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Old 08-07-2009, 10:49 PM   #1
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Default RC12R5 setup for Asphalt

Hi, everyone, my name is Alan. I quitted RC for about 12yrs and recently pick it up again and bought a RC12R5. Have been an AE 1:12 fans since the beginning of the hobby. Lastnight I had my first ride in a local track. Low-med grip asphalt (size: 50m X 30m, full throttle straightway is about 40m. Infield: intermediate).

After 3packs of test drive and changed some setting in the springs, I found out that it runs very smooth on straight (De-tweaked). However, it is understeer at corner entry (i.e the 1st corner after striaght way), but steering kicks-in in a sudden and become oversteer in mid corner and corner exit when it slows down - I never fully let go the throttle, about 1/5-1/6 throttle. I know that if I let go the throttle I would spinned out. Anyway, the rear still feels a bit loose, not enough grip.

The people there are ALL running CRC and claiming CRC is the best, but with no offence, I don't agree! I think if the car is setup properly, every car is pretty much the same, all depends on the driver!!! Anyway, no one here was able to help me with the only AE 1:12 there. I also test drive my friend's CRC, it goes anywhere I want it and I can predict how the car goes around corner, after 2-3 laps, I was already able to get closer and closer to the corners and feels more speed are needed. I hope you know what I mean here.



Currently, my setup:
Camber: 1.5degree
Toe in: 1degree
Caster: the upper suspension arms mounted with the 10degree holes and the caster spacer at 3.25degree.
Front Spring: 0.018"
Shock Spring: Golden (No preload at all)
Side Spring: Blue
Rear Track Width: 170mm (I have 7 rear axles shim (AE Parts No. 4554) each side)
Ride Heigh: (F) 3.5mm / (R) 4mm
Damper Oil: as per manual, 20wt for side and 30wt for centre.
Diff: quite loose, I can just move the spur if I hold onto the rear tires.
Tires: (F) Jaco Purple / (R) Jaco Pink
Traction Compound: Paragon FXII: (F) 1/4 tires width / (R) full tires
Motor: Brushless 10.5
Spur/Pinion: 64pitch - 98 /23 tooth
ESC: KO BMS VFS Ver1.5
Battery: Lipo 2C 2200mah 20C, I will be on 1C soon when my voltage booster arrive.
Radio Setting: all setting at neutral, Travel: 38%.




Q1: What is a good starting setup? I want a easy to drive car which I can predict and can drive comfortably.
- Springs (Front, side, shocks)?
- Tires? I prefer Jaco, since it is what available in the LHS.
- Ride Height?
- etc?


Q2: the 2 major problem I am having now are "sudden-steer-kicks-in" and not enough grip at the rear. Does caster setting have anything to do with it? Any suggestion on how to fix it?


Q3: Frankly, I am a bit confused with the caster setup, the caster mount on upper suspension and the caster spaces. What are the difference? How do these affect handling into corner entry and exit? Is this why the steering pops in a sudden in corners, as described above? I understand no one understand my car/driving style better than myself. So, I am thinking I may not get any answer for Q1, so I think if I can understand how this caster works, I would be able to solve this "sudden-steer-kicks-in" problem.


Q4: Forgive my stupidity, I know that some of the Pros are running rear track width 172mm. How do they do it? By using plenty of Rear Axles Shims (AE Parts No.: 4554)? I currently have 7shims each side to make it 170mm, so I wonder how many are needed each side? is there any particular AE or other brand parts that will do the job?


Any suggestion is welcome. Thank you very much
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Old 08-07-2009, 11:42 PM   #2
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Quote:
Originally Posted by awth View Post
Q2: the 2 major problem I am having now are "sudden-steer-kicks-in" and not enough grip at the rear. Does caster setting have anything to do with it? Any suggestion on how to fix it?

Any suggestion is welcome. Thank you very much
More caster should fix the "push in, loose out" problem.
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Old 08-08-2009, 12:05 AM   #3
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I would say your biggest issue is you are running 2c (7.4) volts. That's alot of power for 1/12ths. For about the last 15 years most (if not all) people are running 4.8 volts max. I bet the cars your driving against to compare are probably running 4.8 or 3.7 volts. Once you change down to the proper battery I bet the car gets better. Make sure you are also running a competitive body against the others. Downforce is extremely important.

