Best Suspension Review Project

 © 2014 Chris Shenefield and RedShift Motorsports, Inc.  All rights reserved.


2006-11 Honda Civic

Coilover Spring Comparison


The information below shows spring rates of the coilovers we have tested.  A higher spring rate means the springs are stiffer and that has the following affect on the car:

  1. It will have a more stiff ride.

  2. It will lean in turns less (stay flatter to the road).

  3. It will dive less under breaking and squat less under acceleration.

  4. It will transition faster which means it will take a "set" faster as you enter a turn.

  5. It will be less comfortable over rough roads.

So, if you want to improve handling, you want to increase spring rates.  However, increasing spring rates makes the car less comfortable.  The old adage holds true here....  you can't have it all.  Although it should be stated that one of the best ways to setup a street car to be comfortable but also handle well is to run softer springs and good adjustable shocks, where the shocks create the stiffness as you adjust them to a stiffer setting.  If the shocks are set soft and the spring are fairly soft, then you can have a nice comfortable car for your commute that can be transformed with the shock adjustment into a canyon carver or weekend track car.  Still, like there is no replacement for displacement when making power, there is also no replacement for higher spring rates to make the car handle better (although not too stiff).  So, adding some spring rates is usually a good idea when you are looking for a little more performance from your Civic.

Here are the spring rate charts, and I have provided some simple conclusion below the charts.  I have added oversized "markers" on the lines to show how far the spring is compressed when the car is at rest.  That is a good reference point to show the spring rate you will see when driving down a perfectly smooth road.  When the wheel moves further into the wheel well, the spring is also compressing more; so you have to look further right on chart to see how the spring rate changes as the spring compresses.



So, a couple of simple conclusions, from soft (comfy) to stiff (track oriented):

  1. Si HFP Springs (Reference) (215F/270R) - The Honda Factory Performance (HFP) springs for the 06-11 Civic Si Coupe are an excellent reference point for this spring testing. Compared to the stock 06-11 Si spring rates of 200F/230R, the HFP springs have very mild spring rates.

  2. KW Variant 1 (240F/305R) - The softest sprung coilover kit tested to date is the KW V1, and it's wonderful!  KW also makes the "Suspension Techniques" coilover, and it's more or less identical to this KW V1 but at almost half the price.  The Suspension Techniques (ST) kit is EASILY my favorite street kit because of its great quality, great comfort, excellent handling, and amazingly low price ($800'ish).  You have to have a very good reason to not get the ST Coilover frankly.

  3. Raceland (275G/345R) - Raceland's reputation for super-cheap coilovers is quite well known.  I am generally not a fan of super-cheap parts in places on cars that can cause serious problems if they fail.  I've seen a couple failures on Raceland coilovers too; so I have real experience with their quality issues.  Still I tested them on our 07 Civic test car, and I actually liked how comfortable they were....very comfortable.  The springs rates are very nice.  But I just cannot get around the cheap build quality.  So, if you only have $400 and have to get the Racelands, they will be very comfy and you will probably be happy in the short run.  Just don't expect them to last very long or impress you with quality... in fact, be prepared to let "just good enough" be ok.

  4.  Tein Street Basis/Advance (330F/370R) - This is another coilover kit I like very much.  The rear springs came up in our testing a bit softer than what Tein advertises (they measured for us at 370 and Tein advertise 448).  So, is that a quality issue or did they change something?  I'm not sure.  What I received and installed I liked very much.  But they are about $100 more than the ST coilover and not any better....so why?  Exactly....ST still is my strong leader in this category.

  5. ISC (360F/305R) - This kit is marketed as having 8k front and 5.5k rear springs.  And that doesn't make much sense... too much spring in the front for such a low rear rate.  But the result of the test showed 6.5k front and 5.5k rear, which makes more sense.  What would make even more sense is 5.5k front and rear.  I wish these guys offered better spring rates because the kit is nice and the shocks are really excellent.  As the kit is now, if you actually get an 8k front spring, it'll feel too hard....  so I hope you get what we got (6.5k) because it's a really nice comfort setup like this.

  6. Buddy Club N+ (390F/370R) - I really like this kit overall in how it feels and how it handles.  Still I think the rear spring rates could be higher for it to be a really superb dual-purpose street/track kit.  However, (and this is important to consider) the fact that it has slightly lower rear spring rates makes it more comfortable as a street kit....  still, like the ISC kit above, this car likes higher rear rates than front rates for best handling; so this kit is great... but the rear spring rates really should be higher.  Would it be better performance wise than the ST coilovers below?  Absolutely.  Will it be as comfortable?  Definitely not.  If you want a street kit, I still recommend the ST.  If you want the best dual-purpose street/weekend-track kit, a RedShift Koni Sport coilover is still the best...and the D2 below is a close 2nd.  But this Buddy Club N+ kit is still very nice overall too.

  7. D2 (410F/440R) - Other than the ST Coilover, this is my other favorite coilover kit.  But this one is a little different in that it runs stiffer springs than the ST kit and adjustable shocks that work really well and don't make the car overly harsh.  I like this better for a performance setup than the Buddy Club N+, and this one is almost $200 cheaper than the Buddy Club N+!!!.  Is it as good as the RedShift Koni Sport coilover for performance?  It's close.... and you'll save over $600.. hard to ignore.  I recommend this one over the RedShift kit if you like the spring rates it provides.

  8. Skunk2 Pro S2 (non-adjustable shocks) is actually quite a good performance spring rate, but I know from testing this kit that the front shocks are too stiff for the stock upper front strut mounts, and that causes bouncing in the front suspension that drove me insane when I tested them.  So, fix the front upper strut mounts, and you have a great performance spring rate.  It would be great on the track... but you have no way to turn the shocks down; so you cannot soften it up at all.  The D2 is a better option I think.

  9. Skunk2 Pro C (adjustable shocks) is definitely more a track kit with those high spring rates.  If you get this kit for the street, you'll probably hate it before long.  But it will be super fast on track.

****Note:  I haven't done testing of the RedShift coilover kit yet, but I will.  Important thing to know about it is that it uses linear race springs of any rate; so you chose whatever spring rate you want....  and the Koni shocks are truly excellent (with a lifetime warranty).  They are expensive for sure at $1600, but if you want exactly what you want, it is an excellent custom tailored setup for very specific requirements (either comfortable or track oriented).... the RedShift kit is like a custom tailored suit....not for everyone but it is special just because you get exactly what you want.

I hope this review has helpful.  If so, please support our efforts.  Thanks!   -Chris Shenefield