Understand Your Tune: Why Preload is Bad

Understand Your Tune: Why Preload is Bad

Spring rate is different from preload

In fact, any more preload than what is necessary to remove any play is bad. Coil shocks include a threaded ring for preloading the coil. Preloading is not the same as using a stiffer (higher spring rate) spring. Preloading does not change spring rate but preload does change the force to start moving the shock and high preload dramatically reduces shock performance over smaller bumps and makes for a more harsh ride and worse traction. Spring rate is the force required to move a certain distance whereas preload adds a fixed force across the whole stroke. Heavy preloading can add over 100 pounds (45kg) of force required to start shock movement whereas optimal shock performance comes from the lowest starting force possible. Heavy preload means those smaller bumps won't even move your suspension. Mountain bike shocks are designed for as little preload as is necessary to take play out of the system. Sprindex allows spring rate adjustment and also allows proper preload.

Proper preload

Preloading more than the minimum to get rid of play is bad. For best shock performance, turn the preload ring until it contacts the spring and then another 1 to 2 turns. No more.

Too much preload

Excessively preloading your coil increases the force to start shock movement which causes poor small bump absorption resulting in a harsh ride and poor traction. Heavy preload destroys shock performance, over-stresses the coil, and can reduce shock travel. Preloading is not the correct method to reduce sag or prevent bottom out. Instead, the correct way to adjust sag and bottom out is by adjusting spring rate.

Here's an overly preloaded shock on the left compared to a properly preloaded shock on the right. Notice how too much preload causes the bike to bounce. The only difference between the two is preload.

Left coil overly preloaded 10 turns. Right coil properly preloaded 1 turn.

Instead of adjusting preload, the correct way to set up your suspension is to have the correct spring rate. Unfortunately, traditionally, this means replacing springs and even then, that means big intervals between available spring rate (typically 50 lb/in increments). Sprindex is the better solution because Sprindex allows you to easily finely adjust your spring rate. A Sprindex coil adjusted to any particular spring rate behaves exactly like a regular spring that was manufactured to that spring rate.

For example, Sprindex adjusted to 360 lb/in spring rate performs exactly the same as a custom made ordinary spring that has a 360 lb/in spring rate.

For example, Sprindex adjusted to 380 lb/in spring rate performs exactly the same as a custom made ordinary spring that has a 380 lb/in spring rate.

Adjusting your Sprindex does not change the length of the coil and so does not change your preload. Preload is adjusted normally and with the threaded ring that came with your shock.

How does Sprindex adjust spring rate?

Sprindex works by altering the number of active coils available for deflection. The spring's active coils are the coils that can flex as the spring is compressed. Fewer active coils makes for a stiffer spring and vice versa. Think of it like this: the less wire there is to bend, the stiffer the spring. The spring rate of a spring is the amount of force it takes to deflect the spring a certain distance (typically pounds per inch or Newtons per mm). Spring rate is a function of 4 characteristics: wire diameter, coil diameter, material, and number of active coils. Sprindex is designed using high tensile steel to handle the stress at the highest adjusted setting.

Most people ride the wrong spring rate. If too stiff, they don't get full travel, have poor small bump absorption, and diminished traction. If too soft, they bottom out on bigger hits. Sprindex solves this. The right spring rate dramatically improves your ride.

Sprindex allows you to easily adjust your coil's spring rate to any rate within a certain range, which can profoundly improve your bike's suspension. Just use your hands to twist the adjustment Dial. Adjustment is so easy and tool free that you may find yourself using different spring rates for different trails, depending on trail conditions and types. Or you may increase your spring rate for long climbs and decrease it for down hills.




Sprindex is compatible with a wide variety of shocks.

There are three different Sprindex lengths and strokes available, and each Sprindex coil can be adjusted through a certain spring rate range. Be sure to use the correct included adapter as described. Make sure that the spring length fits on your shock and that your maximum shock travel is not more than the specified Sprindex coil travel.

