KW V3 Coilovers vs Spax RSX3 – *SPEC* Comparison
Spax have just released their “double” adjustable RSX3 coilovers. This is a spec comparison between the KW V3 coilovers & the Spax RSX3 coilovers to see how the RSX3 stacks up against one of the most popular coilover models available.
A word about Spax Double Adjustable Dampers
Spax is no stranger to double adjustable suspension. They have offered independent bump and rebound adjustment on their Trax Spax damper units for many years. What is different now is that they are offering the double adjustable coilovers as a ready to go off the shelf kit instead of a custom suspension component for racing.
KW V3 Coilovers vs RSX3 – The Scoring
| KW V3 | Spax RSX3 | |
| Reputation | 8 | 5 |
| Bump Rebound Independent | 10 | 10 |
| Low Speed Bump Adj | 10 | 10 |
| High Speed Bump Adj | 5 | 0 |
| Rebound Adj | 10 | 10 |
| Height Adjustment | 10 | 10 |
| App List | 6 | 6 |
| Spring Options | 5 | 10 |
| Weight | 10 | 10 |
| Price | 6 | 8 |
| Total | 80 | 79 |
Scoring Analysis
Reputation
KW is one of the most famous coilover manufacturers on the planet whereas the name of Spax is perhaps less well known outside of the UK. KW wins.
Independent Bump and Rebound Adjustment
Both coilover kits have bump and rebound adjusted separately. Draw.
Low Speed Bump Adjustment
Both kits have low speed bump adjustment. KW with 12 stages, Spax with 28 stages. Draw.
High Speed Bump Adjustment
Neither kit has adjustment for high-speed bump. KW has a high speed, non-adjustable blow off valve. I contacted Spax to ask if their dampers had separate valving for high-speed bump. Their reply did not answer the question. KW wins.
Rebound Adjustment
Both kits have adjustable rebound. KW claim infinite adjustment, Spax claim 28 stages of adjustment. Draw
Height Adjustment
Both kits appear to offer the same height adjustment range, at least on the MK1 Octavia. Height adjustment is done through an adjustable spring seat as opposed to an adjustable bottom bracket. Draw.
Application List Size
The KW V3 and the Spax RSX3 are not what can be called a mainstream coilover solution. For this reason, their application lists are focused on popular performance cars. Draw.
Spring Options
The KW V3 appears to use progressive springs in at least some of their kits. The Spax RSX3 appear to use linear rate springs exclusively. For maximum stability and performance, in my opinion, linear rate springs with helper springs are the way to go. Using linear springs also allows the user to change springs easily to almost any rate they choose. Spax wins.
Weight
Both products appear to use stainless steel bodies. Draw.
Price
For the Octavia MK1 the KW V3 costs around 1800 pounds. The RSX3 for the same cars comes in at 1400GBP. Spax wins.
KW V3 vs Spax RSX3 – Conclusion
On the face of it, the RSX3 looks to be an alternative to the KW V3 coilovers. But even taking into consideration the higher price of the KW V3, the V3 look to be the choice dampers out of these two.
Having said that, Spax not answering my question about high-speed bump valving could have cost them the victory in this comparison.
As someone who has used Spax products in the past and was extremely impressed with the quality of the product it’s a crying shame that Spax can’t make their published product information more detailed and easier to find. This is something they have been guilty of for years. The apparent lack of technical knowledge of the people answering customer enquires is also a problem. In my opinion, these two issues together must be losing Spax tens of thousands if not more in sales and it’s depriving people of experiencing Spax products on their cars. Hopefully they will fix these problems soon.
