How to screw up your cars handling and ride - step by step!

[chaoskaze]

Originally Posted by JozhGoober

Oh, if you've only had the tires on a very short time, it's probably just the tire wearing in. Most tires feel slippery and vague until you wear them in a bit.

http://www.tirerack.com/tires/tirete...e.jsp?techid=5

The only real way to accelerate the process is to have the tires shaved, but then you're cutting away tire life (and doesn't make sense on non-race tires). Put a few hundred miles on them and they should feel much better!

Really? That makes me feel a bit better, because right now by the time I feel what the front tire is doing, I'm already sitting right on top of the things. 😑

It just makes me feel unease cuz it's like running blind...& since the grip is so much higher, if I fuk up I can fuk up big time.. I guess I will see how it is on some twisty canyon run this weekend... Then track.

*But it does turn nicely with the extra grip now.

Originally Posted by strat61caster

@chaoskaze

What tire pressure you running? If you were running low before try returning to the OE 35 psi, maybe try higher at say 38 or even 40 psi. It's a bandaid that may not result in ultimate grip but may help the 'feel' of the setup.

Thank you I will try it. ✌️ I'm on 35 now & it does feel mighty soft. Like it's more comfy then my friends 2010 335i.... >_> I rode in his car this morning right after driving to his home.

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[empower-auto]

Half the stance kids these days ... harsh superlow BC coils or stiff suspension .... 9.5 - 10 inch wide wheels ... low ride height, garbage alignment, and ..... the cheapest Nexen / Nankang / china tire stretched over it.

Handles sick bro! Let's go vape!

[Racecomp Engineering]

Originally Posted by chaoskaze

I haven't done it. I'm putting STI Spring on stock strut this weekend then alignment once spring settles......I literary just put on the PSS less then 24 hrs ago. :/ Is there anyway to remedy this delay on feel? I really don't like it. Please let me know, I'm all ears. Thank you.

Or I should just try my luck & see if I can exchange it for a 215 tire... Really pushing my luck & put myself to shame... :/


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Ahhhh yeah, don't panic. Like JozhGoober said, tires do need some miles to "break in".

Keep an eye on your tire pressures and compare with others.

A good sporty fun alignment will help immensely, too.

- Andrew

[Apex-Apex]

18x10 gives the electronic power steering a nice heavier feel.

[DoomsdayJesus]

Originally Posted by Racecomp Engineering

7.5s are really nice for this car, assuming you're using a quality tire that fits. Go for it.

- Andrew

Oh I have no intention of stretching to extremes. However I am curious what the acceptable width range for 7.5 is without compromising structural integrity or performance. I put BFGoodrich G-Force Comp-2 A/S on my stock rims as a daily driver for the winter, 215/45s with XL load rating. I was wondering if I'd be able to mount those on a 7.5 with no issues for future winter driving in a wet climate or if it's better to just leave them on the stock rims. Wheels and tires are definitely a weak point in my automotive knowledge.

[churchx]

Just google for best+tire+size+for+wheel+width. Many online tools out there to tell you that. For example this. rim size 17x7.5: minimum 205, ideal 215,225, max 235. Of course it is of what is reasonable minimum/ideal/max by tire vendors, not including overboard extreme cases some run with over-stretching "because it's cool" or too wide tires "to get widest possible within stock class regulation limits" ..

[NissanGuy]

Originally Posted by boredom.is.me

As for the hubcentric rings, they aren't needed. They are for people who do not understand how clamping forces work.

As for tire choices, you have plenty. The PSS is a good choice and what I am currently running. I previously came from Potenza RE760 which also did excellent. They were cheaper but I'm sure the PSS will last longer. The Bridgestone Comp 2's are cheap grip, but are still a class under the PSS.

For an 8.5" wheel, a 245/35R18 will keep your speed operating within reason. A 235/40R18 is significantly bigger.

I'm not here to provide track advice, just trying to provide some simple sense.

You've tried the RE760! I was looking at those for my next tires, how was your experience with them?

I loved my ex-MINI Turanza RFTs on my Altima, light tire with great grip and super stiff sidewall makes me feel good about certain fitments of Bridgestone. In low-profile, as seen on 370Z, Bridgestone RE050 are just awful. Hopefully the RE760 offers moderate grip and a nice stiff sidewall for my fitment: 195/55R16.

...what? Stop laughing!