Steve
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Old 08-08-2009, 07:44 AM   #4
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The push-hook problems that I have seen locally (on carpet), driver is going into the corner too hot, scrubbing the front end till the car slows enough for the front tires to hook up, then the rear breaks traction and whips around... If you can solve your problem with a caster/camber change, great. Otherwise, consider your corner entry speed. There is only so much grip, once you exceed it, you can do nothing until the car slows enough to make the corner.

I notice you are only doping 1/4 of the front tires, and running on purples. These are both items you can play with...

I also agree, the 2s is a bit much. Your car must be ballistic.
good luck.
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Old 08-08-2009, 07:58 AM   #5
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you might like 5 or 0 caster blocks, the 10 block seems erratic for me at turn in.

did you try a softer front tire like 2xpink front and rear, a little loose but a consistant balance. its possible with 2s voltage you might be running in so fast that the front is just plowing until it slows down enough for the tires to catch traction?
before you go too far you might try to borrow a 4cell or 1s battery to see if your problems are due to the higher speed and increased weight of 2s.

Also just switching to a spec motor would be a good starting point, a 17.5 instead of the 10.5 would be more drivable.

just saw what Timmay70 wrote, what he said!
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Old 08-08-2009, 10:01 AM   #6
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Thanks for the input. I am sorry, I should have make it clear in the first place. Yes, I am planning to run on 1C Lipo and have already bought 3 packs of SMC 4900mAh, however, the voltage booster has not arrive yet and I was too anxious to test drive my R5.

I was thinking if I can setup my car well enough for higher speed, I should have no problem running with the 1C. So, I bought this small size 2C Lipo 2200mAh for about USD12.00, the size is not more than the 1C. To be honest, it doesn't feel as powerful as the normal size 2C for touring cars and much shorter run time.

Anyhow, I am expecting the same problem when I run with 1C. I seriously think it is more of a setup problem than a "speed VS grip" problem. Believe me, I wasn't going full throttle on the straight, it was my FIRST RUN after 12yrs, I don't want to "TOTAL" my R5 yet!

So, once again, any suggestions are welcome.


P.S. I wish I could show you a pic of the 2C battery, but I have this error message from here, saying "You are only allowed to post URLs to other sites after you have made a certain number of posts. You have not reached that limit yet."
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Old 08-08-2009, 10:02 AM   #7
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Quote:
Originally Posted by corallyman View Post
I would say your biggest issue is you are running 2c (7.4) volts. That's alot of power for 1/12ths. For about the last 15 years most (if not all) people are running 4.8 volts max. I bet the cars your driving against to compare are probably running 4.8 or 3.7 volts. Once you change down to the proper battery I bet the car gets better. Make sure you are also running a competitive body against the others. Downforce is extremely important.

Steve
Thanks Steve, I am running a Protoform Speed 12 Light weight.
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Old 08-08-2009, 10:10 AM   #8
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Quote:
Originally Posted by avs View Post
you might like 5 or 0 caster blocks, the 10 block seems erratic for me at turn in.

did you try a softer front tire like 2xpink front and rear, a little loose but a consistant balance. its possible with 2s voltage you might be running in so fast that the front is just plowing until it slows down enough for the tires to catch traction?
before you go too far you might try to borrow a 4cell or 1s battery to see if your problems are due to the higher speed and increased weight of 2s.

Also just switching to a spec motor would be a good starting point, a 17.5 instead of the 10.5 would be more drivable.

just saw what Timmay70 wrote, what he said!

I tried the Jaco Double Pink, but it was worse. Even more pushy at corner entry.

I was thinking to change the caster block to 0 or 5 too. What would be the difference than using 10? What about the caster spacers? What are the difference between the two? How do these affect handling into corner entry and exit?