IF YOUR SHOCK IS NOT LISTED IN THE BELOW COMPATIBILITY TABLE:

Determine what your shock's stroke is and then compare that to the available Sprindex coils. Sometimes, you can find the stroke specification on the website of your bike brand for your bike model. The stroke printed on your existing coil is a clue, but it might have more stroke than your shock actually needs. Or, just measure the stroke per the picture above. Ideally, choose the Sprindex coil that has at least the amount of stroke that your shock requires, and then measure whether that Sprindex coil overall length can fit between your shock's flanges. The Sprindex coil lengths are listed in the below compatibility table. Note that most shocks can only achieve about 5mm less than their listed stroke because the bottom-out bumper can only be compressed so far, so in most cases it is okay if the Sprindex coil has up to about 3mm less stroke than your shock's stroke rating.

Find your shock on the below table and note which Sprindex family you need.

Shock Brand/Model

Regular or Trunnion

Shock eye to eye

Stroke

Metric / English

Sprindex spring family (stroke x length)

Fox DHX2

230 mm

60 mm

metric

65 x142

Fox DHX2

230 mm

65 mm

metric

65 x 142

Fox DHX2

Trunnion

205mm

60mm

metric

65 x 142

Fox DHX2

Trunnion

205mm

65mm

metric

65 x 142

Fox DHX2

8.5 inch

2.5 inch

English

65 x 142

Fox DHX2

8.75 inch

2.75 inch

English

65 x 142

Fox DHX2

7.875 inch

2.0 inch

English

55 x 126

Fox DHX2

7.875 inch

2.25 inch

English

55 x 126

Fox DHX2

210 mm

50mm

metric

55 x 126

Fox DHX2

210 mm

52mm

metric

55 x 126

Fox DHX2

210 mm

55mm

metric

55 x 126

Fox DHX2

Trunnion

185mm

55mm

metric

55 x 126

Fox DHX2

9.5 inch

3 inch

English

75 x 162

Fox DHX2

Fox DHX2

Trunnion

250mm

225mm

75mm

75mm

metric

metric

75 x 162

75 x 162

Shock Brand/Model

Regular or Trunnion

Shock eye to eye

Stroke

Metric / English

Sprindex spring family (stroke x length)

MRP Hazzard

230 mm

65 mm

metric

65 x 142

MRP Hazzard

230 mm

60 mm

metric

65 x 142

MRP Hazzard

230 mm

57.5 mm

metric

65 x 142

MRP Hazzard

Trunnion

205 mm

65 mm

metric

65 x 142

MRP Hazzard

Trunnion

205 mm

60 mm

metric

65 x 142

MRP Hazzard

Trunnion

205 mm

57.5 mm

metric

65 x 142

MRP Hazzard

200mm

51mm

metric

55 x 126

MRP Hazzard

200mm

57mm

metric

55 x 126

MRP Hazzard

210mm

50mm

metric

55 x 126

MRP Hazzard

210mm

55mm

metric

55 x 126

MRP Hazzard

9.5 inch

3 inch

English

55 x 126

Shock Brand/Model

Regular or Trunnion

Shock eye to eye

Stroke

Metric / English

Sprindex spring family (stroke x length)

Marzocchi 2019 Bomber CR

230 mm

60 mm

metric

65 x 142

Marzocchi 2019 Bomber CR

230 mm

65 mm

metric

65 x 142

Marzocchi 2019 Bomber CR

Trunnion

205 mm

60 mm

metric

65 x 142

Marzocchi 2019 Bomber CR

Trunnion

205 mm

65 mm

metric

65 x 142

Marzocchi 2019 Bomber CR

7.875 inch

2.0 inch

English

55 x 126

Marzocchi 2019 Bomber CR

7.875 inch

2.25 inch

English

55 x 126

Marzocchi 2019 Bomber CR

210mm

50mm

metric

55 x 126

Marzocchi 2019 Bomber CR

210mm

55mm

metric

55 x 126

Marzocchi 2019 Bomber CR

Trunnion

185mm

52.5mm

metric

55 x 126

Marzocchi 2019 Bomber CR

Trunnion

185mm

55

metric

55 x 126

Marzocchi 2019 Bomber CR

250mm

75mm

metric

75 x 162

Shock Brand/Model

Regular or Trunnion

Shock eye to eye

Stroke

Metric / English

Sprindex spring family (stroke x length)

