Fox 38 setup
The 38 is built for big hits, and it only works if the air is right. Put in your weight for your starting numbers, straight from Fox’s own charts.
Pump to 93 psi, then measure sag and adjust.
Compression, spacers and limits
- Compression: 5 clicks out high-speed, 10 clicks out low-speed, counted from fully closed.
- Rebound: Turn the dial fully clockwise until it stops, then count the clicks back out.
- Volume spacers at 170 mm: ships with 2, max 5.
- Max pressure 140 psi.
- Source: FOX 2025 36mm/38mm owner’s manual (tech.ridefox.com/bike/owners-manuals/2979); 2026 manual identical
Fix what you feel
Tap what your fork does. Fixes are for your GRIP X2. Change one thing at a time, then ride the same section again.
Harsh over roots and braking bumps
Too much air, too much high-speed compression, or rebound too slow.
- Check sag first. Under 15% means too much air.
- Open high-speed compression 2 clicks (counter-clockwise).
Dives under braking and on steep roll-ins
Not enough low-speed compression, or too much sag.
- Add low-speed compression 2 clicks (clockwise).
- Still diving and sag is past 20%? Add 3–5 psi.
Bottoms out hard on drops and big landings
Not enough high-speed compression, or the air spring isn’t ramping up enough.
- Add high-speed compression 1–2 clicks. Still bottoming? Add one volume spacer.
- Stay within Fox’s max spacer count for your travel.
Never uses full travel, even on big hits
Too many spacers, too much air, or too much compression.
- If sag is right, remove one volume spacer.
- Open high-speed compression 1–2 clicks.
Bouncy, or clunks at full extension
Rebound is too fast.
- Add low-speed rebound 1–2 clicks (clockwise). If it kicks after big hits, add 1 click of high-speed rebound.
Rides lower and lower through rough sections
Rebound is too slow, so the fork packs down.
- Open low-speed rebound 2 clicks. If it packs on fast hits in a row, open high-speed rebound 1 click.
Tell Suspend how it felt and it gives you the exact click to change on your Fox 38. Free for your first bike.
Full Fox 38 reference
For the 2025 and 2026 38 (GRIP X2 or GRIP). The 2027 38 has a different air spring in Fox’s own manual, with pressures about 18 psi lower and new spacer sizes, so these pressures and spacer counts do not fit it. Check the model-year decal or look up the serial on tech.ridefox.com. Older 38s with GRIP2 have their own charts in their year’s manual.
Fox 38 air pressure chart
| lb | kg | FLOAT | Rhythm | E-Bike+ | 2027 |
|---|---|---|---|---|---|
| under 130 | under 59 | 72 | 59 | 81 | 54 |
| 130–140 | 59–64 | 76 | 63 | 85 | 58 |
| 140–150 | 64–68 | 80 | 67 | 89 | 62 |
| 150–160 | 68–73 | 84 | 72 | 93 | 67 |
| 160–170 | 73–77 | 89 | 76 | 98 | 71 |
| 170–180 | 77–82 | 93 | 80 | 102 | 75 |
| 180–190 | 82–86 | 97 | 84 | 106 | 80 |
| 190–200 | 86–91 | 102 | 88 | 111 | 84 |
| 200–210 | 91–95 | 106 | 92 | 115 | 88 |
| 210–220 | 95–100 | 110 | 97 | 119 | 93 |
| 220–230 | 100–104 | 114 | 101 | 123 | 97 |
| 230–240 | 104–109 | 119 | 105 | 128 | 100 |
| 240–250 | 109–113 | 123 | 109 | 132 | 104 |
psi. Source: FOX 2025 36mm/38mm owner’s manual (tech.ridefox.com/bike/owners-manuals/2979); 2026 manual identical.
Fox 38 rebound clicks by weight
| lb | GRIP | GRIP X2 low | GRIP X2 high |
|---|---|---|---|
| under 130 | 13 | 9 | 8 |
| 130–140 | 12 | 8 | 7 |
| 140–150 | 11 | 7 | 7 |
| 150–160 | 10 | 7 | 6 |
| 160–170 | 9 | 7 | 6 |
| 170–180 | 8 | 7 | 5 |
| 180–190 | 7 | 6 | 4 |
| 190–200 | 6 | 5 | 4 |
| 200–210 | 5 | 4 | 3 |
| 210–220 | 4 | 3 | 2 |
| 220–230 | 3 | 3 | 1 |
| 230–240 | 2 | 2 | 0 |
| 240–250 | 1 | 1 | 0 |
Turn the dial fully clockwise until it stops, then count the clicks back out. Push the fork down hard and let go. If it clunks at full extension, rebound is too fast.
