Can anyone explain
- Thread starter rac12race
- Start date
spincycle
Member
Not sure about "loosening", but I've always believed it helps get the kart to keep turning on high grip/high bite tracks, increasing cross shifts static weight to the RF and LR, trick is getting that extra static weight off the LR and to the right side during cornering....and back to the LR at the corner exit (exit speed) thats where different chassis and different frame tubing/thickness/design come into play....
paulkish
old fart
The simple of it is: ?!?!?!?????
The reason your kart or anything you race becomes loose is because the RR tire looses grip. period. end of quoting me. ...
Factors which allow or cause the RR to loose grip are many.
First up you'll hear bout too much grip up front causing loose.
... well each of the rears can only drive straight and then stagger helps them together not drive straight.
... but each individually can only drive or propel in a "straight" direction.
... because of that the fronts have to turn the backs.
... If you have too much grip/turn/etc up front then you are able to increase the conflict between the RR tire in the back only being able to go straight and the front trying to turn it.
... If the fronts can win the conflict then the RR if it's already on it's limit has to become loose and slide because of loss of grip.
... yada yada yada and now that your a believer in the bull I just wrote ...
There's also the LR helping hold the back end in with it's grip.
If the LR looses grip then all the effort available to hold the back end in and not be loose automatically is put to the RR.
... and the RR can't do it alone so it looses grip and ya get loose.
Cross by definition is a reading of weight put on or to be carried by tire grip of the RF and LR. right???
yep that's right
Jack up cross and the LR is either going to be able to carry the load or it's not.
Jack up cross to the point the LR can't carry it's weight and ... then see and read again my bull about the only reason your loose is because the RR can't carry all the load in the back by itself. ...
Your answer is there is a point where if you put more cross to it, it becomes possible for the weight the LR carries exceeds it's grip.
The LR looses it's grip, pukes on the RR.
The RR can't handle the puke and it too looses grip and ya get loose.
The ONLY reason you can be loose is if the RR looses grip and starts sliding.
Don't matter if the LR is still able to carry some weight and have grip you STILL exceeded the capability of the RR and ya got loose.
... maybe because this is all IMHO and ain't necessarily right anyway. ...
hope I did ok?????
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spincycle
Member
My experience with the PRC Recon was a great example of how adding cross could actually both tighten and loosen the kart, based on track condition and overall set up numbers...if the track surface was low bite/low grip and you uped the cross trying to tighten the kart it would actually overtighten it to the point it would push right into the fence coming off, as it was overloading the LR to the point of little to no weight transfer to the right side tires, if you uped the cross trying to get it to turn better on a high grip/high bite surface it would have a tendency to snap hard loose from center off...Best thing to do is get together with someone knowledgeable or the builder of the specific kart you're running to get the low down on the baselineset up and how changes to it will typically affect the kart handling on the track under speed...
racing promotor
Moderator
Remember that guy that points out there are very few ALWAYS In karting, with that being said are you saying ALWAYS ?
And then to break it down in more detail, if the answer is ALWAYS , do you ALWAYS get the same results by adding more ?
racing promotor
Moderator
When talking cross I prefer the term freeing the chassis VS loosen but that's just me. Like adding cross for a really gripped up properly calcium prepared track on a hot sunny day, I look at it like I'm freeing up the entire set up VS just loosening up the rear of the kart.
"J'-remy
Member
because it has gone over the cliff. this is how some newer chassis are being designed. the idea is to have the kart ride on the right front and left rear in an effort to diminish the scrub created by stagger in the straight. when the steering wheel is turned the kart squats (through caster and kingpin inclination) on all four tires to get around the corner and then lifts itself again for the strait. adding more cross will keep the chassis from squatting therefore making it loose.
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spincycle
Member
Get hold of James Stanley on here, he is the customer support rep for PRC karts, he is always great help...
mike97760
Site Supporter
I have a kart that was in a wreck, bent the RF spindle. Put a new spindle on and didn't see any other obvious problems. Took it to race myself the next weekend and couldnt make a lap without spinning out. Had another experienced driver try it, he had the same results. Scaled it and it was at 40 cross, frame was bent. Thats how I know that lower cross is loose.
Tonypowerkartsupply
Member
Lower cross helps the kart rotate by unloading the lr, this will overwork the rr on the longer run. This is why Lower cross setups work with less RF camber and the LR tucked in.
High cross will not loosen the kart but help keep the RR from being overworked and give you better drive off.
It’s all about finding the balance, not too low and not too high on cross. The more cross you run the kart will want more RF negative camber.
paulkish
old fart
I'm seeing in my mind the squat you told us about as ... maybe ...
... your on the banking in a turn.
... stagger and the banking has your smaller LR tire down hill from the RR tire
... when you turn the squat and camber changes at the front puts the LF down the banking to grip the track
... and it lifts up the RF allowing the front end to squat or reach down with both front tires to get ahold of the track.
... nets out to the LF physically reaches down hill to grab the track and the RF tire raises up to let the whole front end reach down of squat down into the track
Thunkin on it immediately made me think of current latemodels with their huge camber gain letting them drive or push the RF into the track.
Now because of the post by J-remy I'm also thunkin about how it's also helping squat the whole front end down to better grab at the banking of the track. ... again LF down to grab at the track and RF up to lower the whole front ... ??? maybe??
... and same deal on karts except because of lesser available hp it's done to a lesser or maybe better stated to a different degree and ????
this is fun
"J'-remy
Member
The newer karts are much stiffer than they used to be. I was told phantom has a treadmill they put karts on. Because of the split caster and the stagger the kart will always drive to the left. (When you drive down the straight you physically turning the wheel right to hold a strait line) they measure how much force it takes to keep the kart in a strait line with a cable that is pulling the kart to the right. The stiffer chassis is to keep the kart up on the right front and left rear. The kart doesn’t necessarily squat but plants the left rear and the left front pushes towards the track when steering input is applied. If you want to know what’s happening, place your kart on the scales watch across the front end and read the scales while turning the steering wheel to the left. It’s all pretty dramatic.
spincycle
Member
Big variables to try to account for....track size/shape/location...what the driver is doing with the wheel/brake/gas pedal thru the corners where I race around the upper Midwest, typically the tracks are small 1/8th mile bullrings, usually dry/dusty red clay/sandy low grip/low bite with mediocre kart numbers ...compared to tracks in the southeast us....higher kart counts, better quality dirt, tracks bite up/ good grip, bigger circumference speedways, and close to location of kart manufacturers, us guys out here in the sticks sometimes have to try unconventional set ups/thought processes to try to get karts around the tracks around this area...pretty rare to find one that is wide open foot to the floor types, many of them have short radius corners that require full use of the brake, the wheel and the gas pedal, all of which certainly have to require the need for unique set ups one would think...
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flattop1
Dawg 89
Along with that . Most tracks i seen in the south were flat too no banking .
Round here at least there is some banking .
As far as stiffer my 2012 35 is about as stiff as it gets if that chassis squats its a miracle .
King pin inclination , camber and caster all , create weight jacking .
Nothing new there .
Round here at least there is some banking .
As far as stiffer my 2012 35 is about as stiff as it gets if that chassis squats its a miracle .
King pin inclination , camber and caster all , create weight jacking .
Nothing new there .