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View Full Version : what is toe in / toe out?


herman
2008.03.26, 10:48 PM
Toe-in is the angle of the wheels as looked at from directly above the car.

When the wheels are parallel the toe-in is 0-degrees.

When the front of the wheels are pointing away from each other, that is called toe-out.

When the front of the wheels are pointing in towards each other, that is called toe-in.

Toe-in is used to stabilize the car at cost of traction. In case of oversteer (the rear end losing traction before the front end does) extra toe-in on the front may take some oversteer away but also some steering. In case of understeer (the front end losing traction before the rear end does) some toe-in on the rear may help, but this makes on-power cornering a little more difficult.

Front toe-in will make your car easier to drive by improving stability during
acceleration, and gives a slight increase in steering exiting corners.

Front toe-out will increase steering when entering corners but will be slightly more difficult to drive.

http://i148.photobucket.com/albums/s11/hmc_jr/rc%20stuff/toeoutin.jpg

source:http://www.teamxray.com/teamxray/products/prodsetbook.php?setbook_id=116&prod_id=446&kategoria=253&catName=%20-%20Toe-in%20&%20Toe-out&Xnet_Session=518661ec965ade8bb7c3036456c36e0a

herman
2008.03.27, 10:58 PM
in mini-z terms... :D

in the mr015 or mr02, this can be achieved by replacing the stock tie rod with one that offers toe in / toe out option like the one below
available in 0 degree, toe out -0.5 degree, -1.0 degree, toe in +0.5 degree, +1.0 degree
http://www.pnracing.us/new/product_image/240_1.jpg

Action B
2008.03.28, 03:30 PM
I'm new to mini-z. I'm not saying that your wrong, but rather that I don't understand fully. Logically, I feel that Toe in (in the front) increases turning capabilities at the cost of straight line stability. In my mind, as you turn, weight shift towards the outside wheels. From this assumption I think... hmm.. common physics, friction formula ( force of friction= coefficient of friction x force of gravity). In this case, the outside wheel has more weight on it, and therefore a higher force of friction. If it has a higher force of friction, then it is doing the majority of the work to make the car turn. If this is the case, then in toe-in, most of the work is being done by the wheel that is more sharply turned (outside relative to turn) and therefore increases turning capabilities.

However, I'm a biologist not a physicist, let me know whats up with this!


Also, there is a vast amount of information stating that toe-in does increase cornering at the expense of straight line high speed stability. For instance off atomicmods site:

Team AtomicMods Comments:Toe in makes the steering more responsive and cornering more agressive, at the cost of straight line tracking and stability, while toe out does the opposite. For the best results, tune your car for the track you are racing on. Lots of curves, you need more toe in, more straights, go towards toe out. I keep one of each size in my track bag so I can dial in my car to match the track. - Rob

Back of the XMods suspension upgrade:

Toe-In Degree Usage
1.5 Straight stretches and speed
3.0 Some straight stretches and curves
4.5 Tight and curvy roads

That being said, I've also seen evidence of your explanation on the web, but it doesnt make much sense to me... Can anyone clear this up?

mleemor60
2008.03.28, 05:32 PM
I'm new to mini-z. I'm not saying that your wrong, but rather that I don't understand fully. Logically, I feel that Toe in (in the front) increases turning capabilities at the cost of straight line stability. In my mind, as you turn, weight shift towards the outside wheels. From this assumption I think... hmm.. common physics, friction formula ( force of friction= coefficient of friction x force of gravity). In this case, the outside wheel has more weight on it, and therefore a higher force of friction. If it has a higher force of friction, then it is doing the majority of the work to make the car turn. If this is the case, then in toe-in, most of the work is being done by the wheel that is more sharply turned (outside relative to turn) and therefore increases turning capabilities.

However, I'm a biologist not a physicist, let me know whats up with this!


