How to Match Hatch/Hood Gas Struts: Length, Force, and Ends
Hood won’t stay up. Hatch droops on a cold morning. Trunk opens a few inches and stops. Before you add any gas strut (lift support) to the cart, match three things: extended length, force (N or lbs), and end fittings. Wrong force that “kinda fits” is how lids slam or fail to lift. This page is the sizing checklist. For why struts die, how to prop the lid safely, and the one-at-a-time swap, use the existing guide: Your hood or trunk won’t stay up: lift supports.
Quick answer
- Measure extended length: center-to-center of the end mounts with the lid fully open.
- Read the force stamp on the old body (e.g. 400N or 60 lbs). Match it, or use the vehicle-specific listing that already encodes OE force.
- Match end type: ball socket size, eyelet, or bracket.
- Stronger is not always better. Over-force can bend brackets or make the lid hard to close.
- Replace as a pair.
- Choose vehicle-specific when a fitment table exists; use universal only when you measured length, force, and ends yourself.
What you are matching
Extended length
Prop the hood, hatch, or trunk fully open (safe prop: see the lift supports guide for not using both hands and a prayer). Measure from the center of the upper mount to the center of the lower mount. That is extended length. Too short: lid will not open fully. Too long: may bind before latch or stress brackets.
Compressed length matters when the lid closes. If the strut cannot shorten enough, the panel will not latch cleanly. When you buy vehicle-specific pairs, compressed length is usually already correct for that application. On universals, compare both numbers on the listing to what you measured (or to the old part’s printed specs).
Force: N or lbs
Look on the cylinder for a stamp: 400N, 0450N, 60lbs, etc. Newtons ÷ ~4.45 ≈ pounds-force (rough conversion for shopping sense, not a lab certificate).
- Match the stamped force when replacing like-for-like.
- If you added a spoiler, aftermarket hood, or sound deadening, OE force may be marginal. Step carefully, and know that “one notch stronger” is a judgment call, not a blank check.
- Glass-hatch struts and full-liftgate struts on the same SUV are different forces. Ordering “rear lift support” without reading the position note is a common miss (called out in the main guide).
End fittings
Common: 10 mm ball sockets that snap over ball studs; eyelets with a defined hole size; bracket ends that bolt on. Pop one end off (lid propped) and compare. Universal listings often specify eyelet hole size (e.g. ~10.2 mm). Vehicle-specific parts usually duplicate the OE end style for that hood/hatch.
Mismatch symptoms: will not snap on; sits crooked; pops off over bumps (dangerous on a hood).
Stronger isn’t always better
Over-spec force can:
- Bend sheet-metal brackets
- Make the panel hard to close or slam into the open stop
- Stress hinges over time
Under-spec force:
- Droops when cold (gas pressure falls with temperature)
- Needs a prop stick forever
Target match first. Adjust only when you changed the lid’s weight, or when the old stamp is unreadable and the vehicle-specific listing is the safer path.
Replace as a pair
One new + one old = uneven push, twisted lid motion, accelerated hinge wear. Always do both sides on that lid. Swap one side at a time so the remaining strut (plus a solid prop) holds the panel. Full sequence in the lift supports guide.
Universal vs vehicle-specific
| Path | When to use | Watch-outs |
|---|---|---|
| Vehicle-specific | Fitment table lists your year/make/model/position (hood vs trunk vs glass vs liftgate; spoiler notes) | Still verify notes. “With spoiler” vs without can be different force. |
| Universal | You measured extended (+ compressed) length, force, and ends; application is oddball / cabinet / custom | You own the match risk; ball vs eyelet must be correct |
If a vehicle-specific pair exists for your lid, prefer it. Universals shine when you already did the tape measure homework.
Sizing checklist (print / phone)
- Lid type: hood / trunk / hatch / glass / full liftgate
- Extended length (center to center), lid fully open
- Compressed length if available from old part or closed measurement
- Force stamp (N or lbs): photo it before the label wears further
- End type and size both ends
- Pair quantity: 2
- Prefer vehicle-specific SKU; else universal with matched numbers
- Verify fitment table or your measurements again at checkout
Example listings on Tetron
Universals (measure first):
- Universal pair 11.5″ ext / 7.25″ comp / 60 lbs (267 N) : SKU
BXC300054684-2(eyelet ends per listing) - Universal pair 11.5″ ext / 7.25″ comp / 50 lbs (223 N) : SKU
BXC300054683-2
Vehicle-specific examples:
- Ford Focus 2005-2011 sedan trunk pair: with spoiler : confirm spoiler note and years on the page
- Scion xA 2004-2006 rear hatch pair : SKU
BXC300054306-2
Soft CTA only. No fake “OEM equal” claims. Force/length on the Focus and xA pages are application-built; still verify your lid (spoiler / body style) matches the note.
FAQ
Can I mix forces left/right?
No. Pair matched force.
Stamp unreadable?
Prefer vehicle-specific listing for your exact lid; or compare a known OE number.
Is universal OK on a daily driver?
Only if length, force, and ends match what you measured.
Where are install steps?
Lift supports guide. This page is sizing only.
Hood pops off the stud while driving?
End not seated / clip not flat. Stop and fix; see guide.
Next step
Measure twice, match length/force/ends, replace as a pair. Grab a vehicle-specific pair when the table fits you; use universals only with numbers in hand. For the actual swap and safety prop tips: lift supports guide.