TinyRC.com - XMODS, XMOD, Micro Flight, ZipZaps, ZipZaps SE, Bit Char-G, MicroSizers, TTTT, Plantraco Desktop Rover, SuperSlicks, Digi Q, Forums, News, Pictures, Parts, and Shop
Forums, XMODS, XMOD, Micro Flight, ZipZaps, ZipZaps SE, Bit Char-G, MicroSizers, TTTT, Plantraco Desktop Rover, SuperSlicks, Digi Q
XMODS Hop-Ups, XMODS Parts, XMOD Hop-Ups, XMOD Parts, Bit Char-G Hop-Ups, Bit Char-G Parts, MicroSizers Hop-Ups, MicroSizers Parts
  #1  
Old 11-17-2003, 07:55 PM
sperry sperry is offline
Registered User
 
Join Date: Nov 2003
Location: Reno, NV
Posts: 17
Tuning Basics

I thought I'd start a thread with basic tuning info, since not everyone knows a lot about vehicle setups. Comments, corrections and additions are welcome!

The goal of tuning is to set the car up to match your driving style to the surface you're racing on.

A "loose" or "oversteering" car will tend to break rear traction before front, allowing the back-end to "come around". This is good for drifting, but will also lead to more spins. A loose car usually has more traction in the front than the rear.

A "tight" or "understeering" car will tend to break front traction before rear, causing a "push" condition where the car will slide in a straight line. A tight car usually has less traction in the front than the rear. A tight car will not be as fast as a loose car in general, however it will be much easier to drive. Remember, if you're the only one not spinning, you'll dominate the race!


SPRINGS:
Red - Soft
Yellow - Med
Blue - Hard
Silver (stock) - seems to be somewhere between Red and Yellow

Harder springs will result in less body roll, faster bound/rebound, and less overall suspension travel.
+'s: The car will react to steering and power inputs quicker becoming more manuverable.
-'s: The car will "skip" over rough surfaces, and lose traction more easily.

Softer springs will result in more traction, slower bound/rebound and more overall suspension travel.
+'s: The car will have more grip, allowing higher acceleration and latteral G's.
-'s: The car will have more body roll which means longer time between telling the car to turn and when it actually turns. More travel also means a greater chance of bottoming out and rubbing body kits on the ground.

Tuning for tight or loose is a matter of running relative differences in stiffness between the front and rear. If the front is stiffer than the rear, the car will tend to be tighter. If the rear is stiffer than the front the car will tend to be looser.


TIRES:
Soft Treaded - most grip
Soft Slicks
Stock Slicks
Hard Treaded
Hard Slicks - least grip

Tires may be the single easiest way to tune the car, since tossing on a different set of tires is easy and directly effects the traction. It seems like the treaded tires will generate more grip than the slicks, which is contrary to most common tire logic. In my experience however that is the case, at least on linoleum. YMMV.

Like the springs, tuning the tires is a matter of front to rear grip differences. Harder tires in the front will be tighter, while harder in the rear will be looser.

One more thing to note, the soft tires can come off the car pretty easily if you're drifting over rough surfaces. I was able to lose my inside front tire if I slid over a crack in the concrete! If you lose a tire in a race, you'll definately be slower than if you had gone with harder tires that didn't fall off.


STEERING RODS:
**still need rod specs**

The steering rods adjust the amount of "toe-in". Toe is the angle that the tires point towards each other, like the term "pigeon toed". The more toe in, the easier the car will turn and the more stable it will be in a straight line. However, toe in will limit the top speed of the car, and potentially will wear out the front tires faster (however I have yet to wear out a set of tires...)


WEIGHT DISTRIBUTION:
Batts front
Batts middle
Batts rear (except on RSX)

There are 3 positions for the batteries (except on the RSX who's short wheelbase leaves only 2 positions). Sliding the batteries will change the amount of weight over the tires, and will greatly effect the grip at each end.

Batts rear will increase traction in the rear (tight), and decrease traction in the front. This will help prevent spins, and give RWD cars more traction under power. On RWD cars, Batts rear will help with breaking, since only the rear tires stop the car.

Batts front will increase traction up front (loose), and decrease traction in the rear. This will be especially noticable under breaking.

Batts middle is a compromise between the two.

I have found no real reason to run with the batteries anywhere but all the way rear. I tried playing around with them in other places, but I could not tune out the oversteer with other methods.


