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Old April 7th, 2005, 3:38 PM   #1
stiffer
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Default Set up help

Hello I was wandering if any one would be interested in giving me some help on set up and explaining why to change things? For instance if I'm loose coming out and you say put a little in the right rear why? I'm trying to learn what changes to make when I have a problem without always having to ask some one. So iff some one could explain to me how everything works it would be greatly appreciated. The problem I'm having right now is my vehicles are so loose coming out of the corner and on the power it has got me so frustrated I'm ready to hang it up and call it quits. I know part of the problem is the track because I have no problems with loosness at RVR or Monee. So if anyone could explain chassis set up to me and how to adjust for loose stuations I would really appreciate it.
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Old April 7th, 2005, 4:19 PM   #2
Doug Carter
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To keep things simple in your head, try this.

When a car gets "loose" in any part of the corner, one of the 4 tires on the ground is not getting enough traction to keep the car planted and pointed in the right direction. When this happens, you spin out. Coming out of a corner, all of the weight is leaning back on the right rear of the car, thus, the right rear tire is doing a majority of the work trying to get the car off the corner. If it doesn't have bite, you have the problems you are having now.

To solve this, you need to get that right rear tire some more traction from somewhere. The simplest choice is to try a different right rear tire, with a softer compound. A track that may be dusty might want a tire with more grooves, spikes or elements to achieve more tooth into the track. A smooth, moisture-full track might benefit from a slick or a wider tire.

The next step is to allow the car to generate more weight on that corner, by using a softer spring on the right rear, or reducing the amount of preload on that spring. You can also do this by stiffening the spring on the left rear or increasing the preload on the left rear. It's leverage, or weight-jacking, and will increase the corner weight on that tire that needs bite.

If the car is not even close to being stuc, I would try, in order 1) higher bite tire on RR, 2) softer spring on RR, 3) stiffer spring on LR. There are a lot of other things that will make that RR bite harder, but most of them are used once you are closer on the setup to "fine tune" the car.



Don't give up. Try different things, one at a time, and take a LOT of notes on what the changes do to the car. Trial and error is a big part of DO racing, and what works isn't always a perfect science.



Good luck,

dc
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Old April 7th, 2005, 5:16 PM   #3
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[size=2]I just want to reinforce what Doug said about notes, Invest in a notebook and take as many notes as possible. I constantly look back to my notes from a few years back to get back to a basic set up I know works.[/size]
[size=2][/size]
[size=2] Write down everything you can, springs.oil , wing position ,what tires were on the car, camber, track conditions, air temp , and results.[/size]
[size=2][/size]
[size=2] You can never write down to much info and you can download a descent set up sheet from team associated. [/size]
[size=2][/size]
[size=2] When I started racing a few years back I made sure I practiced every time I could and I would just change each spring at a time just to see what it would do and write it down, over time you end up with notes to help you along.[/size]
[size=2][/size]
[size=2][/size]
[size=2] chris osbrink[/size]
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Old April 7th, 2005, 6:10 PM   #4
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if the car wants to kick out comming off the corner when you hammer down try adjusting slipper.

jim
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Old April 7th, 2005, 6:21 PM   #5
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Thanks fo the input Doug that is exactly what I did on my truck. I run a T3 with factory works towers and tc3 shocks on front and .71s out back I also have the battery offset to the left. I have modified the front shock tower and got the suspension to work better. Basicly I didn't like how far out the shocks were mounted it made the front very stiff even running asc. brown buggy front springs. What I did was copy the shock mounting holes from a gbx front tower to the center of mine and moved the shocks back in creating more leverage. This helped a lot with the front bouncing. I ran this truck at the Big O and took first in truck b main. I had bad luck in the qualifiers. But I consistantly was one of the only two trucks to turn laps under 6 sec and did I turn the fastest lap of the night. I wish I would have had better luck in the qualifiers so I could have had a chance at the A main, but oh well. Any way I know the truck works on a track with bite. And this is thew vehicle I have the most problems with on a looser track. But the first thing I tried was a tire with more tread on the right rear. That didn't help much. The I went up one spring weight one the left rear and that seamed to help more.

How does shock oil play into this? Also I have problems with my sprint car pushing bad at Monee what can I try with that? I run hpi slicks on the rear there and a set of very soft bald strikers on the front. How does camber link position affect this also?

