Progressive Springs increase in rate late in stroke to provide additional bottom-out support and open up the use of coil shocks on frames previously only suited to air shocks.

As with our Enduro SL springs, these springs are offered in a single free length per rate that fits most shocks from 200mm (7.875") to 230mm.* They accommodate up to 65mm of shock stroke. A 1.5" / 38mm ID fits our Hazzard natively and spacer kits are available to use with other makes and models.

*See compatibility on our Coil Spring Spacer page. Some shock length and spring rate combinations require spacers to increase the total effective spring length and engage the threading on the shock body and to account for allowable max preload. Reference the listed free lengths and measure your shock to make sure any spring will fit.


Shipping Note: 600+ Progressive Springs are currently on back order with expected availability in late May. You may still place an order and we will notify you once it ships. Thank you!


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Spring Rate and Length Information (select a tab for more info)

  • 300+
  • 350+
  • 400+
  • 450+
  • 500+
  • 550+
  • 600+

Effective base rate:
300 lb/in

Approximate linear-spring rate equivalent at 25% sag (rounded to nearest 25 lb. increment):
...on 51mm (2.0")stroke shock: 275
...on 55mm / 57mm (2.25") stroke shock: 275
...on 60mm stroke shock: 300
...on 63mm (2.5") / 65mm stoke shock: 300
 
Approximate linear-spring rate equivalent at 90% travel (rounded to nearest 25 lb. increment):
...on 51mm (2.0")stroke shock: 325
...on 55mm / 57mm (2.25") stroke shock: 325
...on 60mm stroke shock: 400
...on 63mm (2.5") / 65mm stoke shock: 400
 

Dimensions:
1.5" ID, 126mm

Weight:
383 g

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Effective base rate:
350 lb/in

Approximate linear-spring rate equivalent at 25% sag (rounded to nearest 25 lb. increment):
...on 51mm (2.0")stroke shock: 350
...on 55mm / 57mm (2.25") stroke shock: 350
...on 60mm stroke shock: 350
...on 63mm (2.5") / 65mm stoke shock: 350
 
Approximate linear-spring rate equivalent at 90% travel (rounded to nearest 25 lb. increment):
...on 51mm (2.0")stroke shock: 375
...on 55mm / 57mm (2.25") stroke shock: 400
...on 60mm stroke shock: 400
...on 63mm (2.5") / 65mm stoke shock: 400
 

Dimensions:
1.5" ID, 129mm

Weight:
404 g

Effective base rate:
400 lb/in

Approximate linear-spring rate equivalent at 25% sag (rounded to nearest 25 lb. increment):
...on 51mm (2.0")stroke shock: 400
...on 55mm / 57mm (2.25") stroke shock: 400
...on 60mm stroke shock: 400
...on 63mm (2.5") / 65mm stoke shock: 400
 
Approximate linear-spring rate equivalent at 90% travel (rounded to nearest 25 lb. increment):
...on 51mm (2.0")stroke shock: 450
...on 55mm / 57mm (2.25") stroke shock: 450
...on 60mm stroke shock: 450
...on 63mm (2.5") / 65mm stoke shock: 475
 

Dimensions:
1.5" ID, 129mm (+/- 2.5mm) length

Weight:
412 g

Effective base rate:
450 lb/in

Approximate linear-spring rate equivalent at 25% sag (rounded to nearest 25 lb. increment):
...on 51mm (2.0")stroke shock: 425
...on 55mm / 57mm (2.25") stroke shock: 425
...on 60mm stroke shock: 425
...on 63mm (2.5") / 65mm stoke shock: 425
 
Approximate linear-spring rate equivalent at 90% travel (rounded to nearest 25 lb. increment):
...on 51mm (2.0")stroke shock: 500
...on 55mm / 57mm (2.25") stroke shock: 500
...on 60mm stroke shock: 500
...on 63mm (2.5") / 65mm stoke shock: 525
 

Dimensions:
1.5" ID, 134mm (+/- 2.5mm) length

Weight:
477 g

Effective base rate:
500 lb/in

Approximate linear-spring rate equivalent at 25% sag (rounded to nearest 25 lb. increment):
...on 51mm (2.0")stroke shock: 475
...on 55mm / 57mm (2.25") stroke shock: 475
...on 60mm stroke shock: 475
...on 63mm (2.5") / 65mm stoke shock: 475
 
Approximate linear-spring rate equivalent at 90% travel (rounded to nearest 25 lb. increment):
...on 51mm (2.0")stroke shock: 575
...on 55mm / 57mm (2.25") stroke shock: 575
...on 60mm stroke shock: 600
...on 63mm (2.5") / 65mm stoke shock: 600
 

Dimensions:
1.5" ID, 137mm(+/- 2.5mm) length

Weight:
523 g

Effective base rate:
550 lb/in

Approximate linear-spring rate equivalent at 25% sag (rounded to nearest 25 lb. increment):
...on 51mm (2.0")stroke shock: 525
...on 55mm / 57mm (2.25") stroke shock: 525
...on 60mm stroke shock: 525
...on 63mm (2.5") / 65mm stoke shock: 550
 
Approximate linear-spring rate equivalent at 90% travel (rounded to nearest 25 lb. increment):
...on 51mm (2.0")stroke shock: 650
...on 55mm / 57mm (2.25") stroke shock: 650
...on 60mm stroke shock: 675
...on 63mm (2.5") / 65mm stoke shock: 675
 

Dimensions:
1.5" ID, 141mm (+/- 2.5mm) length

Weight:
572 g

Effective base rate:
600 lb/in

Approximate linear-spring rate equivalent at 25% sag (rounded to nearest 25 lb. increment):
...on 51mm (2.0")stroke shock: 550
...on 55mm / 57mm (2.25") stroke shock: 550
...on 60mm stroke shock: 550
...on 63mm (2.5") / 65mm stoke shock: 575
 
Approximate linear-spring rate equivalent at 90% travel (rounded to nearest 25 lb. increment):
...on 51mm (2.0")stroke shock: 675
...on 55mm / 57mm (2.25") stroke shock:700
...on 60mm stroke shock: 700
...on 63mm (2.5") / 65mm stoke shock: 725
 

Dimensions:
1.5" ID, 143.5mm (+/- 2.5mm) length

Weight:
628 g