20mm Spacers didn't work for me

[monkeybike]

I think 95% of this is in your head.

[Racecomp Engineering]

Originally Posted by churchx

@Racecomp Engineering: can you tell how spacers - in rear - affect grip bias?

I would expect adding only rear spacers to slightly increase understeer.

I would expect adding slightly stickier tires to slightly decrease understeer (in some situations).

- Andrew

[rvoll]

Originally Posted by monkeybike

I think 95% of this is in your head.

Could well be. But it could also be that those of you who have added them are 95% ignoring any difference. In any case, the difference is smaller than I made it seem at the beginning. I retested this morning, and while I can still feel the difference, it is much smaller than I felt when I first did it, probably because it surprised me.

[fatoni]

Originally Posted by rvoll

I know you're taking every opportunity to take a slight, but honestly, I never had to play with the suspension on my Porsches -- only wheels and tires. Track days were for fun with me, and not serious racing. I owned only 928's and my last GTS was stroked. Aside from track wheels/tires, I made no mods. I have a lot of knowledge about wheels and tires and corporate strategy was my avocation, but I'm a novice at suspensions and FI, especially with the BRZ. I do know how the car drives, however. And yes, that's a highly individualized perception and each of our sensitivities are different. I took off the spacers this morning and went for a drive. The difference didn't seem as pronounced as I remembered going the other way, but it was there. The car felt more nimble and controlled. I don't go to the track anymore and don't push my cars as much as when I was young, so how the car feels going about town is of prime importance to me. And no, you won't convince me that wide tires/wheels on this car when NA makes sense from a performance perspective. Looking back, I should not have been so concerned about a more flush look and just stuck to my guns about performance. However, I do read these forums and so many of you run with spacers I thought I'd give it a try.... Done...

I just thought it was kind of inappropriate to make statements earlier using as your justification for your certainty but now you have no problem disregarding that experience because it's a different platform. It just doesn't wish both ways. You still feel like staggered wheels and tires make sense? I'd imagine you have to believe that would exacerbate this situation

[churchx]

@Racecomp Engineering: hmm, stickier tires - decrease understeer? I wonder which those some situations might be. I thought that if same extra grip is added both front & rear, bias should stay same?

[rvoll]

Originally Posted by fatoni

I just thought it was kind of inappropriate to make statements earlier using as your justification for your certainty but now you have no problem disregarding that experience because it's a different platform. It just doesn't wish both ways. You still feel like staggered wheels and tires make sense? I'd imagine you have to believe that would exacerbate this situation

I said that staggered makes sense WHEN YOU ARE USING FI because you are pushing more power through the rear wheels!!!! Do you really disagree with that? Depending on the boost, it also makes sense to stick with close to stock. So I have no clue what you're talking about. I'm not disregarding any experience. Do you have anything of value to add to this discussion? As for me, I've learned a lot from those who understand the BRZ suspension better than me. And questioning me about how much of my perception is real, and how much is psychological expectations, is good as it forced me to retest and validate. I'm just after the truth. What are you really after?

[Aipex8]

I just added 20/25mm spacers to my car, and while I haven't been able to autocross it to truly test the limits, spirited driving around town feels absolutely no different.

I just want to note (and this isn't necessarily for the OP) that any time there is a thread about spacers, someone has to talk about "scrub radius." And that is not just this forum, but many others. The problem I have with that, is that scrub radius is changed by just about any modifications you make to wheels/tires/suspension. Lowering and increasing camber has the potential to change the scrub radius way more than adding a spacer, yet you'll never, ever find anyone mention "scrub radius" outside a spacer discussion. That leads me to believe that no one really understands scrub radius and people are just parroting what they've seen on other forums.

[Icecreamtruk]

Originally Posted by churchx

@Racecomp Engineering: hmm, stickier tires - decrease understeer? I wonder which those some situations might be. I thought that if same extra grip is added both front & rear, bias should stay same?

