Caster and Camber Gain different scenarios?...

[DirtRacer9x]

Hike vs camber gain

[Matt49]

Caster gain is a topic you're not going to get a lot of people talking about on here.
Camber gain: Because of the huge amount of body roll the cars have today, you need camber gain (relative to the chassis as if it were sitting at ride height) to achieve the desired amount of camber relative to the race track itself.
There's more to it than that (some of which I'm sure I don't yet understand) but that's the basics of it.

[grt74]

the entire front end of a race car has a ton of compromises,with that said camber is where you want the least compromise,caster gain or anti dive as some may call it,to me its all about how the driver drives(if he hits the brakes hard or he's really good at rolling in the corner off the gas)
its something that you'll have to play with,not everyone drives the same,most people don't understand anti dive and if you don't,don't mess with it,your chassis manufacture should have this figured out,it will make your car act very silly if you go out of the good area on this adjustment

[grt74]

well here's what i'm trying to understand. I'm not a gurue on it but my understanding is with chassis roll you want camber gain because of this. Now what i'm thinking is when a car isn't hiked and then does hike over that camber gain is needed. Now lets say i have a car that never comes off the bars and runs 2 brake floaters. Like i said i'm not a gurue on this but if i am never off the bars while at speed do i want camber gain? Maybe i have this all wrong but this is how i picture cars having camber gain and why they do. Most cars have one brake floater and the cars come off of the bars that i see but 2 brake floater cars don't as much as long as you're on brake or gas constantly keeping the chassis loaded. Am i close at all? Thank you for your input.

you want your camber gain to be what ever the car wants,and this is very dependant on all your angles and lengths of your uppers and lowers

[grt74]

So can putting longer uppers on help the rf with camber gain? Since it would never be off the bars at speed on track? Is this too technical? I'd like to just know every possible option and its pros and cons.

a longer upper will take away camber gain,a shorter one will add camber gain,also you would be surprised what an 1/8" shim in or out will do it doesn't take much if your close,its all about reading your tires

[Bubstr]

What dynamic camber (with gain) should we shoot for? I was always told 1 to 2 degrees of negative on the RF, but seeing these club 29 cars, it appears to be much more.

[grt74]

What dynamic camber (with gain) should we shoot for? I was always told 1 to 2 degrees of negative on the RF, but seeing these club 29 cars, it appears to be much more.

there good cars but they don't win them all

[grt74]

So are there situations like the one I described why camber gain is desired or not desired?

if your using the whole tire its just plain old common sense its going to be faster on the stop watch,yes there are times that tire scrub will help and thats what club 29 is doing
tire sidewall deflection has a factor in this also

[grt74]

I'm just trying to figure out why we have camber gain exactly. Like why chassis builders built this into their cars. This will help me find my answer I believe.

last answer for me,you need camber gain because your trying to keep the contact patch of your tire flat to the track(so it uses the whole tire and not just the edges,inside or outside)there are however several ways to do this and some are better than others,remember like i said above,tire deflection(sidewalls or how the sidewalls are built)has a factor in this also

[fastford]

get you a pyrometer and go to testing, that's what I do.

[MasterSbilt_Racer]

So camber gain has to do with only tire deflection and chassis roll or a combo of both? What's optimal and why? 1-2* 2-3* and why? Thanks

Both effect how your contact path comes into contact with the track. So both matter. There are situations where more camber gain than optimal can help too. (See Club 29)

You cannot just "figure" a correct answer. You have to test and learn. That is what even the guys who seem to have all the answers are doing.

[7uptruckracer]

the entire front end of a race car has a ton of compromises,with that said camber is where you want the least compromise,caster gain or anti dive as some may call it,to me its all about how the driver drives(if he hits the brakes hard or he's really good at rolling in the corner off the gas)
its something that you'll have to play with,not everyone drives the same,most people don't understand anti dive and if you don't,don't mess with it,your chassis manufacture should have this figured out,it will make your car act very silly if you go out of the good area on this adjustment

Caster Gain is not anti or pro-dive at all. Has nothing to do with wheel loadings as a result of braking forces like anti- and pro- dive do. Caster gain is an area that isn't going to be talked about much its in your spindle design as well as your arm arrangements most try to minimize dynamic caster gain split, BUT you can use caster numbers these days to also effect your camber curves where you normally lose camber in chassis ROLL you can negate the effect with caster gain or untraditional caster numbers. We are using caster on asphalt that will blow your mind like +8-10 on both sides so as you turn the wheel you also change wedge in the car as well as negate LF positive camber loss through dive and you can use it to help roll loss. On the RF you can keep it from going through to much camber transition depending on if your running a tie down setup or one that travels. Look at which setup you run if your tied down you might start with less static on a short RF upper and gain a lot. Or if you don't you could run a longer arm on higher static. Some use the camber thrust theory and some like to utilize the contact patch which seems to be seen less and less. Look at the cup guys they use camber thrust this is why they always blow tires they are running them on the edges its like leaning on a broom stick thats standing straight up you will fall over now kick the handle out and lean on it and you can lean harder because its helping hold you up

[Brian Gray]

Just keep in mind camber thrust is a dynamic force so if you are loading a tire to gain traction the camber thrust can easily over load the tire and cause you to loose traction on that tire. Facts are there are no right or wrong answers it all depends on what you need out of your setup.

[drtrkr244]

Unfortunately, all of these handling concepts, leaves you at the mercy of your tire compound/construction. Theres no technical info available from the Purple beast. They treat you like a spy when you ask for it and then only give vague answers, that you knew already. Only Professor Furney has ever published any such info, but it was only on D-xx compounds. Hoosier wouldn't supply any help to him even though he was trying to help the local racer.

