Ooh handbags at dawn ![Face with rolling eyes :rolling_eyes: 🙄](https://cdn.jsdelivr.net/joypixels/assets/6.6/png/unicode/64/1f644.png)
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I never said we don’t need sag I said all the other settings can be more important you can run the perfect amount of sag & the fork still run poor if you don’t adjust rebound, & low & high speed compression correctly. Rebound is the biggest one that is not setup correctly on most forks. I did used to do all warranty work for BOS suspension so know quite a lot thanks but yes you have yourself a lovely day
YesI would guess most MTB riders run the rebound far too closed (slow) as the manufacturers will send them that way as its arguably safer to do so... And in doing so, it feels harsh as it packs down and stays there.
F*ck me, this thread is full of keyboard worriers (didn't mean warriors)![]()
Thank you I'm having the same issue as you will give this a try**Update - Fixed **
Decided to nip home at lunch and have a play with it as it was bugging me.
And its now fixed.
Since this might be of interest to other owners of any fork, I will detail the procedure I used here:
Step 1: Depressurise the fork slowly whilst equalising as you go down.
Step 2: Remove the air cap completely.
Step 3: Remove wheel and refit axle.
Step 4: Stand on axle and pull up hard, to extend the fork as far and as fast as you can multiple times.
The theory is, the huge depression caused in the lower chamber will suck through any grease blocking the transfer port.
I certainly didn't hear anything happen, but i was huffing and puffing as its hard to pull up against the depression there
I then repressurised as normal and found the fork hits full extension about 75psi now.
Happy days.![]()
I did all that and heard the squelching/sucking sound but only once. After that the compression and pull up felt a lot looser and easier. Great stuff! I reassembled and inflated the fork in stages as required. No change, still got the lost travel!!Just found this thread searching for "lost 10mm travel on my Fox 38".
I will get back out to the garage and follow what @Evolution Stu recommended.
Step 1: Depressurise the fork slowly whilst equalising as you go down.
Step 2: Remove the air cap completely.
Step 3: Remove wheel and refit axle.
Step 4: Stand on axle and pull up hard, to extend the fork as far and as fast as you can multiple times.
Zip tie down the stanchion to release excess negative pressure. Google it.I did all that and heard the squelching/sucking sound but only once. After that the compression and pull up felt a lot looser and easier. Great stuff! I reassembled and inflated the fork in stages as required. No change, still got the lost travel!!
The fork has been serviced by TFTuned twice, the last time 384 miles ago. Suggestions?
I think it does have to do with the air pressure although not sure it necessarilly needs "a shit load"! If you use tokens/spacers it reduces the volume of air and therefore invariably leads to setting a lower air pressure. That is likely to allow the fork to settle rather more just under the weight of the bike ...........and that will also depend on the geo of the bike, for example how much of the bike weight is forward of the BB.Mine actually had a faulty air damper so all my earlier comments are about a faulty fork!
But the fact is that the forks will sag under the weight of the bike if you don't have at least 100psi in them to counteract the battery and motor weight. I have always had to lift my front wheel off the ground when measuring sag.
To me 10mm or so is normal unless you have a shit load of air to hold it up.
I will measure the stanchions.I think it does have to do with the air pressure although not sure it necessarilly needs "a shit load"! If you use tokens/spacers it reduces the volume of air and therefore invariably leads to setting a lower air pressure. That is likely to allow the fork to settle rather more just under the weight of the bike ...........and that will also depend on the geo of the bike, for example how much of the bike weight is forward of the BB.
It might also be worth measuring the total stancion length to see if the fork is nevertheless allowing the 150/160mm travel or not.
I have 2 Fox 38 forks. A 160mm non ebike fork and 180mm ebike tuned fork .....both settle a bout 6 under bike weight but when I pull them up the 160mm fork is 164mm from seal to crown and the 180mm is 180mm!!
Try setting the fork up with fewer or no tokens??
your fork will compress quite easilly at the top of its travel because as you said air pressure is progressive not linear. The more plush your fork at the top of its travel the easier it will settle under bike weight. If the 38 is the Ebike version it also has a damper tune that allows it to be plush at the top of travel but ramp up quickly in mid travel.....more so that the standard tune. Why mention the damper??? The rebound setting also has an impact on SAG which is why it is best to first set airpsring pressure with all compression and rebound settings fully open/fast, and then set rebound ( still with compression settings fully open). It is likely the air spring will need more air pressure the slower you set rebound so it is a balance. Unlike RS forks which I find easier to set up,, it has been my experience the Fox 38 is sensitive to the balance between damper settings and air spring settings.I will measure the stanchions.
I agree with that @Mikerb it's how I do it normally. As for set up I will try the settings from TF Tuned (just in case) and then start from scratch again. which will be pretty much what you recommended anyway.....................
An unrelated point maybe............when setting sag I think it best to be in the ready position up on the pedals. Depending on the reach etc of the bike that may or may not have your chin over the stem but the important thing is ( in my opinion) if that is how you position yourself when riding up on the pedals, so that is how you should set SAG.........ie dont lean further forward over the bars. Any average reach coupled with less that 66 degree head angle will already have you forward enough.
I will try anything. When I first got it, I set up the fork according to the Fox recommendations and it felt awful. It was like riding over broken bricks the whole time (big ones). So I slowly changed the settings.I still reckon you don't have enough air pressure in your forks.
You say 30% sag, but fox recommends between 15 and 20% sag as that's what they are designed for.
If they are ok at 100 PSI on a Dyno without the gravity effect of an ebike on them. Then it suggests more air is needed than you are running.
May I suggest that you stick about 120 psi in them and see if they are fully extended. Then start dropping pressure to the recommended 15% and see what they ride like. Assuming 120 is enough.
They might be awful for you but if there's no lost travel then they are working as designed.
I have mine at 110 psi for 82kg and that gives me 35mm sag. Which is 20%. HSC and LSC open.I will try anything. When I first got it, I set up the fork according to the Fox recommendations and it felt awful. It was like riding over broken bricks the whole time (big ones). So I slowly changed the settings.
When I compared the settings that TF Tuned set up for me (how the hell do they know me?), they weren't that far away from what I have anyway, apart from the air pressure. I will be giving that a go on my next ride.
Good idea to see how high the pressure has to be to get full extension.![]()
I will try anything. When I first got it, I set up the fork according to the Fox recommendations and it felt awful. It was like riding over broken bricks the whole time (big ones). So I slowly changed the settings.
When I compared the settings that TF Tuned set up for me (how the hell do they know me?), they weren't that far away from what I have anyway, apart from the air pressure. I will be giving that a go on my next ride.
Good idea to see how high the pressure has to be to get full extension.![]()
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