Archive for the ‘— 1/12 Tuning Tips’ Category

Hangar 30 R/C Pan Car Clinic Notes: Chassis Setup Tips.

Wednesday, December 7th, 2011

Originally written by Brian Bodine for the H30 Pan Car Tuning Clinic..

Tires:

are the most important part of tuning. Try to use the most aggressive front tire toachieve the fastest lap times. You may find that tuning the edges of the front tires with CA necessary while running Jack the Gripper. The goal is to make the car run for 8 minutes first, then go fast. Not go fast for 5 minutes and then be undriveable at the end. Paragon makes tire choices very easy, you either need more or less traction. All the other traction compounds require a delicate balance of traction with chassis set up.Tried and trued tire combos are as follows:Stock: Yellow/Black, Yellow/Lilac, Yellow/2xPink, Yellow/MagentaSuper Stock/Mod: Pink/Lilac, Pink/2xPink, Pink/Magenta

Hanger 30:

13.5 no-boost is really not all that fast, more like stock speed. Therefore stock type tires should yield the best laps over the course of 8 minutes. Currently yellow/black is the fast combo.  Once the floor cools, look for pink/magenta or magenta/magenta combo to maintain consistent traction through out the run. The “sign” you will be looking for is the car getting loose around the 6 minute mark.

Front ends:

Start with 1/2 degree toe out per side.  Use more toe out if you need the car to turn in more off power, less if you need less turn in.  Caster is the king pin angle fore and aft. Less caster on the king pin will turn in more off power at corner entry, but have less steering power on.  More caster on the king pin will turn in less off power, but will have more steering through the corner and on power. A word of caution, too much caster can cause traction roll.  Set the camber at -1/2 degrees per side.  If you need more steering, increase to camber. If traction roll is a problem, reduce camber. Choose the reactive castor block based on steering characteristics you desire.  10 is more aggressive while 0 is the least aggressive. Test between 10 & 5 and monitor your lap times. .020” have been the best all around spring.  .018” can steer in more initially and exit the corner with more steering, but look for the car to square the apex scrubbing corner speed or an unpredictable corner exit. .022” rarely gets used as they lack the corner exit steering needed. The CRC front end will give additional advantages with camber gain options. Start with the .50mm spring. The stock upper arm position will have the most camber gain with the pin at the short & low upper location. Adding the carbon H brace will elevate the upper pin and reduce some steering by reducing the camber gain. By going to the long upper arm, the camber gain will be reduced even further. This last option should prove beneficial when the track surface turns to “fly paper”. King pin dampening can be used or ignored.  15K to 30K weight silicone diff fluids work very well. Dampening can increase the steering at initial input.

Hanger 30:

The Hanger has good traction, but never high enough that you will need to make special high traction modifications to your front end.  Most stock front ends should work just fine.  Start with 10 degree reactive blocks, one caster shim infront – two in back or about 6 degrees of caster, -1/2 camber, .020” or .50mm springs, no upper braces, stock track width, no spring preload (or CRC: .404”).
Weight Bias: I have found that I prefer a 41/59% bias when racing on Jack the Gripper. any thing less (39/61%), I have found the front tires to scrub excessively eventually over heating which causes the car to pivot on the nose late in the run. Shift the batteries fore& aft for steering and tire balance.  Moving the batteries forward will turn in slightly lesswhile improving the mid and exit steering.  Moving the batteries to the rear will increase off power steering but reduce mid and exit steering. To figure out weight bias, locate a spacer the same height as the weight scale so that they will be level.  Weigh the entire car ready to run, then weigh the rear tires on the scale with the front tires on the spacer. Divide the weight of the rear into the total weight of the car. You will be looking for 0.59 as a result or 59%. (This is old information, but still interesting)Hanger 30: Now that I race with CRC, I do not pay attention to weight bias that much any more. Battery is either back or forward based on the kind of steering needed in the 12th scale. Although weigh bias is all the buzz in wgt right now. Getting the right mix of corner speed handling using weight distribution is driving the designs to a more50/50 bias.

Center Dampening:

30wt oil in the center shock is a good starting point.  If the car reacts too quick off power, reduce to 25 or 20wt. If the car needs more initial steering off power while running 20wt, go up in weight.  20wt may work better on a bumpy track then 30wt. Lighter springs are more forgiving off power and over any bumps.  Heaviersprings will react faster off power, some say has more steering on throttle and should be used on smoother tracks. Heavier tube lube will keep a car flatter at corner entry initiating quicker. It may also make the car square off the corner entry when the gripgets beyond med-high. Going lighter will reduce steering initiation and maybe preferred on higher grip.

Hanger 30: CRC = 30wt in the center shock, 30k in the tubes. Asc = 50-60wt in the center shock, 80 in the cross shock.
Shock Angle/Pod Droop: Raising or lowering the nose of the center shock will affect the on power steering. Raising the nose will increase on power steering. This is done by adding up to 3mm of shims to the antenna mount.  Lowering the nose of the shock will reduce steering on power. Changing shock angle will change pod droop on some cars. Pod droop is controlled by shock length.  Pod droop effects on power steering.  0 is more on power steering while -2 is less. Try various combinations during testing. These can be valuable subtle adjustments once qualifying starts. Set the car up with no shims under the nose ball stud and with -1mm pod droop. (This information contradicts whatʼs in the CRC manual and was created during t-bar testing a few years ago…. your results may very!)

