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Conventional Heavy Duty Suspension Leaf Springs for Semi Trailers

  • 20+ Years of experiences (since 1999)
  • Implementing IATF 16949-2016
  • Implementing ISO 9001-2015
  • Quality standards: GB/T 19844-2018, GT/T 1222-2007
  • Flat bar suppliers from top 3 steel mills in China
  • Leaf length tolerance (mm): ±2 (Exceed spring industry standard ±3)
  • Camber tolearance (mm): ≤±6 (Exceed spring industry standard ±7)
  • Fatigue life ( cycles): >120,000+ (Exceed spring industry standard 100,000 cycles)
  • Annual output (tons): 35,000+
  • SKUs : 5,000+


Application of leaf springs

A leaf spring is the most widely used elastic element in automobile suspensions.

It is an approximate equal strength steel beam composed of several alloy spring sheets of equal width and unequal length. Its main function is to transmit all forces and moments between wheels and frames, relax impactive load caused by the road surface and realize vehicle guidance, make vehicles normal drive.

Leaf springs are widely applied to suspensions for heavy duty trucks, light duty trucks, pick-ups, cars, skeletal trailers, lowbed trailers, flatbed trailers, oil tank trailers, van trailers, wood transport trailers, gooseneck trailers, agricultrucal vehicles, etc. Classification of Leaf Springs include Conventional leaf springs, parabolic leaf springs, Z type air linkers, TRA leaf springs, trailer leaf springs,light duyt trailer spring, boat trailer springs, pickup leaf springs, semi trailer springs, truck springs, farming/agricultural trailer springs, sprung drawbar, bus springs, bogie/boogie springs, heavy truck springs, etc.

For more about WONDEE Leaf Springs Project, please click:

leaf springs project


QC management systemImplementing IATF 16949-2016
Services quality management systemImplementing ISO 9001-2015
Product technical standardsImplementing GB/T 19844-2018, GT/T 1222-2007
Warranty12 months since shipping date
Quality testing byStiffness Testing Machine, Arc Height Sorting Machine, and Fatigue Testing Machine, etc.
Raw materialTop 3 steel mills in China
Flat bar cutting & center hole punchingBy fully automatic CNC cutting & punching production line
Center hole positioning tolerance: <±0.2 mm
Cutting length tolerance: <±2 mm
Leaf spring eye rollingUse automatic CNC leaf eye rolling machines, robot assistance, dedicated molds   and toolings to guarantee below features:
1) Perpendicularity tolerance <1% x leaf width
2) Parallelism tolerance< 1% x leaf width
3) Eye diameter tolerance<±0.5 mm
4) Width tolerance of leaf end: -0.5mm ~ 0 mm   
Leaf tapering/parabolic rollingUse automatic CNC parabolic taper rolling machines, robot assistance, dedicated   molds and toolings to guarantee below features:
1) Taper thickness allowance: <±0.25mm
2) Width tolerance of leaf end: -0.5mm~0 mm
Heat treatment lines1) Heating line:
The large-scale automatic CNC temperature control heating furnace not only ensures the heating time but also ensures that the temperature in the furnace reaches the   design value (the temperature difference is within ±5 degrees), ensures that the leaf springs are heated evenly, and avoids excessively high or low temperatures, thereby ensuring the strength of the leaf springs and the service life limit meets the Crequirements.
2) Quenching & camber making line:
Use special CNC quenching equipment, mechanical oil, camber making machines and robot assistance to ensure that the quenching temperature, quenching time and cambers reach the design requirements.
3) Tempering line:

A dedicated CNC tempering production lines are used to ensure that the tempering temperature and the tempering time meet the design requirements. 

So as to ensure the strength and service life of leaf springs.

Camber tolearance (mm)≤±6 (Exceed spring industry standard ±7)
Fatigue life (cycles)>120,000+( Exceed spring industry standard 100,000 cycles)
Shot peeningUsing special leaf spring shot blasting machines, the new and used steel shots are   mixed for use. On the one hand, the new steel shots increase the deformation of the springs. On the other hand, the used steel shots have no edges and corners to avoid microcracks on the surface of the springs, thereby increasing the fatigue life.   
PaintingNormal painting and E-coating are available.
*E-coating finish line: paint film is uniform and plump, with strong adhesion and high anti-corrosion performance, to avoid dripping, flow marks, stagnation marks and other problems.
* Salt spray test >100 hours

* Clients' logo are supported 

* Design marks or stickers for clients, free of charge

Other inspection equipment*Metallographic Microscope,
*Carbon Furnace

*Carbon & Sulfur Combined Analyzer, and 

*Hardness Tester, etc.