WHEELBASE:
Short (none)
Medium (RSX)
Long (Civic, Skyline, Supra)

The different bodies have different length wheelbases (the distance between the front and rear tires). There's not much you can do right now to adjust this, however as new bodies come out, this will be a tunable setting.

Longer wheelbases tend to be more stable, and harder to turn. A long wheelbase car will spin less often, but won't be able to turn as tightly as a short wheelbase car.

Shorter wheelbases tend to be more manuverable, allowing a tighter turn radius, but an easier chance to spin.


DIFFERENTIALS:
Red - Limited Slip Differential (LSD), comes with the AWD kit.
White - Open Differential

The LSDs are designed to "lock" when the rotational speeds of the wheels on either side of it gets too great. This usually occures when one tire is slipping. As the tire slips, and it's speed becomes greater than the other tire, the differential transfers power to the other tire so that it can drive the car. Open differentials on the other hand will simply spin the slipping tire and the car will flounder. The draw back to the LSD is that it can lock up when the car is going around a tight corner, causing the car to hop as the rear drive axels bind up.

For a tighter car with more straight line traction install LSDs, especially in the rear of the car. However this will increase your turn radius.

For a looser car with a better turn radius, install the open differential. This will be at the expense of overall traction, especially on slippery surfaces.


ALL WHEEL DRIVE:
The AWD kit turns the front tires into drive tires, and comes with two LSDs. AWD dramatically increases the car's overall traction, at the expense of manuverability, top speed, and battery life. On slippery surfaces, it is invaluable, as more RWD cars will simply spin out. AWD also adds 4-wheel braking, since all braking is via the motor, so the AWD kit means the car will stop more quickly.

One trick to get a very manuverable AWD car is to install the AWD kit, but to leave the stock white (open) differential in the rear of the car. You will gain the traction up front, but your turn radius will remain small because the rear won't bind up.

There are reports that the rear control arms that come with the AWD kit are somehow different than the stockers. I didn't see any difference, but if you have please let me know!


METAL BEARINGS:
The metal bearings reduce friction and compliance in the drivetrain. They should increase battery life, and top speed, at the expence of slightly slower acceleration due to weight.


MOTORS:
Drift
Drag
Road Race
Top Speed

The four motors come in two stages, 1 and 2. Stage 1 motors turn at 26k rpms, while the Stage 2 motors turn at 30k rpms. Basically Stage 2 motors are plain old faster than Stage 1, at the cost of battery life. For tuning purposes, what's important are the gear ratios the different motors have.

The gear ratios allow you to convert between torque and power. Torque is what gives you acceleration, while power is what gives you top speed.

The Drift motor is geared for torque over speed. This means it can blast off the line very quickly, and break the tires loose for drifting with a quick stab of the accelerator.

The Top Speed motor is geared for speed over torque. This means it will be far slower off the line, but will have a much higher final top speed.

The Drag motor is a compromise between Drift and Top Speed with an emphasis on torque (acceleration).

The Road Race motor is a compromise between Drift and Top Speed with an emphasis on power (speed).


****Suspension Tuning Summary****

SPRINGS:
Tighter handling: stiffen the front, or soften the rear.
Looser handling: soften the front, or stiffen the rear.

TIRES:
Tighter handling: harder tires in the front, or softer tires in the rear.
Looser handling: softer tires in the front, or harder tires in the rear.

STEERING RODS:
Add more toe-in to gain a smaller turn radius, and better straight line stability
Less toe-in to gain a higher top speed, and less tire wear

WEIGHT DISTRIBUTION:
Tighter handling: move the weight rear
Looser handling: move the weight forward

WHEELBASE:
A longer wheelbase is tighter and more stable
A shorter wheelbase is looser and more manuverable

DIFFERENTIALS:
LSD: More traction on slippery surfaces, harder to turn
Open: Smaller turn radius, less traction on slippery surfaces

ALL WHEEL DRIVE:
Install AWD for tons more traction, especially on slippery surfaces, and 4-wheel braking.
Remove AWD for higher top speed, greater manuverability, and longer battery life.

MOTORS:
Install the drift or drag motors if the course is small and accleration is important.
Install the road race or top speed motors if the course is long and high speed is important.
Reply With Quote
  #2  
Old 11-17-2003, 08:08 PM
SirPoonga SirPoonga is offline
TinyRC Newbie
 
Join Date: Nov 2003
Posts: 17
The Tire thing depends on the surface you drive. A soft tread will have more traction on a dirt path than a hard slick. A hard slick will have more traction on a drag strip than a soft tread.