Also, there is a vast amount of information stating that toe-in does increase cornering at the expense of straight line high speed stability. For instance off atomicmods site:

Team AtomicMods Comments:Toe in makes the steering more responsive and cornering more agressive, at the cost of straight line tracking and stability, while toe out does the opposite. For the best results, tune your car for the track you are racing on. Lots of curves, you need more toe in, more straights, go towards toe out. I keep one of each size in my track bag so I can dial in my car to match the track. - Rob

Back of the XMods suspension upgrade:

Toe-In Degree Usage
1.5 Straight stretches and speed
3.0 Some straight stretches and curves
4.5 Tight and curvy roads

That being said, I've also seen evidence of your explanation on the web, but it doesnt make much sense to me... Can anyone clear this up?

What is missing from the formula is something that Mini-Zs dont have. Ackerman steering. In plain english, Ackerman is how much more one wheel turns than the other from 0 to full lock. Without it you have to exagerate the toe settings to compensate. A little toe out helps the car into the corner by dragging the inside tire into the turn taking load off the outside tire. It's really a lot more complicated than that because caster as well as camber start to come into play. In another life I was a front end man and I still don't understand all there is to know about it. In the old days with bias ply tires if the front end wasn't toed in the car could be very unstable to drive. With the advent of radial tires and different rolling resistances the opposite applied.
It is quite a can of worms. My personal Z set up is -3 camber, -.5 caster and zero toe. Allowing for the normal slop in the tie rod it will set up a little toed out. It is different for everybody. A matter of feel and comfort.

Action B
2008.03.28, 07:13 PM
It still seems odd to me, I feel that the weight transfer must be massive as these arent regular cars, they are crazy fast to scale, turning can even frequently flip many cars with ease, meaning the inside tire (especially with ball bearing differentials) would hardly be used. Can anyone elaborate any more on this?

mleemor60
2008.03.29, 10:53 AM
I build a little droop, usually .020 thousandths so as the car turns in and tries to lift the inside front it doesn't lose contact with the track. Droop also helps on an irregular surface by allowing the wheels to follow the surface. Also, alot of the steering control is done from the rear of the car through the Damper Plate System. Friction and spring rate control the chassis roll rate sort of like a sway(anti roll) bar. Check out reflexracing.net for good tutorials on this and many other items. In my opinion, they are best and most helpful outfit out there. They have been really great to me.

Crusty

bmxtrev
2008.05.24, 09:24 PM
on the kyosho instructions that come with the tie rod set, it is stated that as the toe-in increases, stability increases. i also think this is true based on my own experiences. But with more toe in, you have a little less steering in general.

i think rob made an error when he wrote his comment about toe in and toe out. If toe out does the opposite of toe-in, then toe out would increase straight line stability. But how would 2 wheels that are fighting to go in their own direction increase straight line stability?

I really dont trust anything that has the word xmod in it. when i got the xmod tierod set, i figured they made a mistake.

andreophile
2008.05.25, 09:58 PM
From this assumption I think... hmm.. common physics, friction formula (force of friction= coefficient of friction x force of gravity).
Nope, you got that partially right, but technically it still is incorrect. The frictional force is a product of the coefficient of friction () with the normal reaction force (R). In a state of equilibrium (and also in a dynamic state), the normal reaction force is equal to the weight of the car, as long as no other force acts vertically. Note: weight is a product of mass and gravity. However, if any other force acts along the Y-axis (like aerodynamic downforce for eg.), your equation won't hold true. That's why friction is considered as a product of the normal reaction force with the coefficient of friction, and isn't specifically equated in terms of gravity.

http://img262.imageshack.us/img262/7827/friction04zl1.jpg

bmxtrev
2008.05.26, 11:31 AM
lol, i just read the instructions :o

andreophile
2008.05.28, 09:10 AM
I played around with five different toe settings today from +2.3 (toe in) to -0.6 (toe out). I practically verified with my MA-010 what's common knowledge about toe settings. That is, real car toe characteristics work out identically for the Mini-Z too. Here's what I've verified:

http://img232.imageshack.us/img232/3674/chartke2.jpg

Then I tested how the turning radius is affected at the extremes of toe settings (refer image below; click to enlarge). The steering dual rate was set at 90% and I crawled the car at maximum lock. Surprisingly, I found the turning radius to be shorter for toe-in than for toe-out.

