I actually had similar issues with my Fox 38. I believe the GRIP 2 damper was shot. Just a wild guess. The damper would function the same regardless whether it was fully open or closed. The ride was insanely harsh. Not even Vorsprung could fix the issue so it had to have been the damper.

Have you tried the settings Fox recommends for baseline and go from there? Sometimes it will fix certain issues. Also when was the last time you serviced your forks?

 

Kinda like something in the damper chokes on sharp bumps and rough ground at speed?

 

How many volume spacers? I'd start out at zero and add only as necessary. Sounds like you're hitting the ramp up deep in the travel as Fox forks are usually known to work better at higher speeds at the expense of slower speed suppleness. If that doesn't do it I'd service the air spring but my guess is either too many spacers or the rebound is too slow.

 

Pretty good recommendation here.

Two areas to explore:

1.
Often when people complain about harshness the problem is they are running their fork too soft. They blow through the travel and end up with a fork that is stuck deep in its travel. Feels absolutely terrible.


With a fox fork the correction is too increase your spring rate.

2. If your rebound setting doesn’t match well with your spring rate then your fork is going to be terrible. Too much rebound and it is stuck down, same issues as a fork that is too soft. Too much and it is kicking back before while you are on the bump.


Fox does a pretty good job with their recommended settings. If you go with what they recommend for your weight you are going to be close.

 

My current Fox 34 Rhythm's small bump compliance is excellent but @ about 50% travel (larger high speed hits) is quite harsh. I run my air pressures on the higher side for my weight so being under sprung isn't the issue. I have noticed quite a bit of noise when rebounding lately but the rebound speed hasn't been changed. I am hoping it needs a basic service as it is really past due.

 

Being harsh on large hits really indicates too many volume spacers too. Too much HSC is also possible but less likely on the Grip 2.

 

You'd have to completely ignore the damper to come to that conclusion.

Anything that gives you a lot of shaft speed will feel harsh on GRIP/GRIP2. Because of the way the midvalve works.

 

Thanks for the help guys, greatly appreciated [emoji106]

I’m running the fork as it came out of the box, so I’d need to open it (both actually) to check the volume spacers.

Both forks were set up according to Yeti’s recommendation and I’m running the pressure on the higher side (roughly 5psi difference low to high).
Their recommendation was perfect for the shock, even rather too plush than too harsh.

When this happens on faster parts of the track, the fork simply won’t compress any further. It will extend again but it really shakes my arms badly.
Too little compression on the 34 had the result someone wrote here, very supple at the start and then harsh. I’m running more compression so the first part feels phenomenal, yet the second part of the stroke is still blocked.

Guess I’ll need some tools to check for spacers.
When inflating the fork, it will only extend fully shortly before reaching operating pressure. Usually I increase pressure in 10psi increments to balance the negative chamber but the fork won’t extend fully unless it has at least 60-70psi (I think I run 105?).


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I have a fox rhythm fork 130 and I have felt that I need 4 volume spacers for the dual purpose I use it for. I’m 190 and I run 5-10 psi lower than recommended at 85 psi. And I add air to about 95 when I do some jumps. I think I’m under forked and I have plus tires (at 12psi) to help with the chattering bumps. That works pretty well for me.


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I'm 175 lbs riding rocky terrain and steep terrain. I have a 36 Grip2 (x2 actually) and a 34 Grip2. I run 70-75 PSI and keep the HSC and LSC to a minimum unless I know it will be a very fast rocky run. Then I may click up a bit. I like how compliant they are. They never bottom out or dive too much.

 

The Grip damper for example really has phenomenal support & grip with just 2-3 clicks of compression (from open). But still won't use more than half the travel (140mm total).
I'm running 105psi on both forks, as per my weight incl. gear in kilograms.
Less pressure just killed the support, but wouldn't help with the ramp up.

It may be, but I thought it'd be odd, if both forks had a lot of spacers from the factory or needed burnishing. Thought there could be something else to check before opening them or sending them in.

 

Here's a Fox GRIP2 VVC plot.

 

Sell it and get a suntour durolux. I'm serious. They're amazing.

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@Dougal: perfect, thank you! I’ll take a small part of trail close to my house to take some measurements.

The first part of the stroke is truly amazing. I was running a BOS Deville before this and thought that was an amazing fork. The first part of the stroke is clearly much better on the 36. Really supple (better than a 36 Van I had years ago), good support, great front end grip with the right compression settings.

The trail I’ll test is medium speed and gas two steps at the end where you’d brake under compression, right after the first step. No jumps but the sheer speed and weight shift should use at least 80% travel in my book, especially as the rough section before it already shakes my hands like mad.

The slow extension when putting the fork under pressure, to me, could be an indicator? I’ll see once the tools are here.


