This is why you MUST install Tanabe DF210 TDF185 lowering springs!!!
Member
Joined: Dec 2014
Posts: 605
From: CD
You either get a front end alignment (2 wheels).
or a thrust alignment (4 wheels)
When making suspension changes like a drop a 4 wheel thrust alignment tis normally the right route.
A shock is a tube with a piston it, the bit that wears out normally is the valve stack which has little to do with exact life, length of stroke is not what wears a shock its the number of strokes per second @ a given maximum velocity, as well as the service life of the valve stack, you can buy $2000 a corner Penske's or Bilstein's and wear out the shock in a couple hours of track time. I replace the valve stacks on a open wheel road race car about twice a season or when the car loses stick. On a sprint car I've replaced shocks between 20 minute sessions. Work the shock harder and more heat is generated, the oil squeezing though the valving acts much like oil in a gearbox wearing out the lube.
YMMV and good luck on the project!
or a thrust alignment (4 wheels)
When making suspension changes like a drop a 4 wheel thrust alignment tis normally the right route.
A shock is a tube with a piston it, the bit that wears out normally is the valve stack which has little to do with exact life, length of stroke is not what wears a shock its the number of strokes per second @ a given maximum velocity, as well as the service life of the valve stack, you can buy $2000 a corner Penske's or Bilstein's and wear out the shock in a couple hours of track time. I replace the valve stacks on a open wheel road race car about twice a season or when the car loses stick. On a sprint car I've replaced shocks between 20 minute sessions. Work the shock harder and more heat is generated, the oil squeezing though the valving acts much like oil in a gearbox wearing out the lube.
YMMV and good luck on the project!
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Member
Joined: Mar 2015
Posts: 114
From: Hagerstown
So, when deciding on lowering springs... Back to my original discussion... Choose springs engineered to be as close to the stock springs with spring rate, but a bit stiffer than stock to compensate for the decreased shock travel to prevent premature wearing out of the stock shock. The Tanabe's have that covered, increasing the spring rate 10-15% to compensate for decreased shock travel.
Member
Joined: Oct 2015
Posts: 1,465
From: Portland Or
Your right,, Keeping the spring rate close to stock will keep the spring rate and valving near design spec, you'll have a 10% stiffer(ish) ride, and a accompanying shift in compression and rebound speed as well. Heavier spring should have slower compression and faster rebound (Assuming no adjustment in shock), larger body shocks will run a little cooler for a while but under sustained use they will eventually hit a max temp, Besides using a shorter spring you can go with a similar length to stock but go softer and the car will have a higher sag to get lower as well, but you have to allow for the coil stacking vs travel. When I want a car lower I prefer to change the spring mount not the spring height. Yields more travel without the harsh buggy ride. Haven't rode in a Tanebe equipped car I use H&R or have them wound custom for track cars. Converting street to full track I find almost 2.5x the rate from stock is where I end up to get them to handle at speed. Sometime the sweet spot is quite scary. 
Low speed ride suffers greatly..
Low speed ride suffers greatly..
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Member
Joined: Mar 2015
Posts: 114
From: Hagerstown
Good technical info. Thanks for the feedback. There is certainly a lot of factors when making modifications to a suspension. For practical everyday purposes, you either keep the car stock or very carefully choose the right spring, not only to lower the car within limits of alignment adjustment to retain spec for normal tire wear, but also to retain a slightly higher spring rate than stock to compensate for decreased travel (to not max out the shock travel constantly) to maintain the stock shock life as close to spec as possible. I don't know of any other coil spring manufacturers that engineer their product this way like Tanabe.
Member
Joined: Oct 2015
Posts: 1,465
From: Portland Or
FWIW I've done suspension on several road race cars where the class did not allow coil overs.. It typically takes about 4 sets of springs to find the best combination.. I haven't found a formula to get me right on yet.. And tire type can move you to a whole different setup. One car I work on needs 300b per inch springs on DOT tires, but needs 800 lb springs to handle slicks..
And tire type can move you to a whole different setup. One car I work on needs 300b per inch springs on DOT tires, but needs 800 lb springs to handle slicks..
Tein
Swift
Progress
Top names in spring manufacturing follow similiar guidelines
Drop looks good though. .
Member
Joined: Oct 2015
Posts: 1,465
From: Portland Or
Its also about the source o fhb spring steel and pretty much 100% of the springs for japan source their wire for the same factory, then quality of the wrap kicks in. H&R and Eiback are sister companies if you dig way back, good products.
I have a local shop that can turn out a spring in any length and diameter and coil size I want, and when I check the springs their work is right on.. Dont ignore the small local shops, they can be your friend.
I have a local shop that can turn out a spring in any length and diameter and coil size I want, and when I check the springs their work is right on.. Dont ignore the small local shops, they can be your friend.
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Member
Joined: Mar 2015
Posts: 114
From: Hagerstown
Thanks for the great feedback! I'm really impressed with Tenabe. I will see as time goes on. The rear seems like it's too low? Idk, I guess it'd be good to check a stock Fit EX on level ground and measure the height difference and make sure it's a 2" drop in the rear and not more.
Member
Joined: Oct 2015
Posts: 1,465
From: Portland Or
Eibach/ground control make spacers that can be put under the spring, to adjust the height without a full coil over.. If you need < 1" they work well. You need to shop out of their race products catalog for them..
Member
Joined: Jan 2015
Posts: 358
From: Murica
Depends on your ride preferences. It'll eek out some of the bumpiness of the ride, but I'm not one to care about that too much. Sticking with stock for now.
