Would the setup be similar to an SL spec tire?  Would rear track be narrow, front wide, chassis stiffer in front, rear, CGH raised, more weight forward or back?  How about front end geo?  More, less Ackerman, more or less toe, more or less caster, camber?

Mostly feels like the front end is over responsive then the rear breaks loose.  Going down hill into off camber turns it is very tight and won’t turn.  One of those is a high speed turn.  The other tight and slow.  I drove it and my son. We had the same times within .3 seconds.  He was much faster when we ran the other tires on it with similar weather and track conditions.  Over 3 seconds a lap with same driver and set up.  Only difference was tires and added 19lbs of lead to make class weight.  5 lbs in front of tank on floor, 7 on lower left front of seat, and 7 on back of seat up high a little off center to the left.  I didn’t get to scale with the weights since we didn’t know about the weight limit until we got to the track.

The guys and gals that have been running for a while are 1.5 seconds faster with the same tire.  Some are even heavier than us and they are all bunched up running about the same speed.  Talked to one of the drivers and they said they had the same problem when they switched to the Duro tire from MG whites. Said it took a lot of testing and practice to learn to drive with the tire and set up the kart.  Kart is brand new with 2 races on it now, so don’t think there is anything wrong with the kart other than set up.  One other big difference is the fronts are a total of 2″ narrower and the rears are 2″ wider (both tires combined) than the Burris.  Thinking to use a green track, low grip set up?  Have tried different pressures.  Anywhere from 12-26 psi.  Made a little difference in time (few tenths) and made it easier to drive, but no big gains.

Yep, not sure of what to do differently driving wise, but need to try something different.  Also think something is missing from the set up.  Will try a low grip set up to the extreme and back off from there to see what happens.  Did get good info from a trusted source on psi and it is at the low and high of the range we used.  Some like the high and some the low.  Would guess that a lot would be dependent on the kart setup?  I’m going to try testing without the extra weight since I have good numbers on the scale that way and know it did work work well before.  Then scale with the extra lead bolted on to see where it’s at.  Have the kart stored at the track right now and can’t weigh it until we bring it home.

It might need the clutch cleaned as it has run a couple of races since it was apart, but when we put the Duros on it was a lot harder to drive.  My son spun out a bunch of times when he has rarely spun before.  Made some psi adjustments and got it better, but it just seems to lack grip.  Going to try wider front track and. Narrower rear.  Might also put the front torsion bar in.

Not sure on where they are better?  Engine seems to run fine and is hitting the limiter at 6050 at about the same point as everyone else on the longest strait.  Think I really need to work on side bite.  The Burris tires were feathering on the inside edge about equally all around.  The Duros are doing nothing.  What would be the best way to get side bite without binding the chassis up?

So with losing .5″ on each front tire of contact patch it also narrows the front track width 1″. So I should need to move the fronts out .5″ on each side? Also the rear gained 1″ per wheel so in order to get the same rear track width I should pull the rear wheels in 1″ on both sides? This would take the track width back to the way it was on the Burris tires. Does this sound like a good idea?  Also, wouldn’t the front lose some grip due to the tires being narrower?  The rear should gain from the extra rubber?