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Hello All,

Thank you for all your interest in our products.

In previous posts, 7thGen forum members have questioned the reasoning on our decision to use certain spring rates on our coil-overs.

Coil-over part numbers 75.1007 and 75.1006 both use front: 350 lbs and rear: 650 spring rates. PROGRESS used the platform of the late model Civic Si as the starting point of the engineering/development process. Stock spring rates for the Civic Si were measured at front: 253 lbs and rear: 444 lbs . Although the weight of the EX, LX and similair U.S. and Candians model varied from 2500 lbs to 2900 lbs, the suspension geometry remained the same.

The semingly high spring rate is used to initiate more oversteer due to how far in-board the rear suspension sits versus the front. The 7th Generation Civic, has a large difference in motion ratio. Meaning the way the front suspension cycles (strut) versus that of the rear (coil over shock) suspension.

I hope this brief bit of info helps clear up some questions. For any further questions or concerns, feel free to contact either myself or visit us at www.progressauto.com (note: site is in the process of being updated)

Thank you again for your interest and support.

Silvio M.
silvio@progressauto.com
Product Manager/International Sales
The Progress Group, Inc.

 
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^^^ thank you very much for registering.........i am sure that there are many members that have questions about these coilovers and i hope that u keep in contact to answer them

and to tell u the truth......the spring rate on the rears is keeping me from buying them.........i wanna get to the place i am going without throwing out my back

 
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Thanks for the post, good info. Question though, do you by chance have data on the stock spring rates for the non SI Civics? The reason I ask is that most users here are non SI owners and the data would give us something to compare your rates to. Many thanks.