http://img137.imageshack.us/img137/8343/toesettingssmallap9.jpg (http://img137.imageshack.us/img137/2796/toesettingsrg2.jpg)

Action B
2008.05.29, 06:19 PM
Nope, you got that partially right, but technically it still is incorrect. The frictional force is a product of the coefficient of friction () with the normal reaction force (R). In a state of equilibrium (and also in a dynamic state), the normal reaction force is equal to the weight of the car, as long as no other force acts vertically. Note: weight is a product of mass and gravity. However, if any other force acts along the Y-axis (like aerodynamic downforce for eg.), your equation won't hold true. That's why friction is considered as a product of the normal reaction force with the coefficient of friction, and isn't specifically equated in terms of gravity.

http://img262.imageshack.us/img262/7827/friction04zl1.jpg

yeah, sure, I was trying to simplify some to make it understandable by everyone the basic concept. I realize that force of gravity should be replaced with 9.81 m/s acceleration force (roughly) times the mass(in Kg) plus any other factors that would effect it such as downforce. Not everyone here knows what your talking about specifically, however, I appreciate your attention to detail and the tests you did. I am a biologist so I'm going off memory from the two semesters of physics I did over a year ago anyhow.

There are several people on here that have never taken a physics class and personally I wouldn't recommend it. Just read my post for the general idea.

What I'm trying to say is that your a superior being of higher intelligence and thanks for correcting me lol

andreophile
2008.05.30, 01:29 AM
@ Action B: Nah, it's not about anyone being super intellingent here, nor does my post mean to 'correct' yours, because, like I've already stated, you are practically correct.

I posted that for an academic purpose and most importantly because these threads are a part of the massive Mini-Z information archive. Having studied biology, it's obvious that you're well versed with such basic stuff, but the same might prove useful for a complete layman reading this thread.

Then again, I'd created this diagram to eplain how the Mini-Z shares the same handling dynamics as a real car on another forum. So I was just tempted to use it again :p

marc
2008.10.01, 01:00 PM
Nope, you got that partially right, but technically it still is incorrect. The frictional force is a product of the coefficient of friction () with the normal reaction force (R). In a state of equilibrium (and also in a dynamic state), the normal reaction force is equal to the weight of the car, as long as no other force acts vertically. Note: weight is a product of mass and gravity. However, if any other force acts along the Y-axis (like aerodynamic downforce for eg.), your equation won't hold true. That's why friction is considered as a product of the normal reaction force with the coefficient of friction, and isn't specifically equated in terms of gravity.

http://img262.imageshack.us/img262/7827/friction04zl1.jpg

Um..........what was that you said Bill Nye? :D

ruf
2008.10.01, 01:08 PM
I played around with five different toe settings today from +2.3 (toe in) to -0.6 (toe out). I practically verified with my MA-010 what's common knowledge about toe settings. That is, real car toe characteristics work out identically for the Mini-Z too. Here's what I've verified:

http://img232.imageshack.us/img232/3674/chartke2.jpg

Then I tested how the turning radius is affected at the extremes of toe settings (refer image below; click to enlarge). The steering dual rate was set at 90% and I crawled the car at maximum lock. Surprisingly, I found the turning radius to be shorter for toe-in than for toe-out.

http://img137.imageshack.us/img137/8343/toesettingssmallap9.jpg (http://img137.imageshack.us/img137/2796/toesettingsrg2.jpg)Neat picture! You probably found toe-in to have a slightly tighter turning radius due to the geometry of the steering rack. Toe-in implies that the outer tire is already turned into the corner slightly. This continues to full lock, and if you look closely you can actually see that the outside tire has a larger steering angle on the toe-in example. Despite your best efforts to creep along at low speed, the outside tire will always bear more load than the inside, and thus dictate a slightly tighter turning radius with the toe-in setting. Very cool demo!