This is why your local hotshoe cant compete when the national boys come to town. They think they should make their normal chassis adjustments but the different compounds don't respond like their Saturday nite ones do. The touring guys know what compound to run based on the track conditions and their previous experience.

[Brian Gray]

All you gotta do is cut them apart. The compound bases you will never really know because its always changing depending on what materials are cost effective at the time. But as far as tread belt and sidewall construction all you gotta do is cut them up. You can plainly see the stiffeners and location. That's ultimately what is important.

[grt74]

Caster Gain is not anti or pro-dive at all. Has nothing to do with wheel loadings as a result of braking forces like anti- and pro- dive do. Caster gain is an area that isn't going to be talked about much its in your spindle design as well as your arm arrangements most try to minimize dynamic caster gain split, BUT you can use caster numbers these days to also effect your camber curves where you normally lose camber in chassis ROLL you can negate the effect with caster gain or untraditional caster numbers. We are using caster on asphalt that will blow your mind like +8-10 on both sides so as you turn the wheel you also change wedge in the car as well as negate LF positive camber loss through dive and you can use it to help roll loss. On the RF you can keep it from going through to much camber transition depending on if your running a tie down setup or one that travels. Look at which setup you run if your tied down you might start with less static on a short RF upper and gain a lot. Or if you don't you could run a longer arm on higher static. Some use the camber thrust theory and some like to utilize the contact patch which seems to be seen less and less. Look at the cup guys they use camber thrust this is why they always blow tires they are running them on the edges its like leaning on a broom stick thats standing straight up you will fall over now kick the handle out and lean on it and you can lean harder because its helping hold you up
im not saying I'm right or wrong but i do know this for a fact and if you don't believe me try it on a car,if your lower and your upper are at the same angles,you'll have zero caster gain from o to 3" up and down,the only way to add caster gain is with anti dive,yes you'll set your static settings but if there isn't any anti dive it won't change from 0 to 3",yes there is different spindle inclinations but thats another story altogether,

[let-r-eat]

You can have caster gain/loss without anti-dive. The arch of the lower control arm can move fore and aft the chassis by the strut rod or 2nd piece of the lower if those archs are different.Generally you are correct that anti dive is what causes caster gain/loss because it changes the arch of the outer ball joint fore and aft compared to the lower ball joints arch.I know some change the front mounted strut rod on the rocket to the rear so it doesn't drag and by doing this you change which direction that arch moves. Instead of pulling the lower forward in compression causing gain it then pulls it backwards causing a caster loss.

[grt74]

I'm officially lost haha. But I like reading the input guys. :cheers:
there is a lot to todays front ends,the best thing to do is just keep good notes and try different things,if they don't work go back to what you had,moyer said it best for every 50 things you try 1 or 2 may work

[Bubstr]

Simple answer is, with more caster you get more or less tire loading when you turn the wheel.

When you want this is in the corner. The gain is made with dive and roll.

What it does when wheel turns right, it adds loading because the ark on the spindle drives the tire into the track and opposite for turning left. This also loads or unloads the LR.

So as you go threw the corner loose, you steer right and gain loading on RF and LR that tightens the car up. If your pushing, you automatically turn left, which unloads RF and LR helping to loosen the car up. It's built in chassis adjustment. While on the straits with out caster gain, it doesn't effect the loading as much, keeping your static rear loading for traction. It's not about where the weight is, but where it is transferred to.

This is nothing new, They where using it in the 50s on Midgets and Sprint Cars even the straight axle mods.

[Ltemodel]

Your amount of camber gain is really dependent on how your car rolls.

If your roll center is further left, the entire front end will lower under body roll and will need less camber gain because there will be less camber loss as the body rolls.

If the roll center is closer to the center of the car or RF, the RF will loose camber more under body roll and will need more gain to keep the grip in the RF tire.

A good way to visualize the need for keeping camber in the RF is to take a tire and put your foot on the rim where it bolts to the hub.

Taking a little air out will make this more visual.

Push on the rim with your foot and you can see the outside of the tire is loaded more than the inside. The inside will actually unload to a point where there is no pressure on it at all.

Now, angle the top toward your leg and push on it again.

The inside of the tire will begin to load more and eventually equalize with the outside of the tire.
This is the reason to put gain or keep the camber consistent through body roll. Body roll will naturally want to take camber out. Gain will help keep camber consistent through body roll.

Camber thrust was mentioned earlier in this thread and this will really help turn the car. When stretched rubber will naturally want to return to it's relaxed state.

As the tire is stretched in a turn, and the tire is loaded properly, it will want to continuously 'snap' back into position and push the front end left.

The problem with tire temps is that when the slows or comes to a stop the temps will instantly begin to equalize across the tire.

Unless there is a huge problem tire temps will have a hard time picking it up. The indicator I like is tire wear.

Caster gain is another can of worms. I would recommend digging further into ackerman before caster gain. I think there is more speed to be had through ackerman adjustments than caster gain.

Good Luck,
Kevin

[drtrkr244]

So like white wall in or out? I've never cut one apart. How should say a G60 be mounted?

Per Hoosier website, always mount tire with date code facing the infield. The outside of the tire has a thicker sidewall.

[drtrkr244]

All you gotta do is cut them apart. The compound bases you will never really know because its always changing depending on what materials are cost effective at the time. But as far as tread belt and sidewall construction all you gotta do is cut them up. You can plainly see the stiffeners and location. That's ultimately what is important.

I believe you also have to know tire loading/tire heat gain to determine if you have the proper compound. I only know of one logarithm table that accurately predicts heat buildup. Unfortunately, it only applies to D-xx compounds.