Generally, on a slick surface flat will have more traction as more tire is on the ground. So rougher surfaces tread will have more traction as the tread will "wrap" around the dirt.

Soft and Hard have their place to. Generally for a softer surface you want a softer tire so the tire can form with the surface. So, why would you use a hard tire on anything. Well, a soft tire squishes upon torque of the wheel. This is great for off road and rough surfaces it's like a mini shock. But on a hard surface that is waste power to squish the tire. So for speed you would want hard.

Then you just have to mix and match the two types depending n the surface you are going to race on. Also you can put something like soft slicks on front and hard slicks on rear if you want a car with RWD to accelerate better on a slick surface but have the turnings wheel grip more (for drifting or harder turns).

I like that radioshack includes All different type of tires in one package. They could have easily made them seperate purchases (same with shocks, engines, etc...). Mainly, the best thing to do is play around with different setups on different surfaces. Learn how the car reacts with different setups.

So you really can't say one tire is better than another, they each have their purpose.



I also want to add to AWD. AWD "should" give you faster acceleration as there are 4 wheels doing the work instead of 2. This can differ upon setup too, especially with how differentials are setup. Also it takes more energy from the engine to rotate the 4 wheels. Basic physics right there.

Ever watch a GT race on speedvision. Notice how the Audi's get the hole shot and the BMW's are right behind. That AWD helps them accelerate a little bit faster.

Again, depending on the type of race you are racing, some mods are better than others. Take what is said here by sperry and me and apply it to the type of racing you do.

Last edited by SirPoonga; 11-17-2003 at 08:20 PM.
Reply With Quote
  #3  
Old 11-17-2003, 08:27 PM
4G63T's Avatar
4G63T 4G63T is offline
got boost?
 
Join Date: Oct 2003
Location: Canada,Ontario
Posts: 838
thanks guys for the information
i knew most of this stuff, but it helps to understand to some people
__________________
All Wheel Drive=Fun!!!

Last edited by 4G63T; 11-17-2003 at 10:06 PM.
Reply With Quote
  #4  
Old 11-17-2003, 08:33 PM
sperry sperry is offline
Registered User
 
Join Date: Nov 2003
Location: Reno, NV
Posts: 17
Quote:
Originally posted by SirPoonga
I also want to add to AWD. AWD "should" give you faster acceleration as there are 4 wheels doing the work instead of 2. This can differ upon setup too, especially with how differentials are setup. Also it takes more energy from the engine to rotate the 4 wheels. Basic physics right there.
Good point about the AWD's acceleration advantage. There is more drivetrain power loss in AWD, but the traction advantage usually outweighs it at lower speeds. I race a WRX, I should know these things! lol

Quote:
Originally posted by SirPoonga
Generally, on a slick surface flat will have more traction as more tire is on the ground. So rougher surfaces tread will have more traction as the tread will "wrap" around the dirt.
I agree that generally a slick should have more traction than a treaded tire. I was surprised that emperically it wasn't the case, at least on linoleum. Of course, linoleum isn't all that smooth compared to the size of an XMod tire. I think more testing needs to be done to really figure out what generates more traction. Next time I'm out at the warehouse, I'll toss soft slicks on the front and soft treads on the rear, run around a bit, then swap 'em front to rear and see if the car's tighter or looser.

Quote:
Originally posted by SirPoonga
A hard slick will have more traction on a drag strip than a soft tread.
I have to disagree with you about hard tires having more grip on smooth surfaces. The compound of a soft tire is always going to be sticker. The whole point of having hard tires on an Xmod is that it *isn't* as sticky as the soft. You would run a hard tire to reduce traction on one end of the car in order to adjust the handling of the car, as described above.

