Visual camber tuning

Discussion in 'GT5 Tuning Forum' started by SHIRAKAWA Akira, Aug 30, 2011.

  1. shirakawaa

    Premium
    None  
    PSN:GTP_shirakawaa

    Maybe I just discovered hot water, but recently I've come up with a pretty easy method for tuning camber scientifically, and not only by feel or worse instinct. As everybody knows, in RL camber is usually set up depending on tire temperatures. In GT5 however unfortunately we don't have such information, and telemetry is useless too for that.

    So, it works like this:

    • Go in practice mode, select the Top Gear Test Track.
    • Go on the track.
    • As soon as you acquire control of the car, don't go ahead, but turn back approximately around the big brown 'X' on the ground.
    • From there, apply constant throttle and steering angle and try finding a speed that will allow you to go around in circles at the highest lateral G possible without going out of the track. Be sure to be very smooth and to change speed as little as possible. Don't slide or drift. With a premium efini RX-7 equipped with comfort soft tires the most I could do was 50 Km/h in third gear.
    • Make a few complete turns. Again be sure to be very smooth and to apply the maximum steering possible without causing understeer by excessive steering angle (especially if you're using a wheel).
    • When you're finished, start->exit without completing the lap and return to the track main menu. Select "Replay".
    • Wait until the game replays when you were going around in circles at constant speed and [possibly] high G.
    • Wait again until you get the best angle and maximum lateral car inclination and the press start. Enter photo mode.
    • Here comes the important part. Get a little bit away from your car and be sure that the camera is parallel to the ground. Now analyze its outside wheels (to the turning circles it was doing). Zoom on them and try checking if they're perpendicular to the ground. Chances are that at this point they aren't at all on both axles.
    • Exit photomode and go in the car setup screen. Increase camber some more, then check again by driving again in circles at constant speed, then analyzing the car's outside wheels in photo mode. It will take several tries. Repeat until the outside wheels are perpendicular to the ground.
    • Depending on your car setup, the maximum camber angle that will make the outside wheels perpendicular to the ground will differ on both axles. On my RX-7 with a front sway bar set to 4 and rear set to 1 (spring rates: 8.5/6.4) I ended up with a front camber of 1.0 degrees and a rear camber of 2.4 degrees.
    I'm looking forward to read other user's data and impressions compared to other camber tuning methods. I'm not sure if tuning camber visually is the best method, but in my case it gave good results.

    I'll add some pictures at a later time.
     
    Last edited: Aug 30, 2011
  2. CSLACR

    United States
    PSN:GTP_CSL

    I will definitely try this, can't hurt to try it quick.
     
  3. bigberry

    Scotland
    PSN:bigberry

    At first i thought op is crazy , after reading the whole thing it actually isnt a bad idea :D
     
  4. shirakawaa

    Premium
    None  
    PSN:GTP_shirakawaa

    By the way, the reason I chose the Top Gear Test Track is because it's very flat (which makes checking if wheels are perpendicular to the ground quite easy, since the photomode camera easily snaps to the "neutral" lateral inclination) and you start right on the airfield main straight which is wide enough to run in circles at sustained speeds continuously. A proper skidpad would of course be better suited for this (or even better, proper telemetry and/or tire temperature data).
     
  5. shirakawaa

    Premium
    None  
    PSN:GTP_shirakawaa

    An important thing I just discovered (actually, just "remembered") with this method on a '98 Corolla Levin BZ-R that deserves a post on its own is that by lowering the suspension to negative values, even by not touching the camber values, the effective camber under load at the same lateral G might change, depending on the car's suspension. It is quite visible by the naked eye with the Photo Mode.

    So, optimal camber settings to achieve outside wheel perpendicularity while cornering can also depend on the car's ride height and suspension geometry.
     
  6. Motor City Hami

    United States Dearborn, MI
    PSN:MotorCtyHamilton

    Been doing this for a while. Wish PD would have programed tire temps into their model, but without it, the best we can do is use photo mode.
     
  7. CSLACR

    United States
    PSN:GTP_CSL

    I saw no difference between straight wheels and turning wheels, always had an incredibly small amount of camber, tried with 1.6 front 1.0 rear on a Yellowhat GTR.

    and another thing I've though of is shouldn't you aim to make it flat where you steer to instead of farther then easily reached? In other words, if you mainly steer within the first 90 degrees of steering, you don't want your tires camber to only match at full turning force, right?
     
