5LikesSC10 4x4 Thread
06-11-2012, 01:38 PM
Good work with that bump Cameron sun glass's & hat man...
06-11-2012, 01:39 PM
That is exactly what I have been under the impression of, but WC has a way of taking that and totally flipping it. I get if you do the outer hub mod only that you are raising roll center and taking away traction and if raising inner only you are lowering roll center allowing for more weight transfer(traction) but if done equally(raising inner and outer ballstuds) that should also lower roll center which should create more traction(weight transfer), not resist traction rolls and for high grip as WC puts it. I have read somewhere to raise roll center to fight traction rolls and to decrease grip and that is not what I am personally seeing this mod perform. It is to keep rear end from checking out when coming out of a corner when acclerating which to me is adding rear traction. How is that supposed to help traction rolling on high grip tracks. Seems to me you would want to remove shims from inside ballstud to a point but then you really start running into camber gain on compression. That is when you would also have to lower the outside ballstud to keep camber gain in check, correct?
From the beginning it was said that this mod worked better onloose conditions than tight and i experienced the same thing as traction went up so did the traction rolling. Now with that being said i only had 4mm of inside spacers where i now have 6 and it seems to have solved it since i dont have that issue anymore! its hard to wrap your head around it but the best way is to just sit at the track and try it all!!
06-11-2012, 01:40 PM
Tech Addict
iTrader: (6)
That's awesome Cameron. I wonder how many Losi's will pop up in the for sale forum now, lol. Good job on the finish as it seems the deck was stacked against ya.
06-11-2012, 01:40 PM
Here is a geometry review when it comes to roll centers:
You can simplify a suspension to singular points that forces are applied at. For this example assume the car is in the middle of the corner with no throttle or brakes being applied and we are looking at an outside tire.
Picture 1:
There is a chain of forces at work - the tire against the ground, the tire against the hub, the hub against the links, and the links against the chassis.
The force of the ground against the tire is pushing in, but since it's pushing below the arm, a torque (or moment) is created. To prevent the hub from rotating clockwise, the upper link is in tension countering the hubs rotation. This gives us two forces pushing to the left on the hub. Thus the a-arm is in compression pushing to the right against the tire.
Looking at a simplified version, the arm is pushing on the chassis and the upper link is pulling on it. This is trying to roll the chassis.
You can then change how the forces are acting on the chassis and at what angle. Changing the angle would be like raising or lowering one end of the turnbuckle.
Changing the height at both ends changes the location of the force as well as the magnitude. Remember, torque is a function of force AND distance, so if you have a longer distance you can get away with less force to achieve the same torque. Raising both links reduces the force needed to counteract the torque the tire is placing on the rim/hub. This means there are lower forces in the upper and lower link which technically reduces "bind" since the ball cups and hinge pins are actually under less stress. This is where I think Cherry keeps getting side-tracked. Yes, there is less "bind", but it also changes where the forces are acting on the chassis. Its a two-for-one sale.
This is also why you need the upper link locations, lower link locations, and tire contact patch to calculate the roll center. The roll center is the easy way to understand how the forces exerted on the tire are being applied to the chassis.
06-11-2012, 01:41 PM
Another NW Short Course Nationals in the the books with 182 enties. AE wins again. On a track that looked like it was made by a Team Losi driver the Team AE guys pulled off a win in 2w and 4w. Interestingly enough the winning truck has a EXOTEK chassis on it! I ended up 8th in the A.
Outdoor racing is difficult with wind in the 20-30 mph range all day/night and my light weight set-up was not in favor of the wind. About half my laps where on pace the rest I was blown off course and sometimes I just could not see from my eyes watering. All part of outdoor racing in Eastern Washington I guess.
Live and learn
Some pictures up on thebigSC.com
Outdoor racing is difficult with wind in the 20-30 mph range all day/night and my light weight set-up was not in favor of the wind. About half my laps where on pace the rest I was blown off course and sometimes I just could not see from my eyes watering. All part of outdoor racing in Eastern Washington I guess.
Live and learn Some pictures up on thebigSC.com
After hearing of this i emailed the guy and found out that it was only silver spray paint!! WHEW, I was worried about that!
06-11-2012, 01:42 PM
06-11-2012, 01:50 PM
Tech Addict
iTrader: (6)
There is a balancing act that very few realize is happening with suspension geometry. Camber gain is the primary motivator when looking at initial pivot (hinge or ball stud) locations when designing a car. However, since most cars are designed properly with camber gain being pretty close no matter what holes you choose, everyone focuses on the roll center created by those pivot locations.