Quote:
Originally posted by SirPoonga
Soft and Hard have their place to. Generally for a softer surface you want a softer tire so the tire can form with the surface. So, why would you use a hard tire on anything. Well, a soft tire squishes upon torque of the wheel. This is great for off road and rough surfaces it's like a mini shock. But on a hard surface that is waste power to squish the tire. So for speed you would want hard.
Your talk of "power to squish the tire" is known as "rolling friction" and it is indeed as you descirbed it. It takes more power to roll a soft tire than a hard tire, something easily noticed on a bicycle if your tires are low on air. Hard tires would definately help you achieve a higher top speed. In fact, if you were to shave the tires so only the very center touched the ground that should really help the car top out in a straight line.
Reply With Quote
  #5  
Old 11-17-2003, 08:35 PM
sperry sperry is offline
Registered User
 
Join Date: Nov 2003
Location: Reno, NV
Posts: 17
Quote:
Originally posted by 4G63T
thanks guys for the information
i new most of this stuff, but it helps to understand to some people
I figured most people would know or figure this stuff out, but I'm sure there's some people for which their XMod is their first foray into car tuning/setup and I thought I'd try to compile the basics in one place.
Reply With Quote
  #6  
Old 11-17-2003, 08:37 PM
SirPoonga SirPoonga is offline
TinyRC Newbie
 
Join Date: Nov 2003
Posts: 17
Yeah. If you aren't really into real life racing it's tough to understand what the mods do. I know a good bit because my friends and I are into the Gran Tourismo series and I know a guy who races a first gen rx7 for scca.
Reply With Quote
  #7  
Old 11-17-2003, 08:56 PM
SirPoonga SirPoonga is offline
TinyRC Newbie
 
Join Date: Nov 2003
Posts: 17
Quote:
Originally posted by sperry
[b]Good point about the AWD's acceleration advantage. There is more drivetrain power loss in AWD, but the traction advantage usually outweighs it at lower speeds. I race a WRX, I should know these things! lol
Edit: I hate that you can't PM people. You race SCCA? Ever race at Road America?

Yep, to the rest of the people to understand why this is the case I will use this analogy.

Take two cars, everything is the same accept one is RWD and one is AWD (assume same engine, same weight).
In physics force = mass times acceleration
or
force/mass = acceleration.
Since mass is the same for this example the more force the more acceleration.

Lets same in RWD each wheel is putting out 10N of force on each wheel, 20N total. With the same engine the AWD puts out 6N on each wheel because it takes more energy from the motor to turn the wheel. Total being 24N. Obvious which one will accelerate faster.

Yeah, I am an applied math major, I think scientifically.


Quote:
I agree that generally a slick should have more traction than a treaded tire. I was surprised that emperically it wasn't the case, at least on linoleum. Of course, linoleum isn't all that smooth compared to the size of an XMod tire. I think more testing needs to be done to really figure out what generates more traction. Next time I'm out at the warehouse, I'll toss soft slicks on the front and soft treads on the rear, run around a bit, then swap 'em front to rear and see if the car's tighter or looser.
Yeah, at that scale it's pretty bumpy.

Quote:
I have to disagree with you about hard tires having more grip on smooth surfaces. The compound of a soft tire is always going to be sticker. The whole point of having hard tires on an Xmod is that it *isn't* as sticky as the soft. You would run a hard tire to reduce traction on one end of the car in order to adjust the handling of the car, as described above.
My bad, you are more correct. Soft give more traction for reason "I" said before. Hehe, I contradicted myself, shame on me.

Last edited by SirPoonga; 11-17-2003 at 09:00 PM.
Reply With Quote
  #8  
Old 11-17-2003, 10:00 PM
TypeZer0's Avatar
TypeZer0 TypeZer0 is offline
0reZepyT
 
Join Date: Feb 2003
Location: Boston, MA
Posts: 804
just a note, you said the AWD kit comes with two LSD's, that's incorrect, the extra diff that's not pre-installed in the front assembly is the only LSD, the pre-installed one is an open diff but given a red color
__________________
Friends (Joey's Bag)
Rachel: Exactly! Unisex!
Joey: Maybe you need sex. I had sex a couple days ago.
Rachel: No! No Joey! U-N-I-sex.
Joey: Well, I ain't gonna say no to that.
Reply With Quote
  #9  
Old 11-18-2003, 12:15 PM
johnfish johnfish is offline
TinyRC Pro
 
Join Date: Jan 2003
Location: Midlothian Va
Posts: 43
This should be made into a sticky at the top of the forum. Great Information!

Thanks guys.

John
Reply With Quote
  #10  
Old 11-18-2003, 01:04 PM
sperry sperry is offline
Registered User
 
Join Date: Nov 2003
Location: Reno, NV
Posts: 17
Quote:
Originally posted by SirPoonga
You race SCCA? Ever race at Road America?
I just race autocross up here in the Reno SCCA Region. We're trying to move towards road racing, now that the new road course at Reno-Fernley Raceway is open.