Thanks Jeff
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Old April 7th, 2005, 6:23 PM   #6
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I'm running slipper eliminators. It is just loose coming out on or off the power. The truck carries a lot of corner speed.
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Old April 7th, 2005, 6:46 PM   #7
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"my vehicles are so loose coming out of the corner and on the power"

sorry i must have misunderstood!
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Old April 7th, 2005, 9:50 PM   #8
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make sure you didn't eliminate the ability of the suspension arms to droop when the vehicle is lifted. I put shorter shocks on my truck, handled like crap, and found out that when all the weight shift went to the right rear, the left front and rear lifted off the table. This caused the spin outs that you talk of. Just friendly advice.......
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Old April 7th, 2005, 10:20 PM   #9
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http://www.rc10.com/racerhub/techhel..._handling.html I hope this helps. Read it.
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Old April 8th, 2005, 2:32 AM   #10
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Lots of good advise in this thread.Like Doug said,the first thing would be to try a different tire(or insert) in the rear.If the car is good going in and in the middle you can also just lower the rear of the car evenly on both sides-it will affect the car more on exit than the entrance/middle.
If the front shocks were too soft it would probably be loose in the middle of the corner off power so that is most likely not your problem.Softening the rear shocks may help-this can also make turn-in less agressive.You can also try laying the rear shocks over more(in on tower).
Longer front camber links should help also.In general shortening the front link is a good way to get more steering in the middle/exit of the corner.Longer camber links(both front and rear) will make the car smoother and easier to drive.Changing the front camber may also help.

And they VERY first thing I would try-turn the steering dual rate down on the radio and see if it suddenly drives just fine.(This is so obvious that I forget it all the time!)
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Old April 8th, 2005, 11:59 AM   #11
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Quote:
Originally Posted by stiffer
...the first thing I tried was a tire with more tread on the right rear. That didn't help much. The I went up one spring weight one the left rear and that seamed to help more.
Usually, one step changes will help dial the traction in once the car is close. What you are facing is a drastic "off" from the right setup. Your car needs to get a LOT more bite on the RR, which seems to be the exact opposite of your problem with your sprint car at Monee (more on that in a sec). I would try a different RR tire until you get it closer. I would go to a stiffer LR spring, a softer RR spring, and lighter oil in the RR shock to get more bite. You may even look to a shock piston in the RR that allows more fluid to pass through faster. Try a bit more camber on the right, rear, too. Read the way the dirt is building/wearing/collecting on the tire to see if it may need to be flatter while in the corner. A touch more camber in the RR will flatten the tire out a bit, and give you more bite, as well.

Also, something to look at, and it does happen, is that if you have limiters in your shocks, and the car is leaning over onto them violently, the car may be unloading itself. When that happens, it upsets all of your weight transfer and traction. If the car bounces off the shock limiters or even the shock runs out of travel, the result can be a snap spin off the corner. I'd get rid of any limiters on a loose track.



Quote:
Originally Posted by stiffer
How does shock oil play into this?
Shock oil is important on any track. Generally, a heavier weight in the rear compared to the front is a good place to baseline. Some say a very average 30/40 or 40/50 starting point is a good place to start, but for a looser track, I'd move to the lighter end of the oil scale. The lighter the oil, the more traction you will be transferring to the tires. You might even consider a 20/30 front to rear starting point, and progressively go firmer to get quicker. Get it stuck first, then worry about improving your lap times.



Quote:
Originally Posted by stiffer
Also I have problems with my sprint car pushing bad at Monee what can I try with that? I run hpi slicks on the rear there and a set of very soft bald strikers on the front. How does camber link position affect this also?
Ok, this is the opposite problem. The rear tires are getting too MUCH traction in the rear and overpowering the front end. You almost answered your own question. The bald Strikers aren't giving you any bite. While the massive traction from the HPI slicks is nice, if you can't turn the car, they are hurting your lap times and not helping them. I'd try a harder HPI compound in the rear, and maybe even grooving up a pair of 33Rs to try to dial the rear bite back a bit. You may be better off using a rear tire that will give you more overall car balance like an original Striker or a CW Street Trac. A balanced car will be faster than a car that has massive rear traction. Remember, what everyone else is doing is a good starting point, but by no means the be-all end to your best set-up. Obviously, a stickier front tire is the best solution to this problem, but right now, your options seem to be limited, unless you have a pipeline for fresh & sticky Striker fronts.

Soften the front end to get more steering. It will also rake the car a bit forward (or less ride height in the front than the rear). A lighter spring/oil combo with a stickier tire (slick, maybe) will gain more steering. If you watch cars at Monee, many spend their entire time in the corners with a full wheel lock on the front end. The fastest cars there don't push. Watch them, and you will see what makes them so fast there. The less the front wheels need to turn/steer, the faster the car will be. Cars with the front end cranked all the way over in the corners are just scrubbing speed, and not turning the way they need to be.