Here is a geometry review when it comes to roll centers:
You can simplify a suspension to singular points that forces are applied at. For this example assume the car is in the middle of the corner with no throttle or brakes being applied and we are looking at an outside tire.
Picture 1:
There is a chain of forces at work - the tire against the ground, the tire against the hub, the hub against the links, and the links against the chassis.
The force of the ground against the tire is pushing in, but since it's pushing below the arm, a torque (or moment) is created. To prevent the hub from rotating clockwise, the upper link is in tension countering the hubs rotation. This gives us two forces pushing to the left on the hub. Thus the a-arm is in compression pushing to the right against the tire.
Looking at a simplified version, the arm is pushing on the chassis and the upper link is pulling on it. This is trying to roll the chassis.
You can then change how the forces are acting on the chassis and at what angle. Changing the angle would be like raising or lowering one end of the turnbuckle.
Changing the height at both ends changes the location of the force as well as the magnitude. Remember, torque is a function of force AND distance, so if you have a longer distance you can get away with less force to achieve the same torque. Raising both links reduces the force needed to counteract the torque the tire is placing on the rim/hub. This means there are lower forces in the upper and lower link which technically reduces "bind" since the ball cups and hinge pins are actually under less stress. This is where I think Cherry keeps getting side-tracked. Yes, there is less "bind", but it also changes where the forces are acting on the chassis. Its a two-for-one sale.
This is also why you need the upper link locations, lower link locations, and tire contact patch to calculate the roll center. The roll center is the easy way to understand how the forces exerted on the tire are being applied to the chassis.
Here is a geometry review when it comes to roll centers:
You can simplify a suspension to singular points that forces are applied at. For this example assume the car is in the middle of the corner with no throttle or brakes being applied and we are looking at an outside tire.
Picture 1:
There is a chain of forces at work - the tire against the ground, the tire against the hub, the hub against the links, and the links against the chassis.
The force of the ground against the tire is pushing in, but since it's pushing below the arm, a torque (or moment) is created. To prevent the hub from rotating clockwise, the upper link is in tension countering the hubs rotation. This gives us two forces pushing to the left on the hub. Thus the a-arm is in compression pushing to the right against the tire.
Looking at a simplified version, the arm is pushing on the chassis and the upper link is pulling on it. This is trying to roll the chassis.
You can then change how the forces are acting on the chassis and at what angle. Changing the angle would be like raising or lowering one end of the turnbuckle.
Changing the height at both ends changes the location of the force as well as the magnitude. Remember, torque is a function of force AND distance, so if you have a longer distance you can get away with less force to achieve the same torque. Raising both links reduces the force needed to counteract the torque the tire is placing on the rim/hub. This means there are lower forces in the upper and lower link which technically reduces "bind" since the ball cups and hinge pins are actually under less stress. This is where I think Cherry keeps getting side-tracked. Yes, there is less "bind", but it also changes where the forces are acting on the chassis. Its a two-for-one sale.
This is also why you need the upper link locations, lower link locations, and tire contact patch to calculate the roll center. The roll center is the easy way to understand how the forces exerted on the tire are being applied to the chassis.
06-11-2012, 01:52 PM
Tech Master
iTrader: (9)
Jeff
06-11-2012, 01:53 PM
I am not cool enough for sun glasses at night. The back straight was 100 ft away. Wind+Contacts+Watering eyes= Like looking through a fish bowl. Getting MC goggles for Regionals. 
Thanks, No good excuses other than I was off my game with the challenges. Had my favorite motor short out on me too. 
We all raced in the same conditions just seem the heaver trucks won the battle again.
Oh it was real and he did like it so it has me looking for a deal on one to try now. Although I will have mine anodized black. Regional's are at the same track in a month. 
We all raced in the same conditions just seem the heaver trucks won the battle again. Regional's are at the same track in a month.
06-11-2012, 01:58 PM
I completely ignored the COG in my example to keep it simple, but it plays a huge role (HA!) as well. Imagine applying a torque to a broom. You hold it vertically and grab the broom in the middle (at the COG) and rotate it. It rotates easily without much resistance. Now grab the broom at the bottom (below the COG) and rotate it. Now the broom willingly keels over. Now grab the broom at the top of the handle (above the COG). The broom actually resists rolling. Where ever you grabbed the broom is like the roll center and how it interacts with the chassis and center of gravity.
06-11-2012, 02:15 PM
I am not cool enough for sun glasses at night. The back straight was 100 ft away. Wind+Contacts+Watering eyes= Like looking through a fish bowl. Getting MC goggles for Regionals.
Thanks, No good excuses other than I was off my game with the challenges. Had my favorite motor short out on me too. We all raced in the same conditions just seem the heaver trucks won the battle again.
