How much retraction should you use? On a Bowden setup, 4–6 mm at 40–45 mm/s usually works well, while Direct Drive only needs 0.8–1.5 mm at 25–35 mm/s — the difference comes from how far the filament has to travel before it reaches the melted tip. If you're just starting calibration and looking for a starting point for Porima PETG or any other material, this article gives you concrete numbers, a settings table, and a list of the mistakes that most often ruin the result.
Retraction is simply a short pull-back of the filament before the nozzle travels over empty space. Done well, it eliminates strings and oozing. Done poorly, it ruins the first layer, causes under-extrusion, or in extreme cases grinds the filament against the drive gear. Below you'll find starting settings, the logic behind the Bowden/Direct Drive difference, and a step-by-step calibration method.
Starting Retraction Settings for Bowden and Direct Drive — Table
| Parameter | Value | Comment |
|---|---|---|
| Retraction distance (Bowden) | 3–6 mm | Start at 5 mm, then tune in 0.5 mm steps |
| Retraction speed (Bowden) | 25–45 mm/s | Too high a speed strains the extruder's drive gear |
| Retraction distance (Direct Drive) | 0.6–2 mm | Shorter filament path, so a smaller distance is enough |
| Retraction speed (Direct Drive) | 20–40 mm/s | A slower start reduces the risk of motor skipping |
| Minimum travel distance before retraction | 1–2 mm | Below this value retraction doesn't trigger |
| Z hop | 0–0.2 mm | Only enable it if the nozzle visibly catches on the model |
| Coasting | 0–0.3 mm equivalent | Disabled by default in most profiles |
| Wipe on retraction | 1–2 mm | Reduces single blobs on the print surface |
| Retraction on layer change | matches the main setting | Don't change it separately without a specific reason |
| Temperature during retraction | unchanged from printing | Changing temperature during retraction isn't standard practice |
The values above are a starting point, not a fixed rule — you'll find specific temperatures for individual materials in our print temperature table, which is worth keeping open next to your slicer during calibration.
Why Bowden and Direct Drive Need Different Retraction Settings
In a Bowden setup, the extruder motor sits far from the hotend, and the filament travels through a flexible tube — often 30–60 cm long. That tube compresses and "breathes" under pressure, so before the filament pull-back even reaches the melted tip, part of the distance is absorbed by the elasticity of the system itself. Hence the larger retraction values: 3–6 mm isn't excessive, it's compensation for the physical slack in the tube.
In Direct Drive, the motor sits right above the hotend, so the filament's path to the melt zone is only a few centimeters, not several dozen. The pull-back effect is almost instant, so a fraction of a millimeter up to two millimeters is enough. If you copy Bowden settings 1:1 onto Direct Drive, the most common result is under-extrusion at the start of every segment — the first millimeters of each line come out thinner, because the nozzle is effectively "catching up" on missing material. You can read more about the phenomenon itself and how to recognize it in our guide to stringing, which is the most common symptom of poorly set retraction in both systems.
A third factor is the mass and inertia of the extruder assembly itself. A heavier Direct Drive unit on a moving X axis slows down the head's accelerations, so some users deliberately keep retraction to a minimum to shorten every travel move. In a Bowden setup, the mass on the X axis is smaller, so this trade-off barely exists.
Retraction on a Bowden Setup
Typical range: distance and speed
For most Cartesian printers with a Bowden setup (Ender, Prusa MK3 with a long PTFE tube, and similar designs), a sensible starting point is 5 mm at 40–45 mm/s. If you still see strings after running a retraction tower test (described below), raise the distance in 0.5 mm steps up to an upper limit of around 6–7 mm. Above that value, you risk the drive gear starting to grind the filament with every pull-back.
The most common problems with bad retraction on Bowden
Too small a distance leaves strings between parts of the model. Too large a distance combined with too high a speed causes a characteristic "click-click" sound at the extruder — a sign that the drive gear is skipping over the filament instead of feeding it. If you hear this, lower the retraction speed by 5–10 mm/s before increasing the distance any further.
Retraction on Direct Drive
Why a short filament path changes the rules
On Direct Drive you don't need to compensate for slack in a tube, so start low — 0.8 mm is a safe starting point for most hotends with a short melt zone. Increase it by 0.2 mm at a time, watching the result on a test tower, instead of copying values known from Bowden setups.
The risk of grinding with excessive retraction
Direct Drive typically has a smaller gear ratio than a typical Bowden extruder, so excessive retraction leads more quickly to filament grinding on the drive gear. The symptom: a round indentation on the side of the filament and weaker grip on subsequent layers. If you notice this, lower the distance and check whether the extruder's spring tension is set too high.
Retraction and Filament Type
PLA and PETG
PLA tolerates a wide range of retraction settings and rarely causes problems — stick to the values in the table above. PETG is more viscous when molten and prone to stringing, so it often needs 0.5–1 mm more distance than PLA on the same setup, while keeping the same speed.