Oversea sales volume (tons)14,000+
Overseas market30+ countries ( German, France, Poland, Portugal, Russia, Filand, USA, Canada, Mexico, Thailand, Vietnam, Malaysia, Singapore, The Philippines, Indonesia, Brazil, Bolivia, Argentina, Ecualor, Chile, Peru, Guatemala, Panama, Egypt, South Africa, Nigeria, Tanzania, etc)
Clients (overseas)91+
Land area (square meters)30,000+
Tons of annual output35,000+
Number of equipments (sets)200+
Number of employees260+
Number of engineers10+
Available certificatesCOC, PVOC, CIQ, SONCAP, BV, C/O, FORM E, FORM A.

Comprehensive Info of  Leaf Spring:

Leaf spring typesConventional leaf springs, parabolic leaf springs, Z type air linkers, TRA leaf springs, trailer leaf springs, boat trailer springs, pickup leaf springs, semi trailer springs, truck springs, farming/agricultural trailer springs, sprung drawbar, bus springs,   bogie/boogie springs, heavy truck springs, light duty trailer springs/small springs, etc.
Materials grade:SUP7, SUP9, SUP9A, SUP10, SUP11, SUP11A and SUP12
60Si2Mn, 55CrMnA, 60CrMnBA, 50CrVA, 60CrMnBA, 60Si2CrA
61SiCr7, 55Cr3, 60CrB3, 51CrV4
9260, 5155, 5160, 6150, 51B60, 9254
Spring width range (mm)44.5~125 mm
Spring thickness (mm)6~50 mm
ColorsRed, shinning black, dark black, grey, blue, as required.
Optional parts, components, & related partsCentor bolts, clamps, 

Copper bushes, bi-metal bushes, steel rubber bushings, rubber bushes, nylon bushes. 

U-bolts, brackets, pins.

PackageFumigated wooden pallets, steel pallets, as required.
Standards implementedIATF 16949-2016, ISO 9001-2015, GB/T 19844-2018, GT/T 1222-2007
Payment termsTT, LC, DP.
Lead timeAbout 25~35 working days.
MOQ60 pcs


Wondee semi trailer leaf spring

Conventional leaf springs for heavy duty semi trailers:

Item Number

Section WxT


Cut Length of 1st Leaf L (mm) Free Camber H   (mm)



WLS76-EA13 76x13 1120 110 10
WLS76-EA14 76x14 1178 76 7~8
WLS76-EA16 76x16 1178 76 7~8
WLS90-AM13 90x13 1130 85 7~13
WLS90-AM16 90x16 1130 85 7~13
WLS90-AM20 90x20 1130 85 7~13
WLS100-EU10 100x10 1120 65 10~16
WLS100-EU12 100x12 1120 65 10~16
WLS100-EU14 100x14 1120 65 10~16

Note 1: Other leaf springs for heavy duty trailers are available;

Note 2: Other classification of leaf spring are available, include: conventional leaf springs, parabolic leaf springs, Z type air linkers, TRA leaf springs, trailer leaf springs, light duyt trailer spring, boat trailer springs, pickup leaf springs, semi trailer springs, truck springs, farming/agricultural trailer springs, sprung drawbar, bus springs, bogie/boogie springs, heavy truck springs, etc.

WONDEE hot selling leaf springs OEM numbers:

