Front tire spacing

jacobsdad

Member
I am curious about a couple of setup options. What effect does moving the left front wheel in or out have on handling? And where should I measure from?
This question is not specific to any kart in particular or any specific handling problems.
this season I raced my sons kart some. Usually we run the left front in as close as we can and the right front 1 inch out measured from the point on the frame that the kingpin bolt goes through. His kart had a bent left front spindle. It is not bent too bad that we can’t get the camber set but it prevents the wheel from sliding onto the spindle far enough. For a quick fix in the pits to get him back on the track I flipped the wheel around. It worked but the valve stem was on the inside making it hard to check air pressure.
When I was racing it I got tired of messing with it so I flipped the wheel back leaving it about 2 inches out instead of 1 inch. I don’t care if I win or not, I’m happy following the pack, so handling didn’t matter a lot but when I did this it cornered a lot better.
tonight we were in the shop getting the karts fixed up and ready to store when I started thinking about that. What does moving the front tires in or out do to handling? And I guess also what relationship does the front track width have with the rear track width?
This is for dirt oval tracks.
 
Move tires in for more front "bite" and better turn in. If you are loose, you can pull front tires out a bit to help.
 
Thanks. I wasn’t specifically looking for a fix to a particular problem, I’m just trying to increase my knowledge. I have been reading about setup changes for a few years, but I don’t retain what I read well.
 
When ever you move any tire to some extent you effect at that corner of your chassis:

1. Grip. For anything to happen you must first have grip.
2. Where weigh moving to a corner of your chassis is applied to the contact patch.
3. The direction projecting weight is aimed when traveling to the corner of the chassis.
4. How moving weight mechanically operates your chassis.
5. How weight applied to the tire contact patch is leveraged to the contact patch.
6. The distance between the spot on the track the chassis is using as a fulcrum point to leverage the tire into the track and the tire contact patch.
7. The radius of the arc the tire will travel.
8. All weight on the chassis will tend to flow in the direction your VCG(vertical center of gravity) is projected by each type of acceleration.
9. Where weight to be directed via the VCG is located on a moving chassis is proportional to where grip is located.

Which one of the above do you want to talk about, comment on it's validity or have questions on? ... :)
 
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Thanks. I wasn’t specifically looking for a fix to a particular problem, I’m just trying to increase my knowledge. I have been reading about setup changes for a few years, but I don’t retain what I read well.

I'm not saying your offering will not help.
I'm only mentioning for discussion my mindset say you "never" fix any on track problem by reducing grip anywhere, unless it's a last resort.

With that thought process in mind and just for discussion wouldn't a better solution be to increase rear grip or make the back somehow better at turning to fix a loose problem, instead of reducing front grip to balance front to rear grip better?

Don't know just asking.
 
For simplicity, some use the adage, for entry problems, adjust the front, for exit programs, adjust the rear. Always fix the first occurring problem first.

As weight always transfers due to g forces acting on the vcg, the front must make enough weight change mechanically to maintain tire grip until g forces apply more weight.

The lf always gets things rolling by jacking weight to the rr, which adds traction to start pushing the front to the left. Ie, making stagger effective, Moving the lf out on the spindle changes the amount of weight moved mechanically at turn in.

The rf has a pretty big job to do. It must provide the lions share of the turning force from the front. As such, we do not want to lose any of the weight that is there already, until weight transfer adds to it. So we do not want to jack any weight here as it will lose weight at turn in.

Moving the wheels in and out on the spindle changes the amount of weight jacking each wheel does.

To verify this, place kart on scales with 1 tie rod removed and that wheel locked straight ahead. Turn in a specific amount. Read scales. Move wheel on spindle. Read again.
Some time spent here can answer a lot of questions.
 
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Every year I try to study one specific adjustment trying to get a good grasp on setup. I know our local track and with a lot of help from people here I have is running good there. I know what changes to make for specific issues but this past summer we traveled to several different tracks. Different sizes, different bank to the corners, different radius of turns and different track surfaces. We did decent but I need to keep learning.
 
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