__COIL SPRING
RATE CONVERSION__**
**- A. Hyde 5/2000 update
11/2010

**Background** Math: relating to
force

1 lb = 0.454 kg and 1 kg = 9.81 Newtons (1
**Newton** N = 0.1 kg = 0.22 lb) 1 **lb****f**
= **pounds-****f****orce**
(not pounds foot lb/ft)

Force is designated as a Newton in the metric SI system

**Converting pounds force into Newtons:
**Force=Mass x Acceleration -> lbf = 0.454 x 9.81 (accel due to
gravity) -> 1 lbf = 4.45 N (Newtons)

**Converting Newtons to millimetre (N/mm):**
**N/mm** = 4.45 / 25.4** **= ** 0.175** (a unitless
conversion factor)

__To Convert lbf/in
____to__** N/mm**
(

**lbf/in x ****0.175****
= N/mm, ** Example: 100 lbf/in x **0.175** = 17.5
N/mm

__To Convert N/mm ____to
__** lbf/in**
(inverse = 1 / 0.175 =

**N/mm x ****5.714****
= lbf/in, **Example:**100 N/mm** spring x 5.714 = **514
lbf/in
OR
N/cm** x 0.5714 =

100 = 17.5 220 = 38.5 450 = 78.75 120 = 21 240 = 42 500 = 87.5 130 = 22.75 260 = 45.5 550 = 96.25 140 = 24.5 280 = 49 600 lbf/in =105 N/mm 150 = 26.25 300 = 52.5 650 = 113.75 160 = 28 320 = 56 700 = 122.5 170 = 29.75 340 = 59.5 800 = 140 180 = 31.5 360 = 63 900 = 157.5 190 = 33.25 380 = 66.5 1000 = 175 200 lbf/in = 35 N/mm 400 lbf/in = 70 N/mm 1200 = 210

**EIBACH ERS SPRING DATA
**# 200 60 60 (typical part
number for Eibach ERS springs

Length mm ID mm Rate N/mm

**200-60-60** Rate
60 N/mm ~ 342 lbf/in, block 85 mm

**200-60-70** Rate
70 N/ ~ 400 lb, block 89 mm

**200-60-80** Rate
80 N/ ~ 457 lb, block 94 mm

**200-60-90** Rate
90 N/ ~ 514 lb, block 92 mm

**180-60-70** Rate
70 N/ ~ 400 lb, block 75 mm

**180-60-80** Rate
80 N,/ ~ 457 lbblock 80 mm (15% stiffer than 70 N)

**180-60-90** Rate
90 N/ ~ 514 lb, block 80 mm (30% stiffer than 70 N)

**170-60-80** Rate
80 N/ ~ 457 lb, block 64 mm (170-64=104 travel) (15% stiffer than 70
N) New product length

**160-60-70 **Rate
70 N/ ~ 400 lb, block 65 mm

**160-60-80** Rate
80 N/ ~ 457 lb, block ...

**160-60-100**
Rate (100 N / ~571 lb, block ...

**TENDER
SPRINGS**

**60-60-60** Free
length 95 mm, Solid height 37 mm, flat spacing 27 mm c/c

4 active coils, 7.2 to 7.4 flat wire, OD=, ID=60

**40-60-30** free
length 64, static to block 25.5

**HELPER SPRINGS
**(only one spec available, then catalog to TENDER springs)

60-60-2

60 length, 60 ID 2 N rate / ~ 11 lb block 13 mm

**
**

Back to Volvo
Turbo
World
*or Back to
**Quick
Technical Index*