Fox 38 Harshness?

[KnollyBro]

Yes, its a bit strange. I read a review about my bike that mentioned that the fox 38 generelly has a strong rebound damping which could lead in partly too slow rebound when riding with low pressure (light rider), even with rebound fully open.
Open doesnt mean no rebound in this case. My front heel doesnt bounce or something, its dampened.
I ride a turbo levo expert size S4.

shock is an x2 but there is no problem. I set it to default setting and it works fine. I just had problems with the fork which felt really stiff.

If you have a link to that review about your bike, I wouldn't mind reading it. I am not understanding what you mean when you say that
"even with the rebound fully open. Open doesnt mean no rebound in this case" as fully open means there is very little to no oil going thru the rebound circuit which in my mind would make your fork very lively even with low tire pressure! Which Fox 38 are you using? Grip 2 damper? In the video below, I am cruising down a trail that has 4-6 foot table top jumps (medium size) and what I see is a fork that pops up a small amount when I land. I would think if I set the rebound any faster, I would be landing on my back tire and coming down a lot harder on my front tire. I am running around 18 PSI front and back with Cushcore on a Kenevo SL. Spring Rate: 92 PSI with 3 volume spacers, HSR:3, LSR:2, HSC:6, LSC:14, I weigh 88 Kg with my gear. The video is pretty boring but it does show how the fork behaves on small jumps starting around the 4:30 minute mark.

 

[j.e.]

With fully open I mean 9 clicks from closed, as described in the fox tuning guide. Propably this isn’t fully open.

I found the review what i meaned. It was this review about the Fox 38 (not about the bike), FOX 38 GRIP2 Factory review – Power and control

„Very light riders might struggle with the heavily dampened low-speed rebound: our 80-90kg testers opened it up almost completely. This suggests that lighter riders running lower air pressures might have a hard time adjusting the fork to respond quickly enough.“ (from the german version)

 

[j.e.]

If you have a link to that review about your bike, I wouldn't mind reading it. I am not understanding what you mean when you say that
"even with the rebound fully open. Open doesnt mean no rebound in this case" as fully open means there is very little to no oil going thru the rebound circuit which in my mind would make your fork very lively even with low tire pressure! Which Fox 38 are you using? Grip 2 damper? In the video below, I am cruising down a trail that has 4-6 foot table top jumps (medium size) and what I see is a fork that pops up a small amount when I land. I would think if I set the rebound any faster, I would be landing on my back tire and coming down a lot harder on my front tire. I am running around 18 PSI front and back with Cushcore on a Kenevo SL. Spring Rate: 92 PSI with 3 volume spacers, HSR:3, LSR:2, HSC:6, LSC:14, I weigh 88 Kg with my gear. The video is pretty boring but it does show how the fork behaves on small jumps starting around the 4:30 minute mark.

Nice video! I wish I could show you some too but i don’t have a gopro.
Your low Speed rebound is definately waaay too slow with just 2 clicks.

 

[KnollyBro]

With fully open I mean 9 clicks from closed, as described in the fox tuning guide. Propably this isn’t fully open. View attachment 93971
I found the review what i meaned. It was this review about the Fox 38 (not about the bike), FOX 38 GRIP2 Factory review – Power and control

„Very light riders might struggle with the heavily dampened low-speed rebound: our 80-90kg testers opened it up almost completely. This suggests that lighter riders running lower air pressures might have a hard time adjusting the fork to respond quickly enough.“ (from the german version)

Thanks for finding the article. It still makes no sense to me how a rider can run a fork without very little rebound unless they are weighing in at under 60 kg but with rebound being directly related to spring rate (air pressure), when you mentioned you were up in the 90 PSI range, it had me scratching my head. Then again, I seem to be under the recommended spring rate at 92 PSI for my weight (97 PSI) and am probably only getting around 10-12% SAG. As I dive deeper into all of this, I am starting to see a lot of personal preference and riding style creeping in! As long as we are enjoying how are bikes are feeling, vive la différence!