TPU and flexible filaments
Flexible materials, like Porima TPU 98A, behave differently from rigid filaments: on a Bowden setup, retraction above 2–3 mm often causes a jam, because the soft filament bends inside the tube instead of pulling back. On Direct Drive, TPU tolerates a small amount of retraction (0.5–1 mm), but many users start close to zero and only add minimal distance if real strings show up.
Coasting, Wipe, and Other Settings That Work Alongside Retraction
Coasting stops feeding filament just before the end of a line, using residual pressure instead of full retraction — this reduces load on the mechanism, but only works well with stable flow. Wipe moves the nozzle 1–2 mm sideways after retraction, eliminating a single blob at the stopping point. Neither of these settings replaces well-calibrated retraction — treat them as a complement, not a substitute.
How to Calibrate Retraction Step by Step
The retraction tower
The simplest way is to print a test tower where the slicer automatically increases the retraction distance every few layers (most slicers have a ready-made plugin or downloadable model for this). Set the range from the minimum to the maximum value in the table, and leave temperature and speed unchanged from your normal print.
How to read the result and what to fix
After printing, examine the tower level by level: the point at which strings disappear is your target distance. If strings don't disappear even at the highest value in the test, the problem usually lies elsewhere — in print temperature that's too high, travel moves that are too slow, or damp filament — not in retraction itself.
When to recalibrate
Retraction isn't a set-it-and-forget-it setting. It's worth repeating the tower test after replacing the nozzle with a different diameter, after changing the extruder's spring tension, and when switching to a filament with noticeably different viscosity — for example from PLA to nylon. If your printer has been running stably for months and strings suddenly return, first check the condition of the drive gear and its tension before changing values in the slicer.
Settings for Popular Configurations
| Configuration | Retraction | Comment |
|---|---|---|
| Bowden (Cartesian, open frame) | 4–6 mm, 40–45 mm/s | Classic Ender-type setup, needs more allowance for tube slack |
| Direct Drive (Cartesian) | 0.8–1.5 mm, 25–35 mm/s | Short filament path allows for gentler settings |
| CoreXY, enclosed chamber, Direct Drive | 0.6–1.2 mm, 25–35 mm/s | Higher ambient temperature favors oozing, but retraction stays low |
| AMS / CFS (multi-material system) | manufacturer settings | Retraction is part of the feed system's calibration — don't change it manually without testing |
The Most Common Retraction Mistakes
Copying settings from the internet without testing on your own printer. The same hotend model can vary between two units — always verify the value with a test tower instead of pasting someone else's profile.
Carrying Bowden settings over 1:1 to Direct Drive. This is the most common cause of under-extrusion after converting to Direct Drive — start calibration from scratch, from low values.
Raising retraction speed instead of distance. A higher speed without the right distance rarely removes strings, but it does increase the risk of grinding on the drive gear.
Ignoring print temperature as a source of stringing. Too high a temperature makes the filament runny enough that no amount of retraction fully helps — check the lower end of the temperature range for the material before raising the distance further.
No minimum travel distance. If retraction triggers on every single travel move, even the shortest one, the mechanism works nonstop and wears out faster — set a sensible threshold of 1–2 mm.
Changing several parameters at once. Modifying distance, speed, and temperature in the same test makes it impossible to tell what actually improved the result — change one variable at a time.
Too much retraction on flexible filaments. On TPU and similar materials, excessive retraction is more likely to cause a jam than improve quality — stick to the lower end of the range.
Frequently Asked Questions
What retraction works well for PETG?
Start with the same value as PLA on your setup and add 0.5–1 mm, since PETG is more prone to stringing. Leave the speed unchanged.
Does TPU need retraction at all?
Yes, but minimal. On Direct Drive, 0.5–1 mm is usually enough; on Bowden, it's best not to exceed 2–3 mm, since soft filament can bend instead of pulling back.
Why do I still get strings despite good retraction?
Check your print temperature and filament moisture — these are the two most common causes of stringing, which retraction alone won't solve. Only after ruling them out should you go back to tuning distance.
What happens if I set retraction too high?
Most often you'll see under-extrusion at the start of lines, along with a risk of the filament grinding on the extruder's drive gear, especially at high retraction speed.
How do I check whether retraction is well calibrated?
Print a retraction tower with increasing distance and check at which level the strings disappear completely — that's your target value for that filament and setup.
Summary
Retraction on Bowden and Direct Drive follows different physics: the longer filament path in a Bowden setup needs a larger distance (3–6 mm), while the short path in Direct Drive lets you go down to a fraction of a millimeter (0.6–2 mm). Before you keep raising values indefinitely, check your print temperature and filament moisture — these are most often what's behind strings that look like a retraction problem.
If you're looking for a material to run your own retraction tower test on, check out our technical filaments collection — PETG, ASA, and nylon are the materials where the difference between well-tuned and poorly-tuned retraction shows up most clearly.