Mugen MTX-4
07-20-2006, 09:11 AM
#5461
Tech Fanatic
Originally Posted by wallyedmonds
try it you dont know till you try it,my setup is on page 181
07-20-2006, 10:10 AM
#5462
Originally Posted by speedy100
my new set up looks prettry close to yours....additionaly, i have just got my new kawahara front upper mount which can adjust the upper arm further out. have anyone tried ?
Not yet, but hopefully if weather permits, I'll get to experiement this weekend.
07-20-2006, 02:39 PM
#5463
Originally Posted by speedy100
my new set up looks prettry close to yours....additionaly, i have just got my new kawahara front upper mount which can adjust the upper arm further out. have anyone tried ?
07-20-2006, 02:52 PM
#5464
Tech Adept
Hi guys,
This is my interpretation of roll centre:
Hope this helps!
This is my interpretation of roll centre:
Hope this helps!
Originally Posted by SNACKPACK
RAISING THE ROLL CENTRE: To raise the roll centre you make adjustments so that the top arm/link is at a greater angle in relation to the lower arm. To do this LOWER the INSIDE pivot point (the pivot point located on the shock tower on most cars) of the top arm/link OR RAISE the OUTSIDE pivot point (located on the suspension upright on most cars) of the top arm/link. Raising the outside pivot point of the top arm can be achieved by adding shims to the upright.
As raising the roll centre reduces the distance between the centre of gravity and the roll centre, the car will roll less when cornering forces are applied. Because the car rolls less, the wheels will have less weight transferred to them and therefore have less traction.
Effects of rasing the front roll centre: The front tyres will have less grip, and therefore the car may understeer at higher speeds (off power). However because less weight is being transferred from left to right, the car will react more quickly and feel more responsive in low speed corners (if traction is sufficient).
Effects of raising the rear roll centre: The rear tyres will have less grip, and therefore the car will change direction faster and generally be more responsive.
LOWERING THE ROLL CENTRE: To lower the roll centre you make adjustments to the top arm/link so that it is more parallel (grammar?) in relation to the lower arm. To do this RAISE the INSIDE pivot point of the top arm/link OR LOWER the OUTSIDE pivot point of the top arm/link.
As lowering the roll centre increases the distance between the centre of gravity and the roll centre, the car will roll more when cornering forces are applied. Because the car rolls more the wheels will have more weight transferred to them, and therefore have more traction.
Effects of lowering the front roll centre: The front tyres will have more grip and therefore the car will have more off power steering. However because more weight is transferred from left to right the car will generally be less responsive (especially at low speeds).
Effects of lowering the rear roll centre: The rear tyres will have more grip and the car will have a tendency to understeer (on power). The car will react less responsively and will usually feel more docile and controllable.
As raising the roll centre reduces the distance between the centre of gravity and the roll centre, the car will roll less when cornering forces are applied. Because the car rolls less, the wheels will have less weight transferred to them and therefore have less traction.
Effects of rasing the front roll centre: The front tyres will have less grip, and therefore the car may understeer at higher speeds (off power). However because less weight is being transferred from left to right, the car will react more quickly and feel more responsive in low speed corners (if traction is sufficient).
Effects of raising the rear roll centre: The rear tyres will have less grip, and therefore the car will change direction faster and generally be more responsive.
LOWERING THE ROLL CENTRE: To lower the roll centre you make adjustments to the top arm/link so that it is more parallel (grammar?) in relation to the lower arm. To do this RAISE the INSIDE pivot point of the top arm/link OR LOWER the OUTSIDE pivot point of the top arm/link.
As lowering the roll centre increases the distance between the centre of gravity and the roll centre, the car will roll more when cornering forces are applied. Because the car rolls more the wheels will have more weight transferred to them, and therefore have more traction.
Effects of lowering the front roll centre: The front tyres will have more grip and therefore the car will have more off power steering. However because more weight is transferred from left to right the car will generally be less responsive (especially at low speeds).
Effects of lowering the rear roll centre: The rear tyres will have more grip and the car will have a tendency to understeer (on power). The car will react less responsively and will usually feel more docile and controllable.
07-20-2006, 03:38 PM
#5465
i thot adding shims to the rear uprights makes more camber change, to do roll center you change the lower arm position LOW MID HIGH. IDONO this stuff allways meses me up, if i need more traction i add shims to the upright,
07-20-2006, 03:45 PM
#5467
Originally Posted by GrandeGixxer
Changing the inner point of the camber link up will raise the r/c, down will lower the r/c. Raising the outside will lower it and lowering it will raise the r/c
07-20-2006, 03:58 PM
#5469
XXX MAIN BOOK written by martin crisp (xxxmain.com)
07-20-2006, 07:11 PM
#5472
Originally Posted by Slo-MTX4
When you change the bottom arm spacer, do you have to change the upper link aswell and if you do, do you change the inner or outer and which way?
07-20-2006, 07:42 PM
#5473
A “roll center” is a theoretical point around which the chassis rolls, and is determined
by the design of the suspension. Front and rear suspensions normally have different roll
centers. The “roll axis” is the imaginary line between the front and rear roll centers.