DVO Jade Coil

230 mm

65 mm

metric

65 x 142

DVO Jade Coil

230 mm

62.5 mm

metric

65 x 142

DVO Jade Coil

230 mm

60 mm

metric

65 x 142

DVO Jade Coil

230 mm

57.5 mm

metric

65 x 142

DVO Jade Coil

Trunnion

205 mm

65 mm

metric

65 x 142

DVO Jade Coil

Trunnion

205 mm

62.5 mm

metric

65 x 142

DVO Jade Coil

Trunnion

205 mm

60 mm

metric

65 x 142

DVO Jade Coil

Trunnion

205 mm

57.5 mm

metric

65 x 142

DVO Jade Coil

210mm

50mm

metric

55 x 126

DVO Jade Coil

210mm

52.5mm

metric

55 x 126

DVO Jade Coil

210mm

55mm

metric

55 x 126

DVO Jade Coil

Trunnion

185

50

metric

55 x 126

DVO Jade Coil

Trunnion

185

52.5

metric

55 x 126

DVO Jade Coil

Trunnion

185

55

metric

55 x 126

DVO Jade Coil

250 mm

70 mm

metric

75 x 160

DVO Jade Coil

250 mm

75 mm

metric

75 x 162

DVO Jade Coil

Trunnion

225mm

70mm

metric

75 x 162

DVO Jade Coil

Trunnion

225mm

75mm

metric

75 x 162

Shock Brand/Model

Regular or Trunnion

Shock eye to eye

Stroke

Metric / English

Sprindex spring family (stroke x length)

X-Fusion Vector Coil HLR

222 mm /8.75 in

69 mm

Metric/English

65 x 142

X-Fusion Vector Coil HLR

200mm

57mm

metric

55 x 126

X-Fusion Vector Coil HLR

240mm

76mm

metric

75 x 160

Shock Brand/Model

Regular or Trunnion

Shock eye to eye

Stroke

Metric / English

Sprindex spring family (length x stroke)

Cane Creek DB coil CS

222 mm

63 mm

Metric

65 x 142

Cane Creek DB coil CS

222 mm

66 mm

Metric

65 x 142

Cane Creek DB coil CS

Trunnion

205mm

57.5mm

Metric

65 x 142

Cane Creek DB coil CS

Trunnion

205mm

60mm

Metric

65 x 142

Cane Creek DB coil CS

Trunnion

205mm

65mm

Metric

65 x 142

Cane Creek DB coil CS

230mm

57.5mm

Metric

65 x 142

Cane Creek DB coil CS

230mm

60mm

Metric

65 x 142

Cane Creek DB coil CS

230mm

65mm

Metric

65 x 142

Cane Creek DB coil CS

210mm

50mm

metric

55 x 126

Cane Creek DB coil CS

210mm

52.5mm

metric

55 x 126

Cane Creek DB coil CS

210mm

55mm

metric

55 x 126

Cane Creek DB coil CS

200mm

50mm

metric

55 x 126

Cane Creek DB coil CS

200mm

57mm

metric

55 x 126

Cane Creek DB coil CS

Trunnion

185mm

50mm

metric

55 x 126

Cane Creek DB coil CS

Trunnion

185mm

52.5mm

metric

55 x 126

Cane Creek DB coil CS

Trunnion

185mm

55mm

metric

55 x 126

Cane Creek DB coil CS

250mm

70mm

metric

75 x 162

Cane Creek DB coil CS

250mm

75mm

metric

75 x 162

Cane Creek DB coil CS

Trunnion

225mm

70mm

metric

75 x 162

Cane Creek DB coil CS

Trunnion

225mm

75mm

metric

75 x 162

Cane Creek DB coil IL

210mm

50mm

metric

55 x 126

Cane Creek DB coil IL

210mm

52.5mm

metric

55 x 126

Cane Creek DB coil IL

210mm

55mm

metric

55 x 126

Cane Creek DB coil IL

200mm

50mm

metric

55 x 126

Cane Creek DB coil IL

200mm

57mm

metric

55 x 126

Marzocchi before 2018, some models

65 x 142

Shock Brand/Model

Regular or Trunnion

Shock eye to eye

Stroke

Metric / English

Sprindex spring family (length x stroke)

