Material Comparison

TPU Shore Hardness Chart

85A, 90A, 95A, 98A - what the numbers mean, how they print, and which one to buy for your project.

Last updated: July 2026

TL;DR
  • 95A is the default. If you've never printed TPU, start here.
  • 85A-90A feels genuinely rubbery, but needs direct drive and slow speeds (15-25 mm/s).
  • 98A is almost rigid. Good for impact resistance, poor choice if you actually want flex.
  • Dry before printing. Wet TPU pops, strings, and prints badly at any hardness.
  • Picked a hardness? Compare the cheapest TPU filament prices across every store we track before you buy.

TPU hardness is measured on the Shore A scale: 85A is soft and rubbery, 95A is the firm all-round standard, and 98A is nearly rigid. Softer TPU flexes more but prints slower and needs a direct-drive extruder; 95A is the right starting point for most printers and most parts.

For a full overview of TPU and other flexible filaments, see our TPU material guide:

TPU Filament Guide
The Shore A scale explained

Shore A measures how hard a flexible material is. The test is simple: a standardized needle is pressed into the material under a fixed load, and the depth of penetration determines the number. Lower number = softer and more flexible. Higher number = harder and more rigid.

For context: a rubber band is roughly 25A. A pencil eraser is about 40A. A car tire tread is around 70A. Shoe soles range from 50A-80A. The TPU filaments you can buy for 3D printing typically range from 85A to 98A - they are all on the harder end of the Shore A scale.

The key thing to understand: the Shore A scale is not linear in how it feels. The difference between 85A and 90A is very noticeable. The difference between 95A and 98A is subtle. And once you pass 98A, you are basically printing a rigid material that happens to have some impact resistance.

TPU hardness chart: 85A to 98A at a glance
Hardness Feels like Print difficulty Extruder Max speed Use cases
85A Silicone, gel insole Hard Direct drive only 15-20 mm/s Soft grips, watch bands, gaskets, vibration dampeners
90A Gummy bear, soft shoe sole Moderate Direct drive only 20-30 mm/s Phone cases, flexible hinges, soft bumpers
95A Shoe sole, firm rubber Easy (for TPU) Direct drive (Bowden possible) 25-40 mm/s Wheels, belt tensioners, seals, protective cases
98A Hard rubber, hockey puck Easiest Direct drive or Bowden 30-50 mm/s Tough wheels, impact-resistant housings, stiff but not brittle parts
When to use
85A - 90A (Soft)

This is the range where TPU actually feels flexible. 85A bends easily in your hand like thick silicone. 90A has noticeable give, like a soft phone case. These are the hardness levels you want for gaskets, vibration dampeners, soft-touch grips, and flexible hinges that need to bend hundreds of times without fatigue.

The trade-off is printability. At 85A, the filament is soft enough to compress and buckle between the extruder gears and the hotend. You need a direct drive extruder with a constrained filament path[1], very slow speeds (15-20 mm/s), minimal or zero retraction, and patience. Stringing is basically guaranteed - plan to clean up your prints.

Popular brands at this range: NinjaTek NinjaFlex (85A), Sainsmart (85A), Polymaker PolyFlex (90A).

A note from our price data: true 85A spools are scarce in retail stock at any given time. 90A is the softest grade you can reliably buy off the shelf. Browse live 90A TPU listings.

Community tip: If you are buying 85A for the first time, print a simple 20mm calibration cube first. If it comes out clean, your setup can handle it. If it jams immediately, check your filament path for any gaps where the soft filament can escape.
When to use
95A (Standard)

95A is the default TPU for a reason. It is flexible enough to be obviously rubbery (it bends, compresses, and bounces back), but stiff enough to feed through most direct drive extruders without constant jams. If you have never printed TPU before, start here. Most of the TPU tutorials and profiles you find online are tuned for 95A.

95A works for the vast majority of flexible print applications: wheels for robots or RC cars, belt tensioners, phone cases, cable strain reliefs, protective bumpers, and seals. It gives you real flexibility with manageable print difficulty.

