Picking New Tires, Trying To Get More Front Grip

Jordo! · 07-04-2015, 10:30 PM

Quote:

Originally Posted by ScottOmatic

GT Porsche 911 track cars often run harder rear compounds due to all the weight being over the rear axle but of course, those are engineered to work correctly from the tire supplier and the rest of the setup is dialed in in every other aspect along with track time.

I think running 2 different street tires with different compounds and different tread patterns that are meant and have only been tested running on all 4 corners is hairy at best.

Even if the effect is generally positive in the dry it could be a nightmare in the wet.

As you touched on, the other idea I have had was upgrading the rear sway-bar and leaving the front alone. This would be a pretty cheap upgrade and I could always add the front later when getting new springs/struts or Coil-Overs, which I am sure would take out most of the understeer with default tire sizes.

The reason I don't want to just spend the money on a full suspension setup right now is that I am trying to pay off my 2014 FJ Cruiser early (that currently takes precedence when funneling money into cars) and to be honest, I am slightly worried I will get the bug for a different sports car in a few years and know it will be hard to get my money back in upgrades (Currently under 23,000 miles on my Z so everything but the tires are still pretty fresh).

Maybe I will get some new suspension components in awhile, maybe I will eventually get a tune, but until I make that decision I am going with the bang for the buck approach.

I should say I already bit the bullet on a cat-back exhaust a year ago, I'm sorry but the default exhaust setup just had to go!

I think that's great idea! The OEM tires are actually pretty good (the Nismo RE-11's are better, but the ones you have now are still excellent).

Also, it's probably best to play with only one (or two) variable(s) at a time. I think go with the stiffer rear sway and hold off on the front for now, as you said, and see how that feels.

The only other change you might play with at the same time would be alignment, but otherwise, manipulating one thing at a time (in this case rear sway) is the best way to gauge its individual effect.

So, in summary (I'm rambling, sorry

), a good way to go might be to try the rear sway first, see how it feels, and then either do front sway or tweak alignment next.

jpkirk · 07-06-2015, 04:02 PM

Quote:

Originally Posted by Jordo!

Hmm. I was going to suggest a square set up as well, but really in order to keep tire size and compound a constant more than to play with relative grip -- a lot of that will depend on alignment settings and weight distribution/suspension more than anything.

I guess you could buy ultra sticky fronts relative to the rears, but that sounds like it will just make the car unpredictable...

So, assuming equal sized tires of same make, you want to stiffen up the rear relative to the front. That means a beefier rear anti-sway bar and firmer damper settings in the rear and softer in the front, if you can adjust them. Any other bracing you can add to the rear (without adding significant weight) will tend to nudge you more towards oversteer.

I think, maybe a little more camber in the front relative to the rear will help tuck the nose in too... not 100% certain on that one off the top of my head.

Scan over this site for lots and lots of advice on setting up cars for road racing

Autocross to Win (DGs Autocross Secrets) - ATW Home Page

This thread is helpful too

Suspension adjustments and how they affect handling

Dang, beat me to the Far North Racing link.

imjello · 07-04-2015, 12:30 PM

I was in the same boat and after enjoying much understeer on my first autocross event, I also started reading threads for solutions. I went from the base 18's Bridgestone 225 & 245 to Rays Sport 19's on Bridgestone S-04 Pole Position 265/40zr19 and 285/35zr19. They fit perfect and I can turn much harder without issue.

geddy lee · 07-04-2015, 01:51 PM

Finally a replacement for spinners

Spooler · 07-04-2015, 09:02 PM

Your best savings will be reading and searching. I do quite a bit of that on here. Only spend the money once, will save you a fortune in the future.

kenchan · 07-06-2015, 06:05 PM

almost sounds like someone didnt read my post about S04's being unreasonably narrow in the 275/35/19 size for some reason, bought it and now trying to convince one's self it's the way it should be?

the 285/35/19 S04's i run on my G's 10.5" are

ScottOmatic · 07-07-2015, 12:52 AM

As for the roll-bars, its interesting what Red and Rusty are pointing out and what people are saying on the track forum, more front bar and stock or taking out the rear giving more oversteer.

