Tune With Camber Links
#1216
I'm not sure but i think it has to do with weight transfer. If you ride a 1:1 gocart you are told to lean outward in the turns to get more grip. You put more weight on the outside tires and at the same time create more preasure and grip?
And when your rc car is rolling more it puts more weight on the outside wheels and thereby creating more grip?
And when your rc car is rolling more it puts more weight on the outside wheels and thereby creating more grip?
Go-karts do not have that capability as it is a fixed axle. Completely different.
#1217
#1218
Tech Apprentice
iTrader: (2)
Joined: Jul 2012
Posts: 68
I have never seen such massive traction that couldn't be compensated for with the right tire selection, spring choice, shorter camber link, and a high roll center. Are we talking about running on carpet? I think we might be talking about a 1% scenario when most of us are going to set up our cars for the other 99% of the off road surface conditions.
#1219
Wow at the information overload I asked for . Tks for the views .
Yea I'm just trying to apply the knowledge with this thread to my on road racing as well as of road .
On road we tend to change inner hinge pin location to deal with role center and the camber link is more for camber gain .
Not to mention offroad cars offer way more camber setting changes than on road (wide range )
But anyhoo , with carpet racing traction is super high at times and rolling becomes a issue and stiffening (less role ) setup sometimes makes it worse , so even tho less role scrubs traction it seems to make the rolling issue worse .AAlso with on road we r dealing with flat tires instead of rounded so that's something some of us don't think about when talking about camber setups.
With this said I have a team Durango desc410v2 and it traction roles in the sweeper on our indoor clay track .
It has a short low link in the rear with about 4deg of camber in the rear . But in slower areas it loose . I want to keep it from rolling in the sweeper but don't want to loose and mechanical grip in the rear thru the infield (tight track with a lot of tight turns) next weekend I'm going to try more role in the front and more caber in the rear first (local guys r telling me to go with stiffer front springs but I can't do that correctly without changing the rear for balance .
Am I off in my thoughts on my changes I'm wanting to make?
Yea I'm just trying to apply the knowledge with this thread to my on road racing as well as of road .
On road we tend to change inner hinge pin location to deal with role center and the camber link is more for camber gain .
Not to mention offroad cars offer way more camber setting changes than on road (wide range )
But anyhoo , with carpet racing traction is super high at times and rolling becomes a issue and stiffening (less role ) setup sometimes makes it worse , so even tho less role scrubs traction it seems to make the rolling issue worse .AAlso with on road we r dealing with flat tires instead of rounded so that's something some of us don't think about when talking about camber setups.
With this said I have a team Durango desc410v2 and it traction roles in the sweeper on our indoor clay track .
It has a short low link in the rear with about 4deg of camber in the rear . But in slower areas it loose . I want to keep it from rolling in the sweeper but don't want to loose and mechanical grip in the rear thru the infield (tight track with a lot of tight turns) next weekend I'm going to try more role in the front and more caber in the rear first (local guys r telling me to go with stiffer front springs but I can't do that correctly without changing the rear for balance .
Am I off in my thoughts on my changes I'm wanting to make?
#1220
Joined: Sep 2010
Posts: 3,569
From: My house.
If it's just traction rolling on the sweeper I would add a anti-roll bar.Years ago I raced on astroturf tracks with an 1/8th buggy and when it would TR if I could not take any more droop or cushion the grip spike with camber or softer springs I would cut off the outer row on the tires.
#1221
Yes raising the front camber link on the tower will allow the front to roll more and give you more traction/steering. If you still need a little more and you want to try another fine tuning adjustment, move your front shocks in one hole at a time on the tower until your desired steering is achieved. You will probably notice some smoother steering too. Post your results.
#1222
The primary tuning book I use was written by the famous chinese author "Who Flung Poo",
the theory is if you throw enough zhit on the wall something will stick.