Fox 38 sag in millimetres
| Travel | 15% (firm) | 20% (plush) |
|---|---|---|
| 150 mm | 23 mm | 30 mm |
| 160 mm | 24 mm | 32 mm |
| 170 mm | 25 mm | 34 mm |
| 180 mm | 27 mm | 36 mm |
Measure with the compression adjusters fully open, dressed to ride, weight spread across saddle, bars and pedals.
Fox 38 compression settings
| Damper | Start at |
|---|---|
| GRIP X2 | 5 clicks out high-speed, 10 clicks out low-speed, counted from fully closed. |
| GRIP | Lever fully Open for descending. Use the positions between Open and Firm for more support (Rhythm: sweep it toward Firm). |
Fox 38 volume spacers
| Travel | Ships with | Max |
|---|---|---|
| 180 mm | 1 | 4 |
| 170 mm | 2 | 5 |
| 160 mm | 3 | 6 |
| 150 mm | 4 | 6 |
| Travel | Ships with | Max |
|---|---|---|
| 180 mm | 2 | 4 |
| 170 mm | 3 | 5 |
| 160 mm | 4 | 6 |
| 150 mm | 5 | 6 |
| Travel | Ships with | Max |
|---|---|---|
| 180 mm | 0 | 4 |
| 170 mm | 1 | 5 |
| 160 mm | 2 | 6 |
| 150 mm | 3 | 7 |
The 2027 38 uses new 5 cc and 10 cc spacers; see Fox’s 2027 38 manual for counts.
Spacers change how hard the fork ramps up at the end of its travel, not its sag. Add one if you bottom out too easily, remove one if you never get near full travel. A Rhythm E-Optimized ships with one more spacer than a Rhythm (180: 1, 170: 2, 160: 3, 150: 4) and has the same max.
Which Fox 38 damper do I have?
- GRIP X2: Two dials on top of the right leg (a high-speed ring around a low-speed dial) and two stacked at the bottom.
- GRIP: One lever on top of the right leg and one rebound dial at the bottom. On a Rhythm the lever sweeps from Open to Firm with no Medium click.
GRIP X2 comes on Factory (160–180 mm) and Performance Elite (170 mm). GRIP is on the Rhythm, sold only on complete bikes. Fox does not offer GRIP X on the 38.
Fox 38 service interval
Fox recommends a full service every 125 hours of riding or once a year, whichever comes first.
Questions
What air pressure should I run in my Fox 38?
Start from Fox’s chart for your riding weight with gear. A 170–180 lb rider starts at 93 psi on a 38 FLOAT, 80 psi on a Rhythm, and 102 psi on an E-Bike+. Then set sag to 15–20%. Fox says up to 10 psi off the chart is normal. Never go over 140 psi (120 on a Rhythm).
How much sag should a Fox 38 have?
15–20% of travel: 25–34 mm on a 170 mm fork. Measure with the compression adjusters fully open, dressed to ride, with your weight spread across saddle, bars and pedals.
How many clicks of rebound on a Fox 38?
From fully closed, a 170–180 lb rider starts at 8 clicks out on GRIP, or 7 low-speed and 5 high-speed on GRIP X2. Lighter riders run more clicks out.
Does this work for my older Fox 38?
Only for the 2025 and 2026 38. The 2027 38 uses a different, lower pressure chart, and older 38s with GRIP2 have their own charts in their year’s manual on tech.ridefox.com.
Related guides
Sources · last checked 2026-10-09
- FOX owner’s manual: FORK 2025 36mm/38mm (tech.ridefox.com)
- FOX owner’s manual: FORK 2026 38mm (tech.ridefox.com)
- FOX owner’s manual: FORK 2027 38mm (tech.ridefox.com)
- FOX 38 product page: dampers, travel and click counts (ridefox.com)
- FOX serial lookup: 2025 Rhythm E-Optimized 38, “Grip, Sweep-Adj” (damper type for Rhythm)
Starting points from the manufacturer’s charts, not a substitute for your fork’s manual. Always confirm with a sag measurement and stay under the max pressure.