  8. shirakawaa

    Premium
    None  
    PSN:GTP_shirakawaa

    Cars with stiff suspensions and low body roll don't need much camber.
    Unless on your car the front suspensions make camber increase the more wheels are turned, as long as you're hitting high constant G, it doesn't matter much in my opinion. You could use the whole track instead of turning in circles, to check at higher speeds and a lower steering angle, but it makes the process longer and more complex as it might be harder to determine in other corners if the outside wheels are perpendicular to the ground or not. I haven't tried yet to be honest.
     
    Last edited: Aug 30, 2011
  9. Corse

    Plzen
    PSN:CCorse

    It's quite nice to find out camber with photo mode. Just one thing to think about:
    You now find the right camber for your speed of 50km/h. That's a really tight corner and you'll probably get this way the maximum camber settings needed for your car.
    On faster, wider corners, the needed angles of the camber should be lower to find the most grip, because the aero off the car helps to press it on the track.
    So maybe it's better to use the photo mode on the important corners (the ones preceeding a high speed straight) of the track you like to have a tune for, to find the best setting.
     
  10. shirakawaa

    Premium
    None  
    PSN:GTP_shirakawaa

    As I said, I chose the Top Gear Test Track's main straight due to the fact that it is known to have no camber and being essentially flat. This makes it easier to determine wheel angle (on other tracks there is always some amount - even minimal - of camber, or bumps). Unfortunately, as you suggest, this limits camber optimization to tight corner speeds (~50 Km/h on comfort soft tires).

    Today I realized that with the Tokyo Bay (Kart) Course Maker theme it's possible to make flat tracks for camber tuning at higher speeds. With this theme there are no elevation changes at all (meaning 0.0 m, completely flat track); also, compared to other ones, cambered corners are not possible with it. A custom track based on it (which possibly includes some constant speed corners) at a width of +5 would probably be better suited for the job than the Top Gear Test Track.
     
  11. CSLACR

    United States
    PSN:GTP_CSL

    Well, one of the reasons camber works so well IRL on front wheels, is because the further you turn the wheel, the more positive camber the outside wheel generates, due to steering geometry.
    IDK if this has been simulated in GT5 or not, just saying the first car I tested had wheels not flat going straight, and equally not flat when turning, it seemed they didn't move at all when I turned the wheel.
     
  12. shirakawaa

    Premium
    None  
    PSN:GTP_shirakawaa

    Oh, now I see what you mean. It doesn't seem that this effect it is simulated in GT5 to me either.
    However, it might be that it isn't visually displayed, just calculated in the physics engine. Unfortunately there are not many ways to know if this true, currently.

    I'll test other cars to be sure. Probably Premium ones will work better for this as they might have been more carefully and accurately portrayed in-game than Standard ones.

    EDIT:

    I'm testing a stock Premium '68 Chevrolet Corvette Convertible, with just racing suspensions equipped.
    I lowered damper settings to 3 (from 4) and Anti-Roll Bars from 2 to 1. Spring rates and ride height were left to their default values.
    On my custom test track for camber it appears that with the optimal camber angles to make the outside wheels parallel to the ground on maximum lateral G at a speed of 90 Km/h are 0.6 (front) and 1.7 (rear). This appears to be yet another car I tested where rear camber with this system ends ups being greater than on the front.

    Are are a few photos:

    Standard suspensions:

    [​IMG] [​IMG]

    Racing suspensions, default camber values:

    [​IMG] [​IMG]

    Racing suspensions, tuned camber values (0.6 degrees front / 1.7 degrees rear):

    [​IMG] [​IMG]
     
    Last edited: Aug 30, 2011
  13. This is called caster;
    Caster is basically the difference in the mounting point of the lower ball joint and the upper. Positive being the top joint back from the bottom. this puts the pivot point ahead of the contact patch and makes the car more stable at speed. It also more bite while turning by kicking the bottom of the tire out on the outside wheel and kicking the top out on the inside, making it harder to drag that tire, just like camber.
    Imaging pushing a shopping cart with the front wheels backwards, you would have to push it perfectly straight on a perfect surface to keep them out front.
    Another way to look at it a motorcycle that uses a round tire patch and has a lot of caster, when it turns its kinda like throwing a prop up out there to keep it on its line.
    To decribe caster that you can feel on the street when you turn around in a median a full 180 deg, once you have put enough wheel in it you can just let go of the wheel and continue to accel and the wheel straightens itself out. But if you have ever driven a four wheel drive that has almost no caster you have to pull the wheel all the way back straight or you will continue to turn.

    This is all real life by the way and it sucks this is not in the game.