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Tried this again today with an “open” damper, regular pressure of 105psi.
I lost grip and control, but didn’t really gain any comfort. The fork still uses 90mm out of its 160mm total.
Before, I was using this setting (as per Yeti’s recommendation, clicks open from fully closed:

HSR 6 (of 9)
LSR 7 (of 14)
HSC 4 (of 7)
LSC 11 (of 15)

Next step will be to check the forks internals. Not really my thing but I guess I won’t find anyone to service and turn it around swiftly in the current situation.


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Has your air spring ingested oil?

Time to whip the lowers off and see which side won't compress properly.

 

Yep need to remove the volume spacers.

 

That doesn't sound right to me. I am a 140lbs and even with 105psi I would use more than 90mm of travel just bouncing around on the street.

Have you measure your sag?

 

I'll try with zip ties. The bleed valve does exactly what you're describing, a little air will get out and that's it.

@Dougal: Can't say yet as it's still unopened, but I'll check. Should it run out if I remove the core & put it upside down?

 

I’d do a lower leg service and definitely pull the air spring and check it. Sometimes air gets stuck between the spacer and it won’t work properly or feel harsh.

 

Stiffen the HSC to about 75%.

 

If you guys are that unhappy with your forks, perhaps sending them off to a good tuning company might be a good idea for you.

 

Does anyone think all this fuss with volume spacers is possibly causing some of the problem?

Neg & pos air springs got bigger. Then volume spacers were used to reduce them?

My forks were butter 15+ years ago and now I find both my Pike and 34 harsh in the 30-70% travel range. Big hits are plush but the chatter bumps are handled terribly.

 

Neg & pos air springs got bigger. Then volume spacers were used to reduce them?

Positive volume spacers are used because long travel forks are more progress than short travel so when the chassis is staying the same and you're just making the air shaft shorter it's necessary to reduce positive volume.

What forks use negative volume spacers?

I think the harshness most people complain about is due to preloaded compression damping.

 

^ Nice!

 

I’ve noticed that my new Fox 36 continues to feel better with mileage. I have about 500 miles on it now.

 

LMN - some of the closest people in my life are acclaimed world champions. As well, I ride and work with some of the fastest riders in the world. We all own suspension products from various manufacturers. I’m here to share our unbiased experiences and observations.

Dougal - I make my living selling suspension products from a competitor of the company I am $hitting all over in this thread.

 

Nah, I make my living on service and tuning. If you could refrain from making up BS quotes that would be great.

Fan-boys really hate being told their product isn't perfect. Even when they've already proven it to themselves by riding with LSC closed and seeing how bad the internal tune is.

BTW pros are fast in spite of their equipment. Put them on a rigid fat-bike and they'll still leave you behind.

 

I probably don’t know any better but since the OP I have bumped the air pressure 5lbs from the highest recommended by Fox and added a volume spacer and it feels great to me now. I was able to back off compression to barely off open and the rebound now feels perfect where before it felt half a click too much.
The 5lb bump advice came from this thread and it did help with dive while not making it feel much different on small bumps so that was a nice surprise, thanks to who suggested that.

 

I was able to back off compression to barely off open and the rebound now feels perfect where before it felt half a click too much.

Is "barely open" "almost closed" or "almost open"? Thanks.

 

I have similar complaint with my Fox 36 Factory fork that is nearly new. I only use about 50 to 60% of the shock travel and the shocks are never "plush" feeling. What's the point in 150mm of travel if you only get 125mm? So I have been dropping the pressure by 5psi from original 85psi (I'm 170 lbs) to 65 psi now and still only use up to 60%. It finally occurred to me that there may be too many volume spaces for my weight and riding style. I checked with the bike manufacturer and found that there are 2 of a potential 7 volume spacers installed on the shock from the factory. Fox website verifies that this is the case. The number of volume spacers Fox includes depends on the designed travel of the shock. Anyway I am hoping that removing both of these spacers will finally enable me to enjoy my very expensive fork. Has anyone else made this change and found good results?

As to the other possible adjustments to this Fork I have dialed everything back to zero. No rebound dampening, no compression dampening. If I can get to full travel on this fork, I will experiment with adding some back, but at this point these adjustments seem useless.

 

This is my set-up procedure.
1. Put air to recommendation by Fox.
2. Check sag, should be somewhere between 15-25%. I like forks around 20% myself but that is my personal preference. Outside of desired sag, adjust airpressure.
3. Go outside and do a stomp on the bike. Basically push down on the fork as hard and quickly as I can. My target is 80-90% of the travel. If I am in that range volume spacers are good, outside of that range I need make changes. This is important test it measure your abilty to exert force on your bike.
4. Make sure my rebound and compression is set to fox's recommendations.
5. Go and repeat a test trail and try single click adjustment of rebound (LSR first and then HSR). Find where I am happiest.
6. Do the same thing adjusting compression only.


Order matters.
1. Set spring rate
2. Set volume spacers
3. Set rebound.
4. Set compression.

#1, 2 are set in the basement and test on the street. #3 and 4 you take a guess at at home but tune on the trail.