1 SH63-1430-FA 31 8-97092-445-1-FA 61 911B-0508-R2 91 SCN-1421061-RH 121 41310-80010-RA
2 55020-1T400-HA 32 8-94118-505-1-HA 62 911B-1102A-F1 92 SCN-1303972 122 55020-Z5106-RA
3 MC031096-HA 33 8-97073-224-M-HA (5L) 63 48220-5891A-R1 93 SCN-1421060-LH 123 48210-3V610-RA
4 54010-01Z17-FA 34 97073-225M-HA (9L) 64 352-320-1302-F1 94 XCMG 9020-1780-F1 124 55020-G6105-RA
5 48120-5380B-FA 35 8-97073-224M-RA 65 FCP37-R1 95 XCMG 9020-1780-F2 125 8-97070-508M-RA
6 1-51110-051M-FA 36 48110-60391W-FA 66 FCP37A-R1 96 XCMG 9020-1780-F3 126 MC114890-RA
7 1377695-RA 37 MB294032-FA 67 48210-60742 97 MK383732-FA 127 48210-87C14-HA
8 257888-FA 38 54010 31Z61-FA 68 48210-8891A-R1 98 3V610-HA 5L 128 8-97070-508M-HA
9 29FDZ1-02010 FA 39 352-320-1302-FA 69 70×11×1300 M12.5 99 MC114890 RA 129 HNIT300-FA
10 352525 40 48110-3V790-FA 70 60×7×1300 M10.5 100 CW53-02Z61-FA 130 TD50M3-RA
11 CW53-02Z61HD-FA 41 621 320 0002 RA 71 HOWO90161800 101 SH63-1430-FA-HD 131 55020-Z2302-RA
12 48220-3430-HA 42 48210-2341 72 833150P-R1 102 227-M-FA-0 132 55010-C1301-HA
13 55020-Z9001-HA 43 51310-7800-RA 73 833150P-R2 103 3W920-FA-3L 133 48210-5180B-HA
14 55020-Z3001-RA 44 54010-Z3007-FA 74 833150P-R3 104 3V790-RA+HA 3L 134 720612-TA-12.5
15 624 320 0006 RA 16L 45 48110-5570A-FA 75 55020-Z5176-H1 105 48120-5380B-M20 FA 135 48220-3360B
16 54010-G5500MH-FA-HD 46 101199SC-RA 76 48110-5350A-F2 106 W023-34-010B-FA 136 48220-3430A-RA
17 1915-90-30-41 47 48120-4340-FA 77 48110-5350A-F1 107 8-94118-505-1-RA 137 CAMC RA
18 MK 382877R 48 1-51340-010-0-HA 78 48210-2002B-R1 108 8-94101-345-0-FA 138 29AD-02010-B FA
19 48110-87338A-FA 49 0178-01-TA 79 48210-5180B-R 109 54010-1T700-FA 139 0022-RA 2L
20 48210-87C37A-RA 50 54010-Z2006A-FA 80 48220-3430A-R2 110 265627-FA 140 55022-1T400-RA
21 48210-87C14-RA 51 48110-8780A-FA 81 48210-5180B-R2 111 W782-28-010-RA 141 21200078 TA
22 48150-1890A-FA 52 54011-99117-FA 82 269087-R2 112 W782-34-010-FA 142 257653 RA
23 48210-830T0-RA 53 48150-2341A-FA 83 470131-R1 113 8-97092-450-M-FA 143 257654 RA
24 8-94343-130-0-RA 54 48150-2341A-FA-HD 84 470131-R2 114 535173-RA 144 257847 RA
25 8-94343-082-M-FA 55 55020-Z0073A-RA 85 09475-01-T1 115 1-51300-524-0-RA 145 972015M-TA
26 MK310031-FA 56 257624M-R1 86 EZ9K869691101-F1 116 1-51130-433-0-FA 146 257867 FA
27 48110-87334-FA 57 54010-01Z17-F3H 87 EZ9K869691101-F2 117 1-51300-524-0-HA

28 TYT 48210-OK020HD 58 54010-NB100-F3 88 EZ9K869691102-F1 118 MB339052-RA

29 8-97092-449 FA 59 MK306251-R1 89 EZ9K869691102-F2 119 MR448147A-RA

30 48110-3V700-FA 60 911B-0508-R1 90 EZ9K869691102-F3 120 MC110354-FA


About production processes of leaf springs, please kindly visit YOUTUBE link:

How to make leaf springs

Workshops of WONDEE Autoparts leaf springs :

WONDEE leaf spring workshops

(Flat bar workshop, production processing workshop, leaf spring assembly workshop, leaf spring finished production)

Processes & equipment of WONDEE Autoparts leaf springs :

WONDEE spring equipments

(1. Flat bar cutting and hole punching→ 2. Spring ends processing→ 3. CNC automatic eye rolling→ 4. Spring heating→ 5. Spring quenching→ 6. Spring tempering→ 7. Spring shot peening→ 8. Leaf spring assembling→ 9. Spring e-painting)

QC equipment of WONDEE Autoparts leaf springs :

WONDEE spring Testing equipment

(Material Metallographic analysis, spring spectral analysis, raw material inspection, eyes inspection, spring camber inspection, spring hardness test, salt spray test, fagigue life test, spring rate test)

Warehousing & Logistics of WONDEE Autoparts leaf springs: 

WONDEE spring warehousing and container loading

(leaf spring finished prodution, spring packing, spring warehousing, leaf spring container laoding)

Other spring types of WONDEE Autoparts leaf springs:

leaf spring (1)


Components & spare parts of WONDEE Autoparts leaf springs 

WONDEE spring components

(Bi-metal bushings, Composite bushes, Rubber bushes, Center bolts, Spring pins, Leaf spring hangers, Spring brackets, Spring steel flat bars)

In addition to supplying leaf springs, WONDEE Autoparts also supply different types of semi trailer components as below:




Xinhe Industrial Park, Xiamen, Fujian, China 361006





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