Also, don't forget other forces like camber thrust...

marc
2008.10.01, 02:42 PM
One way to look at it is to use your feet. Look down at your feet and move your toe's inward with your heal's outward. Then try and walk a streight line and turn. Then move your toe's outward and repeat. That's how I learned it and understood it back when. Granted not exactly the same thing as wheel's, but helps explain toe-in toe-out!

bmxtrev
2008.10.01, 09:16 PM
^ ha, i actually got up and tried this, and it makes very good sense! good one marc :)

marc
2008.10.01, 09:32 PM
Ahhhhhhh, another plus one in my book. :D Too bad it doesn't work for camber though.:eek:

hrdrvr
2008.10.02, 06:51 AM
^ You have to bend at the knees to try camber, lol.

andreophile
2008.10.02, 08:04 AM
Neat picture! You probably found toe-in to have a slightly tighter turning radius due to the geometry of the steering rack. Toe-in implies that the outer tire is already turned into the corner slightly. This continues to full lock, and if you look closely you can actually see that the outside tire has a larger steering angle on the toe-in example. Despite your best efforts to creep along at low speed, the outside tire will always bear more load than the inside, and thus dictate a slightly tighter turning radius with the toe-in setting. Very cool demo!

Also, don't forget other forces like camber thrust...

Thanks. I knew that weight shifts onto the outer wheel (with a sharper turning radius) during acceleration, which affords a toed-in car with better on-power steering. Conversely, a lack of substantial weight transfer gives considerable traction to the inner wheel (with a shallower turning radius) and hence induces understeer during off-power cornering. I've even empirically verified all this.

This baffled me more when toe-in provided a tighter radius after I did the tests by crawling the Z to emulate off-power condition. But your post gives clarity on my inherent mistake. Weight transfer occurs even when crawling, so I erred at the outset. I should've just accelerated and cut the power off to emulate off-power cornering. In fact, I just tried it out this afternoon and found the that results verify with my toe-control setting chart.

ProfoxCG
2008.11.07, 12:17 AM
how does Toe-in or toe-out affect the amount of steering during,
entry, mid and exit of a turn?

Im having some issues, my AWD, had lots of steering mid - exit (on power) but not much at entry off power,

I have the kyosho #4 toe-in bar which is 1.5* (in the front)

my MR02, has 0 toe, and does not have my steering mid-exit (on power)

Based on this thread:

for my AWD I should, DECREASE FRONT TOE so that I have more steering off power.

for my MR02, since i need more mid to exit on power, I should probably toe-in the wheels some?


(also does the same apply for the rear?) more toe-in in the rear will allow for the rear end to rotate some while providing grip? - the way I learned it was that the more rear tio, the harder for the car to rotate bc I hooked to the road more.

ProfoxCG
2008.11.08, 09:44 AM
someone answer my post please =)

Slipstream
2008.11.09, 07:48 PM
Toe out will give you more entry or initial steering. It will give you less mid corner and exit steering.

Toe in will do the opposite.

To answer your questions 2 posts above, yes you should try what you said for both your awd and -02.

eztuner12
2008.11.09, 10:22 PM
I played around with five different toe settings today from +2.3 (toe in) to -0.6 (toe out). I practically verified with my MA-010 what's common knowledge about toe settings. That is, real car toe characteristics work out identically for the Mini-Z too. Here's what I've verified:

http://img232.imageshack.us/img232/3674/chartke2.jpg

Then I tested how the turning radius is affected at the extremes of toe settings (refer image below; click to enlarge). The steering dual rate was set at 90% and I crawled the car at maximum lock. Surprisingly, I found the turning radius to be shorter for toe-in than for toe-out.

http://img137.imageshack.us/img137/8343/toesettingssmallap9.jpg (http://img137.imageshack.us/img137/2796/toesettingsrg2.jpg)

Man:eek: this is a great ilustration, o yeah!