4:1 heat
shrink tubing.
Adhesive-lined dual wall that collapses to a quarter of its supplied diameter — for the step-downs 3:1 cannot close. Eleven metric sizes, 4 mm to 52 mm. Arriving shortly.
- ◆ Shrinks 4:1
- ◆ Adhesive-lined dual wall
- ◆ 4mm – 52mm
- ◆ −55°C to +125°C
Every 4:1 size, supplied to recovered.
Recovered diameter is the supplied diameter divided by four, exactly, at every size. Pick the row whose supplied diameter clears the widest thing the tube must pass over, then check its recovered diameter is smaller than the thinnest thing it has to grip. If both hold, that is your size.
| Size | Supplied ID | Recovered ID | Inch equiv. |
|---|---|---|---|
| 4mm | 4 mm | 1 mm | 5/32" → 3/64" |
| 6mm | 6 mm | 1.5 mm | 1/4" → 1/16" |
| 8mm | 8 mm | 2 mm | 5/16" → 5/64" |
| 12mm | 12 mm | 3 mm | 1/2" → 1/8" |
| 16mm | 16 mm | 4 mm | 5/8" → 5/32" |
| 18mm | 18 mm | 4.5 mm | 23/32" → 11/64" |
| 20mm | 20 mm | 5 mm | 25/32" → 13/64" |
| 24mm | 24 mm | 6 mm | 15/16" → 15/64" |
| 32mm | 32 mm | 8 mm | 1-1/4" → 5/16" |
| 40mm | 40 mm | 10 mm | 1-9/16" → 25/64" |
| 52mm | 52 mm | 13 mm | 2-1/16" → 33/64" |
The 4:1 line is built on a metric grid, so the inch column holds conversions rather than nominal sizes — 18 mm is 23/32", not 3/4". Order by the millimetre figure. Our 2:1 and 3:1 lines are the other way round: imperial sizes, with millimetres as the conversion.
What the extra ratio buys you.
One tube across a steep step-down
A 3:1 tube big enough to slide over a battery lug or a connector backshell often will not close down onto the cable behind it. At 4:1 the same starting diameter recovers half again as far, so one sleeve spans the whole transition instead of two overlapping ones.
Fewer sizes on the van
Each size covers a wider band of work, so a short set of 4:1 diameters reaches jobs that would otherwise need a longer ladder of 2:1 sizes. That is why the line arrives first as assortment kits rather than single rolls.
The adhesive still has to reach
A high ratio without a liner leaves voids at the shoulder of the joint, which is exactly where water gets in. The 4:1 line is dual wall for that reason: the hot-melt inner flows into the step and bonds to the jacket as it cools.
When 3:1 is the right answer
Most automotive, marine and battery work does not need 4:1. Crimp connectors, butt splices and ring terminals sit inside a 3:1 tube's range, and the 3:1 line comes in the imperial sizes those jobs are specified in. Reach for 4:1 when the diameter change is genuinely severe — a large connector body or lug dropping onto a much thinner cable — or when you want one kit to cover an unusually wide spread of cable sizes. Full ratio comparison →
Specification
- Material
- Polyolefin, cross-linked
- Construction
- Dual wall — adhesive-lined
- Shrink ratio
- 4:1
- Size range
- 4 mm – 52 mm (11 diameters)
- Operating temperature
- −55 °C to +125 °C
- Shrink temperature
- 100 °C
- Adhesive flow temperature
- 120 °C
- Longitudinal shrinkage
- ≤ 10%
Figures are the manufacturer's published values for this line. Certification and voltage detail will be published per size once the line is in stock and we hold the file record for it — we would rather post that late than post it unsourced. Ask us for a file number any time.
Tell me when it lands.
The first 4:1 shipment is in transit and arrives as adhesive-lined assortment kits — an eight-size box and a ten-size box — with single sizes following in a later batch. One email when it goes live. Nothing else.
4:1 questions, answered.
What is 4:1 heat shrink tubing?
4:1 heat shrink tubing collapses to one-quarter of its supplied diameter when heated — the widest shrink ratio in common use. A 24 mm tube recovers to about 6 mm. That range lets a single sleeve pass over a large connector body, backshell or lug and then shrink down tight onto the much thinner cable behind it, which a 2:1 or 3:1 tube of the same starting size cannot do.
What does 4:1 heat shrink shrink down to?
Recovered inside diameter equals the supplied inside diameter divided by four. A 12 mm tube recovers to 3 mm, an 18 mm tube to 4.5 mm, and a 52 mm tube to 13 mm. Size by the widest point the tube has to pass over, allowing roughly 10 to 20 percent clearance, then check that the recovered diameter is smaller than the thinnest part it has to grip.
What sizes does 4:1 heat shrink tubing come in?
The Helixal 4:1 line is manufactured on a metric grid of eleven diameters: 4, 6, 8, 12, 16, 18, 20, 24, 32, 40 and 52 mm. Those are supplied (expanded) diameters, recovering to 1, 1.5, 2, 3, 4, 4.5, 5, 6, 8, 10 and 13 mm respectively. Unlike the 2:1 and 3:1 lines, which are built on imperial sizes, the 4:1 sizes are round millimetres and the inch equivalents are conversions.
Is 4:1 heat shrink tubing adhesive lined?
Helixal 4:1 is dual wall with a hot-melt adhesive inner lining. The outer polyolefin wall shrinks while the inner adhesive melts and flows into the gaps around the joint, so when it cools the tube is bonded to the cable jacket rather than just clamped over it. That is what seals the very large diameter transitions 4:1 exists for — a bare single-wall tube at that ratio would leave voids at the step-down.
Should I use 4:1 or 3:1 heat shrink?
Choose by how severe the diameter change is. If a single tube has to cover a bulky connector body or lug and still grip a much thinner cable — a step-down steeper than about three to one — you need 4:1. For ordinary crimp connectors, butt splices and ring terminals on automotive, marine and battery work, 3:1 dual wall already covers the transition and seals it, and it comes in the imperial sizes those jobs are specified in.
What temperature does 4:1 heat shrink tubing shrink at?
The tube starts shrinking at 100 °C, and its adhesive lining flows at 120 °C — so keep heating past the point where it looks shrunk, until adhesive shows at both ends. A heat gun kept moving gives even shrinkage without scorching the outer wall. The finished joint is rated for continuous service from −55 °C to +125 °C, and longitudinal shrinkage is held to 10 percent or less, so the tube does not pull back off the ends of the joint as it recovers.
When is the Helixal 4:1 line available?
The first shipment is in transit. The 4:1 line arrives first as adhesive-lined assortment kits — an eight-size box and a ten-size box — with individual sizes following in a later batch. Join the notify list on this page and we will email you once when it goes live, with no other marketing attached.