Ohlins TTX22 coil

230mm

57.5mm

Metric

65 x 142

Ohlins TTX22 coil

230mm

60mm

Metric

65 x 142

Ohlins TTX22 coil

230mm

65mm

Metric

65 x 142

Ohlins TTX22 coil

Trunnion

205mm

65mm

Metric

65 x 142

Ohlins TTX22 coil

210mm

50mm

metric

55 x 126

Ohlins TTX22 coil

Trunnion

185mm

55mm

metric

55 x 126

Ohlins TTX22 coil

7.87 inch

2.0 inch

English

55 x 126

Ohlins TTX22 coil

7.87 inch

2.25 inch

English

55 x 126

Ohlins TTX22 coil

9.5 inch

3.0 inch

English

75 x 162

Ohlins TTX22 coil

Trunnion

225mm

70mm

metric

75 x 162

Ohlins TTX22 coil

Trunnion

225mm

75mm

metric

75 x 162

Shock Brand/Model

Regular or Trunnion

Shock eye to eye

Stroke

Metric / English

Sprindex spring family (stroke x length)

Rockshox Super Deluxe Coil RCT

230mm

60mm

metric

65 x 142

Rockshox Super Deluxe Coil RCT

230mm

65mm

metric

65 x 142

Rockshox Super Deluxe Coil RC World Cup

230mm

60mm

metric

65 x 142

Rockshox Super Deluxe Coil RT Remote

230mm

60mm

metric

65 x 142

Rockshox Super Deluxe Coil RT Remote

230mm

65mm

metric

65 x 142

Rockshox Super Deluxe Coil R

230mm

60mm

metric

65 x 142

Rockshox Super Deluxe Coil R

230mm

65mm

metric

65 x 142

Rockshox Super Deluxe Coil RCT

Trunnion

205mm

57.5mm

metric

65 x 142

Rockshox Super Deluxe Coil RCT

Trunnion

205mm

60mm

metric

65 x 142

Rockshox Super Deluxe Coil RCT

Trunnion

205mm

65mm

metric

65 x 142

Rockshox Super Deluxe Coil RCT

210mm

55mm

metric

55 x 126

Rockshox Super Deluxe Coil RT Remote

200mm

57mm

metric

55 x 126

Rockshox Super Deluxe Coil RC World Cup

250mm

75mm

metric

75 x 162

Rockshox Super Deluxe RC

Trunnion

225mm

70mm

metric

75 x 162

Rockshox Super Deluxe RC

Trunnion

225mm

75mm

metric

75 x 162

Shock Brand/Model

Regular or Trunnion

Shock eye to eye

Stroke

Metric / English

Sprindex spring family (stroke x length)

