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Understanding F1 Tuning: Letís break it down

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Understanding F1 Tuning: Letís break it down

Old 03-05-2018, 11:10 AM
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Originally Posted by cementsurfer86 View Post
Has anyone tried the Gravity premounts on gray carpet?


I'll be giving my personal car a shakedown run on Wednesday with them, but wanted to hear from some of you guys as well.
I have and had better luck with CRC Premounts. The Gravity did better for me when I used tire warmers though, still not as fast as the CRC
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Old 03-05-2018, 11:28 AM
  #107  
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Originally Posted by rtebbe View Post
Is there a secret to getting more steering consistency on an F1? I am running a CRC WTF1 FC16. I feel like I fight the car down the back stretch just to keep it straight. I've upgraded my servo to a standard size servo and changed the mounting of it which changed the servo saver orientation from perpendicular to horizontal. It just feels like it wants to drift, like it has a mind of its own. I've checked my alignment. I've set my end points. I'm turning fast laps but feel like I am losing some time simply because I just can't "drive it". I have to fight it.

Running on black carpet, btw.
Try thicker oil in the side dumpers. Something like 20-30K.
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Old 03-05-2018, 01:14 PM
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Originally Posted by mleemor60 View Post
Caster makes the car go straight and helps it steer off the corner. Toe out will make the car wander while trying to travel in a straight line. I'm not a big fan of caster in scale race cars so the toe becomes very important. I like a net "0" toe when pressure is applied inward at the rear of both front tires so you cannot force toe out. That coupled with .5 to 1* of caster is all I would look for to start. This should at least make the car roll straight. If it will coast in a direct line but still wander or otherwise be directionally unstable on acceleration then look to the diff.

On the diff prep I too am looking for answers on how to prep the pegs since they seem to be more than the diff ball height. Somewhere on this forum I read about someone making a jig to cut the pegs to a specified length so they would work in conjunction with the balls as opposed to replacing them.
Originally Posted by robk
Originally Posted by liljohn1064 View Post
BP is right. We currently are on the too much side of traction for a standard ball diff . I know some of the AE drivers are running pins instead of diff balls. Not as elegant as a gear diff, but it works. The pins/gears/diff balls only have to slip a little and predictably. This works for any ball diff. As far as F1 as a class, we are in another one of those periods where popularity of the class is driving change by manufacturers and not necessarily by the racers themselves. I haven't had any issue since switching to the Xenon 16 ball spurs and running a much drier diff.I guess we all dance on the razors edge now and again. As far as the gear diff, I was going to try one, but the previously mentioned spur change did what I needed it to do.
Well since you let the cat out of the bag, you can put Traxxas slipper pegs in the inner row of the diff gear. This is lighter than the gear diff by a large margin. I have been doing this for about a year now. A good friend used to make spools for sedans this way in the foam tire days before spools were commonly available, and suggested it to me.

The peg must be cut precisely. I made a jig that helps me cut them. 3.05mm works on most spurs I have. IT also pays to only lube the diff balls, but not the rings. The ring needs a clean path for the peg to make friction.

The other thing is that most 1/12 style axles need to have the thread pinned to the axle, other wise the thread portion can pull out of the axle under high tension. You may not always run the diff that tight, but once you pop the threads, its usually over for the axle. A small drill bit matched to something like.055 music wire, is good. The music wire is glued in and then cut off carefully, and sanded flush. This is not necessary for Tamiya axles, which have a one piece steel thread, or any similar design.

The other thing is that this works better with a true thrust bearing, like Hudy or slapmaster. Again, if you run it tight, it will eat standard 1/4" bearings.

So the outer ring of holes is diff balls, and the inner ring of holes is pegs, the number of which can be varied to your liking.

This goes a long way toward preventing diffing out. Too tight can kill mid corner rotation. It will also make the car undriveable on low traction or green tracks. This is not useful on asphalt in my opinion.
I'll also be honest, the more toe out you run, the more stable the car gets. I know this is backwards to common thought but it works. Too much toe out will kill midcorner steering, and too much toe in makes it twitchy midcorner.
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Old 03-05-2018, 01:25 PM
  #109  
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Originally Posted by RKeasler View Post
Question on chassis tuning what is the first change to increase steering especially on power ?
An easy one is taking droop out of the front end. This can take away some mid corner steering, but on power should be a little better.

As noted, stiffer center spring, until "it slows down in the chicanes" per Rick Vessel. Stiffer center spring can kill some of the pod articulation it seems.

Caster, as noted will turn the car on power, and also turn the car over when you don't want it to. The camber it induces can cause traction roll.

You may also try widening the rear track a little.

Slightly raise rear ride height. If your car is "in the track", this can help, since it's along the lines of raising the rear roll center.

Move the battery forward a little. This also helps reduce traction rolling, but the car may not be as responsive.
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Old 03-06-2018, 09:37 AM
  #110  
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Originally Posted by RKeasler View Post
Question on chassis tuning what is the first change to increase steering especially on power ?
front tires
front wing

Tires are king in F1


what tires and front wing do you run?
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Old 03-06-2018, 07:44 PM
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Originally Posted by JayL View Post
front tires
front wing

Tires are king in F1


what tires and front wing do you run?
I'm running stock WRC front wing and will be running the Gravity pre mount F1 tires at the Carpet Nats this weekend. Very high traction track, I'll stiffen the car and glue the sidewalls and see how it goes early on for practice.
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Old 03-06-2018, 09:01 PM
  #112  
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Originally Posted by robk View Post
An easy one is taking droop out of the front end. This can take away some mid corner steering, but on power should be a little better.

