Left rear adjustment

flattop gave you the correct answer to your question, but heads up you don't want to be moving rear hub spacing as a go to handling adjustment set it before scaling and let it alone, make other adjustments.
 
^^ care to explain why? Every other form of karting uses hub spacing as a tuning tool...often. Just curious. I have less experience on dirt. Want to know if there is a quantifiable reason or if this is more of the kart voodoo...lol Thanks... ~Ted
 
It's just a band aid effect you can help the handling, but doesn't increase speed when used as a bigger swing adjustment, it's ok to make minor tweaks to find that little xtra, but not to fix a handing issue. Your saying tuning tool yes minor changes for fine tuning not bigger swings, I may have not clarified as well as I should have, I guess what I'm saying most is don't get in a habit of it being a go to adjustment, like stagger, or camber would be.
 
When moving the l/r you are making 2 changes at once.C/W and track offset( meaning the centerline of the rear track is offset from the c/l of the front)These 2 changes are going in opposite directions and effect different parts of the corner.I typicaly set it and leave it alone.
 
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Hm. I'm curious to try a couple things then. In asphalt sprint, track width is used to tighten or free kart (mainly affecting Vcg effects because the leverage ratio changes.) In a LTO, the driver is lower, so VCg change is less, per se. I guess I can see what you're saying. Leave the LR alone, and slide RR in or out, that way the LR/RF relationship isn't shifted. I'm surprised more karts don't have a tunable RF rail system to affect torsional rate without screwing with caster/camber effects... Thanks for your explanation.
 
quick question Ted: On a sprint kart does widening the rear tighten up or loosen up the back? I always get confused thinking about it and did not understand from your answer which did what. And what are your thoughts on why one or the other does what it does? I'm thinking your answer is a good read and I'm starting to see what you offered.

thanks

... ok now I do got to get that coffee ... :)


almost forgot the most important thing ! Happy Cash Out Your Gifts Day
 
0151titanriders said:
By moving the left rear in or out will it increase or decrease cross or does it not affect the cross ?
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I'm going to read through and comment on both what others offered and try to put down my thoughts which will hopefully also be ok.

I. As flattop1 and racing promotor offered move the LR hub out and it decreases cross, in increases cross.

Reasons why:

1. flattop1 explained moving the hub in moves it closer to the center of gravity. He did not say it was moving it closer to the vcg (vertical center of gravity) and I think his reference is correct because your weight measurements for cross, nose and left side are done on a flat plane which does not take into consideration looking at it in 3D. It's also not necessary when using cross to consider where the vcg is located.

2. I also think flattop 1 is correct.

3. RCJ offered new insight we don't often get to read about on here. He introduced us to looking at the relationship between the center line between the two rear tires and the center line between the two front tires. He also brought into it that he has an understanding of how changes in the relationship effect different parts of the corner. I'm chomping on the bit to learn more on that. Sorry not trying to hijack your thread because I think you got correct answers to your original question, but I have to ask RCJ if he considers the center line of the rear axle to be the center line for the whole kart? And would you please give us more insight into how front and rear center line changes effect different parts of the corner. For me that's a WOW I got to hear more about it type of thing. Or it's going to be something I'm going to have to study up on. ... :)

4. I'm going to add in because your using stagger the rear axle also slants downward to the left. That means if you move a hub to the left it also lowers the left rear corner and if you move it in it raises the left rear corner. The relationship between raising and lowering cross and how you spread out weight gets complicated. Because of that I'll just leave it at moving the hub in raises the left rear corner of the kart.

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Did you get your original question answered ok?


Do you have more questions on it?

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RCJ I have to ask you a question. Would you say the relationship between the front center line and the back center line if it's not the actual 'roll axis' of our LTO karts, it's probably the best thing to use as the 'roll axis'? thanks, I'm thinking you will say yes but don't know?
 
Paul -- typically, widening either end on asphalt makes it "looser" (ie. induces push in front, oversteer in rear. ). In extreme cases of grip or narrowness, pulling the tires in leads to bicycling. On dirtphalt, I'm not sure what the effects would be. I need to read up more on cross. I am thinking that there's some time to be found on today's karts in the chassis side...
 
When we were racing street stock camaros the front track was 62'' wide.we were putting 64'' ford rearends under them.What i founds was to line up the r/s tires and let the l/r stick out( this was offsetting the c/l of the rear track 1'').This would make the car a little tighter on throttle exit.If you build a little leggo car and offset the rear track to the left quite abit you can see how this would make the car tight on throttle.Next I started spacing the r/f out,it real didn't help.What i found was that wheel offset and spacers didn't work for some reason,If i cut the a arms and made them wider by about an inch the cars were better on entry and to the apex.Because of the low c/g and no springs to tune the kart i can't say were you should be on a kart, but the laws of physics are the same for everything.
 
If the kart is dialed in pretty well but is tending to get a bit assey about half way through the corner to the exit I will slide my LR out 1/2 inch and that will generally fix me up for the day. LR in or out and air pressures are about all I will touch once I have the kart scaled up to my liking for our local track. Just remember to slide it back in to your original scale setting at the end of the race day.
 
OVALTECH1 said:
If the kart is dialed in pretty well but is tending to get a bit assey about half way through the corner to the exit I will slide my LR out 1/2 inch and that will generally fix me up for the day. LR in or out and air pressures are about all I will touch once I have the kart scaled up to my liking for our local track. Just remember to slide it back in to your original scale setting at the end of the race day.
Click to expand...

Since you stated after moving LR your good for the day, am I correct your making that adjustment for kart being assey after practice ?
 
Correct or in our case after the first heat (heats) when they finally decide to let the track dust and up a bit. Certain racedays I can leave kart as is (scaled setting) other days your messing with air and sliding a tire out. That track is never the same twice. And at the end of the day it was probably just me driving in a little too deep and a bit too low but that little adjustment usually helps me go wild man and not spin.
 
I ask because provided your close on tires for practice and know the tire to race on, an assey kart in practice was always a good sign track would come to us, I'd say your chasing it to early and giving credit to an adjustment that not really helping, the difference your seeing is other factor's coming to play.
 
You may be correct in that statement because there were days that the track would come around and I would have a kart for the feature that seemed too locked down and I was wishing I had that loose kart from earlier in the day.
 
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