Dec 17, 2010)

I stayed with the green,don't remember the settings he set it up,sorry.


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## Hobblyjig (Jun 28, 2011)

tuumbaq said:


> Try flipping the bike upside down, cycle the fork a few times and measure your sag again.Make sure to STAND on the bike with your body weight to the front...


Thanks for the help, but I have to ask why flip it upside down? What's that going to do? And are you saying I should cycle the fork a few times while its upside down?


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## ak pura vida (Dec 15, 2008)

so i ordered a new seal kit and some redline 10wt oil. i'll rebuild it and see how it feels with both springs. time will tell...


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## gladegp (Aug 21, 2007)

gladegp said:


> I'm 170 lbs and should be on the blue spring, but I'm only getting 15-20% sag with zero preload. Seriously considering trying the purple spring. Then I could run more compression damping, currently running a few clicks in from zero just to have some but I really want it more plush


Soooo much better with the purple spring. Now the fork feels like the high end fork it is. Ten times better


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## Hobblyjig (Jun 28, 2011)

I'm 200 w/o gear, and I swapped from blue to green to try it out. I wound up sticking with green because I felt more balanced. But I also feel it a lot more when I'm going though a section of trail with a lot of small bumps (washboard or whatnot).

Like a lot of people have hinted at, there is more to consider than weight when choosing a spring. If you're riding at pro speeds you need a heavier spring rate to to get faster rebound...at least that's how I understand it.


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## nmfly (Sep 28, 2007)

AT 165 with the blue spring - still running stiff, my 66Rc still outperforms the 40 for plush. Maybe there is some inconsistancies with the fork spring ratings.... Given only one spring to compare to I can't make a statistical comment. Like the 40RC but it's sprung to stiff.


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## lelebebbel (Jan 31, 2005)

I'm 165 also and changed my blue for a purple, which is better. The blue spring was ok but not ideal, had to run almost no HSC or LSC, or the fork would be too harsh. Now with the purple spring, the adjusters are closer to the middle of the range and the fork does feel a lot better. Too bad the purple spring isn't available as a titanium spring, it actually weighs a bit more than the blue Ti spring.

Keep in mind that the head angle and geometry of the bike in general makes a difference, too. A slack bike with short chainstays would require a lighter spring than a steep bike with long chainstays for example.
Also, it is quite common to have at least a +/- 5% manufacturing tolerance on the spring rates. So the blue spring at a claimed 40lbs/in could be anywhere between 38-42lbs/in, the purple could be about 33-37lbs/in. In other words, you could have one fork with a purple and one with a blue spring, and they could feel almost exactly the same, or quite noticeably different.


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## TXBONE (Nov 28, 2011)

i weigh 185 lbs also and when i first got my fox 40 it felt way too soft for me, so i had my brother respring it and then it felt better with the black spring in there i think, the next stiffer one after stock spring


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## Gurterno (Jul 29, 2012)

After servicing my fork with new oil, the new low friction seals and slick honey lube on the seals it suddelly feels as if my purple spring is too soft and I might have to go back to the blue.

Soo much less friction, I can almost get full travel by bouncing in the parking lot as where I previously couldn't get it on big hits when biking


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