I have been setting the CRC pod at -2mm and went racing.  I have not spent much time changing the elevation of the shock as these settings are subtle butare worth keeping in the back of your mind.

Side Springs:

Softer side springs will give the car more rear grip and a smoother steering feel around center. Stiffer side springs make the car more aggressive offcenter and in low bite, could make the car oversteer. You can either preload the springs or set them for float. More preload will free up the rear end.  Float will make more rear grip and make the steering less reactive.Hanger 30: For 12th scale, the base side spring is white just touching. Although we have found that the blue (softer then white) actually lets the car rotate more.  In WGT reds work very well.  I have not used preload much in 12th scale, but itʼs very common in wgt. Just touching in 12th, 2 to 4 turns preload in wgt.Ride Height: Ride height needs to be measured race ready on a set up board.  Higherride height can be used on slick or bumpy surfaces which will allow more weighttransfer.  Lower ride height should be used on high bite which will allow quicker direction change.  Should use about 3mm for carpet, 4+mm on asphalt.  Raking the chassis canincrease off power steering (about a 1/2mm higher in the rear).

 

 

Hangar 30 1/12 Pan Car Clinic Notes: About Tires.

Wednesday, December 7th, 2011

Originally written by Brian Bodine from the pan car clinic he taught at Hangar 30, Seattle.

Tires, tires, tires…..

I think they are singular most important item on the car. While I think that you can get a car towork properly on mag/mag or pink/mag, you always need to consider what the yel/blackcombinations can do. Even if it means 2, 3 times the consumption. There is a quality about yel/black that simply excels in limited power classes. It’s likely the rubber content of the foam ishigher in magenta & pink that bind the car to the surface more then the low rubber content foams (yel, gray, black). That “binding” can rob some of the cornering potential of the car. That said, there are also good results with a blend; yel/mag. It all comes to the fine subtleties thatyou are looking for out of the car at the time on those track conditions. What seems like endlesspossibility of combinations is what really frustrates most 12th scalers.

Here’s some CRC combinations I would suggest:

Yellow – black, a very good combination for low power classes, doesn’t turn in to aggressivelyeven with 90% front traction, usually do not have to make special chassis alterations to get goodresults, may not always be the fastest combination to drive, very good for bumpy tracks, verygood for heavy traction on the carpet.

Yellow – gray, another good combination in low power classes, turns in more aggressively thenblack with 75% traction, may likely need to CA the edges, may need to add a front brace or gostiffer on a front spring, set up window will get narrower to hit to get good results, good forbumpy tracks, good for heavy traction on the carpet.

Graylow – black, along with being just a bit more durable then yellow, g/l will “stick” the rear endjust a little bit more and not have that “free” feeling of yellow, a good tire to use when cornerentry is a bit unpredictable currently on yellow, this is usually not a fast combination for clubtracks, only used this combo at big races or a heavy sauced Jack track.

Graylow – gray, this is a combination that may only work at big races that the traction is gettinghigh and you are coming from yel/black, fronts will need CA, may need less reactive caster, mayneed front brace.

Yellow – Magenta, more aggressive then gray fronts, fronts will need CA, better on smoothertracks, better with medium grip track, should work better in a heated environment, will need tobe trued small (41/42).

Graylow – Magenta, just a little more stable in the rear then the yel/mag combo, used very littlein the past, will need to be trued small.

Pink – Magenta, a very good combination for medium power classes, better on smoothertracks, fronts will need CA, good in medium grip tracks, may need front brace or less reactivecaster, may not work with heavy Jack tracks – look for car to get too tight on the nose or loosefrom the rear late in the run, could be building temperature sensitive.

Magenta – Magenta, a very good combination for medium & modified power, better onsmoother tracks, fronts will need CA, may need front brace or less reactive caster or lesscamber gain, may not work with heavy Jack tracks – look for car to get too tight on the nose or loose from the rear late in the run, could be building temperature sensitive.

Magenta – pink, mag rears, pink fronts that is, good for modified racing in order to get enoughsteering.

White and Gray rears are missing from my list as they are rarely used.

Tuning for track width.

Thursday, December 1st, 2011

Tuning the width of your 1/12 is a valuable tuning aid.  It’s important to take these measurements into consideration as they are a great benefit to the handling of the car.

Width is measure from the edge of the outside of the wheel, across to the otherside of the wheel.

How to measure?

Most setup boards are marked with lines and numbers telling you your track width, but a simple ruler or large set of calipers does the trick also. I prefer using a metal straight edge myself.

172mm is maximum track width.  Typically it makes the most sense to widen the car out to this and narrow it as you need to.  A narrower car will generate more grip, and depending on the surface create grip and increase corner speed – too narrow will generate too much grip and cause scrubbing however.  The wider the  car is the least amount of grip it will have, but the smoother it will be to drive and less ‘on edge’ it will feel.

