phantomkartracer
Member
Why run so much? I see some chassis with some pretty high numbers. What is the purpose/what is the functionality of running such high negative R/S camber?
RF Camber question
- Thread starter phantomkartracer
- Start date
racing promotor
Moderator
You want to use as much as you can but still turn, less tire contact less rolling resistance, Sr Champs always require more RF camber which I've always chalked up to the chassis being so tight with the welded cage, however with a flat kart set up higher RF camber seems to go hand and hand with higher cross set ups, again less tire patch contact less rolling resistance. This would be the K.I.S.S response.
Per Todd Goodwin the smart guy's response would be, RF camber works with the same physical phenomena as the LF. Camber thrust and tire spring rate. It also has the same tendency to move the effective scub radius around except that the negative camber on the RF tends to move the center of the contact patch in closer to the centerline of the chassis ( decreasing scrub radius ). Because we tend to run substantially higher camber angles on the RF, the effects on corner stiffness tend to be more pronounced. Because the RF is so heavily loaded on today's karts, it has more pronounced effects throughout the corner. One of the places RF camber can be used to adjust the kart is at corner entry. If the kart is pushing right at turn - in using a little less negative RF camber will often eliminate the problem. It will stiffen the RF corner causing it to load a little faster and eliminate the push. Another place RF camber can affect the kart is on exit, although at this location of the turn it is a little more difficult to predict how the adjustment will affect the kart. On one hand is the stiffness and the way it impacts the reloading of the rest of the chassis and on the other is the amount of tire on the track and the amount of involvement the outside sidewall plays. With respect to the stiffness, as the steering wheel is straightened , a stiffer RF will load the LR slightly faster ( unloading the RR at the same time ) slightly changing the grip balance across the back of the chassis.
Per Todd Goodwin the smart guy's response would be, RF camber works with the same physical phenomena as the LF. Camber thrust and tire spring rate. It also has the same tendency to move the effective scub radius around except that the negative camber on the RF tends to move the center of the contact patch in closer to the centerline of the chassis ( decreasing scrub radius ). Because we tend to run substantially higher camber angles on the RF, the effects on corner stiffness tend to be more pronounced. Because the RF is so heavily loaded on today's karts, it has more pronounced effects throughout the corner. One of the places RF camber can be used to adjust the kart is at corner entry. If the kart is pushing right at turn - in using a little less negative RF camber will often eliminate the problem. It will stiffen the RF corner causing it to load a little faster and eliminate the push. Another place RF camber can affect the kart is on exit, although at this location of the turn it is a little more difficult to predict how the adjustment will affect the kart. On one hand is the stiffness and the way it impacts the reloading of the rest of the chassis and on the other is the amount of tire on the track and the amount of involvement the outside sidewall plays. With respect to the stiffness, as the steering wheel is straightened , a stiffer RF will load the LR slightly faster ( unloading the RR at the same time ) slightly changing the grip balance across the back of the chassis.
Last edited:
Randy Major
Member
Simply put; RF camber is directly related to RF dynamic load and getting the best footprint.
paulkish
old fart
Less rolling resistance and
You might have also asked what's the advantage of running such a big RF tire which led to your camber question.
I think originally someone just tried a big RF tire and it worked for them leading into all kinds of reasons for it being good.
First reason I remember hearing was the big tire dissipated heat built up from working with the track.
Then came the camber idea of less rolling resistance on the straight and still being able to use the amount of tire as needed in the turn.
Then came it's all about timing when you load the RF and reload the LR.
I'll throw another one in the mix.
No matter what you read about setup and all the nerd scientific things mainly conger-ed up by those ancients who raced turning both directions. ...
There's two things which flow through all of the screw with your head stuff and they are:
At all cost reduce rotating weight and reduce unsprung weight.
Well there are two kinds of things rotating on what you race besides the mumbo jumbo going rolling around in your head.
They are rotating weight you use to accelerate and the rotating weight of what you race.
No question about it about reduce rotating weight you use to accelerate, until a discussion of gearing sizes of equal ratio gets going. ...
The other is about weight placement and the mechanical and dynamic movement of different bits, pieces and masses on what you race.
Except occasionally from me who will surely get shouted down on it, I think some unsprung weight has a useful place.
It's simply about if you always can use and store some weight at a particular place on what you race then why screw around moving it to and from where your going to need it?
And that weight will be called by me as "useful unsprung weight".
A quick reference IMHO is dumping a ton of weight on the LF racing indoors and why?
The why is you don't want it on the LR because it can cause you to bicycle and if your going to use it up front to turn, then just put it there.