Oh it was real and he did like it so it has me looking for a deal on one to try now. Although I will have mine anodized black. Regional's are at the same track in a month.
Thanks, No good excuses other than I was off my game with the challenges. Had my favorite motor short out on me too.
We all raced in the same conditions just seem the heaver trucks won the battle again. Oh it was real and he did like it so it has me looking for a deal on one to try now. Although I will have mine anodized black.
Regional's are at the same track in a month. Oo Man ! That's Right ...
You were screwed !!
Forgot about the late hour mains ...
Been screw by the wind before & not just parachuting effect ones deals with...
Been three years now sense I'v been back.
One of my favorite tracks in Eastern WA... ...
06-11-2012, 02:18 PM
The camber changes as the suspension cycles and you can affect the camber with the height or length of the camber rods.
But I did not like geometry class so I'm not the guy to ask
06-11-2012, 02:31 PM
06-11-2012, 02:40 PM
06-11-2012, 05:12 PM
When thinking about suspension I find it helpful to keep the truck as my point of reference rather than the ground...I will explain.
Rather than thinking of a diagram where the wheels stay in place on an imaginary plane (the ground) I keep the chassis in place, it provides a bit of insight on where forces are going.
Lets apply this "view" to a scenario.
So lets say we are working on our roll center and link adjustments (seems to be the hardest to visualize) and we are trying to figure out why we are loosing rear traction. Now "viewing" the truck from behind lets "watch" the suspension work as we make a left hand corner, as we turn in the right tire lifts up (remember the truck is rolling to the outside) and goes back down as we straighten the steering.
With that view you can come to a couple conclusions that may be different than you would initially think.
1.The "weight transfer" from center to the right side is applying pressure to the right side of the suspension...I believe we all agree on that one.
2.The suspension is absorbing some of this pressure, we know this because the right tire is lifting up.
3. Not all of the weight that has transferred is being directly applied to the tire.
4. With a surface that has ample traction (lets say for a moment that it is ideal and there is no slide) there is no need for the right tire to lift, in fact if it pushed down it would actually help us get MORE traction.
If you want to see this concept in action watch a fast drag car launch. Your initial thought would be that the best launch would transfer a bunch of weight to the rear, the suspension would squat, and the car would launch and be gone. In reality, most fast drag cars do not squat at all they actually stay rather level or the rear of the car lifts (anti-squat) getting the maximum amount of force to transfer from the chassis directly to the tires and then into the ground.
Of course it is different in our application because we are A. Talking about turning and B. on a sub optimal surface. The challenge becomes figuring out if the suspension reaction is too stiff causing too much weight to be applied or too soft absorbing more of the weight that should have been transferred. In all reality (not quite sure but it should be right) the same amount of weight is transferring from left to right its just where it gets absorbed or transferred that we are trying to control.
Happy tuning!
Rather than thinking of a diagram where the wheels stay in place on an imaginary plane (the ground) I keep the chassis in place, it provides a bit of insight on where forces are going.
Lets apply this "view" to a scenario.
So lets say we are working on our roll center and link adjustments (seems to be the hardest to visualize) and we are trying to figure out why we are loosing rear traction. Now "viewing" the truck from behind lets "watch" the suspension work as we make a left hand corner, as we turn in the right tire lifts up (remember the truck is rolling to the outside) and goes back down as we straighten the steering.
With that view you can come to a couple conclusions that may be different than you would initially think.
1.The "weight transfer" from center to the right side is applying pressure to the right side of the suspension...I believe we all agree on that one.
2.The suspension is absorbing some of this pressure, we know this because the right tire is lifting up.
3. Not all of the weight that has transferred is being directly applied to the tire.
4. With a surface that has ample traction (lets say for a moment that it is ideal and there is no slide) there is no need for the right tire to lift, in fact if it pushed down it would actually help us get MORE traction.
If you want to see this concept in action watch a fast drag car launch. Your initial thought would be that the best launch would transfer a bunch of weight to the rear, the suspension would squat, and the car would launch and be gone. In reality, most fast drag cars do not squat at all they actually stay rather level or the rear of the car lifts (anti-squat) getting the maximum amount of force to transfer from the chassis directly to the tires and then into the ground.
Of course it is different in our application because we are A. Talking about turning and B. on a sub optimal surface. The challenge becomes figuring out if the suspension reaction is too stiff causing too much weight to be applied or too soft absorbing more of the weight that should have been transferred. In all reality (not quite sure but it should be right) the same amount of weight is transferring from left to right its just where it gets absorbed or transferred that we are trying to control.
Happy tuning!