Some users have printed 95A successfully on Bowden tube setups (Ender 3, etc.) at very slow speeds (15-20 mm/s), but it is not reliable. Direct drive is strongly recommended.

Community tip: Disable retraction entirely on your first 95A print. Only add retraction (0.5-1.5mm, slow speed) if stringing is unbearable. Too much retraction causes jams - TPU compresses rather than retracting cleanly.
Best 95A TPU deals right now
When to use
98A (Firm)

98A is barely flexible. It feels like hard rubber - think hockey puck or a hard-soled work boot. You can bend a thin-walled 98A print if you try, but it is not going to flex back and forth like a phone case. What 98A gives you is impact resistance: parts that absorb hits instead of shattering like PLA or PETG would.

98A is the easiest TPU to print. It feeds through Bowden tubes (at reasonable speeds), has less stringing than softer TPU, and can print at 30-50 mm/s without major issues. If you need a part that survives drops and impacts rather than one that actually flexes, 98A is the most practical choice.

Ideal for: drone frames, impact-resistant housings, tool grips, wheels that need to be tough but not soft, and parts that get dropped or crashed regularly. Browse live 98A TPU listings.

Community tip: Many people buy 98A TPU expecting flexible phone cases and are disappointed. If you want visible flex in a thin-walled print, go 95A or softer. 98A is for impact absorption, not flexibility.
Printer compatibility by category

TPU hardness compatibility comes down to one thing: how constrained the filament path is between your spool and the hotend. Direct drive setups with no gaps handle the full hardness range. Bowden setups — where filament travels through a long PTFE tube from extruder to hotend — let softer TPU compress and buckle inside the tube. Specific printer models change every year; the categories below stay relevant.

Printer category 85A 90A 95A 98A
Consumer direct drive
Most current consumer printers — Bambu A and P series, Prusa MK series, Creality K series, Anycubic Kobra, Elegoo Centauri, etc.		 Works, slow + tuning Good Trivial Easy
Enclosed / commercial direct drive
Enclosed-chamber printers and commercial-tier rigs — Bambu X and H series, Prusa XL, Voron, Qidi X-Max, etc. Chamber helps layer bonding on soft TPU.		 Good Trivial Trivial Easy
Bowden tube
Filament feeds through a long PTFE tube from a stationary extruder. Most entry-level and older printers — stock Ender 3, Prusa MINI+, etc.		 Won't print Buckles in tube Unreliable, very slow Works

How to tell which category you have: look at the print head. If the extruder gears sit directly on the toolhead and feed straight into the hotend, that's direct drive. If a PTFE tube runs from a motor on the printer's frame up to the toolhead, that's Bowden.

The Bowden workaround: direct-drive conversion kits exist for most popular Bowden printers (Sprite, Microswiss, BIQU H2 and similar) for $50–100. After conversion, soft TPU prints reliably at slow speeds — the modification is the dividing line, not the brand.

What "enclosed" buys you on top of direct drive: ambient warmth around the build plate reduces warping on soft TPU and improves layer bonding. The same printer without an enclosure still prints soft TPU; the surface finish and Z-bond just won't be as clean.

TPU and the AMS: what actually works

Multi-material systems are the new Bowden problem. An AMS pushes filament through several meters of PTFE, a four-way hub and a buffer before it reaches the extruder, and soft TPU compresses and jams in that path exactly the way it does in a Bowden tube. Bambu Lab's own guidance is blunt: regular TPU (95A and softer) should not run through the AMS, AMS 2 Pro or AMS lite at all. The same applies to Creality's CFS.

Printing regular TPU on an AMS printer: use the external spool holder. Every Bambu machine has one, the A1 mini included, and the direct drive toolhead handles 95A without drama once the AMS is out of the loop. Load it as External in Bambu Studio, drop speeds per the table above, and keep the AMS idle for that print. Switching from PETG to TPU mid-project works the same way: finish the PETG job, load TPU from the external holder, purge 50-100 mm at around 230 °C and carry on.

