- 1. Where Steel Shims Are Used Across Five Vehicle Types
- 2. Size Chart: Inner Diameter and Thickness Range
- 3. Material Selection: Sandvik 20C, SK4, SK5, C100S, 65Mn, 45# and Stainless
- 4. BONPORA Shims Program: MOQ 500, 250 pcs per Bag
- 5. FAQ
- 5.1. What is the smallest steel shim BONPORA can supply?
- 5.2. Which material is best for shock absorber valve shims?
- 5.3. Can BONPORA mix different thicknesses in one order?
- 5.4. What is the MOQ and packing?
- 5.5. Do you supply shims for modified 4x4 and off-road trucks?
- 5.6. How do I request a sample?
- 6. Request a Shim Sample Pack
Steel Shims: Size Chart, Materials and Applications for Bike, Motorcycle, Passenger Car, Off-Highway and 4x4
A steel shim is the thin, flat ring that sets clearance, preload, chainline, valve opening or bearing position inside a vehicle. It is small, but a 0.10 mm mistake changes shifting feel, shock damping, brake rotor runout or wheel bearing life. BONPORA supplies precision steel shims across five vehicle segments: bicycle, motorcycle, passenger car, off-highway engineering vehicles and modified off-road 4x4. This guide gives the full size chart, material selection table and application notes so buyers can spec the exact shim in one email.
Where Steel Shims Are Used Across Five Vehicle Types
| Vehicle Segment | Typical Shim Application | Common Thickness |
|---|---|---|
| Bicycle | Freehub cassette spacer, bottom bracket adjusting shim, hub axle washer, headset preload shim | 0.10 – 2.0 mm |
| Motorcycle | Brake caliper alignment shim, sprocket spacer, fork preload shim, shock absorber valve shim | 0.10 – 0.50 mm |
| Passenger car | Wheel bearing preload shim, brake rotor runout shim, drive shaft thrust washer, suspension arm shim | 0.10 – 1.00 mm |
| Off-highway / engineering vehicle | Hydraulic pump shim, valve plate shim, center bearing shim, chassis alignment shim, ring gear shim | 0.20 – 1.00 mm |
| Modified off-road 4x4 | Leaf spring shim, shackle alignment shim, wheel spacer, transfer case shim, steering knuckle shim | 0.30 – 1.00 mm |
Size Chart: Inner Diameter and Thickness Range
BONPORA stocks and custom-stamps steel shims in the following standard inner diameters and thicknesses. Mixed-size sets are available as a shim kit for repair shops and R&D departments.
Inner diameters (ID)
6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 12 mm, 12.5 mm and 16 mm
6 – 10 mm: brake caliper, motorcycle sprocket, bicycle hub, small hydraulic valves.
12 – 12.5 mm: wheel bearing, drive shaft, shock absorber rod, control arm bolt.
16 mm: off-highway kingpin, steering knuckle, heavy-duty thrust washer.
Thicknesses
0.10 mm, 0.15 mm, 0.20 mm, 0.25 mm, 0.30 mm, 0.34 mm, 0.35 mm, 0.40 mm, 0.45 mm, 0.50 mm and 1.00 mm
0.10 – 0.25 mm: shock absorber valve shims, brake rotor truing, fine bearing preload.
0.30 – 0.50 mm: chainline, sprocket alignment, suspension arm clearance.
1.00 mm: heavy off-highway thrust and axle alignment.
Outer diameter (OD) is made to the drawing. Tolerance on thickness is ±0.02 mm, and flatness is held under 0.02 mm per 100 mm.
Material Selection: Sandvik 20C, SK4, SK5, C100S, 65Mn, 45# and Stainless
| Material | Type | Hardness / Use | Best Application |
|---|---|---|---|
| Sandvik 20C | High-carbon spring steel strip (Sweden) | Very fine flatness and fatigue life | Shock absorber valve shims, high-frequency cycling, premium suspension kits |
| SK4 / SK5 | Japanese carbon tool steel | HRC 48 – 55 after heat treatment | Sprocket shims, brake shims, general stamped washers |
| C100S | European high-carbon steel (1.1274 / CK101) | Close to Sandvik 20C, cost-effective alternative | Valve shims, thrust washers, European OEM programs |
| 65Mn | Chinese manganese spring steel | HRC 45 – 52, good resilience | General suspension shims, leaf spring shims, 4x4 kits |
| 45# | Chinese medium carbon steel (C45 / 1045) | Tough, low cost, not hardened through | Structural spacer washers, off-highway alignment shims |
| Stainless steel | SUS301 / SUS304 / SUS420 | Corrosion resistant, magnetic or non-magnetic | Marine, salt-road trucks, motorcycle exterior shims |
For valve shims that cycle millions of times, Sandvik 20C or C100S is the standard. For general stamped washers, SK5 or 65Mn is the cost default. For corrosion duty, SUS304.
BONPORA Shims Program: MOQ 500, 250 pcs per Bag
MOQ: 500 pieces per size per material. Stock sizes ship from 100 pieces.
Packing: 250 pcs per VCI anti-rust bag, then inner carton and export carton. Mixed-thickness shim kits are packed in labeled compartments.
ID range: 6, 7, 8, 9, 10, 12, 12.5, 16 mm (other IDs on request).
Thickness range: 0.10, 0.15, 0.20, 0.25, 0.30, 0.34, 0.35, 0.40, 0.45, 0.50, 1.00 mm (other thicknesses on request).
Materials: Sandvik 20C, SK4, SK5, C100S, 65Mn, 45#, SUS301 / 304 / 420.
Finish: bright, black oxide, zinc or nickel plated.
Export port: Shenzhen Yantian / Shekou, with weekly sailings to worldwide ports.
Send the drawing, a sample, or just the ID, thickness and vehicle. We reply with a dimension sheet and a sample quote within two working days.
FAQ
What is the smallest steel shim BONPORA can supply?
The thinnest stock is 0.10 mm, commonly used for shock absorber valve shims and fine brake truing. Inner diameter starts at 6 mm.
Which material is best for shock absorber valve shims?
Sandvik 20C and C100S are the preferred materials because they hold flatness and fatigue life over millions of cycles. SK5 and 65Mn are cost alternatives for general suspension shims.
Can BONPORA mix different thicknesses in one order?
Yes. We supply shim kit sets with 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.50 and 1.00 mm in one labeled box, ideal for repair shops and R&D departments.
What is the MOQ and packing?
MOQ is 500 pieces per size per material. Standard packing is 250 pieces per VCI anti-rust bag, then inner carton and export carton. Customer labels are available.
Do you supply shims for modified 4x4 and off-road trucks?
Yes. Leaf spring shims, shackle alignment shims, wheel spacers and transfer case shims in 0.30 to 1.00 mm are common. 65Mn and 45# are the typical materials.
How do I request a sample?
Send the ID, thickness, material and application by email to sales@bonporaparts.com, or upload a drawing through the contact page. Free sample packs are available for qualified buyers.
Request a Shim Sample Pack
If your program covers bicycle, motorcycle, passenger car, off-highway or modified 4x4 suspension, send BONPORA your drawing or required size. We ship from Shenzhen Yantian port worldwide, with MOQ 500 pieces and 250 pieces per bag.
Contact: sales@bonporaparts.com