CSG and RCE tag-team suspension Q&A thread! Ask us anything!

[SubieNate]

Originally Posted by Kostamojen

First time driving on the freeway after installing Racecomp Yellows and my new wheels/tires (similar sizing to the Racecomp BRZ with the BBS's) and my steering feels very loose when cruising at speed...

Any idea what caused this?

Just a guess, but did you align it afterwards? Toe out cab make a car feel really loose.

[Kostamojen]

Originally Posted by SubieNate

Just a guess, but did you align it afterwards? Toe out cab make a car feel really loose.

Thats what I was thinking since its not aligned yet, but I want to make sure its not something else to do with the electronic steering...

[7thgear]

absolutely get it aligned, the forces involved in 4 pieces of mass spinning in different directions at high speeds make for one hell of a ride

[solidONE]

Speaking of alignment. Anybody have some good idea for easy (relatively) do it yourself quick alignment checking devices or methods that they use or recommend?

[7thgear]

if it drives straight and doesnt shake, keep on trucking

[Kostamojen]

Originally Posted by 7thgear

absolutely get it aligned, the forces involved in 4 pieces of mass spinning in different directions at high speeds make for one hell of a ride

Oh im getting it aligned, just ran out of money for the time being. I've been swapping suspension bits and doing wheels/tires on my Subarus for almost 15 years now. The car drives straight and true and I'm pretty good about getting camber settings optimal right off the bat, but I cant check toe without a real alignment obviously.

Still curious though if anyone has any issues with the electronic steering and suspension mods and such.

[7thgear]

you've been eyeballing your alignments for 15 years? good lord

[Racecomp Engineering]

Originally Posted by 7thgear

you've been eyeballing your alignments for 15 years? good lord

I think he just means he can get it close when reinstalling which is true sometimes, but yes get that alignment Kosta! Shouldn't have any weird issues like that.

- Andy

[solidONE]

Originally Posted by Kostamojen

Oh im getting it aligned, just ran out of money for the time being. I've been swapping suspension bits and doing wheels/tires on my Subarus for almost 15 years now. The car drives straight and true and I'm pretty good about getting camber settings optimal right off the bat, but I cant check toe without a real alignment obviously.

Still curious though if anyone has any issues with the electronic steering and suspension mods and such.

Toe is the easiest one to measure yourself. All you need is a couple of straight edges about the length of the diameter of your wheels and a couple of measuring tapes. It's camber and caster that require special tools.

[Wepeel]

Originally Posted by solidONE

Speaking of alignment. Anybody have some good idea for easy (relatively) do it yourself quick alignment checking devices or methods that they use or recommend?

I do my own alignments, using string and bubble levels.

I use the bubble level to determine camber - of course the ground has to be flat. But touch the level to the bottom of the wheel (wheel, not tire), use bubble to verify it is vertical, then measure the distance to the top of the wheel. Both the 17" OEM wheels and Enkei RPF1 are actually 47mm in diameter, so with some geometry you can determine the camber degrees by the distance from the top of the wheel to the level. The conversion for a 47mm wheel is 1mm=0.12 degrees. So 2 degrees would be about 17mm, 3 degrees is about 25mm (an inch).

For toe, the setup is the important part. Measure the track at the bottom of the tires in the front and back. Getting the exact center of the tire isn't important as choosing easy points to measure between, and keep it consistent how you do it front and rear. Using the edge of the first tread block from the shoulder is convenient usually. So the absolute value isn't important, just the difference between front and rear.

This is the first part in determining how to set up the strings. If the wheels are evenly cambered, you don't have to do anymore. Set up the strings parallel to the sides of the car using jackstands at the end. Pull tight so the string is under some tension Raise the string to the middle centercap level of the wheel. If you measured a front track width as 10mm wider than the rear, then the strings will need to be 5mm farther away from the front than the rear on each side. This will take 2 or 3 iterations on each end to get both ends of the measurement correct.

Now you can measure the distance from the front of each wheel from the string and compare it to the distance to the rear of each wheel from the string. If they are even, it's zero toe, if the front of the wheel is closer to the string than the rear of the wheel, then it's toe out, and if the rear of the wheel is closer to the string than the front of the wheel, then it's toe in. Do this of all 4 wheels. Just like the camber relationship, 1mm difference between front and rear of the wheel is 0.12 degrees.

Now, if the wheels are cambered differently, you will need to slightly modify the procedure to set up the strings to account for the difference in track width at the center of the wheel (since we measured from the bottom). You can use the same method that we used for camber measurement, but just measure distance from the vertical level to the center of the wheel (instead of the top). But the geometries are all the same, so a wheel with 2 deg of camber will tilt inboard about 8mm at the wheel center, and a wheel with 3 deg of camber will tilt inward about 13mm. If you have -2 in the rear and -3 in the front, you need you'll have an additional delta to stagger the wheels by of (13-8)/2=2.5mm. Note this is really small when compared to the wheelbase of 2,540mm, so if there's a slight error here it's almost negligible.

[solidONE]

Sweet! Thanks @Wepeel!

[Kostamojen]

Originally Posted by 7thgear

you've been eyeballing your alignments for 15 years? good lord

No, you misread what I typed. I always get "real" alignments, but Ive been doing this enough to where when I actually get the alignment, its not very far off and doesn't require much adjustment to be perfect.

[was385]

Originally Posted by Kostamojen

First time driving on the freeway after installing Racecomp Yellows and my new wheels/tires (similar sizing to the Racecomp BRZ with the BBS's) and my steering feels very loose when cruising at speed...

Any idea what caused this?

Alignment is definitely your first step because that's most likely the issue. I just did the same install and I can't imagine anything you would have done that would have caused that issue. I've driven mine two days on an alignment that has been killed by potholes this winter and the added grip of new tires combined with increased responsiveness of the springs has made for a pretty wild highway ride on a car that isn't properly aligned.

[leicaboss]

Okay guys, back again...

I have a suspension install coming up soon and I want to get my camber settings dialed in.

Here's what going on my car:

• Swift Sport BRZ spec springs (3.8/kg Front + 4.5/kg Rear)
• SPC Lower Control Arm (w/ Toe Adjustment)
• SPC Front Camber Bolts
• Resulting drop will be about 1"

Here's what I'm looking to get out of the car:

• 80% daily driving, 20% spirited twisties, HPDE, AutoX
• Running stock wheels/tires for the time being
• Maintain "BRZish" handling that is forgiving for a beginner; not too tail happy!

I'd appreciate any feedback for the suggested all-around camber setting it seems I'm looking for Thanks in advance.