"TPU for AMS" is a hardness workaround, not magic. Bambu's TPU for AMS is Shore 68D, which sits above 98A on the hardness ladder (Shore D is the scale for stiffer materials; 68D lands near a stiff shoe heel, nowhere near a squishy phone case). It survives the AMS path precisely because it barely flexes. Expect semi-rigid, impact-absorbing parts rather than rubbery ones. Third-party semi-rigid grades in the 58D-68D range behave the same way.

If you want genuinely soft parts on an AMS machine: no soft TPU feeds reliably through an AMS today. Print soft grades from the external spool, or split multi-material models so the flexible part prints separately. And if what you actually need is toughness rather than flex, PCTG or PETG through the AMS gets you impact resistance without any of the feeding drama.

Shopping for either kind: live TPU prices cover standard 95A spools and semi-rigid AMS-safe grades across every store we track.

Common failures and what causes them

TPU fails in specific, recognizable ways. Match the symptom to the cause before changing five settings at once.

Extruder grinds, filament stops feeding
Drive gears are crushing soft filament instead of pushing it. Drop speed by half. Back off extruder tension. More common on 85A-90A than firmer grades.
Filament buckles above the extruder
Filament path has a gap where soft TPU can kink sideways. Common on A1-class printers. Either close the gap (PTFE guide tube, spring clip) or drop to 95A.
Stringing everywhere
Almost always wet filament, not retraction settings. Dry at 65-75 °C for 6-8 hours. If it's still stringy after drying, drop nozzle temp 5 °C and raise travel speed.
Popping or crackling during extrusion
Moisture flashing to steam inside the hotend. Dry the filament. Wet TPU also prints weaker layers regardless of the surface symptoms.
Blobs at every layer start
TPU oozes more than rigid filaments. Tune pressure advance first. Enable coasting or wipe. If your slicer supports scarf seams, turn them on — see the seam guide for details.
Part peels off bed mid-print
Bed too cold or surface too smooth. TPU grips textured PEI. On glass or smooth PEI, use a glue stick. Bed at 50-60 °C holds 95A and above; softer grades prefer 40-50 °C.
Prints look stretched or blurry
Printing too fast for the material. TPU needs time for pressure to equalize in the hotend. If scaling down speed fixes the look, that was the issue.
The community verdict

Buy 95A unless you have a specific reason not to. It is the goldilocks hardness: flexible enough for real applications, stiff enough to print reliably on a direct drive machine. If you need something softer, go to 90A. If you just need impact resistance without real flex, go to 98A.

Do not buy 85A as your first TPU. Start with 95A, get your settings dialed in, then work downward in hardness as your confidence and printer setup allow. The softer the TPU, the more you need to fight your printer to make it work. And always dry your TPU before printing - it absorbs moisture fast and prints terribly when wet.