I would think the same as well, but experience has proved me wrong. Stickier tires make the rear easier to rotate, and the stickier, the looser the rear got (on stock suspension). Spacer in the front turns it into a very tail happy car, while spacers on the rear added some more understeer. On stock suspension but with -3 camber on front and Maxxis RC-1 or nitto NT01 tires (entry level r compounds), I found a 20mm spacer on the rear to be less fun to drive, but slightly faster than no spacers at all. 20mm on the front made it for a very hard car to handle in fast direction changes, but fun everywhere else.

[JimmyMac]

Originally Posted by churchx

@Racecomp Engineering: hmm, stickier tires - decrease understeer? I wonder which those some situations might be. I thought that if same extra grip is added both front & rear, bias should stay same?

Not if both front and rear are drifting/sliding/not gripping the road or track. Weight of the car will push it to the outside of the turn. If total grip is increased to adhere to the track, then the car would not push out as much or if at all. Maybe kinda like snow tires vs summer tires in the winter.

[nikitopo]

Originally Posted by rvoll

I said that staggered makes sense WHEN YOU ARE USING FI because you are pushing more power through the rear wheels!!!! Do you really disagree with that? Depending on the boost, it also makes sense to stick with close to stock. So I have no clue what you're talking about. I'm not disregarding any experience. Do you have anything of value to add to this discussion? As for me, I've learned a lot from those who understand the BRZ suspension better than me. And questioning me about how much of my perception is real, and how much is psychological expectations, is good as it forced me to retest and validate. I'm just after the truth. What are you really after?

Don't bother with him. It doesn't really worth it. Same with a few more people over here.

[mrg666]

Adding spacers will change the driving dynamics but the main problem is added number of studs and increased risk of failure theoretically. I know people will come to swear there is no such problem. To me, it is a suboptimal solution and I never liked the idea of using spacers because of that. It is obvious to me that the car will tend to understeer with just rear spacers. A suboptimal mod done worse!

I have +40 offset 8 inch wide wheels, which give about 20mm lateral extension at all corners using 245 tires. Car has less tendency for both understeer and oversteer. It is like driving on rails on street. Oversteer is still possible if I push the limits. I have never noticed any understeer tendency with my setup.

[fatoni]

Originally Posted by rvoll

I said that staggered makes sense WHEN YOU ARE USING FI because you are pushing more power through the rear wheels!!!! Do you really disagree with that? Depending on the boost, it also makes sense to stick with close to stock. So I have no clue what you're talking about. I'm not disregarding any experience. Do you have anything of value to add to this discussion? As for me, I've learned a lot from those who understand the BRZ suspension better than me. And questioning me about how much of my perception is real, and how much is psychological expectations, is good as it forced me to retest and validate. I'm just after the truth. What are you really after?

you keep saying wider tires add no grip but then recommending wider tires to help with rear grip. also, i only think forced induction affects going. not so much stopping and turning. if you dont agree with that the point is dead, but if you do, the car would handle the same off throttle and its clear you arent pleased with the change in characteristics.

[rvoll]

Originally Posted by fatoni

you keep saying wider tires add no grip but then recommending wider tires to help with rear grip. also, i only think forced induction affects going. not so much stopping and turning. if you dont agree with that the point is dead, but if you do, the car would handle the same off throttle and its clear you arent pleased with the change in characteristics.

I know you are trying to make an argument, but instead of trying to find inconsistencies (of which there are none), please actually think about what you are saying. Given the weight and power of a vehicle, there is a point where wider tires do not add more grip because no more grip is needed. Add weight and or power and those things change. Capish? With our car, I can find no evidence that when driving the car on the street under all conditions, including dry and wet, that standard size tires, or close to it, won't give you maximum benefit. And no, I didn't like what I perceived to be added understeer with the rear spacers. Some people may not notice it or even like it, and that is fine. Things are different on the track where things like tire temps and need for more lateral grip may be optimal especially on dry pavement. Even there, people will tell you there are optimal setups that balance grip and handling.

[JeremyR]

So much confusion in this thread..

If you only put spacers on the rear, than you definitely increased the amount your car will understeer.

if you put spacers all around, but wider ones in rear, you'll have the same effect.


This isn't rocket science..