Which goes against the generalized principals but I guess when something is at an extreme value, especially relative to the other end of the car, many theories can go out the window.

I may actually just try to take out the rear ARB and see how that changes the handling dynamics before I get the new tires, I still probably have a couple months before I have to really.

onzedge · 01-06-2016, 10:31 AM

Quote:

Originally Posted by ScottOmatic

As for the roll-bars, its interesting what Red and Rusty are pointing out and what people are saying on the track forum, more front bar and stock or taking out the rear giving more oversteer.

Which goes against the generalized principals but I guess when something is at an extreme value, especially relative to the other end of the car, many theories can go out the window.

I may actually just try to take out the rear ARB and see how that changes the handling dynamics before I get the new tires, I still probably have a couple months before I have to really.

Rusty · 01-06-2016, 01:09 PM

Quote:

Originally Posted by onzedge

EzDz · 01-06-2016, 01:38 PM

You can do everything or one of the many good ideas posted here but after you do take it to a track oriented suspension shop and have it aligned for your square or staggered set up.

07-04-2015, 12:30 PM	#3 (permalink)
imjello Enthusiast Member Join Date: Nov 2014 Location: texas Posts: 285 Drives: F80 M3, S5 B9 Rep Power: 13	I was in the same boat and after enjoying much understeer on my first autocross event, I also started reading threads for solutions. I went from the base 18's Bridgestone 225 & 245 to Rays Sport 19's on Bridgestone S-04 Pole Position 265/40zr19 and 285/35zr19. They fit perfect and I can turn much harder without issue. ScottOmatic likes this.

07-04-2015, 09:02 PM	#5 (permalink)
Spooler A True Z Fanatic Join Date: Jun 2014 Location: Ga Posts: 14,123 Drives: 2013 Nismo 370z Rep Power: 2684394	Your best savings will be reading and searching. I do quite a bit of that on here. Only spend the money once, will save you a fortune in the future. ScottOmatic likes this.

01-06-2016, 01:38 PM	#10 (permalink)
EzDz Enthusiast Member Join Date: Aug 2015 Location: Pittsburgh Posts: 309 Drives: 2016 370z Nismo Tech Rep Power: 10	You can do everything or one of the many good ideas posted here but after you do take it to a track oriented suspension shop and have it aligned for your square or staggered set up. __________________ Nismo \| Moore Performance \| AAM \| Tein \| PPE \| Tomei \| Eibach \| Z1 Sponsored: Mishimoto

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07-04-2015, 01:51 PM	#4 (permalink)
geddy lee Base Member Join Date: Mar 2012 Location: delaware Posts: 161 Drives: 350Z Rep Power: 14	Finally a replacement for spinners

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kenchan A True Z Fanatic Join Date: Aug 2009 Location: N/A Posts: 76,801 Drives: N/A Rep Power: 141521	almost sounds like someone didnt read my post about S04's being unreasonably narrow in the 275/35/19 size for some reason, bought it and now trying to convince one's self it's the way it should be? the 285/35/19 S04's i run on my G's 10.5" are

07-07-2015, 12:52 AM	#7 (permalink)
ScottOmatic Base Member Join Date: Jun 2013 Location: Madison, WI Posts: 63 Drives: '88 Porsche 928 S4 Rep Power: 13	As for the roll-bars, its interesting what Red and Rusty are pointing out and what people are saying on the track forum, more front bar and stock or taking out the rear giving more oversteer. Which goes against the generalized principals but I guess when something is at an extreme value, especially relative to the other end of the car, many theories can go out the window. I may actually just try to take out the rear ARB and see how that changes the handling dynamics before I get the new tires, I still probably have a couple months before I have to really.