[DoomsdayJesus]

Originally Posted by churchx

Just google for best+tire+size+for+wheel+width. Many online tools out there to tell you that. For example this. rim size 17x7.5: minimum 205, ideal 215,225, max 235. Of course it is of what is reasonable minimum/ideal/max by tire vendors, not including overboard extreme cases some run with over-stretching "because it's cool" or too wide tires "to get widest possible within stock class regulation limits" ..

Thanks, I just wasn't 100% sure from a performance standpoint, especially with XL load tires. Online tools and guides I've seen are generally for regular drivers and not necessarily performance oriented.

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[atlbrz]

I am new to the BRZ/FRS platform, but I have been modifying Miatas for a dozen years or more. I don't have any plans on tracking this car, but I would like to eliminate the car's tendency to understeer. I would like to replace the OEM tires with a more aggressive tread in either a 215/45/17 or possibly a 225/45/17 on the OEM rims for now. Maybe some 17x8 rims in the future. I am partial to Bilstein and have used both PSS/PSS9/PSS10s. My plan is to go with the Bilstein PSS with a 3/4 - 1" max drop. What will this drop do to my camber ft/rr? Based on Andy's comments and past experience, I am fine running around 1.5 neg camber. It sounds like the car responds pretty well to equal camber or a bit more negative camber in front. Will just camber bolts be sufficient in the front? Do I just live with the new camber in the rear? I really don't want to spend a bunch of money on camber/caster plates and lower adjustable arms. Thanks.

[strat61caster]

Originally Posted by atlbrz

I am new to the BRZ/FRS platform, but I have been modifying Miatas for a dozen years or more. I don't have any plans on tracking this car, but I would like to eliminate the car's tendency to understeer. I would like to replace the OEM tires with a more aggressive tread in either a 215/45/17 or possibly a 225/45/17 on the OEM rims for now. Maybe some 17x8 rims in the future. I am partial to Bilstein and have used both PSS/PSS9/PSS10s. My plan is to go with the Bilstein PSS with a 3/4 - 1" max drop. What will this drop do to my camber ft/rr? Based on Andy's comments and past experience, I am fine running around 1.5 neg camber. It sounds like the car responds pretty well to equal camber or a bit more negative camber in front. Will just camber bolts be sufficient in the front? Do I just live with the new camber in the rear? I really don't want to spend a bunch of money on camber/caster plates and lower adjustable arms. Thanks.

I ran the B14s for a month, IMO the understeer is primarily alignment induced by lack of negative camber in the front. Lowering the front will get you almost no additional camber and bolts will land you in the -1 to -1.5 range, lowering the rear which is multilink so psuedo double wishbone will get you somewhere in the neighborhood of -1.5 to -2 or more. IMO this is still an understeering setup, I ran my b14s with camber plates, no bolts and no rear lca and it was only a minor improvement over stock and I liked it less than my OE springs and dampers with camber bolts and plates and nothing else, I was missing the camber from the bolts and added a bunch of grip in the rear and it didn't leave me wowed. I also think part of the equation is that Bilstein utilizes bump stops that are too long, they're at about 2" and total compression travel is ~3" stock so once you lower an inch the kit advertises your pretty much on them at all times.

I think it could work well as a setup you can beat and drive to work on, but not out of the box. Comfort was on par with OE, but it was worse on the big bumps. If I'm driving for speed I'm cranking the front camber up over -3 degrees, rear seems to be happy around the -2 range from what I've heard. And I really liked running 215 Z2SS on my car all last year, wouldn't bother with 225 unless I was competing in a class that restricted wheel widths. I think if I had cut the bump stops and worked harder on the alignment I could have been happy with them but decided to try something else.

[atlbrz]

Thank you for the reply strat61caster. You provided a lot of good information. I did have to cut the rear OEM bump stops on my last set of PSS. Based on your response, I am almost tempted to just put some money into a good set of front camber plates so I can add some camber and adjust caster. With a goal of getting at least 1.5 in front with the understanding the rear is around 1.0 stock. It is less than ideal, but should be an improvement. That may be a bit of overkill versus just doing camber bolts in the front, but I am not a huge fan of camber bolts. I am pretty surprised how well the car handles stock versus the ride comfort, but I would definitely like to reduce the feel of the front end pushing in the corners. What is the consensus on which caster/camber plates offer the best value?

[Vincent Nguyen]

I have 18x9.5 +35 work xd9. I am regretting getting them now because they're heavier than many other wheels. My question is with only camber bolts and lowered with trd springs, will i be able to fit the wheels in the front without rubbing? I might run with 245/40 or 245/35 tires

[strat61caster]

Originally Posted by atlbrz

What is the consensus on which caster/camber plates offer the best value?