Hope this helps, and wasn't too confusing.



doug
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Old April 8th, 2005, 12:07 PM   #12
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Also, something you might want to try to combat the problem is to center your battery, and get rid of the inside weight offset. That will move some more static weight to the outside tires and should help the bite problem. Moving weight around manually can make the most drastic changes and instant improvement, and might be the first thing you should try.


Good luck,



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Old April 8th, 2005, 4:13 PM   #13
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On the sprinter I have as set of hpi 23s as well as 27s the 23s usually are to much and the 27s seem to be loose so I normally run a 23 on the left and a 27 on the right rear. The bald striker fronts seem to work better that the street tracs and I do have 2 brand new sets of front strikers one set has softer inserts. Just haven't had a chance to try them yet. The setup on the sprint car is what Mark Corns told me to run on it. HE is a good friend of mine he just never has time to help me at the track. He's always too busy with his new cars. And it gets old always bugging him. That is why I'm trying to learn for my self. I'll try some of the sugestions tomorrow night and see if I have any luck.

SET UP Truck
Front 30 wt oil #2 pistions
green buggy springs
left 2 deg pos right 2 deg neg

rear 40 wt oil #2 pisions
blue buggy left silver buggy right
left 2.5 deg pos right 2.5 deg neg


SET UP Sprint
Front silver tc3s
25 wt oil #2 pistions
left 2 deg pos right 2 deg neg

rear cut gold truck front springs
50wt oil #2 pistions
left 1.5 deg pos right 1.5 deg neg

My dual rate on the truck is set at 40. The front camber links are shorter than stock do to the custom works caster blocks the rear are also shorter than stock. That is part of how I got the truck to quit scrubbing corner speed. LIke I said before I only have problems on low bite tracks with the truck. It is actually a dream to drive on a high bite track. It drives very easily and carries a lot of corner speed. The track I'm having problems at is fine if I run right after watering. Thanks again for everyones help. If anyone has any more sugestions please post them.
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Old April 9th, 2005, 10:21 AM   #14
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Doug,
Question on your post..
Are you saying a car/truck gets loose under acceleration because the RR "doesn't have enough bite"???


Stiffer: Do you run Rear toe in on your sprint?? How tight is your Diff?? What type of sprintcar is it. Have you ever messed with front to back wing placement?
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Old April 9th, 2005, 6:34 PM   #15
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Quote:
Originally Posted by lugnut727
Doug,
Question on your post..
Are you saying a car/truck gets loose under acceleration because the RR "doesn't have enough bite"???

Based on the physics and weight transfer of a car coming off the corner, the right rear has the most work to do. If the car is not hooking up after the apex and on throttle, then yes, the right rear does not have nearly enough traction.
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Old April 10th, 2005, 10:53 AM   #16
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Hey eeveryone thanks for the help!! I actually go my latemodel hooked up last night, And had the fastest car on the track in the main. I just need to get better at avoiding people running in to me and pile ups LOL. The truck still went away when the track started getting loose. Oh well I'm gonna put the battery back in the center. Thanks to the info I helped set up two other cars also. Thanks a bunch. If anyone has anymore tips feel free to post I will still be checking.
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Old April 10th, 2005, 8:02 PM   #17
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On the T3, what is the rear toe? I run nearly the same set up (except .56's on the front)and changed to a 0 deg suspension mount . The truck was faster everywhere except exiting the turns it was a real handful (loose). I can see the benefit of 0 deg toe on a high bite track but my track is clay with a lot of organic material in it. So I currently run the stock 3deg susp mounts. Also, I run strikers with dual stage buggy foams and to get more grip on the rear I have grooved every other V on the tire. Definetly some good advice on this thread. I will be taking note of some of the things I have read here.
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Old April 10th, 2005, 8:53 PM   #18
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Quote:
Originally Posted by Doug Carter
Based on the physics and weight transfer of a car coming off the corner, the right rear has the most work to do. If the car is not hooking up after the apex and on throttle, then yes, the right rear does not have nearly enough traction.

To expand on this idea a bit. Would it not be prudent to "preload" the left side static weight. We are in a sense of the word, trying to fool the car in to thinking that while it is in the corners, it is actually going in a straight line, which everyone should agree is the fastest direction any car can go.

This would lean towards the idea that a soft left side suspension, and a higher left and rear weight bias would help us in this. For example if you were to set the static weight of the car so that say 60% (hypothetical) of the weight of the car is sitting in the rear tires. Also, that same 60% figure (again hypothetical) would be on the left side tires. So that in a sense the car is leaning to the left side when going down the straights.( as in full scale ). The car would transfer that weight ( physics of inertia) to the outside wheels upon entering the corner, theoretically making the car think it is going straight. We would set our suspension on the outside to help resist this force, hence the thicker oil and harder springs. We could also suppose the harder right side compound of tire and foam insert to help.