I am hoping to know it in advance, so I can do the setup at home and try it immediate at the track when I get there, which is not gonna to happen until this coming weekend.
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Old 08-08-2009, 10:50 AM   #9
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OK,

Good to hear about your body choice, that is a good one. I would also suggest trying normal (black can paragon) if you have some. FX2 is good stuff but not necessarily the correct traction compound for 1/12th. It is very common for asphalt touring car rubber tires though. I feel its better for this application than 1/12th foam, if you can find some from a friend do try the black can stuff, works great. Let it sit on the tires, especially the rears for as long as possible. You should be saucing the fronts about 1/3rd of the inside of the tires.

Caster blocks, you should have 0*, 5*, and 10*. This is called reactive caster blocks, what they allow is for you to get the best of both worlds. For instance, when your car is running at full speed (like on a straight) the chassis lifts up and the weight transfers slightly to the rear. Your car will be at max caster, when you get to the end of the straight the chassis will transfer weight to the front and your caster will decrease automatically. When the chassis has max caster you gain high speed steering and also stability and when you loose caster like described above you gain low speed steering into the corner. So the 10* block gives you the most of this feature. It is very common when running mod horsepower and when you have good traction. The 5* blocks take some of this away, its a milder setting but still allows some of this to take place. The 0* block will not create any of this. I believe this is a common block in oval racing. You should use at least the 5* block but realisticly you should use the 10* when you get your car to work better.

The shims on the upper arm are used for you caster settings at a static setting, before the reactive caster take place. If you put both caster shims behind the block (towards the rear of the car), you will have the most caster, if you put both clips in the front of the block, you will have the least static caster. You can also split then clips then you will have a middle caster setting. You can refer to your manual for the exact degrees when setting up the front end.

One final question, are you running the link version of the R5 or the tbar version?

Steve
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Old 08-08-2009, 12:41 PM   #10
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Thanks Steven, superb explanation, I think I understand it 100%. Since I am already running the 10 caster blocks. I think I will have to try different combination of springs. I was running on:

0.018LB front
Gold (kit) 12LB shock
blue 5.63LB side spring

I am thinking of stiffer front spring. Do you think this is the right approach? What ride height do you recommand for asphalt? Currently, (F) 3.5mm / (R) 4mm.

I had tried the Paragon Ground Effect (black can), pretty much the same result.

I am running link.
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Old 08-09-2009, 01:37 AM   #11
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awth,

I am glad the explanation made sense, I would rather show someone then explain it to them but in this case we don't have that option

I would try staying with the black paragon, full traction in rear for 30 minutes, then inner third of the fronts for 10 minutes and see what happens. For tires I would try Jaco Pink Prism rears and probably double pink Jaco Prism fronts. But maybe someone else could chime in on here or you can get help from someone else on the actual 12R5 thread.

For ride height I would try to have the car level, same in front as rear. If the asphalt is smooth try 3mm if its bumpy try 4mm, but try to have it level. If the nose is lower than the rear it will typically have more steering, if the front end is higher then it tends to push or plow. You can try to put a small amount of lube on the front kingpins to try to slow the front down a bit.

Finally, I would suggest that if this does not help much to try to get help in the real thread. There are "Team" guys that visit that thread that can suggest the correct springs and how much preload to run on them. I hope your car gets better for you soon, they are a blast when they do what you want them too. Good luck.

Steve
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Old 08-09-2009, 06:32 AM   #12
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Default Rear droop

You stated that your setting: Shock Spring: Golden (No preload at all).

You should probably have some preload by limiting the amount of rear droop. If you lift your car how much does the lower pod come down. It should be limited to 1 to 1.5 mm by adjusting the rear shock length. Set the rear shock preload such that the chassis is level at the rear suspension pivot point (straight line at pivot).

The 12R5 stock caster block have multiple holes that allow you to set dynamic caster between 0, 5 and 10 degrees without replacing the block like previous AE front ends.

I run asphalt and use 2xpink front and pink rear.

Try adding some drag brake with the ESC to get the turn in. This may prevent the pushing that turns into snap oversteer.
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Old 08-09-2009, 08:39 PM   #13
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Thank you both, Peter and Tuner
I will try agin this weekend and see what happens.
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