Straight Reducing Silicone Hose

127mm Long 3 & 4 Ply SAEJ20R3

SSR012008R-ASH

£6.10

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Silicone Straight Reducer is a reinforced, high-performance connector designed to join pipes and tubing of different diameters in automotive, marine, and industrial systems. Constructed with a smooth extruded silicone compound inner layer, reinforced with multiple layers of polyester braids, and finished with a durable silicone outer layer, the reducer provides excellent flexibility, strength, and long-term resistance to heat and pressure. Built to SAE J20 R3 standards, it withstands continuous operating temperatures from -50°C to +250°C, making it suitable for demanding environments such as engine bays, cooling systems, and turbocharger pipework. Supplied in a standard 127 mm length, the silicone straight reducer is available in a wide range of diameters from 6.5 mm to 102 mm, ensuring compatibility across diverse installations.

Key Features:

Inner Layer: Smooth extruded silicone compound for reliable sealing and flow efficiency.
Reinforcement: High-strength polyester braids for durability and pressure stability.
Outer Layer: High-grade silicone for ozone, abrasion, and heat resistance.
Construction: 3–4 ply reinforced wall with smooth bore design.
Operating Temperature: -50°C to +250°C (peak +250°C).
Internal Diameter Range: 6.5 mm to 102 mm.
Working Pressure: From 12.33 bar (small bore) down to 2.8 bar (large bore).
Bursting Pressure: Typically 3x working pressure (up to 37 bar).
Bending Radius: From 16 mm (small bore) up to 70 mm (large bore).
Length: 127 mm overall length for secure coupling.
Standard: SAE J20 R3 compliant.

The silicone straight reducer combines strength, flexibility, and durability, making it highly effective in systems where a transition between different pipe sizes is required. Its polyester-reinforced construction provides dimensional stability and pressure tolerance, while the high-grade silicone outer layer resists cracking, ozone, and environmental degradation. The smooth internal bore supports efficient fluid or air transfer with minimal turbulence, while the robust wall thickness ensures long-term resilience under vibration, heat, and continuous use. With working pressures up to 12.33 bar for smaller diameters and burst ratings up to three times the working pressure, the reducer offers a wide safety margin for both performance and heavy-duty applications.

Applications include automotive cooling and induction systems, turbocharger and intercooler connections, marine cooling circuits, industrial fluid handling, and agricultural machinery. The silicone straight reducer is widely used in motorsport, custom fabrication, and engineering projects where durable, heat-resistant, and size-transitioning connectors are essential. Keywords: silicone straight reducer, reinforced silicone hose reducer, high-temperature silicone coupler, SAE J20 R3 compliant reducer, industrial silicone hose connector, silicone transition hose.

Specifications

Type: Straight Reducer
Colour: Red
Standard: SAEJ20R3
Length: 127mm

Size Guide

Inside Diametermm	Outside Diametermm	Wall Thicknessmm	Working Pressurebar	Bursting Pressurebar	Bending Radiusmm	Number Of Ply
6.5	15.5	4.5	12.33	37	16	3
8	17	4.5	11.67	35	16	3
9.5	18.5	4.5	11.67	35	16	3
11	20	4.5	9	30	16	3
12	21	4.5	9	30	16	3
13	22	4.5	8.33	27	16	3
16	25	4.5	7.17	25	18	3
19	28	4.5	6.5	19.5	18	3
22	31	4.5	5.8	17.4	20	3
25	34	4.5	5.5	16	30	3
28	37	4.5	5.33	16	30	3
30	39	4.5	5.33	16	30	3
32	41	4.5	5.17	15.5	32	3
35	44	4.5	5	15	35	3
38	47	4.5	5	15	35	3
40	49	4.5	4.83	14.5	35	3
45	54	4.5	4.67	14	40	3
48	57	4.5	4.5	13.5	45	3
51	62	5.5	4.5	13.5	51	4
54	65	5.5	4.33	13	60	4
57	68	5.5	4.33	13	60	4
60	71	5.5	4.17	12.5	60	4
63	74	5.5	4	12	63	4
65	76	5.5	3.85	11.5	65	4
68	79	5.5	3.6	11	65	4
70	81	5.5	3.5	10.5	65	4
76	87	5.5	3.5	10.5	65	4
80	91	5.5	3.33	10	70	4
83	94	5.5	3.17	9.5	70	4
90	101	5.5	3	9	70	4
102	113	5.5	2.8	8.5	70	4

Measurements are nominal and may vary slightly.

How to measure ID

1

Measure the pipe, not the old hose

Heat and age make a used hose swell and go out of round. Take your reading across the metal outlet the hose slides onto — that measurement is your ID.

2

Use vernier calipers

Set the outer jaws across the widest point of the pipe. A tape measure round a curve reads low by a millimetre or two — enough to buy the wrong size.

3

Take three readings, keep the largest

Rotate 60° between each. If they disagree the pipe is oval; size to the biggest figure so the hose still seals.

4

Round to the nearest listed bore

Silicone stretches slightly. If you land between sizes, go down to the smaller bore for a tight seal — never up.

Order by ID, always. Every hose on this site is listed by internal diameter. OD is given for clearance only — it changes with wall thickness and ply count, so it is never the ordering size. On reducers, quote both ends, largest first.

