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iTrader: (88)

I am working on trying to learn as much as I can about R/C and in the process realized that my understanding of certain tuning options was somewhat lacking. So in an attempt to learn more I decided that I would start threads so that we can discuss each area and learn as a community. We can ask questions of the fast guys so that we can all learn and ask those questions that you have been wondering about for years. There has been a lot of discussion recently about tires so here is a great way to discuss them.

I think that most of us understand the concepts but understanding how each change affects the car will be extremely helpful. Most of these concepts are focused towards touring cars, but can apply to other types of R/C racing.

**Understanding that car tuning is a struggle in car balance from front to rear and side to side based on track conditions. Any change you make will affect the entire car, as an example if you change springs in the front it will affect the rear traction**

Lesson 1: Tires

I think this area has the biggest affect on how you car handles. Understanding how tires regardless of foam or rubber can really make a difference in how the weight gets transferred from the front to the rear and side-to-side.

Rubber tires have three components:
Tire
Insert
Wheel

Rubber Tires: Rubber tires are classified by temperature range. Almost exclusively the higher the number the firmer the tire.

Here are some examples:
Take Off CS-27 (46F-109F)
RP-30 (59F-122F)
RP36 (68F-140F)
Sorex 28 (68F-84F)
Sorex 32 (81F-96F)
Sorex 36 (96F-151F)
Jaco Green (Med-Soft)
Jaco Blue (Med-Firm)

It is important to select the correct compound based on track and temperature conditions. Each tire is designed to optimally work at a specific temperature range.
The softer the tire the more weight transfer which typically increases traction. In some cases if you transfer too much weight you can cause handling issues with either tires lifting off of the ground while turning or chassis components could contact the ground and cause the suspension to get unsettled.

Finding the correct tire compound should be the place you start from and adjust your setup to work for the tires that produce the best traction. Once you have found the correct tires you can begin to work on other suspension components to better tune your car for the track and conditions.

Typically if you are over heating your tires there could be two possible paths, either you have the incorrect tires on your car or the setup is causing the tires to over heat. Typically if you are blistering and rolling over tires the car suspension is too hard. This mostly occurs in the front of your car and not the rear.

Proper tire care is really important as well. The compounds in the tires will only stretch and contract so many times and eventually you will feel the tire go away and as such will cause inconsistencies in car handling.
Cleaning rubber tires should be done with a product that will not harm the rubber compounds such as WD-40 and or Simple Green. Cleaning the tires after a run with these products will lengthen the tire life.
Traction compounds are typically designed to soften up the rubber compounds in the tire so that you can get maximum traction for the first part of the race after that they typically wear off.
Some people also use tire warmers for the purpose of baking the traction compound into the tire so that it is turn lasts longer. It also heats up the tires on those cold days.

Inserts:

Inserts are like tires the firmer they are the less traction that they provide.

Wheels:

Wheels do not make a huge difference in tire handling, but have some affect. The softer the rim the more traction it can provide, but the softer the rim the easier they brake under a high impact. Most of the rubber tires have pretty firm wheels for added durability.

Foam tires have two components:
Foam
Wheel

Foam Tires: Foam tires are classified by shore ranting. Almost exclusively the higher the number the firmer the tire. Foam tires are really comprised of a mix of rubber and foam that are glued to high impact nylon wheels.

Here are some touring car examples:
Jaco Pink (30 Shore)
Jaco Magenta (32 Shore)
Jaco Double Pink (35 Shore)
Jaco Lilac (38 Shore)
Jaco Purple (40 Shore)
Jaco Double Pink/Orange (60 Shore)


The concepts are the same for foam tire, but the evidence of the wear are displayed differently. A very aggressive car will cause excessive wear on foam tires and with the high amount of traction this can be difficult to tune out of your setup. If you are going through tires very quickly (in a couple of races) then your car is improperly setup. Inconsistent wear on the foam will be displayed in a few ways. Tires coning typically shows camber/caster issues. To fix Coning typically you can re-true the tire to a consistent thickness across the entire surface of the tire.

Tire trueing is something that most foam tire racers do very often when racing. A tire truer is an electronic device ( a motor with a special blade for cutting across the surface of a foam tire) that is used to decrease the amount of foam on the rim. People true the tires for a few reasons; one of them is to reduce chunking (chunking is where a piece of the foam comes off of the tire creating inconsistent traction) and the other is to create a consistent gearing ratio in the car. Tire size directly affect a concept call roll-out, and must be adjusted in-order to ensure that your motor runs at the optimal temperature.

Nitro foam tires are different then carpet foam tires. Nitro foam tires are designed to utilize heat to increase the traction, and carpet foam don’t need as much heat to work well. Nitro foam tires do not work well on carpet and should only be used on paved surfaces.

Unlike rubber tire racing it is not unusual that you will run different shore tires both front and rear, but most people will stay within 5 shore difference front and rear with the harder tire being on the front.
Also, many nitro racers will run not only different compunds but will also run staggered sizes on the car. Some drivers will put a larger tire on the left or right rear of the car as well.

