Springs for my Ride...

User avatar
jondee86
Moderator
Posts: 2352
Joined: Fri Jan 11, 2013 10:21 pm
Location: Wellington, New Zealand

Springs for my Ride...

Postby jondee86 » Sun Jul 13, 2014 11:39 pm

This post follows on from Talking about Springs.

Image

Changing the springs on your car is a choice that you make to get
the result that you want. Maybe you want LOW for looks. Maybe you
want FIRM for good handling. Maybe you want SOFT for a limo ride,
or maybe you want HARD for easy sliding. The choice is yours, but
just remember there is always a degree of compromise involved.

The job of the spring is to store the energy used to push a wheel up when
your car rides over a bump, and then push the wheel back down on the
other side of the bump. The shock absorber (damper) controls the rate
at which the wheel drops back down (rebound). The springs hold your car
up, so the ride height of your car is set by the springs.

For the springs to do their job, they must be able to compress freely when
the car hits a bump. Consider one front wheel of an AE86 that has about
300kg leaning on it and a spring rated at 5kg/mm. When the wheel hits
a small bump that generates a force of 1G the spring will compress by
300/5=60mm. If you don't have 60mm of bump travel, your suspension
will bottom out. Best case the bump stops will do their job and you will
just feel a kick in the butt. Worst case your suspension hits steel on steel
because you took the bumps stops out when you slammed your car, and
now your back hurts :(

Image

Factory springs have thin wire, big coils and lots of turns. TRD coils have
thicker wire, big coils, and less turns than OEM springs. They are designed
to be used with shortened factory strut tubes and short stroke shocks. If
you install TRD springs on standard suspension, your springs will not be
captive at full droop, and that is bad. Worst case, your rear springs can
actually fall out if you get airborne over a big bump. As a minimum you
need to install short stroke shocks to limit the droop and keep the springs
captive at all times. Uncut TRD RACE springs look like this...

Image

The point being that when you go low you are limiting your suspension
travel. That means you have to use stiff springs to stay off the bumpstops.
Coilovers typically use small diameter "racing" springs that are available
in a range of spring rates to suit the application. Good coilovers allow the
height of the car to be adjusted without pre-loading the spring. So you can
use a spring that allows sufficient suspension travel, while still being able
to set the car at the ride height you want.

Image

Spring rate and suspension travel are linked... stiff springs need less travel
and soft springs need more. Coilovers like the BC units pictured above only
have around 60mm travel above the bumpstop. Allowing 2/3rds for bump
travel, this gives 40mm of bump and 20mm of rebound. That's enough for a
1G bump with the BC 8kg/mm spring... and when you are going fast it is
pretty easy to hit 1G bumps out on the street. Don't even think about trying
to use these with softer spring rates.

So when you are considering changing the springs in your car, talk to people
who have used the same springs and rates that you want. Better yet get a
ride in their car to see how it performs and feels. Don't cut springs. Use the
factory stuff until you can do the job properly. That means changing springs
and shocks as a package if you are going more than 25mm down.

Cheers... jondee86
Give a person a fish, they eat for a day. Suggest they search before posting, and they learn a skill for a lifetime.

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.


User avatar
saiGone
Club4AG Expert
Posts: 352
Joined: Tue Apr 08, 2014 1:42 pm

Re: Springs for my Ride...

Postby saiGone » Mon Jul 14, 2014 10:56 am

Good intro to springs..... You working on a manual bro? lol
Club 4AG member since 05 (Formally SaigonsSon)

Image

User avatar
jondee86
Moderator
Posts: 2352
Joined: Fri Jan 11, 2013 10:21 pm
Location: Wellington, New Zealand

Re: Springs for my Ride...

Postby jondee86 » Mon Jul 14, 2014 3:41 pm

saiGone wrote:Good intro to springs..... You working on a manual bro? lol

These posts are intended to try and help people who are looking at
changing the springs on their cars. Unless you understand a little bit
about springs, and how springs and shocks work together, it is easy
to end up with something that doesn't work as you had hoped :?

A car that is "slammed" by cutting the springs will be constantly on
the bumpstops. So while it may have the "look" is will be uncomfortable
to ride in, handle like a pig, and basically be dangerous to drive at speed.
On the other hand, with correctly selected springs and shocks, you can
be decently low and still have a good handling car 8-)

Cheers... jondee86
Give a person a fish, they eat for a day. Suggest they search before posting, and they learn a skill for a lifetime.

User avatar
riddleyo
Club4AG Enthusiast
Posts: 106
Joined: Sun Mar 24, 2013 4:48 pm
Location: Ohio

Re: Springs for my Ride...

Postby riddleyo » Mon Jul 14, 2014 7:01 pm

Nice info. How listing some good, well tested spring/shock set ups to start with. And then after that explaining the physics behind how the ever elusive traction brackets work. :)

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.


User avatar
jondee86
Moderator
Posts: 2352
Joined: Fri Jan 11, 2013 10:21 pm
Location: Wellington, New Zealand

Re: Springs for my Ride...

Postby jondee86 » Mon Jul 14, 2014 11:01 pm

Traction brackets are easy ;)

But there are already a thousand threads about coilovers and
shock/spring combo's for the AE86. Everyone has an opinion, so
kind of a minefield to be entering !!! Maybe I'll do something on
the AGX Camaro/SW20 combo with realistic street springs, as
I have that in my car and it does OK for the street.

Cheers... jondee86
Give a person a fish, they eat for a day. Suggest they search before posting, and they learn a skill for a lifetime.

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.



Return to “TECH: Corolla AE86”

Who is online

Users browsing this forum: No registered users and 9 guests