Construction

1 · Outer cover

High-grade silicone

Ozone, abrasion, and heat resistance

2 · Reinforcement

High-strength polyester braids

Durability and pressure stability · From 12.33 bar (small bore) down to 2.8 bar (large bore) · Typically 3x working pressure (up to 37 bar)

3 · Inner liner

Smooth extruded silicone compound

Reliable sealing and flow efficiency · -50°C to +250°C (peak +250°C)

Conforms to SAE J20 R3.

31 bore sizes6.5mm to 102mm internal diameter

37 bar burst12.33 bar working on the smallest bore

SAE J20 R3 built to standardthe automotive coolant hose standard

3–4 ply reinforcementstepped up on the larger bores

Joins anything. Leaks nothing.

The silicone connector range, made to the same standard as the hose it joins.

INTERNAL DIAMETERS

6.5mm to 102mm

RATED

−50°C to +250°C

WORKING PRESSURE

Up to 12.3 bar

REINFORCEMENT

3 and 4 ply braid

BUILT TO

SAE J20 R3

Find your perfect colour

The colour goes right through the silicone compound rather than sitting on top as a coating, so it will not fade, peel or discolour in service. Built to SAE J20 R3 in all three.

Red

Blue

Black

Colours shown are indicative — screen rendering varies.

Specification at a glance

Across the whole 6.5mm–102mm range.

6.5mm –102mm Inside diameter

15.5mm –113mm Outside diameter

4.5mm –5.5mm Wall thickness

16mm –70mm Bending radius

2.8bar –12.33bar Working pressure

8.5bar –37bar Bursting pressure

Inside diameter (mm)	Outside diameter (mm)	Wall thickness (mm)	Working pressure (bar)	Bursting pressure (bar)	Bending radius (mm)	Ply	Length (mm)
6.5	15.5	4.5	12.33	37	16	3	127
8	17	4.5	11.67	35	16	3	127
9.5	18.5	4.5	11.67	35	16	3	127
11	20	4.5	9	30	16	3	127
12	21	4.5	9	30	16	3	127
13	22	4.5	8.33	27	16	3	127
16	25	4.5	7.17	25	18	3	127
19	28	4.5	6.5	19.5	18	3	127
22	31	4.5	5.8	17.4	20	3	127
25	34	4.5	5.5	16	30	3	127
28	37	4.5	5.33	16	30	3	127
30	39	4.5	5.33	16	30	3	127
32	41	4.5	5.17	15.5	32	3	127
35	44	4.5	5	15	35	3	127
38	47	4.5	5	15	35	3	127
40	49	4.5	4.83	14.5	35	3	127
45	54	4.5	4.67	14	40	3	127
48	57	4.5	4.5	13.5	45	3	127
51	62	5.5	4.5	13.5	51	4	127
54	65	5.5	4.33	13	60	4	127
57	68	5.5	4.33	13	60	4	127
60	71	5.5	4.17	12.5	60	4	127
63	74	5.5	4	12	63	4	127
65	76	5.5	3.85	11.5	65	4	127
68	79	5.5	3.6	11	65	4	127
70	81	5.5	3.5	10.5	65	4	127
76	87	5.5	3.5	10.5	65	4	127
80	91	5.5	3.33	10	70	4	127
83	94	5.5	3.17	9.5	70	4	127
90	101	5.5	3	9	70	4	127
102	113	5.5	2.8	8.5	70	4	127

Show all 31 sizes → Show fewer

How it's built

Three layers, each doing one job.

Three layers, from the outside in: high-grade silicone, high-strength polyester braids and smooth extruded silicone compound. Each one is doing a different job.

1

Outer cover

High-grade silicone

Ozone, abrasion, and heat resistance

2

Reinforcement

High-strength polyester braids

Durability and pressure stabilityFrom 12.33 bar (small bore) down to 2.8 bar (large bore)Typically 3x working pressure (up to 37 bar)

3

Inner liner

Smooth extruded silicone compound

Reliable sealing and flow efficiency-50°C to +250°C (peak +250°C)

Product gallery

Frequently Asked Questions.

Answers to the questions we’re asked most about sizing, fitment and performance.

Still can't find your answer?

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What is a reducer for?

It joins two pipes of different diameters with a smooth internal transition, rather than stretching one hose over an oversized stub or stacking adaptors. That keeps flow efficient and gives a joint that will not creep loose.

How do I order the right one?

Reducers are quoted large bore to small bore - 38mm to 32mm means one end fits a 38mm pipe and the other a 32mm pipe. Measure the outside diameter of both pipe stubs with vernier callipers. Available in internal diameters from 12mm To 8mm to 127mm To 102mm, in red, blue and black.

Which way round does it go?

The larger bore end goes on the larger pipe. Dry-fit before you clamp anything up - it is surprisingly easy to fit a reducer the wrong way round when you are working blind in a tight engine bay.

What is it rated for?

Built to SAE J20 R3 with a smooth extruded silicone inner layer, polyester braid reinforcement and a silicone outer. Smaller bores are 3 ply and larger bores step up to 4 ply - each size is built with the reinforcement it needs, so you do not have to specify it. Like all standard silicone it is not suitable for fuel or oil.

Will it restrict flow?

A gradual moulded transition is far better than a sharp step, and the smooth bore keeps turbulence low. What does cost you is the reduction itself - flow is limited by the smallest bore in the system - so avoid reducing down and back up again if the run can be redesigned.

What clips do I need?

Two different sizes, one for each end, sized to the outside diameter of the fitted hose rather than the bore. This is the classic reducer mistake - it is easy to order a matching pair and find one will not close far enough.