John H

From Grassroots Magazine May 2006. Excellent mag by the way.

CWhaley

great magazine for tidbits of random information.

SundayDriver

Joe was a huge contributor to amateur motorsports and is (and will be) missed.

FYI for those that don't know, Carroll Smith's "Engineer in Your Pocket" has the same kind of info, but in more detail. I always kept that in my toolbox.

forklift

Stiffen front springs or roll bar for mid corner understeer??? I'm fighting US right now...enough that I completely disconnected my front sway bar completely for my first race ever (doh!) at Summit....and it worked. I had OS everywhere.

onefastviking

Remember it's a package where everything has to work together, if you have one part off it will change the results you see with other changes.
Thats why I,JRG,VR,LH, and many others on here always suggest hiring good help to dial in cars. A good coach and good mechanic will help you work thru the setup to end up with a car that outhandles all the rest. It's not rocket science, but it does take a lot of knowledge and many years of experience. You don't have to hire me, but hire someone that has proven successes as well as the years of experience, you will find it worth every penny.

CWhaley

^ So True....

JustinL

I'm puzzled by this as well. Anyone care to explain the mechanics behind it?

onefastviking

At midcorner you had better be on the gas, all your turning is already done. If we were talking at turn in then the recommendations would be much different.
That help ?

forklift

Thanks Viking,

Yes good point and I really do need to get my coach back out here to Summit (Chris Cervelli) to help as it has been a few years and my driving and suspension (springs) has changed since then. I did manage to get Mike Skeen in my car at VIR for a session (he was coaching someone else that weekend) in Sept but the car was behaving then and Skeen thought so too. I can usually get my car to handle well at VIR (and seem to know what adjustments to make to get it there), but not at Summit for some reason which is my home track. I don't think I have ever been happy w/ the car at Summit but usually am at VIR. I have come a long way since I bought the double JRZs in 07 but still have lots to learn. I'm also now questioning my 245s on 7" wheels again as part of the problem (which I know is too wide for that rim) and hope to go to a 8" rim up front this year.

Also a big thanks to you, Larry, Bob T and others (and Chris of course) who answer all my dumb PMs and emails along the way! I've had Larry in my car before but that was a few years back and would like to get him back in the passenger seat (and driver's seat) again at some point.


Thanks,

Jim

JustinL

Not really The article says "steady state", which would imply a constant radius skid pad type exercise or a carousel/highway off-ramp type corner. I'm trying to understand how stiffening the front ARB loosens the handling.

John H

I definitely an a strong believer in having a pro set up the car and just doing some minimal tinkering from there under the circumstance presented i.e, track, weather, condition of tires etc. That is all I use the chart for: mild, mild tinkering.

Larry Herman

I'll toss in one big caveat - make sure that your "pro" has a similar driving style to you. Sure, most capable pros can get in a car and find any major flaws in the setup, but to take a car and tune it perfectly for you takes someone who understands your driving style. A car that is setup to be finessed into a corner will not be happy in the hands of someone who likes to throw it into the turn.

Jeff Lamb

When Joe Stimola was referring to "mid-corner" understeer, he clarifies that he is referring to "steady state handling" in his more detailed comments. Therefore, in my opinion, he is referring to the portion of the corner where you have finished corner entry and you have not yet began your corner exit. In some corners, there is almost no "steady state" because you almost immediately transition from corner entry to corner exit and there is almost no time spent at a "steady state" in the corner. Whereas, in longer high speed corners, you will have a defined period of "steady state" between your corner entry and your corner exit.

In a simple constant radius corner, the "steady state" portion of the corner is one where you are maintaining the constant maximum speed that your car and tires can give you for the radius of the corner. In other words, you have finished your braking and turn in and you are now feathering the throttle to keep the car at a constant maximum speed you can maintain in the middle of the corner before you begin corner exit where you transition to maximum throttle.

During the long corners where you have a defined "steady state" during the middle of the corner, the car has "taken a set" and if your front springs or swaybar are too soft, Joe is pointing out that you will likely have too much weight transfer at the front of the car which can cause the front to lose traction and cause understeer. Make sense??

Jeff

Larry Herman

No it doesn't because spring rate does not affect the amount of weight transfer, only the speed of it.

Jeff Lamb

Larry, you make a good point. Therefore, in your opinion, how do you increase or decrease understeer in a the "steady state" portion of a corner?

Jeff