You can adjust the front and rear separately to get a certain feel for the car, if the front is digging in too much sometimes going 1mm wider can help, or in turn, going 1mm narrower in the rear.

Width is also a personal feeling; many top drivers like Peter Robinson and Donny Lia feel wide is best.  To a point I share in this feeling, I’ve always tended to like a car with a slightly narrower front however; for whatever reason it suits me, and I am usually 1-2mm narrower in the front.

How to widen?

Behind the front wheel install 1/8 x .010-030″ shims (available at most hobby shops that cater to racing cars.)

For the rear there are shims for the axle that are also available, most of the manufacturers carry them for their car and because of the universal size of the 1/12 axle any will do. You will install these behind your hub, equally on both sides.

Tuning tips for Hangar 30, Seattle.

Thursday, December 1st, 2011

Seattle’s Hangar 30 which is part of the Seattle RC Racers club is a beast of epic proportions.  This temporary track is made up of many giant rolls of fresh ozite, and is considered to be a bumpy medium grip track.  Even though some bumps persist, it has made a good solid foundation for a thriving 1/12 class to develop.

CRC tuning tips from Travis Schreven;

“And for those with CRC 1/12 cars at the Hangar 10deg Caster, blue side springs, medium crc tube lube, Gold Center Spring. 2deg Camber with 1deg toe-out. Ride height 3-3.5mm

Tires-I find the car works better on bigger tires and is much easier to drive through the bumps as well. CRC Black-Yellow Combo 1.73 Rear/1.68 front Jaco/Parma Black-Yellow Combo 1.725 rear/ 1.625. The Jaco/Blackhawk Combo with a smaller front wheel tends to drive smoother and ive always done my fastest laps on this combo. Even when the tyre split comes closer the car stays smoother with the smaller front wheel.

Width-Max’d out as wide as roar rules will allow. Like Pete N Wess wider is better. A 172mm wide car will always drive smoother than and more consistent than a narrow car.”

Travis’s recommended tire sizes;

(CRC)

Front = 1.68″ or 42.7mm
Rear = 1.73″ or 43.9mm

*This gives a 1.2mm front/rear bias.

(JACO)

Front = 1.625″ or 41.25mm
Rear = 1.725″ or 43.8mm

*This gives a 2.55mm front/rear bias.

A good starting point for tires is often recommended 44mm front / 46mm rear for the Hangar 30 track.

Todd Masons’ views on his 12R5.2….

“I’ve made some recent changes to my 12R5 lately that have been working well. I thought I would share them, as someone else might find it helpful. This applies to both of my cars, an original 12R5 and my newer 12R5.2.

I’ve softened the car up all around. I’m running .018 springs up front with approximately 1mm of droop measured at the nose. 30K kingpin damping fluid.

I’m running very soft side springs. Greens on my 12R5, and SpeedMerchant .018 linears on my 12R5.2. The point being: soft. Together with the soft front springs, the overall steering is balanced, and the cars are still very responsive and not at all lazy. But they ride nice. And I find this is not a H30-only thing. It was actually Hebert who turned me on to it at the TZGP. He was running black side springs, which I normally associate with low-grip asphalt, not high-grip carpet.

Still using blue center springs on both cars.

This next is my own thing, but it has been nothing short of revelatory, at least on my two cars. I’ve added three .015 shims behind the wheels on the front. This adjustment has been huge for me. Some old 1/12th scaler will probably laugh and say it’s so basic they never thought to mention it. I’m studying it and working up a theory to explain what’s going on, but it’s obvious that it affects the arc of the wheels as they swing through their steering range. The effect on the track has been more precise steering and greater stability. Also, I think I’m scrubbing less and carrying more corner speed. Pretty good!”

Tuning tip: measure in thousandths.

Tuesday, November 29th, 2011

1/12 tuning is done in smaller measurements than you may be used to.  0.25mm changes have effect; from ride height to ball stud locations if you raise or lower something just .25mm (.010″) you can be making a drastic change.

One thing to experiment is with your ride height.  Set a car up square, or 3.5mm across the entire chassis from front to rear.  If you lower the front just .25mm you’ll notice a change in steering and how the car rotates.  I see sometimes new racers not paying as close attention and wondering why their car is so odd driving when it has 3.5mm of ride in the front and 4.2mm in the rear, or worse; vice versa!

 

Tuning front tires.

Monday, November 28th, 2011

Quick tip:

If you do not glue the side wall of your front tires the front tire will feel very “edgy” as the sidewall grabs harder.  Not only does this make the front dig in more, but it can cause the tire to wear faster or even chunk on the outer edge.

Prior to truing your tires apply a bead of thin CA-glue along the side wall.  When you true the tire, radius the edge of the tire. This will leave a clean glue sidewall that will resist wear.  You can add CA to the sidewall as the tire wears or the CA chips off.

Radius the edge of the tire so that you have no vertical edge.  If you have to, radius the tire before gluing.

Using a high grit sanding file on the sidewall can polish the glued edge and take even more edge out of the tire.