#1223
Well hey, let's not get too far from the Gospel according to Fred Swain. Shock hole positions are used for setting spring rates, nothing else. Once set, they shouldn't be touched.
With that said, if going out on the tower made the problem better, it sounds like your front spring rate may have been a little too soft. Have you ever gone through and tried the method laid out in this thread by Fred?
Although, I am having a hard time figuring out how your on power steering could be better than your off power steering. Seems backwards to me. Have you tried adding toe-out up front? That will make the car turn-in quicker.
With that said, if going out on the tower made the problem better, it sounds like your front spring rate may have been a little too soft. Have you ever gone through and tried the method laid out in this thread by Fred?
Although, I am having a hard time figuring out how your on power steering could be better than your off power steering. Seems backwards to me. Have you tried adding toe-out up front? That will make the car turn-in quicker.
#1224
good ole toe.... as long as it doesn't wander around at speed a little more does turn in better. A couple degrees feels massive to me.
#1225
Tech Addict
iTrader: (1)
Joined: Nov 2008
Posts: 650
From: Tampa, FL.
Ok I need some guidance. Setting up an SC10 2wd w/BB shocks. I've done the push down and release test. I tried three sets of springs front and rear...same results. The chassis comes up level and at the same rate every time. However, when I do the 6" drop test, the front oscillates two times and the rear almost five. Again, using three sets of springs I get the same results. I just bought two more spring sets to try. Should the rear oscillation match the front or vice-versa? By performing either test, is there something I should be looking for so I don't use springs that are too stiff...or too soft?
#1226
Ok I need some guidance. Setting up an SC10 2wd w/BB shocks. I've done the push down and release test. I tried three sets of springs front and rear...same results. The chassis comes up level and at the same rate every time. However, when I do the 6" drop test, the front oscillates two times and the rear almost five. Again, using three sets of springs I get the same results. I just bought two more spring sets to try. Should the rear oscillation match the front or vice-versa? By performing either test, is there something I should be looking for so I don't use springs that are too stiff...or too soft?
#1227
Tech Adept
iTrader: (25)
Joined: May 2012
Posts: 199
I disagree with your premise. Why do you suggest that reducing roll too much causes traction rolling? The physics should be the same regardless of the surface type. Less roll= less weight transfer= less traction, not less roll to a certain point and then massive traction kicks in.
I think your combining roll center, camber link position, and camber gain, the length of the camber link. However, if we take your example, it sounds like your assuming the camber at corner entry is at 0 and at the apex it reaches a +4. That scenario might work on a very high grip surface where you need to "reduce traction" in the corner to allow the car to rotate or prevent traction rolling. In most off road scenarios, the car is set up with a negative camber, less traction, and as the car transfers weight in the corner the camber gets closer to zero, or the greatest amount of traction.
I think your combining roll center, camber link position, and camber gain, the length of the camber link. However, if we take your example, it sounds like your assuming the camber at corner entry is at 0 and at the apex it reaches a +4. That scenario might work on a very high grip surface where you need to "reduce traction" in the corner to allow the car to rotate or prevent traction rolling. In most off road scenarios, the car is set up with a negative camber, less traction, and as the car transfers weight in the corner the camber gets closer to zero, or the greatest amount of traction.
Now if you study the roll resistance of the front versus rear that is where you can see how traction moves around. The softer end gets the most traction because more of the weight is distributed to each tire versus the stiff end which may have one wheel off the ground in extreme cases.
This may differ than conventional tuning wisdom, but this is the basics. More complex discussions can involve camber and tire issues, but in my view its important to take a step back and understand the basics. If your car is rolling, lower the ride height, add aero forces, increase track width, reduce traction, or slow down.
#1230
You need to watch the rate at which the chassis moves back up from a compressed state. Any other movement after the chassis moves back up is pretty much a result of extra inertia from the motor. That's why I prefer the push the chassis down and release it method. Its easier to see the return speed that way. Make sense?



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