Frequently Asked Questions

What is the difference between 85A and 95A TPU?
85A is noticeably softer and more rubbery; 95A is firmer and much easier to print. 85A bends and compresses like thick silicone, which makes it good for gaskets, soft-touch grips and vibration dampeners, but it needs a direct drive extruder and slow speeds (15-20 mm/s) or it buckles and jams. 95A still flexes like a firm shoe sole yet prints reliably on most direct drive machines at 25-40 mm/s. Choose 85A only when you specifically need the extra softness and your printer can handle it; otherwise 95A is the faster, more forgiving default.
Is 85A TPU softer than 95A?
Yes. On the Shore A scale a lower number means softer, so 85A is meaningfully softer and more flexible than 95A. The gap is large enough to feel by hand: 85A compresses easily like a gel insole, while 95A feels closer to a firm rubber wheel. The trade-off is printability. Softer TPU is harder to feed, so 85A needs direct drive and slower speeds than 95A.
Can I print 85A TPU on a Bowden tube printer?
Almost certainly not reliably. 85A TPU is soft enough to buckle and jam in a Bowden tube, even at very slow speeds. The long, unguided filament path gives the flexible filament too much room to compress and kink. Direct drive is mandatory for 85A. Even some direct drive setups struggle - you want a constrained filament path with minimal gap between the drive gears and the melt zone.
What is the most common TPU hardness?
95A is the industry standard. When a brand sells "TPU" without specifying hardness, it is almost always 95A. This is because 95A hits the sweet spot of being flexible enough for most applications while still being printable on most direct drive printers. Brands like Overture, eSUN, and Elegoo all default to 95A for their standard TPU offerings.
What speed should I print TPU at?
It depends on hardness. 95A-98A can typically print at 25-40 mm/s on a direct drive printer. 90A should be slowed to 20-30 mm/s. 85A often needs 15-20 mm/s or even slower. Retraction should be minimal (0.5-2mm) or disabled entirely, as TPU compresses rather than retracts cleanly. Print speed is the single biggest factor in successful TPU printing - going too fast causes jams, not just quality issues.
Is 98A TPU actually flexible?
Barely. 98A TPU feels like hard rubber - it has some give if you squeeze it hard, but it does not flex freely like a phone case or gasket would. Many people buy 98A expecting rubbery flexibility and are disappointed. If you want noticeable flex, go with 95A or softer. 98A is better described as "impact absorbing" rather than "flexible."
Do I need to dry TPU before printing?
Yes. TPU is hygroscopic and absorbs moisture from the air within hours. Wet TPU produces stringing, bubbling, popping sounds during extrusion, and rough surface finish. Dry at 65-75 °C for 8 hours before printing, and ideally print from a dry box. See our filament storage guide for drying tips. This applies to all hardness levels.
Can you print TPU with an AMS?
Regular TPU (95A and softer), no. Bambu Lab excludes it from the AMS, AMS 2 Pro and AMS lite because the long PTFE path and hub let soft filament buckle and jam; Creality's CFS has the same restriction. You have two options: print regular TPU from the external spool holder (every Bambu printer has one, and the direct drive toolhead handles 95A fine), or use a semi-rigid grade sold as AMS-compatible, like Bambu's TPU for AMS at Shore 68D. The catch: 68D is stiffer than 98A, so AMS-safe TPU gives you impact absorption, not rubbery flex.
Is TPU hard or soft?
TPU is a family, not one material, and it spans soft to semi-rigid. 85A feels like a gel insole, 95A like a firm shoe sole, 98A like hard rubber, and Shore D grades (60D-68D) feel closer to stiff plastic with a little give. A typical phone case sits around 90A. So the honest answer is: softer than any regular printing plastic, but how soft depends entirely on the Shore number on the spool. That number is the whole point of this guide.
What TPU hardness is best for gaskets?
85A-90A for seals that need to compress: the softer the TPU, the better it conforms to mating surfaces under light clamping force. 95A works for structural gaskets where the part mostly locates and cushions rather than seals. Print gaskets solid (100% infill) with 2-3 perimeters so compression does not collapse internal voids. For genuinely watertight or chemical-facing seals, cast silicone still beats any printed TPU.
Is TPU food safe?
Assume no. Filament-grade TPU is rarely certified for food contact, additives vary by brand, and printed parts have layer grooves that trap bacteria regardless of material. For anything touching food, use a filament with an actual food-contact rating and a smooth sealed surface, or better, keep printed parts out of direct food contact. Our food-safe filament guide covers the materials and the caveats that actually matter.
What is the difference between TPU and TPE?
TPE (thermoplastic elastomer) is the broad category. TPU (thermoplastic polyurethane) is a specific type of TPE. In practice, when filament brands sell "TPE" it is usually softer (often 80A-85A) and harder to print than their "TPU" offerings. If a product just says "TPE" without a Shore rating, expect it to be quite soft and challenging to print.

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References

  1. NinjaTek NinjaFlex (85A) Printing Guide. https://ninjatek.com/ninjaflex/
  2. Prusa Knowledge Base - Flexible Materials (TPU/TPE). https://help.prusa3d.com/article/flexible-materials_2057