BLITZ springs

Looks great lowered and with 18's. I wish I could see that setup with the kenstyle body kit.

 

Thanks for the measurements and pics, your Prius looks great! How are the stock shocks handling the lowered ride height and increase in spring rate?

 

drees - I was looking at the spring rates too and comparing them against those for the Standard Prius and Touring Prius, and was wondering if you knew whether, as a general matter, increased spring rates in the springs result in a softer ride (as OP mentioned in his initial post)?

 

Stiffer springs always result in a stiffer ride. Especially when those springs result in a reduction in ride height without any other changes.

Whether or not it feels stiffer depends primarily on your butt-dyno where results can vary dramatically between people as well as a huge number of other factors: vehicle weight, shock valving, suspension design, bushing hardness, outside temperatures, ambient noise levels, etc.

While I haven't measured travel or investigated the Prius too closely, I suspect it's similar to all the other strut-based and fixed axle-based vehicles I've looked at.

For example, if we examine the struts in the front, we've got a couple different primary suspension components which control wheel motion - strut, spring, "bump stop" (ignore the sway bar). Your typical strut has somewhere around 6-8" of total travel. Let's say it's 8", so at ride height, it's usually somewhere close to the middle of that so you have 4" of compression travel and 4" of droop travel.

Now what happens if you lower the car an inch is that you've reduced your compression travel by 25% and now only have 3" of compression travel left. If you want to keep the car from bottoming out under similar conditions as before, you have to increase the spring rate by at least 25%. You also will tend to start engaging the bumpstop (typically is around 2-3" long) more frequently, which normally has a spring rate that is pretty progressive, meaning that the further you get into it the faster overall spring rate (spring+bumpstop) gets.

As for the resulting ride - most smaller bumps that only move the wheel a small amount will probably not feel much different than before. But bigger bumps which cause the wheel to get into the bumpstop which causes the spring rate shoots up rapidly will definitely result in the car reacting faster to the bump which will typically feel harsher. Combined with the fact that you haven't increased shock damping to compensate for the increase in spring rate can result in less wheel/vehicle control and the sensation of "bouncing".

Sudden drops in the pavement will also result in the vehicle falling more quickly to the lower pavement level.

So overall with a slightly lower, stiffer spring - smaller bumps should be a bit harsher - bigger bumps/drops will definitely be felt more. Vehicle will react more quickly to direction changes. But don't expect body roll to necessarily decrease (that brings up a whole 'nother suspension topic - roll centers)!

 

Stiffer/lower springs can wear out shocks/struts sooner since the stiffer rate can put more load on the shocks/struts. If they are relatively new, I wouldn't worry about it, it's really more of a concern on high mileage shocks/struts which are close to the end of their life anyway.

If you notice that the car takes longer to settle on high speed undulations, then you'll know the shocks have reached the end of their useful life.

I didn't see that Koni had any inserts for the Prius (at least, not on their website).

I do see that KYB at least has the GR-2 (OE replacement style) something for the 2004 Prius and the rears are likely the same for the 2005-2008, but the front struts may be different?

 

i would think that your mileage would be slightly better. you should have less rolling resistance.

also id be a lil a lil worried that the springs would ware out my stock shocks faster. it might really be a non issue though.

 

very slick look.

what do all the prius wheel owners think about Gram light rims? tirerack say's they will fit in either a 16 or 17 with 205 tires. Would I need new spring's if i get these tires/wheels.

Im aware of the sensor..which is more reason why I have yet to get aftermarket wheels...cost

 

did you have to do an alighnment? can you please let me know. here is my ride on a 17x8 rear and 17x7.5 front. i would love to drop it like yours.
http://i2.photobucket.com/albums/y36/slkgitong/IMG_4152.png
http://i2.photobucket.com/albums/y36/slkgitong/IMG_4149.png

thanks