I have been using this dudes methods for tuning suspension:

 

[KnollyBro]

Nice video! I wish I could show you some too but i don’t have a gopro.
Your low Speed rebound is definately waaay too slow with just 2 clicks.

You can tell the LSR is way to slow from the video? To be honest, I am more of slow speed Freeride tech rider than a high-speed park shredder (I can ride ALINE but prefer Miss Fire/In Deep at Whistler). After smashing my calcaneus bone into 13 pieces a few years back, I have decided to make a conscious effort to stop crashing! My local trails (North Shore and Squamish) are more tech so my suspension setup has been adapted to keep my 60 year old body going!

Ladies Only is a trail I have been riding for over 10 years. I am not getting any better at it but I can still make it down it!

 

[j.e.]

Thanks for finding the article. It still makes no sense to me how a rider can run a fork without very little rebound unless they are weighing in at under 60 kg but with rebound being directly related to spring rate (air pressure), when you mentioned you were up in the 90 PSI range, it had me scratching my head. Then again, I seem to be under the recommended spring rate at 92 PSI for my weight (97 PSI) and am probably only getting around 10-12% SAG. As I dive deeper into all of this, I am starting to see a lot of personal preference and riding style creeping in! As long as we are enjoying how are bikes are feeling, vive la différence!

View attachment 93990

View attachment 93989

I have been using this dudes methods for tuning suspension:

the 38 has a very strong rebound. If i compress my fork and let it snap the tire stays on the floor. Even with my fast rebound setting. If you really got only 10-12 % sag you are running way too much pressure. With this high pressure you need a stromg rebound setting.
The fox recommendations for pressure etc don‘t account the bike weight o r riding style. I suggest you to set sag properly to 20%, so your fork gets softer on small bumps, and to set your rebound faster, that it recovery fast enough for the next hit.

 

[j.e.]

I dont know if you even got a problem, lol.
When youre satisfied with your fork, everything is fine. I didnt want to teach you or something like that.

 

[j.e.]

You can tell the LSR is way to slow from the video? To be honest, I am more of slow speed Freeride tech rider than a high-speed park shredder (I can ride ALINE but prefer Miss Fire/In Deep at Whistler). After smashing my calcaneus bone into 13 pieces a few years back, I have decided to make a conscious effort to stop crashing! My local trails (North Shore and Squamish) are more tech so my suspension setup has been adapted to keep my 60 year old body going!

Ladies Only is a trail I have been riding for over 10 years. I am not getting any better at it but I can still make it down it!

I dont know if your rebound feels too slow. But since this is a thread about the fox 38 feeling harsh I assumed you got that problem, too.

 

[Mcharza]

If you have a link to that review about your bike, I wouldn't mind reading it. I am not understanding what you mean when you say that
"even with the rebound fully open. Open doesnt mean no rebound in this case" as fully open means there is very little to no oil going thru the rebound circuit which in my mind would make your fork very lively even with low tire pressure! Which Fox 38 are you using? Grip 2 damper? In the video below, I am cruising down a trail that has 4-6 foot table top jumps (medium size) and what I see is a fork that pops up a small amount when I land. I would think if I set the rebound any faster, I would be landing on my back tire and coming down a lot harder on my front tire. I am running around 18 PSI front and back with Cushcore on a Kenevo SL. Spring Rate: 92 PSI with 3 volume spacers, HSR:3, LSR:2, HSC:6, LSC:14, I weigh 88 Kg with my gear. The video is pretty boring but it does show how the fork behaves on small jumps starting around the 4:30 minute mark.

I think it works exactly as it should. The fork stops the movement on the descent really nicely. That's how it should work.

 

[KnollyBro]

I dont know if you even got a problem, lol.
When youre satisfied with your fork, everything is fine. I didnt want to teach you or something like that.