Back to the original thought I was presenting.
The reason for the big heavy RF tire and why it worked for who ever did it first or afterwords is to put/dump some weight at the RF where it's needed or going to be needed.
If your going to always need some extra weight on the RF and you can store it without loss of speed there, then put it there.
All the rest is about the geek why of it and fine tuning it's use.
... maybe because this is all IMHO and ain't necessary right anyway. ...
If the above bs is even remotely close i'd bet racing motor cycle side cars are not always set for minimum weight letting all weight get transferred by a big fat butt rider? ...
Not knowing or ever looked into it I'll bet they adjust the unsprung weight of the side car for track conditions.
Same with what we race no matter what it is on ovals. IMHO unsprung weight can be useful.
... or not? ?????????????????????????
edit: just had another thought on it.
Isn't lowering the COG always among other things about reducing the amount of the actual use of unsprung weight for grip?
... never looked at COG in that way before but right now it seems appropriate????????????????
Isn't lowering the COG using unsprung weight to reduce grip, use already available grip more efficiently and to reduce tendency to roll? Especially when your only turning left how could you accomplish all the same with sprung weight?
answer: You can't or maybe you can't. Either answer provides a use for unsprung weight and disproves the common statement of
Always work towards reducing unsprung weight and increase sprung weight.
Maybe the real answer is in my saying "work towards"? nawwwwwww
... ok where's that coffee?
You might have also asked what's the advantage of running such a big RF tire which led to your camber question.
I think originally someone just tried a big RF tire and it worked for them leading into all kinds of reasons for it being good.
First reason I remember hearing was the big tire dissipated heat built up from working with the track.
Then came the camber idea of less rolling resistance on the straight and still being able to use the amount of tire as needed in the turn.
Then came it's all about timing when you load the RF and reload the LR.
I'll throw another one in the mix.
No matter what you read about setup and all the nerd scientific things mainly conger-ed up by those ancients who raced turning both directions. ...
There's two things which flow through all of the screw with your head stuff and they are:
At all cost reduce rotating weight and reduce unsprung weight.
Well there are two kinds of things rotating on what you race besides the mumbo jumbo going rolling around in your head.
They are rotating weight you use to accelerate and the rotating weight of what you race.
No question about it about reduce rotating weight you use to accelerate, until a discussion of gearing sizes of equal ratio gets going. ...
The other is about weight placement and the mechanical and dynamic movement of different bits, pieces and masses on what you race.
Except occasionally from me who will surely get shouted down on it, I think some unsprung weight has a useful place.
It's simply about if you always can use and store some weight at a particular place on what you race then why screw around moving it to and from where your going to need it?
And that weight will be called by me as "useful unsprung weight".
A quick reference IMHO is dumping a ton of weight on the LF racing indoors and why?
The why is you don't want it on the LR because it can cause you to bicycle and if your going to use it up front to turn, then just put it there.
Back to the original thought I was presenting.
The reason for the big heavy RF tire and why it worked for who ever did it first or afterwords is to put/dump some weight at the RF where it's needed or going to be needed.
If your going to always need some extra weight on the RF and you can store it without loss of speed there, then put it there.
All the rest is about the geek why of it and fine tuning it's use.
... maybe because this is all IMHO and ain't necessary right anyway. ...
If the above bs is even remotely close i'd bet racing motor cycle side cars are not always set for minimum weight letting all weight get transferred by a big fat butt rider? ...
Not knowing or ever looked into it I'll bet they adjust the unsprung weight of the side car for track conditions.
Same with what we race no matter what it is on ovals. IMHO unsprung weight can be useful.
... or not? ?????????????????????????
edit: just had another thought on it.
Isn't lowering the COG always among other things about reducing the amount of the actual use of unsprung weight for grip?
... never looked at COG in that way before but right now it seems appropriate????????????????
Isn't lowering the COG using unsprung weight to reduce grip, use already available grip more efficiently and to reduce tendency to roll? Especially when your only turning left how could you accomplish all the same with sprung weight?
answer: You can't or maybe you can't. Either answer provides a use for unsprung weight and disproves the common statement of
Always work towards reducing unsprung weight and increase sprung weight.
Maybe the real answer is in my saying "work towards"? nawwwwwww
... ok where's that coffee?
Last edited:
Andy Collier Racing
Member
Are you suggesting more negative camber in RF for a champ kart?
racing promotor
Moderator
First I must say I'm no champ guy, but on avg yes if 2.65 I'd avg for flat kart, 3.35 is probably avg for champ.
JRC_Performance
Member
At least -3.5.... I’ve had guys running -4.25....