No consensus, lots of options out there from Racecomp, Vorshlag, Raceseng, Beatrush etc. etc. If you're getting Bilsteins I believe you want compatibility with OE suspension, that will inherently narrow down the options. Find the few that fit, google this site for reviews, good luck.

[Lateral G]

Originally Posted by Racecomp Engineering

I remember the first time I drove a BRZ a little before it hit the streets and thinking....damn....Subaru/Toyota got serious.

Anyway, this is a list of things that I see owners doing to their 86's...often with good intentions and parts bought hoping to improve things, but they end up chasing more parts to get things right. All of these on their own are detrimental, but can sometimes be "worked around" to some extent. Unfortunately many cars check off multiple boxes and sometimes all of them...resulting in a car that is a big step back from the factory.

I'll skip "stanced" cars (slammed, stretched tires, massive camber)...I don't think anyone does that expecting not to sacrifice function for what they think looks good. Different strokes.

These are some of the common things I see:

1. Staggered wheels/tires

It's a good look and definitely makes your car look like it has a lot of power. Unfortunately our cars don't have a lot of power.

It's also a great way to build in some extra understeer that's difficult to tune out. Staggered wheels are common on cars with a lot of power but are not necessary MOST the time here.

This one CAN be worked around but there's just no need to complicate things.


2. Big ass heavy wheels

Even if you got a great deal on a buddy's 18x9.5 wheels, it may not be a great idea to use 27 lb steamrollers at each corner. Most of us don't need that much tire either. Keep it light and it'll feel like your dampers are much more capable. You'll stop and go faster too.


3. Big drop on lowering springs

If it looks a racecar then it must handle like one, right? Unfortunately, it doesn't exactly work like that. A little drop can improve things with proper spring rates, but past an inch or more and you start making big compromises and riding the bumpstops before you even hit a bump. It's a sure way to downgrade your handling. Aftermarket shocks may help in some ways, but don't solve the travel problem.


4. Big drop on coilovers

With some coilovers you don't need to worry about bump travel as much, but geometry is still a concern when lowering 2 inches. A big change in roll center height and changes in the dynamic alignment can be felt from the driver's seat...and it feels sloppy.

I know what you're thinking. There are a ton of cars on here that hit the track and handle well with a lowered ride height. If you must have that really low center of gravity than you must use very firm spring rates (and then quality dampers to match) or use geometry correction parts. That's what the fast guys and girls at the track are doing....not slamming their crappy coilovers to the ground and expecting all to be well.


5. Poor or mismatched dampers

Whether it's running very stiff springs on the stock shocks (or riding the firm bumpstops), or turning your adjustable dampers up to full stiff, damping that's not matched to the springs won't feel good. Underdamped will feel bouncy, floaty, and generally crappy in transitions. Overdamped will feel harsh, crashy, and might hurt your back. None of this is good for ride quality or handling.

Sometimes an adjustable won't have a "good" setting because the quality of the valving is just plain bad. This is more noticeable with firmer spring rates.


6. Alignment

Anything less than -1 degrees camber up front is a recipe for understeer. I still see people trying to get their camber "back to 0" after lowering. Don't do this! Tire wear isn't really a concern until you get to -2, so don't be shy...add a little camber and enjoy. Most enthusiasts will get BETTER and more even tire wear anyway. Toe is the tire killer.


7. Tire choice

Really stiff springs with all season or OEM tires can reduce grip as you'll be quickly/easily overloading the tire. Match your spring rates to your tire choice.

Running sticky tires on soft OEM springs is a problem too, but you will still gain grip from the tire. It'll just feel sloppy and move around a lot.


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Follow all of these steps and you can turn your well tuned factory BRZ/FRS into a sloppy, numb, slow reacting, pig of a car. Please don't though, it's too much fun when set up right.


- Andy

Thanks for the thread. Great advice! I recently replaced tires with the slightly grippier Dunlop Direzza dz102 in stock size. Immediately noticed more body roll and understeer. (I once ruined the fun of an MX-5 with MPSS and so stayed close to stock grip levels)

I was able to dial out most of the understeer with tire pressure. Grip levels are up but turn in is diminished and things are just a bit "squishy", less direct. What alignment settings would you recommend for a autocross/DD combo? I live near the Dragon and run it dozens of times a year as well. Any advice is greatly appreciated!