This is all that I have for now lets discuss…

These two threads are also great resources:
http://www.rctech.net/forum/showthre...r+tire+dummies
http://www.rctech.net/forum/showthre...r+tire+dummies

revolution31

iTrader: (6)

I personally don't think it is weight transfer that is increasing the traction. Im not an expert at this, but I'm pretty sure weight transfer is controlled solely by the suspension components and the suspension geometry. The way I understand it, the softer the tire, the more it is able to "squish" when the weight is transferred, thus the more traction you have.

While I agree with you about the overheating of tires, from what I have been told, you want to run as hard of a suspension as possible (even if that means going through tires). A harder suspension (to a point) will allow your car to carry more corner speed, since a car that rolls scrubs speed and won't transfer weight back to center as quickly. I think that the type and competitiveness of racing being done decides what tires and suspension setup I am going to run.

+1....I also store my tires in a plastic bag that has minimal air in it when my tires aren't in use.

I find that traction compound usually hurts my driving more than anything because for asphalt racing it is so inconsistent. I have noticed in the morning or any time it is humid, the compound doesnt seem to soak in as much as it does in the mid-afternoon, making it much harder to get the same consistency between runs. I stopped running traction compound on asphalt for this reason.

On top of these tips....

I also rotate my rubber tires after every race. By the end of the race day, each tire has been on each corner of the car. If you leave tires in one specific corner of the car, the inserts seem to break up faster or bunch up in one side of the tire which gives some odd handling problems. I really noticed this in the Trans-Am car since the inserts are much bigger.

I have heard of other guys drilling bigger/more holes in the rims of their tires. Is there anyone doing this? How is it affecting your car's handling, and how does it work?

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iTrader: (88)

Most of these concepts are provided by either setup books, online resources, and other experinced drivers.

Simply the harder the suspension the more the tires have to work...The more they work the hotter they get. The hotter they get the easier they will blister and roll over. So your car may be faster, but you better have an unlimited supply of tires. Those top drivers that are running harder setups also only run tires once then they thrown them away or sell them on RC tech. I personally cannot afford to have one or two run tires. My tires need to last for at least weeks. If I soften the car and let the suspension do the work the tires do not need to.

I am no expert either, but this concept makes a lot of sense and also seems to be working for me. I run a lot of laps in the course of a week and since I have softened my car my tire wear is much improved.

Thanks for the input lets keep it coming lots to learn from all of the experinced drivers in this region.

syndr0me

iTrader: (32)

Chapter 1: Tires

artwork

iTrader: (88)

dead link

syndr0me

iTrader: (32)

What the shit, it just worked a minute ago!

http://web.archive.org/web/200703041...8/c1/index.htm

theDr

The problem as I see it is that apparently you're attempting to over-generalize this soft suspension theory of yours.
We are talking about RACING here aren't we? Because by your thinking the suspension set-up on a regular passenger car should make for a faster set-up than that on a real race car, and that's not true.
I'm not saying that some of us aren't looking to cut corners so to speak to save a buck or two on the tire bill, but trying to justify a soft set-up as a race set-up because it saves tires doesn't cut it either.
But the reality of it is that no matter what you do at some point or another you have to get to some sort of happy medium, because it's possible that even going too stiff doesn't allow the suspension to work at all or enough for optimum handling.

Paul Ohlsen

Thats why you hear 1:1 car racers refer to this as balance when it comes to car set up.

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iTrader: (88)

Once again this is not my thoery, but I do see that it works for me. Every car will work differently based in the driver. This concept works on both my Xray and TC5 so far.

There is not one way to setup a car, but I was merely trying to show that car setup does in fact affect tire wear directly.

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iTrader: (88)

The other day I was messing around with the concept of a softer setup, and I noticed that when I softened both ends of the car at the same time that car drove very simular as it did with the harder setup, but tire wear seemed to get better. It was cool to watch my car work so well in a softer setup. I could not tell if my lap times went down but my car seemed easy to drive and pretty fast.

rocket-mtrsprts

iTrader: (1)

Seems as if what you're suggesting allows the car to wallow a lot through the entire suspension travel which never keeps the contact patch of the tire in contact with the surface of the track, which would then lead to not only slower lap times as well as premature wear on the outside halves of the tires and as a result excessive tire wear.

XXX Racer

I know this is generalized but 99% of the time this is right and to the point

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iTrader: (88)

These guides are really good but they never explain why you make a change.

I will give you an example...If the car needs more steering it says you can put a stiffer spring on the rear well why would you do that? As most of you know the stiffer spring in the rear will actually reduce rear traction which in turn will create more front traction thus providing more front grip. Understanding why I make changes is more important to me then just making changes.

This guide has been around for a while, but never really helped me. Like for tires is says that finding the right tire combination is 99% of car tuning. I too think tires play a very big role. What puzzles me is if it is that important why not spend some time discussing the properties of tires and how they can affect your car. The most practical explanation for tire influence comes from the XXX main book and the rubber tires for dummies thread on this forum. Other resources just show the physics and leave out all of the practical applications.

a_main_attendee

iTrader: (2)

I'm sure many people have seen many different versions of this, but i found it a while ago and i think it helped me understand the forces at hand that affect the way the car handles as well as how it reacts to different changes in more than just one straitforward general way.

http://users.pandora.be/elvo/

From ackerman to aerodynamics, this guide has it all.


-Kyle

RCworks216

iTrader: (26)

Good info