JWL and Impact Testing Explained

We get a lot of questions about the weight of our wheels and the relevance of weight to performance and to safety.  The weight is important – this is what makes the difference to the unsprung weight.  It also matters where the weight is concentrated or reduced in order to affect the performance – the moment of inertia. Safety is critical and the authorities governing this are the JWL/JASO – you will find the JWL logo on any car or motorcycle wheel that is road legal and it is internationally recognised. A JWL wheel has to pass the impact tests that JWL defines.

Impact Testing – Understanding the Loads

In order to pass the JWL Impact Test, the IMPACT requirements are defined and clear, and must be performed on a test rig defined by JWL:

Strike Weight:

Front Wheel must withstand the impact from a weight 2.5 times the published Static Load rating.

 

BST published Static Load rating is 150kg.
Impact weight = 150 x 2.5 = 375kg.  The BST wheel can withstand an impact of 375kg.

 

Rear Wheel must withstand the impact from a weight 1.5 times the published Static Load rating.

 

BST published Static Load rating is 250kg.
Impact weight = 250 x 1.5 = 375kg.  The BST wheel can withstand an impact of 375kg.

 

Check The Facts on the Published Static Load:

Published Static Load of 180kg on a Front Wheel: the strike weight must be 450kg (180 x 2.5).

Published Static Load of 280kg on a Rear Wheel: the strike weight must be 420kg (280 x 1.5).

This is all defined in the JSAE JASO T230 (1985) publication:

The highlighted section is definitive.

Manufacturer

Wheel
Published Static
Load Rating – kg
Strike Weight
Tested – kg
Strike Weight
Required – kg
Difference
Pass JWL
Requirements
BST Black Mamba

Front
150
375
375
Yes
BST Rapid TEK

Front
155
388
387.5
YES
BST Black Mamba

Rear
250
375
375
YES
BST Rapid TEK

Rear
280
420
420
YES
Other

Front
180
225
450
-225.00
NO
Other

Rear
280
375
420
-45.00
NO