The amount that a chassis rolls in a corner depends on the position of the roll axis relative
to the car’s center-of-gravity (CG). The closer the roll axis is to the center of gravity, the
less the chassis will roll in a corner. A lower roll center will generally produce more grip
due to the chassis rolling, and the outer wheel “digging in” more.
Roll-centers have an immediate effect on a car’s handling, whereas anti-roll bars, shocks
and springs require the car to roll before they produce an effect.
by the design of the suspension. Front and rear suspensions normally have different roll
centers. The “roll axis” is the imaginary line between the front and rear roll centers.
The amount that a chassis rolls in a corner depends on the position of the roll axis relative
to the car’s center-of-gravity (CG). The closer the roll axis is to the center of gravity, the
less the chassis will roll in a corner. A lower roll center will generally produce more grip
due to the chassis rolling, and the outer wheel “digging in” more.
Roll-centers have an immediate effect on a car’s handling, whereas anti-roll bars, shocks
and springs require the car to roll before they produce an effect.
07-20-2006, 07:43 PM
#5474
EFFECTS OF FRONT ROLL CENTER ADJUSTMENT
Front roll center has most effect on on-throttle steering during mid-corner and corner exit.
Front roll center Effect
Lower
• More on-throttle steering.
• Car is less responsive.
• More weight transfer at front of car.
• Better on smooth, high grip tracks with long fast corners.
Higher
• Less on-throttle steering.
• Car is more responsive.
• Less weight transfer at front of car.
• Use in high grip conditions to avoid traction rolling.
• Use on tracks with quick direction changes (chicanes).
EFFECTS OF REAR ROLL CENTER ADJUSTMENT
Rear roll center affects on- and off-throttle situations in all cornering stages.
Rear roll center Effect
Lower
• More on-throttle grip.
• More weight transfer at rear of car.
• Less grip under braking.
• Use to avoid traction rolling at corner entry (increases rear grip).
• Use under low traction conditions.
• Increases traction, reduces rear tire wear.
Higher
• Less on-throttle steering.
• Less weight transfer at front of car.
• Car is more responsive.
• Use in high grip conditions to avoid traction rolling.
• Use on tracks with quick direction changes (chicanes).
Front roll center has most effect on on-throttle steering during mid-corner and corner exit.
Front roll center Effect
Lower
• More on-throttle steering.
• Car is less responsive.
• More weight transfer at front of car.
• Better on smooth, high grip tracks with long fast corners.
Higher
• Less on-throttle steering.
• Car is more responsive.
• Less weight transfer at front of car.
• Use in high grip conditions to avoid traction rolling.
• Use on tracks with quick direction changes (chicanes).
EFFECTS OF REAR ROLL CENTER ADJUSTMENT
Rear roll center affects on- and off-throttle situations in all cornering stages.
Rear roll center Effect
Lower
• More on-throttle grip.
• More weight transfer at rear of car.
• Less grip under braking.
• Use to avoid traction rolling at corner entry (increases rear grip).
• Use under low traction conditions.
• Increases traction, reduces rear tire wear.
Higher
• Less on-throttle steering.
• Less weight transfer at front of car.
• Car is more responsive.
• Use in high grip conditions to avoid traction rolling.
• Use on tracks with quick direction changes (chicanes).
Last edited by Nitro$junkie; 07-20-2006 at 09:43 PM.
07-20-2006, 07:46 PM
#5475
ROLL CENTER IN ACTION
When cornering, centrifugal force is applied to the car’s CG, which tends to push the car
to the outside of a corner. This causes the CG to rotate around the RC. Since the RC is
below the CG, cornering force causes the car to rotate AWAY from the force. Hence, the
car rolls to the OUTSIDE of the corner.
• When the RC is far away from CG (lower RC), when the car corners the CG has more
leverage on the RC, so the car will roll more.
• When the RC is closer to CG (higher RC), when the car corners the CG has less
leverage on the RC, so the car will roll less.
• If the RC was right on top of the CG, when the car corners the CG has no leverage on
the RC, so the car would not roll at all.
• Depending on what the car is doing, you will want one end or the other to roll more
or less. You change the height of the RC accordingly to make it closer or further from
the CG (which for all intents is a fixed point).
When cornering, centrifugal force is applied to the car’s CG, which tends to push the car
to the outside of a corner. This causes the CG to rotate around the RC. Since the RC is
below the CG, cornering force causes the car to rotate AWAY from the force. Hence, the
car rolls to the OUTSIDE of the corner.
• When the RC is far away from CG (lower RC), when the car corners the CG has more
leverage on the RC, so the car will roll more.
• When the RC is closer to CG (higher RC), when the car corners the CG has less
leverage on the RC, so the car will roll less.
• If the RC was right on top of the CG, when the car corners the CG has no leverage on
the RC, so the car would not roll at all.
• Depending on what the car is doing, you will want one end or the other to roll more
or less. You change the height of the RC accordingly to make it closer or further from
the CG (which for all intents is a fixed point).
Last edited by Nitro$junkie; 07-20-2006 at 07:56 PM.