Stagger would help this situation in that it would help the car turn into the corner and rotate correctly at the apex to allow us full advantage. the thicker right side oils and springs would load the left side of the car when exiting the corner allowing the rear tires to get maximum bite, hence quicker acceleration off the corner??

Im gonna stop to let this settle in a bit..

thoughts anyone? Hope this helps the situation
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Old April 10th, 2005, 10:27 PM   #19
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Hi Doug,
If the car is loose from the apex out, the car is lacking in left rear traction(bite). The reason the rear end of the car kicks out is because the right rear tire is driving more than the left rear tire. So in order to solve this problem you need to put more weight to the left rear to give that tire more traction(bite). So it's not that the right rear is lacking in bite, but it's the left rear lacking bite. You agree?

Lets keep this coversation going, I like it!! thanks
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Old April 10th, 2005, 11:54 PM   #20
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Hmmm, I'd debate that. In a traditional solid axle dirt oval car (real), that would be the case. Our cars behave more like IRS/differential asphalt cars in that they drive off of the tire taking the most weight transfer, which is the RR coming off the corner. A dirt car sliding sideways in loose dirt may have some more leverage to the inside, but for the most part, our cars get set up like a pavement car.

Coming into a corner, the right front bears the weight of the car and has the biggest effect on handling (turn-in), and coming off the corner, the right rear takes the most weight. Cars that lift the inside front wheel are not transferring weight to the inside rear. I have driven and seen many well balanced cars finish races, and some even win even after they had lost the left front tire. That's a cross-balanced car that is putting a LOT of weight on the RR. Think playground teeter-totter. That fat kid sitting on the RR is keepinig the skinny kid on the LF barely on the ground. It's all about levers and balance.

I can see how it would be reasonable to assume that one tire on the outside spinning more will drive the car into a spin to the inside, but with diffs in our cars, that isn't necessarily going to be the case. Cars will spin to the inside of a turn because the front end is biting harder than the rear end, and centrifugal force is carrying the back around in the natural direction it was originally headed. I have never seen a car coming off of a corner spin from the inside out, it goes against the laws of motion. One potential flaw in the thoery that the weight is mostly on the LR tire.


The things mentioned in that previous link are a lot of technical jargon that may or not really be applied to R/C cars in different environments. Some of those mathematics are interesting to read, but not very helpful in trying to get your car set up at the track. Good stuff to know, but real world applications of those formulas are just about pointless for R/C cars.


One guy's opinions.



d


BTW, stiffer, nice work this weekend. I hope you took notes on what worked and what did not!
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Old April 11th, 2005, 7:07 AM   #21
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I have to agree with lugnut in his explanation. By getting more traction on the left rear( in the situation being discussed) you also gain one very important thing. That is traction to BOTH rear tires not just driving off the right rear. ultimately you want both rear tires pushing the car as hard as they can exiting the corner.Your car will drive of the corner harder, gaining more speed quicker.
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Old April 11th, 2005, 7:54 AM   #22
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I also have to agree with lugnut. If the car is "looping" coming out of the corner it needs left rear bite.
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Old April 11th, 2005, 9:05 AM   #23
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Regardless of what or who you believe, to cure a loose car off the corner, you soften the RR and stiffen the LR. You need to get more traction in the RR. Standard, long-time tested, simple chassis tuning.
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Old April 11th, 2005, 5:41 PM   #24
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I tryed stiffening the left rear and softening the right and it helped. I was amazed at how very little preload changes made drastic handling changes on my intimidator 10. One 1/8 inch clip out of the right and the car went from loose to pushing. So I pulled a 1/16 out of the right rear and put it in the left and this fixed the problem. Part of the trucks problem I think is battery placement so its going back in the middle I think this will fix the problem.

Lets keep this thread going I like hearing everyones set up tips, the knowledge, wisdom and combined years of experience of the members of this site is priceless
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Old April 11th, 2005, 5:46 PM   #25
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Now that you see the effects of spring preload, you would benefit from threaded shock bodies. One small turn of a shock adjustment collar might be all you need to dial it in. There is a big benefit to being able to quickly adjust the shock preload right there on track.

Associated, Losi, HPI, CRC, Schumacher all make nice threaded shocks. Associated and Losi also offer longer shocks intended for off-road cars, if you are so inclined.
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