Well... its human nature to question and "harsh" is a relative term. I never fully understood my fork's setup and the further I deviated from the factory suggested settings made me wonder what others were experiencing. The internet is full of info, some good, some not so good. For instance, apparently some people have found that their new forks from the factory have been packed with too much grease which was the cause of their complaints about their forks. Mine has been serviced once so that is not my issue. As for "teaching me" or offering anecdotal advice, I am always willing to learn, which what I believe this Forum's main focus is about. Thanks for your input

 

[Gyre]

A couple of things I wanted to update. I prepped a 160mm 38 and serviced a 170mm Zeb, both with Vorsprung Secus mods and burnishing the bushings (I've done this with a couple of 38 lowers, both were very tight, the Zeb bushings were fine as is). I used Fox Gold lube as recommended by the factory on the 38, and a mix of 50/50 Motorex Supergliss 68k / 100k on the Zeb. The Secus on the 38 was new, and I replaced/greased the seals on the Zeb's Secus.

I switched back and forth on subsequent days on the same trails. The Zeb ran noticeably better over chatter bumps than anything else I'd ever used before (including the same Zeb last year). The 38 didn't reach that level of smoothness, but it still performed well.

This wasn't controlled enough to be a meaningful comparison, but the terrible performance I experienced in the original post was nowhere near what the fork can do, and it's possible that Fox manufactures their bushings extra tight.

Edit: Finally got around to taking apart the 38 that was giving me grief. Bushings were okay (not loose, not tight), grease in the air spring wasn't too bad. The problem seemed to be that it came with so many tokens that allowing the sag to sit low was a recipe for ramp-up disaster. I took out 2/4 tokens, regreased lightly with Slickoleum, added the Supergliss 68k/100k mix, and set sag around 15-20%. Working worlds better now on small and medium hits. I might add one token back trying to find the right balance of progression and linearity for me.

 

[DaveG01]

Wow. Stripped the air spring on my fairly new 38s tonight and removed all the excess grease. Took my KSL for a spin over a dh rough field locally near my house. Night and day. Worth doing this is you haven't (Shame it needs to be done on a new bike)

 

[aperock]

Agree

 

[Evolution Stu]

According to Fox, it’s a different tune
- initial stroke is softer, the end stroke ramps up to provide the right amount of support for those bigger hits.

Thanks for this info @Rob Rides EMTB, it just cost me some money

For reference, having discussed this with both James and Tayah at Silverfish (Fox UK) today, this tune is available as part of a Fork service and is now known as their "Fox factory Tune"

They say this:
"Engineered by FOX Factory, verified on the trails surrounding the Fox Service Centre in South Wales. As part of your fork service, you can now upgrade any Grip2 VVC fork to Factory Tune (Only available for 2021 Grip2 VVC forks onwards). Reduced feedback in hands, improved high speed compression movement for better overall ride performance. Available now for a £50 upcharge on your service, includes orange adjuster caps and stem cap (subject to availability)."

It costs £50 for the damper upgrade during a Fork service so I have just booked a slot to have the GRIP2 from my new 38 done whilst they change the bushes in my spare Fox36 fork.

 

[GeordieKenevo]

Thanks for this info @Rob Rides EMTB, it just cost me some money

For reference, having discussed this with both James and Tayah at Silverfish (Fox UK) today, this tune is available as part of a Fork service and is now known as their "Fox factory Tune"

They say this:
"Engineered by FOX Factory, verified on the trails surrounding the Fox Service Centre in South Wales. As part of your fork service, you can now upgrade any Grip2 VVC fork to Factory Tune (Only available for 2021 Grip2 VVC forks onwards). Reduced feedback in hands, improved high speed compression movement for better overall ride performance. Available now for a £50 upcharge on your service, includes orange adjuster caps and stem cap (subject to availability)."

It costs £50 for the damper upgrade during a Fork service so I have just booked a slot to have the GRIP2 from my new 38 done whilst they change the bushes in my spare Fox36 fork.

Any update on your upgrade @Evolution Stu ?

