Expert: Dan Liddy - 3/26/2007

Question
QUESTION: Dan,
You say 2 degrees possitive caster on the left front and 3-5 degrees negative on the right front for oval track FWD racing, can you explain that more to me?  Right now we are getting an '87 Honda prelude ready for asphalt, we have about 2.5 degrees possitive on the RF and about .75 degrees possitive on the LF.  This enters the turn slightly loose but comes off much better than our last setting which had about 1 degree negative on the LF and made the car push like mad, ruined the front right tire in 18 laps.  I'm pretty happy with this in comparison, however I don't want to be missing the boat altogether if your recommendation would work better.  Also when we purchased the car it had the setting you describe, or at least very close and they said it was a winning car.  What do you think on this matter.  We also added a spring rubber to the right rear which helped the push also.
ANSWER: Maybe I am missing something, but I think you are mistaking caster for "camber", or the amount of vertical 'lean' in the front tires.     The inside front should lean into the turn ( positive camber) and so should the outside tire, (NEGATIVE camber) They both are leaning the same direction , into the turn. Unless you have an absolute rock solid steering system, you also want to run a small amount of toe OUT in the front, about 1/32" on each wheel for a total of about 1/16"   Experiment with this until you notice a reduction in the pushing.  Please only change one thing at a time and take lots of notes. Lte's go back to about 2 Deg. positive on the LF and about 4.5 Deg. hegative on the RF.

Caster on the other hand is the inclination of the steering axis, and to a point, the more the better.  It's measuredd with a caster/camber guage and is a complicated process.   The guage is about $130. and read the directions several times until you understand them .  I don't think the stock Honda suspension allows for much adjustment of caster.  check your service manuals. Anything around 4 or 5 Deg. is good and it will make the car a BEAR to steer in the paddock.  

Finbally, after all this, if it wants to 'hunt' or wander on the straights at speed, reduce the toe out just a little.  Sometimes you just have to stay on the wheel to go fast. My Datsun, for instance , will turn right into the wall at Daytona if you don't stay on top of it, and that's at about 145 to 150 MPH, but it's blistering through the turns.


Please get a tire pyrometer of soem sort and take the temps on three places IMMEDIATELY as you come off the track . Take the temps on the outside edge, in the middle and the inside, write them down and send them to me.  I'll know more after I see them. Try these things, again , taking notes, and let me know what happens.  Please remind me which car it is, I'm working with several at this time.

Dan Liddy
Sarasota,Florida

---------- FOLLOW-UP ----------

QUESTION: Sorry Dan, I did mistake the word camber for caster in your previous answer to Don (10-6-06) on FWD set up.  Yes, we are going to add camber the way you described and that will help.  All the car builders in the area were talking about caster also and we did set that the way I described earlier.  We could get a little in it but not a lot, however, we put as much possitive as we could in the RF and about half that much possitive in the LF. That seems to be better.  I'll get back with you after the race on Sarurday at Franklin County Speedway (UCAR division) in Virginia. www.franklincountyspeedway.com Thanks, Taft

Answer
Do let me know what happens, and get those tire temperatures ASAP- - - that will tell us a lot.

While we're at  it, think about adding an anti roll bar (sway bar) to the rear- - -we can use that to loosen it a bit if it needs it.  They're easy enough to make- - -

Dan