urBan_dK

You got me

s2000Junky

Oh crap

Boredom is the root of all evil.... or should I say ideological people who are bored and need a newb to pick on

Carry on

s2000Junky

Why not go for their 10" +72 with the 255? You will get a slightly wider contact patch down to the ground and it will handle sharper. Or you worried about having a slightly stretched look and getting too much shit for it? I realize the going Pac NW trend here is to pinch as wide a tire as possible on the skinniest rim

You could run the 275/40 on that rim also if you wanted... if you had a roots to get them turning, be a bad ass combo Jeff You could also forget the front bar at that point and retain your front grip with the 255 wile increasing the rear 275 for a similar grip balance, but more total grip.

I don't quite understand the principle of running a non staggered set up and then running a bigger front sway bar to lesson grip bias again, this isn't the first I have heard of this, do you have any insight on this Jeff? The precision in handling would improve so I get that, but this doesn’t seem to be the driving force in performing this mod, to me it kind of seems to defeat the purpose of increasing front grip with a wider front tire if your just going to stiffen it back up to balance out the rear grip again, don't you think?

jerrypeterson

The proper solution is to change spring rates and damper settings. Often guys are using sway bar adjustments just because it is easier to implement... or they don't know better.

Stretched tires come at a performance premium. What is so hard to understand about that? Without sidewall flex, you are robbing yourself of potential grip. You almost always want to run with as much tire as will fit under the fender.

s2000Junky

[QUOTE=jerrypeterson,Feb 26 2010, 12:36 PM] The proper solution is to change spring rates and damper settings.

jerrypeterson

Yeah at the end of the day this is a street driven car. It's not a big deal.

Note however, these are adjustable dampers but not adjustable spring rates. Springs carry the load, dampers are mainly for the transistions. You can tweak damper settings all day long but it a band-aid type of fix, much like swapping out sway bars. The Stock Class Autox guys are uber experts at this because the rules prevent them from changing spring rates or ride height. (This is another reason you see so many discussions around sway bar settings.)

I get the feeling you are approaching the whole stretched tire thing with the philosophy that a stiff/hard tire will provide the largest dynamic contact patch. This is false. And that is why we keep going in circles. Yes, the 10" wheel is optimum for a 255. But if you need to compromise, you generally should go with a larger tire, not a larger wheel. Also, and again, there is a wheel size limitation in Stock Class autox but no tire restriction other than a DOT label. A lot of discussions on the board occur because of this limitation. In the absence of restrictions, the question is always how much tire can fit.

s2000Junky

[QUOTE=jerrypeterson,Feb 26 2010, 04:40 PM]
Yeah at the end of the day this is a street driven car.

jerrypeterson

More tire means more fast. That is all anyone really needs to know.

All those suspension tweaks are meant to increase contact patch when there is load on the tire. There are plenty of rules even when you don't have them. For example, the optimum car setup for a lapping day at track X is not necessarily the same as track Y. And these have next to nothing to do with a street setup. Then there is the Pesky Revised Code of Washington... especially the part where the wheel setup on the Junky-mobile is illegal. Very annoying.

Where we disagree is your belief that a stiff tire profile means a larger contact patch. It simply isn't true under dynamic load. Steady state sure... but not under load. Check your tire sections with a pyrometer after the next hard drive. Me bets there is some interesting stuff to follow-up on.

s2000Junky

No, that's not my statement, that's your interpretation of my statement. There is a distinguishment. A stiffer tire profile has nothing to do with contact patch, its only quicker to respond to inputs and creates a tighter handling car, which I like, some may not. Secondly, a set tire size such as a 255 will have a wider contact patch on a 10" rim vs a 9" as stated previously, which you agree. So lets say for the sake of argument, either the rules or preference say you can only run a maximum of a 255, well in that case I would choose to run it on a 10" wheel for the two reasons I gave. You seem to be confused on how they relate to one another, or how you think I relate to this. I wanted to know why Jeff in choosing to run a 255, would choose to mate it to a 9" wheel given what I know about the relationship between the sizes.

lig

I want to be able to retain full lock up front so IMO the 9 - 255 setup will give me that ability.

Not really looking to get the absolute maximum - just a good workable setup that seems to yield good results.

My auto-x setup is 245/275 17s but I'm not a huge fan of how tall the 275/40s are.

Given that the car is barely making 200whp (if that) taller gearing isn't what I'm really after but that's what I've got for the moment.