Rockshox Vivid

200

57

55 x 126

Rockshox Vivid

216

63

65 x 142

Rockshox Vivid

222

70

65 x 142

Rockshox Vivid

240

76

75 x 162

Push

2.25 inch

English

55 x 126

Push

2.5 inch

English

65 x 142

Extreme Racing

EXT STORIA LOK V3

200

57

English

55 x 126

EXT STORIA LOK V3

217

63.5

English

65 x 142

EXT STORIA LOK V3

222

67

English

65 x 142

EXT STORIA LOK V3

210

50

Metric

55 x 126

EXT STORIA LOK V3

210

52.5

Metric

55 x 126

EXT STORIA LOK V3

210

55

Metric

55 x 126

EXT STORIA LOK V3

230

57.5

Metric

65 x 142

EXT STORIA LOK V3

230

60

Metric

65 x 142

EXT STORIA LOK V3

230

62.5

Metric

65 x 142

EXT STORIA LOK V3

230

65

Metric

65 x 142

EXT STORIA LOK V3

250

67.5

Metric

75 x 162

EXT STORIA LOK V3

250

70

Metric

75 x 162

EXT STORIA LOK V3

250

72.5

Metric

75 x 162

EXT STORIA LOK V3

250

75

Metric

75 x 162

EXT STORIA LOK V3

Trunnion

185

50

Metric

55 x 126

EXT STORIA LOK V3

Trunnion

185

52.5

Metric

55 x 126

EXT STORIA LOK V3

Trunnion

185

55

Metric

55 x 126

EXT STORIA LOK V3

Trunnion

205

57.5

Metric

65 x 142

EXT STORIA LOK V3

Trunnion

205

60

Metric

65 x 142

EXT STORIA LOK V3

Trunnion

205

62.5

Metric

65 x 142

EXT STORIA LOK V3

Trunnion

205

65

Metric

65 x 142

EXT STORIA LOK V3

Trunnion

225

67.5

Metric

75 x 162

EXT STORIA LOK V3

Trunnion

225

70

Metric

75 x 162

EXT STORIA LOK V3

Trunnion

225

72.5

Metric

75 x 162

EXT STORIA LOK V3

Trunnion

225

75

Metric

75 x 162

EXT STORIA LOK

200

57

English

55 x 126

EXT STORIA LOK

217

63.5

English

65 x 142

EXT STORIA LOK

210

50

Metric

55 x 126

EXT STORIA LOK

210

55

Metric

55 x 126

EXT STORIA LOK

230

60

Metric

65 x 142

EXT STORIA LOK

230

65

Metric

65 x 142

DH Racing:

EXT ARMA HBC V3

222

67

Metric

65 x 142

EXT ARMA HBC V3

241

74

Metric

75 x 162

EXT ARMA HBC V3

230

57.5

Metric

65 x 142

EXT ARMA HBC V3

230

60

Metric

65 x 142

EXT ARMA HBC V3

230

62.5

Metric

65 x 142

EXT ARMA HBC V3

230

65

Metric

65 x 142

EXT ARMA HBC V3

250

70

Metric

75 x 162

EXT ARMA HBC V3

250

72.5

Metric

75 x 162

EXT ARMA HBC V3

250

75

Metric

75 x 162

EXT ARMA HBC V3

Trunnion

205

57.5

Metric

65 x 142

EXT ARMA HBC V3

Trunnion

205

60

Metric

65 x 142

EXT ARMA HBC V3

Trunnion

205

62.5

Metric

65 x 142

EXT ARMA HBC V3

Trunnion

205

65

Metric

65 x 142

EXT ARMA HBC V3

Trunnion

225

70

Metric

75 x 162

EXT ARMA HBC V3

Trunnion

225

72.5

Metric

75 x 162

EXT ARMA HBC V3

Trunnion

225

75

Metric

75 x 162

EXT ARMA HBC

222

70

Metric

75 x 162

EXT ARMA HBC

241

76

Metric

75 x 162


PERFORMANCE ADAPTERS

Performance Adapters are included. Sprindex coils fit a wide variety of shocks, but you must use the Performance Adapter for most of them. Our Performance Adapters both improve the fit between the coil and your shock and are made of low friction Delrin to improve shock performance by allowing the spring to twist during high deflection. See bottom of Performance Adapter for direction of which adapter you should use. For Rockshox, no adapter is necessary but we recommend you use the Performance Washer Adapter for shock performance.

COIL DIRECTION

The Sprindex coil can be installed in either direction and should be installed in the direction that provides the best adjusting access. If your entire shock has good access, then install the Sprindex with the Dial away from the piggyback for easiest hand access.

ADJUSTING SPRING RATE

To adjust the spring rate, hold the coil with one hand and twist the Dial with your other hand or vice versa. The spring rate value is identified by the printed number on the coil displayed through the Dial opening. Preload is not a substitute for a spring that is too weak.

Metric Spring Rate Conversion

Spring rate is shown in pounds per inch (lb/in) on Sprindex coils. Below is a conversion from lb/in to N/mm.

Lb/in

350

360

370

380

390

400

410

420

430

440

450

N/mm

61

63

65

67

68

70

72

74

75

77

79

Lb/in

460

470

480

490

500

510

520

530

540

550

560

N/mm

81

82

84

86

88

89

91

93

95

96

98