As noted, stiffer center spring, until "it slows down in the chicanes" per Rick Vessel. Stiffer center spring can kill some of the pod articulation it seems.

Caster, as noted will turn the car on power, and also turn the car over when you don't want it to. The camber it induces can cause traction roll.

You may also try widening the rear track a little.

Slightly raise rear ride height. If your car is "in the track", this can help, since it's along the lines of raising the rear roll center.

Move the battery forward a little. This also helps reduce traction rolling, but the car may not be as responsive.
Stiffer side springs too, no?
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Old 03-07-2018, 03:53 AM
  #113  
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Do bodies actually make any difference in handling like TC?
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Old 03-07-2018, 07:44 AM
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Originally Posted by RKeasler View Post
I'm running stock WRC front wing and will be running the Gravity pre mount F1 tires at the Carpet Nats this weekend. Very high traction track, I'll stiffen the car and glue the sidewalls and see how it goes early on for practice.
Try this, I've had good results with it on my WRC so far:

Frt spring .016 Assoc
Droop 1mm
Caster 6'
Toe out 1.0'
10K lube on kingpins

Center shock 3 hole piston
Shock oil 400wt
Rebound 0
Spring kit red or Tamiya short blue
Preload chassis level

Side springs kit with no preload
Damper tube 20K

Rear droop 2mm

Ride height 4.5 frt 5.0 rr

Gravity fronts push more than TCS/CRC/Pit so glue or tape sidewalls and sauce full width
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Old 03-07-2018, 09:22 AM
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Originally Posted by iTz Nicholas72 View Post
Do bodies actually make any difference in handling like TC?
If you believe the manufacturers of course. If you believe some people, the right body and wing combo can evidently provide enough downforce to drive the car upside down in a tunnel!!
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Old 03-08-2018, 04:02 AM
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Originally Posted by rtebbe View Post
Shimizu tires. I am running friction pegs in the diff as I was trying to combat riffing out.
Here is a note on this. A gear diff or pegs do "zero" to help a car that is diffing out. The pegged diff will make a car that is diffing very hard to drive on corner exit and over any type of traction variance. A pegged diff is for conditions where grip is very high, consistent and the car is dialed in with no diffing out.

To fix the diffing out go with the following.
Softer side springs.
Lighter side dampening.
Less caster.
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Old 03-08-2018, 08:29 AM
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Originally Posted by mstrfahrenheit View Post
Stiffer side springs too, no?
On carpet going stiffer generally sends you toward traction rolling, so i try to avoid it. It will help more in the sweepers than slower corners. Usually stiffer side springs stablize the car. More preload is similar.
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Old 03-08-2018, 10:34 AM
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What about raising the front roll center to cure traction rolling?
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Old 03-08-2018, 07:26 PM
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Originally Posted by liljohn1064 View Post
What about raising the front roll center to cure traction rolling?
That should make it worse- you're basically making it more difficult for the car to roll, like stiffening the springs
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Old 03-09-2018, 03:14 PM
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In the foam tire sedan days, we would actually lower the roll center to combat traction roll. The car rolls slower, and may roll a little more.

Raising RC rolls faster. The car reacts quicker. The other thing is that a softer spring can be used. For example, on the old HPI Pro 2, HPI offered a "roll center kit" which was basically the back half of a chassis you used to lift up the rear end suspension parts and bulkheads. Since the stock roll center location was really low, on carpet especially, we ran really stiff springs, which was not good. If you raised the roll center, you could run a softer spring and treat the tires a little better. So part of higher roll center may just be letting the cars run softer springs, which let the car work within the suspensions travel without flipping.


I think, at least in sedan, some raise the roll center since that end of the car will break traction easier. It "frees" the car up. I know I have raised the links on my F1 in the rear to free the car in the corner on high traction. It does hike a bit more depending on the rest of the setup.

That seems like an important part of the distinction here. When you can alter the upper link, like on the front end, some of the changes can work together because the camber gain might work with a certain lower arm (RC) height. Obviously, the upper arm affects the RC as well, which is confusing on the level of some experts telling guys "raise the roll center", meaning increase upper am angle, versus raising the lower arm in height. Increasing that angle will increase camber gain, and can let the tire break away easier. That can fight the traction roll, but more from a camber gain perspective. IT pays to be specific with information just because general terms can make things even more baffling.

Even worse, I have made changes that were great at one track and the same thing stinks on ice in at a different track with really similar conditions. I actually raised up the lower front arm on my at the the Cleveland US Indoor champs and the car was money (driver, less so). Traction was pretty high. At home, bleh, even when the bite was up . So the point is none of this 100% dial o matic information.

Looking at what I just wrote, it's all over the place. That probably is part of the reason why there's not always solid answers....it just depends on a lot of factors
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