Quote:
Originally posted by TypeZer0
just a note, you said the AWD kit comes with two LSD's, that's incorrect, the extra diff that's not pre-installed in the front assembly is the only LSD, the pre-installed one is an open diff but given a red color
Really!? I thought they were both the same, since RS has done a pretty good job of color coding all the parts.
Reply With Quote
  #11  
Old 11-18-2003, 01:05 PM
sperry sperry is offline
Registered User
 
Join Date: Nov 2003
Location: Reno, NV
Posts: 17
BTW: for more technical discussion about this, my friend who's a mechanical engineer went over this post here:

http://www.seccs.org/forums/viewtopic.php?t=809
Reply With Quote
  #12  
Old 11-18-2003, 01:17 PM
TypeZer0's Avatar
TypeZer0 TypeZer0 is offline
0reZepyT
 
Join Date: Feb 2003
Location: Boston, MA
Posts: 804
yeah, spin the wheels with the red diff from the front assembly, it feels exactly teh same as the stock white one. teh ball diff feels different
__________________
Friends (Joey's Bag)
Rachel: Exactly! Unisex!
Joey: Maybe you need sex. I had sex a couple days ago.
Rachel: No! No Joey! U-N-I-sex.
Joey: Well, I ain't gonna say no to that.
Reply With Quote
  #13  
Old 11-19-2003, 01:56 AM
SR20DETT SR20DETT is offline
TinyRC Pro
 
Join Date: Nov 2003
Location: Southwestern U.S
Posts: 64
If you want to see the AWD ver RWD in action, watch the european super car series on speed channel. From a standing start the AWD Audis are crushing the more powerful RWD drive cars off the line. Ecspecially if conditions are less than perfect.PEACE
__________________
If your going to grab the shark by the tail, you'd better have a plan for dealing with the teeth.
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Antenna Tuning aperson XMODS 12 03-26-2004 05:50 PM
XS tuning wheels for xmods paul4170 XMODS 0 11-07-2003 09:41 PM
cleaning tuning help faulkbeets ZipZaps 5 07-11-2003 06:47 PM
Battery Basics 101 Namuna Bit Char-G / MicroSizers 35 06-29-2003 09:17 PM


All times are GMT -5. The time now is 12:26 AM.


Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Mini Inferno Sale - Up to $85 Instant Savings!
Micro-T Hop-Ups
RC18R, M18, Micro RS4, Mini-LST, TamTech-Gear, Minizilla, RC18T, RC18B, RC18MT
shop.tinyrc.com Products
Tiny RC Community News
[03/17/10] Kyosho Mini-Z F1 MF-010 SP2... : The Kyosho Mini-Z F1 MF-010 SP2 Carbon Limited ASF 2.4GHz Tx-Less Chassis Set - more»
[10/23/09] Kyosho Mini-Z MR-03 In Stock! : The Mini-Z MR-03 (http://mr-03.com) is now In Stock and Pre-Orders are shipping! - more»
[09/06/09] Labor Day Savings - $5 Off... : Labor Day traditionally marks the unofficial end of summer - but we're not ready to let go! So, we - more»
Mini-Z, Mini-Z Racer, MR-02, MA-010
M18, M18T, RC18T, Mini-LST, Mini-T, Micro RS4, XRay, 1/18, 18th scale
XMODS, XMOD, Micro Flight, ZipZaps, ZipZaps SE, Bit Char-G, MicroSizers, TTTT, Plantraco Desktop Rover, SuperSlicks, Digi Q
Mini Inferno, Mini Inferno ST, half EIGHT, 1/16, 16th scale
Epoch, Indoor Racer, 1/43, 43rd scale
E-Savage, eSavage, eZilla, e-Zilla, HPI
Robots, Bots, Bipeds, Wheeled, Manoi, Roomba, NXT, Lego, Hacking
Crawling, Crawlers, Micro, RC, Losi Mini-Rock Crawler, Duratrax Cliff Climber
Kyosho Minium, Caliber 120, Minium Forums
Mini-Z Hop-Ups, Mini-Z Parts, Mini Inferno Hop-Ups, Mini Inferno Parts, M18 Hop-Ups, M18 Parts