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

[CSG Mike]

Originally Posted by FR-S Matt

So I have my Tarmac 0's on, absolutely love them. I got one small alignment with the stock LCA's, but now I have SPC LCA's to help with the camber in the back and I was also worried about the toe. Should I go with some SPC camber bolts up front and do those let me go a little negative? I know the stock ones let you adjust back to 0, but nothing negative camber.

Also, do I need to worry about UCA bushings on the rear or am I okay with only using the SPC LCA's? I know they are a pain to install, but I definitely don't want to put heavy strain on a part and have it go out on me later.

My car is a daily driver, occasionally drive spirited here and there. Looking for some great advice on what kind of camber I should aim for without ruining my tires. I've got a square setup, and roughly a 1.3-1.4" drop for a flush look on 18X9.5's, 245/35.

With wear in mind, I would recommend adjusting your camber based on whether your inner or outer edge (of the tire) is wearing faster. If the outer is faster, add more negative camber. If the inner is faster, take out negative camber.

Keep in mind, toe is what really chews up tires, not camber.

Everyone's setup is different, so everyone's alignment will be slightly different.

Do you have front camber plates? Are you comfortable with having a looser rear?

-1.25 front camber (can be done with camber bolts only), and -1.5 rear camber (within reach of your setup) should be a good starting point. Inspect your tires regularly, and adjust camber accordingly.

0 front toe, and rear toe to taste. 0 rear toe will yield the least tire wear, but also the loosest (least stable) car. 1/16" or 1/8" total toe-in may be a good compromise. AFAIK, the stock FRS comes with 5/32" total toe-in, while the BRZ comes with 0; keep in mind the two have a VERY different spring rate balance front/rear.

[solidONE]

Awesome, @Wepeel! Thanks for going though the trouble of putting that together.

[Pete156]

I have installed Buddy Club race spec coil overs on my BRZ. The dampening is OK but the springs are too stiff for the street unless I wear a bite guard. Any suggestions where I might shop for a softer set of springs for these dampers?

[CSG Mike]

Originally Posted by Pete156

I have installed Buddy Club race spec coil overs on my BRZ. The dampening is OK but the springs are too stiff for the street unless I wear a bite guard. Any suggestions where I might shop for a softer set of springs for these dampers?

If you can get specs for the springs, we can source them for you. We are direct with Hyperco, Swift, and Eibach, and I'm sure we can find the exact spring you need between the three.

[RYU]

Gentlemen, just a small public service announcement.

This is hands down my favorite thread on here. Mike and Andy are providing invaluable feedback to us free of charge because they love Motorsports and love the community. yet, we all need to make a living so please extends your thanks with at least letting them earn your business. their prices are great and their support even better! they are enthusiasts first but also vendors.

thanks for reading. carry on

$0.02

[FR-S Matt]

Originally Posted by CSG Mike

With wear in mind, I would recommend adjusting your camber based on whether your inner or outer edge (of the tire) is wearing faster. If the outer is faster, add more negative camber. If the inner is faster, take out negative camber.

Keep in mind, toe is what really chews up tires, not camber.

Everyone's setup is different, so everyone's alignment will be slightly different.

Do you have front camber plates? Are you comfortable with having a looser rear?

-1.25 front camber (can be done with camber bolts only), and -1.5 rear camber (within reach of your setup) should be a good starting point. Inspect your tires regularly, and adjust camber accordingly.

0 front toe, and rear toe to taste. 0 rear toe will yield the least tire wear, but also the loosest (least stable) car. 1/16" or 1/8" total toe-in may be a good compromise. AFAIK, the stock FRS comes with 5/32" total toe-in, while the BRZ comes with 0; keep in mind the two have a VERY different spring rate balance front/rear.

Front camber plates no, using stock tops. I might go the route with the SPC camber bolts. That should allow a little negative camber over the stock adjustable ones.

Thanks for the advice on the toe. The SPC LCA has a toe kit with it and I'll probably adjust it to those specs you provided. Unlike many who enjoy losing the back end, I like my grip! Toe up front will stay 0. Definitely would like a little negative camber to match my rears, but not a lot.

[utekineir]

Originally Posted by RYU

Gentlemen, just a small public service announcement.

This is hands down my favorite thread on here. Mike and Andy are providing invaluable feedback to us free of charge because they love Motorsports and love the community. yet, we all need to make a living so please extends your thanks with at least letting them earn your business. their prices are great and their support even better! they are enthusiasts first but also vendors.

thanks for reading. carry on

$0.02

Fully agree

As a lurker this thread is fantastic.

On my end, I'd like to see the car lower, but this is the first car i've had that the suspension hasn't really felt lacking out of the box on.

Dd on shit roads, limited time available for the track/autox life.

Doesn't feel right to rock the boat just for cosmetics.

[OICU812]

Originally Posted by utekineir

Fully agree

As a lurker this thread is fantastic.

On my end, I'd like to see the car lower, but this is the first car i've had that the suspension hasn't really felt lacking out of the box on.

Dd on shit roads, limited time available for the track/autox life.

