Understeering with Grimmspeed front bar
 

Just installed the Grimmspeed front tower bar. It's tough to tell yet if it feels sharper/more responsive but I definitely sense the understeer now. I'm wondering if a rear bar would correct this and restore the neutrality? Any other suggestions? It's a lease so I can't go too crazy.

Camber bolts and a front-end alignment. You can probably get to around -1 to -1.5 degrees with just camber bolts, which will be a nice improvement over the stock alignment.

Sounds good but I'm not sure I want to alter/accelerate the treadwear. Looking to keep these Primacy summer rubbers for the duration of the 3yr lease period if possible (a guy can dream)

What about just adding the rear bar?

Rear bar will only tighten the rear end up (less slop). I dont think your strut bar is making your car under-steer. It always did that but now that you added the bar you are driving into the corners harder and its just the placebo effect

Yeah, strut bars (front and rear) don't do a whole lot except for make you believe you can take a corner faster. It's not that the bar has made things that much stiffer, it's that you believe it did, so you're able to push more without that mental block kicking in.

1 or 2 degrees of negative camber shouldn't prematurely wear your tires down, either.

I think toe effects tire wear more than camber.

If you're not tracking/autocrossing/drifting the mountain pass or doing >15k miles/year the Primacy's will last. -1.5 degrees of camber won't change that. Mine made it to 30k over about 2 years and I got rid of them because I thought the grip was gone for track/autox purposes (2x HPDE's, ~4x autox). They would have been fine for another year to 45k no problem even with more autox/track abuse.

go_away is right, the car understeered before, you just weren't hard enough into the corners to feel it until now.

Rear bars aren't going to help much. I've had cars that had OEM alignment specs at -1.5 camber and never had a tire wear issue. Just make sure your toe is within factory specs and you'll be fine.

The strut bar didnt cause the understeer. This car understeers from factory. Add -1.5 camber up front and itll go away. Keep 0 toe and it'll be good for 3 years assuming you dont have a 45k mile lease lol

exactly. see my sig :laughabove:

LOL yeah I remember reading that a while back and laughing my ass off.

How often do you drive your car?

Learning to drive my car fixed my understeer issues. This is even on a staggered setup with stock alignment. I don't understand why it's always the car's fault on this forum.

Where are you driving the car to experience this? How are you managing brakes, gas, and steering?

I'm not expert but I find that keeping my foot on the gas early on in corner helps with the under steer dramatically. Quite different to drive compared to a FWD Celica I used to drive.

Thanks all. Good to know they don't cause uneven tread wear. I'll look into it. Oh, and "learning to drive my car" lol

With the amount of driving I do that's not racing, I'm not having much problem with -3.3 camber and tire wear...

And, yeah. Learning how to drive the car.

When I added camber to the front I was astounded how much more grip was available, no other changes, just front camber adjustment. Being able to drive the stock setup fast is a good skill to have but to say the car is faultless is narrow-minded.

I'm running -2.1,-1.3. I never said the car is faultless, but if you don't know how to instegate or prevent a particular situation as the driver, making the car more capable will only get you into trouble sooner. But whatever, I guess I'm too narrow minded by looking further ahead than just this.

As others have said, before spending money on a rear bar, try camber bolts and an alignment. Aim for -1.5 degrees camber in the front & 0 toe all around. I found that was a near neutral alignment at the track with the 2013 suspension on worn NT05 tires. It had a little more understeer on fresh BFG Rivals, but still quite balanced.

More camber, won't hurt your tire life. Cornering too hard and rolling your tires because you don't have enough camber will affect tire life. Get more camber.

Figured I'd jump in here when i read that our STB was making your car understeer!

Everyone here has already pretty much nailed it, but the car always understeered, you're just more willing to push it to that limit. Front engine, rear wheel drive "performance cars" are almost always set up to default to understeer as it is the perceived "safer condition" compared to oversteer.

And the change that you're sensing (despite what everyone here who maintains the "strut bars do nothing mentality despite having not done the testing and not owning one, let alone ours) is that the strut tower bar really is keeping the tension and compression between the two towers tied together. No longer is one towers going left and the other right over a bump or through a turn, they both are opposing the forces and either going one direction, or none at all. The most surprising thing I learned was in a turn (we posted all this data in our development thread) was that the loading on the strut towers was cyclic, that is alternating between tension and compression. Granted these are very small deflections, but when those deflections are going the opposite directions of each other they double. When They are tied together they don't anymore, and end up with deflections in the same direction. This lends to more predictable handling because the car isn't gaining and losing camber and more importantly toe on opposing wheels when going through a turn.

So, there are some good suggestions in this thread (and don't worry about camber wear if your toe is correct, toe is the tire killer). But i mainly chimed in to remind everyone about the rear suspension design and rear strut bars:

A front strut bar is effective because there is no material between the two front strut towers. Also the strut is connected directly to the spindle and thus wheel in a very stiff, solid connection.

The rear strut towers have a lot of material between them. Some obvious and some non-obvious. But the springs and shocks are connected to the lower control arms, and hinged. So the strut tower bar would see 0 to near-0 lateral load, and very very little "up and down" load.

So I'd put your money elsewhere too ;)

Chase
Engineering

Thanks Chase! It definitely sounds like dialing in a bit of neg. camber (and maybe a slight drop) is my next journey!