I've just bought some Factory 38s and fitted them but not got out on the bike yet due to the snow up here in the north east of England but hoping mine aren't full of grease!

 

[Bones]

Any update on your upgrade @Evolution Stu ?

I've just bought some Factory 38s and fitted them but not got out on the bike yet due to the snow up here in the north east of England but hoping mine aren't full of grease!

I've had the factory tune done on mine and apart from the orange caps I don't think it's any different!!!
After various issues, Silverfish UK have replaced the damper and air shaft and done the factory tune.
Im finding it is still harsh off the top but it's early days for setting it up.
83kg kitted up and I'm trying a softer air spring setup between 20 to 30 percent sag. On the 170mm that is between 34 - 42 mm. Currently trying 38 mm and I need 95psi to achieve that with the fast rebound at 1 click out from fully closed as anything more lifts the front wheel off the ground during the garage test.
What I do find is that the sag is more after a ride and everything is nice and free, so this is a good time to do any adjustments.

 

[Growmac]

Depending on how you get on, next step might be to talk to Fin at Full Factory. He's now demoing the TruTune porus spacers that are supposed to be really interesting allowing more fork setup options. I have Fox e36s on my bike, sadly, so he's trying to get a 34 for me to try.

 

[Mikerb]

My experience with a Performance Elite 38 which is not e bike tuned was that the number of air spring tokens used made a huge difference. I went from 3 to 2 , set SAG the same at 20% and was surprised how much difference it made to all compression and rebound settings. My air pressure is a bit less than Fox suggest but others settings are now close to what they recommend. Previously with 3 tokens fitted lsc and hsc were nearly fully open.
My point being there seems to be a very specific balance between spring rate and damping that needs to be found .

 

[GeordieKenevo]

My experience with a Performance Elite 38 which is not e bike tuned was that the number of air spring tokens used made a huge difference. I went from 3 to 2 , set SAG the same at 20% and was surprised how much difference it made to all compression and rebound settings. My air pressure is a bit less than Fox suggest but others settings are now close to what they recommend. Previously with 3 tokens fitted lsc and hsc were nearly fully open.
My point being there seems to be a very specific balance between spring rate and damping that needs to be found .

What weight are you fully kitted up? I'm around 100kg with everything inc water and I don't think my factory 38s have any tokens in as stock so was going to start with zero.

 

[Growmac]

What weight are you fully kitted up? I'm around 100kg with everything inc water and I don't think my factory 38s have any tokens in as stock so was going to start with zero.

I honestly think it's worth getting new forks serviced immediately so you can then get them properly set up for your weight and riding. 38s are fairly sticky compared to 36s , so for someone of a medium weight it would/might be worth a token or two to allow lower pressures and more small bump sensitivity. Maybe?

 

[Mikerb]

What weight are you fully kitted up? I'm around 100kg with everything inc water and I don't think my factory 38s have any tokens in as stock so was going to start with zero.

I am 72 kg naked so probably 76kg with summer kit....78 with full armour and the bike is a Whyte E160 RSX. ( so 160mm travel fork). The bike came with 3 tokens .Just to correct one thing I said above I actually set SAG to 25% not 20% and originally that was 70 PSI. Reducing to 2 tokens I set the same SAG which was then 85 psi. My settings now with that spring rate are now
LSR 6 HSR 5 HSC 5 LSC 10 ( all from closed) .

Obviously your settings will be quite different because you are heavier and your bike has more travel and a slacker head angle ( I think)................but my point was that there seems to be a very fine balance between spring rate and damper settings with this fork. I think this is because the damper tune is designed for full on enduro and therefore on the harder side. If the spring rate is too low, the damper can dominate the response. I would have thought for your weight a good starting point would be with 2 tokens which seems to be most often what is fitted by factory for most forks (i.e before brands mess with it!).