Doesn't feel right to rock the boat just for cosmetics.

Understood I have crap roads to. But I think the consensus is if done right there no real penalty. It depends on needs for sure. Some can live with wheel gap I couldn't deal with the 4x4 look myself. Honestly if this car had came stock only 1" lower I would never have touched a damn thing and I don't think you'd see half the options in relation to suspension exist. Maybe I'm off my rocker but I'm willing to bet many here would've never touched anything if it had been inch lower off boat.

[ZDan]

Originally Posted by solidONE

I think an actual formula for calculating wheel rate would help me better wrap my mind around that.

It's better to use geometry (CAD helps a lot!), as the formula you'd have to use to account for all the angles would be a PITA. Suffice it to say, it's not as easy as taking ratios of a few measurements. The motion ratio *changes* throughout suspension stroke, it is not fixed.

Edit: I'm just going to leave this link here for @Dimman , @Wepeel and @ZDan. According to this guy that created the PDF file linked, motion ratio on a mac stut system is dependent on the centerline location of the wheel, thus wheel offset. [backs away slowly]

He's doing fine, but then he makes the same basic mistake that I made with Figure 1, that a strut is analogous to a swing axle. It's not. I totally agree with his statement not to assume 1:1, but his diagram is not correct for getting a strut motion ratio. His D1 and D2 ratio is just wrong.

FWIW, I just did a simple model with a 300mm LCA, strut at 15degrees initial angle, with different offset wheels placing centerline ~325mm and 375mm outboard from the inner LCA pivot. I.e., 50mm difference in offset, 50mm different scrub radius.

Going by D1/D2, you'd have motion ratios of .923 and 0.80 respectively between the two cases. Big difference.
Correctly modeling the geometry (the critical difference is that in the correct model, the hub doesn't rotate with the LCA, but with the strut, which isn't rotating nearly as much), you have motion ratios of 0.95 and 0.93. Practically the same.
If the strut were infinitely long, they *would* be the same.

Another thing worth pointing out: Struts will continue to gain negative camber in bump until the lower control arm angle is *perpendicular* to the strut. They do NOT start to lose camber past LCA going horizontal.

[Calum]

Originally Posted by CSG Mike

With wear in mind, I would recommend adjusting your camber based on whether your inner or outer edge (of the tire) is wearing faster. If the outer is faster, add more negative camber. If the inner is faster, take out negative camber.

Keep in mind, toe is what really chews up tires, not camber.

Everyone's setup is different, so everyone's alignment will be slightly different.

Do you have front camber plates? Are you comfortable with having a looser rear?

-1.25 front camber (can be done with camber bolts only), and -1.5 rear camber (within reach of your setup) should be a good starting point. Inspect your tires regularly, and adjust camber accordingly.

0 front toe, and rear toe to taste. 0 rear toe will yield the least tire wear, but also the loosest (least stable) car. 1/16" or 1/8" total toe-in may be a good compromise. AFAIK, the stock FRS comes with 5/32" total toe-in, while the BRZ comes with 0; keep in mind the two have a VERY different spring rate balance front/rear.

I'm often surprised to see 0 toe recommended for this platform, but it seems to be the going opinion. I'm used to running a little toe in so that bushing deflection will bring the dynamic toe to zero while the car is moving.
With that in mind do your preferred alignment settings change with stiffer/less deflecting bushings?

[CSG Mike]

Originally Posted by Calum

I'm often surprised to see 0 toe recommended for this platform, but it seems to be the going opinion. I'm used to running a little toe in so that bushing deflection will bring the dynamic toe to zero while the car is moving.
With that in mind do your preferred alignment settings change with stiffer/less deflecting bushings?

I have no idea... we haven't tried them

The 0 rear toe recommendation comes from the inherent stability of the platform, and the way it's designed. I certainly don't run 0 toe on my S2k...

[RYU]

Originally Posted by CSG Mike

I have no idea... we haven't tried them

The 0 rear toe recommendation comes from the inherent stability of the platform, and the way it's designed. I certainly don't run 0 toe on my S2k...

And I run a total toe of 4mm in my other Honda.

Talk about tire wear McFly!

[CSG Mike]

Originally Posted by RYU

And I run a total toe of 4mm in my other Honda.

Talk about tire wear McFly!

That's almost exactly what I run on my Honda...

[ZDan]

Regarding toe...

I tried running a lot of rear toe on my '01, and it sucked, bad, for everything. Worse tire wear, worse straight-line stability in dicey conditions, worse turn-in, worse everything.

In my experience with the AP1, minimal toe is FAR preferable to maximal toe. 0.15 degrees total was totally predictable and driveable for me, while on the high side at 0.64 degrees wear was outrageous and the car's handling was atrocious over bumps and in wet/inundated conditions.

More toe doesn't necessarily give more "stability", though that was preached for a long time at s2ki...

Anyway, I can't speak for the 86, but I would definitely first try to optimize the car around minimal, near-zero toe all around. Having the tires grind away working against each other is IMO a poor utilization of the most valuable traction-generating assets we have!