I would point out that I can get wildly different SAG results depending how I do that. The most accurate ( imho) is if the SAG is measured on the last "release" after cycling the fork through c 20% of travel 3 or 4 times. The least accurate is if you set SAG just by standing on the pedals and measuring the fork travel.

 

[Growmac]

I think this is because the damper tune is designed for full on enduro and therefore on the harder side. If the spring rate is too low, the damper can dominate the response.

I hear from my expert friends at TF and Full Factory that the main problem is that big bushings and stanchions are just stickier compared to those on the 36s. They inherently have a lot more stiction and thus worse small bump sensitivity, but compensate by being much better on big drops to flat and through really rough stuff. As you're a light rider, you might do better with a 36. Or, coil convert your 38?

 

[Mikerb]

I hear from my expert friends at TF and Full Factory that the main problem is that big bushings and stanchions are just stickier compared to those on the 36s. They inherently have a lot more stiction and thus worse small bump sensitivity, but compensate by being much better on big drops to flat and through really rough stuff. As you're a light rider, you might do better with a 36. Or, coil convert your 38?

I was replying to @GeordieKenevo !...........Perfectly happy with my 38s thanks.

 

[Growmac]

I was replying to @GeordieKenevo !...........Perfectly happy with my 38s thanks.

Slightly odd tone to take. Good luck getting it sorted.

 

[Mikerb]

Slightly odd tone to take. Good luck getting it sorted.

Sorry mate.....I was not trying to be rude, just clarifying that I dont have issues with my 38s ( or at least saying how I have sorted them) and was replying to a question posed to me a bove. I should have linked his post then it would have been clearer!

 

[Evolution Stu]

Any update on your upgrade @Evolution Stu ?

I've just bought some Factory 38s and fitted them but not got out on the bike yet due to the snow up here in the north east of England but hoping mine aren't full of grease!

Yes!
I i tended to come back here and update this and clean forgot.

I can confirm that the tune costs £50 at Silverfish (Uk) and comes with some pretty nice looking orange caps.

As for how it rides, I can only echo Rob’s feelings. It’s softer in your normal, low speed, chattery braking bump type terrain but has lost none of its high speed support when you hit it hard (or run out of talent and land on the front wheel in my case of late…)

The slightly fatigued hands I had have now gone. Well pleased.
Absolute bargain upgrade, and caps look great too.

 

[GeordieKenevo]

Just an update on my new Fox 38 factory fork which if you haven't got time (or the will) to watch my first 25 min ride video with it below these are the settings that seemed to work for me on my 2019 Kenevo so far...

~ 100kg total riding weight
114psi
Hsr - 6
Lsr - 3
Hsc - fully open for now
Lsc - fully open for now

 

[Mcharza]

Just an update on my new Fox 38 factory fork which is you haven't got time (or the will) to watch my first 25 min ride video with it below these are the settings that seemed to work for me on my 2019 Kenevo so far...

~ 100kg total riding weight
114psi
Hsr - 6
Lsr - 3
Hsc - fully open for now
Lsc - fully open for now

When you have had to adjust the compressions completely open, isn't there too much compression in the fork, which should be tuned differently

 

[GeordieKenevo]

When you have had to adjust the compressions completely open, isn't there too much compression in the fork, which should be tuned differently

Possibly yes but I was under the impression it was best to start from fully open for compression but happy to be corrected and learn more

Edit - this video from around 5 mins recommends starting with Lsc and HSC fully open

 

[KnollyBro]

Possibly yes but I was under the impression it was best to start from fully open for compression but happy to be corrected and learn more

Edit - this video from around 5 mins recommends starting with Lsc and HSC fully open

But are you using around 80% of the travel on your fork on your regular trails? If not, you have too much air pressure and you are not using your fork as much as you could. If you are bottoming out on hard hits, then add HSC and volume spacers. I weigh around 80kg and run my Fox 38 at 75 PSI with 1 volume spacer and a Luftkappe Air Piston Kit which I found reduced the harshness and added mid stroke support on the trails I ride.