Can too much front toe cause understeer?
#1
Le Mans Master
Thread Starter
Can too much front toe cause understeer?
I went to a bit more toe in front and experienced some more understeer than I seem to remember (this was my first drive this season).
It may have been the older tires or driver characteristics but I'm wondering if I should back off the toe a bit?
Curious on inputs.
Thanks,
Jon
It may have been the older tires or driver characteristics but I'm wondering if I should back off the toe a bit?
Curious on inputs.
Thanks,
Jon
#2
Melting Slicks
I dont like front toe-in period. Car doesn't turn in too well like that and there is not enough ackerman in the front..........................Use "some" toe out for road course and "more" for autocross
#3
Drifting
yellow01 - what are you using the car for? Also, when you reflect on it, is the understeer at initial turn-in, is it in steady state, is it during corner exit, or some combination thereof?
Excessive toe-in (or even moderate toe-in) for autocrossing will cause your car to not want to transition.
#4
Le Mans Master
Thread Starter
Sorry sorry guys. I worded it poorly.
I meant front toe-out [space] in front Toe-out was assumed. Sorry for the poor wording. now, same question again, sorry.
I noticed it mainly in a fairly tight sweeper. It may have been too much speed (if I sawed a little bit at the wheel I massaged it in a bit). I just don't remember it handling like that before. I'm asking to try and learn.
Last time out I ran -1.5 in front, now I'm at -2.3 and a bit more toe-out. I don't have the sheet in front of me (sorry again).
Turn-in was fantastic (I like the toe-out for that) but I'm wondering if I went too far.
I meant front toe-out [space] in front Toe-out was assumed. Sorry for the poor wording. now, same question again, sorry.
I noticed it mainly in a fairly tight sweeper. It may have been too much speed (if I sawed a little bit at the wheel I massaged it in a bit). I just don't remember it handling like that before. I'm asking to try and learn.
Last time out I ran -1.5 in front, now I'm at -2.3 and a bit more toe-out. I don't have the sheet in front of me (sorry again).
Turn-in was fantastic (I like the toe-out for that) but I'm wondering if I went too far.
Last edited by yellow01; 05-22-2006 at 11:40 AM.
#5
Burning Brakes
Depending . . . yes, technically anything can cause understeer in some component part. I'm with Al -- where in the turn are you seeing understeer? Is it consistent?
I'm guessing that you're not running 2.3deg out, but rather 2 degrees camber . . . . if you ARE running 2 degrees toe, you're WAY too far out IMO. For road courses, I'll normally run 1/16th out [f] and 1/16th in [r], but have run up to 1/8th out. Much more, and the car started getting unpredictable (again, IMO). For an 18" wheel that 1/16th translates to ~ 0.2 degrees IIRC, for comparison sake.
Not saying that toe is your culprit, but it could be a factor depending on where you're seeing understeer (as Al mentions)
I'm guessing that you're not running 2.3deg out, but rather 2 degrees camber . . . . if you ARE running 2 degrees toe, you're WAY too far out IMO. For road courses, I'll normally run 1/16th out [f] and 1/16th in [r], but have run up to 1/8th out. Much more, and the car started getting unpredictable (again, IMO). For an 18" wheel that 1/16th translates to ~ 0.2 degrees IIRC, for comparison sake.
Not saying that toe is your culprit, but it could be a factor depending on where you're seeing understeer (as Al mentions)
#6
at road atlanta this year i was "helped off the track" at T7 in a race, i spun and when i went off it tweaked my right front alignment (significantly more negative camber and subsequently more tow out)...the car did not want to turn left after that (it understeered at corner entry)...
so yes, in my experience, too much tow out in the front can cause understeer
so yes, in my experience, too much tow out in the front can cause understeer
#7
Le Mans Master
Thread Starter
Originally Posted by emf
I'm guessing that you're not running 2.3deg out, but rather 2 degrees camber . . . . if you ARE running 2 degrees toe, you're WAY too far out IMO. For road courses, I'll normally run 1/16th out [f] and 1/16th in [r], but have run up to 1/8th out. Much more, and the car started getting unpredictable (again, IMO). For an 18" wheel that 1/16th translates to ~ 0.2 degrees IIRC, for comparison sake.
Not saying that toe is your culprit, but it could be a factor depending on where you're seeing understeer (as Al mentions)
Not saying that toe is your culprit, but it could be a factor depending on where you're seeing understeer (as Al mentions)
I'm not being very clear today am I
-2.3* Camber and .12* out (this is between 1/16 and 1/8th, 17" front so probably closer to 1/8th).
I changed camber and toe all at once so am trying to learn what response that got me.
Straight line is fine, and turn-in is fantastic (actually feels a bit like a small car and less like a 3400lb gt).
#8
Melting Slicks
Originally Posted by yellow01
Sorry sorry guys. I worded it poorly.
I meant front toe-out [space] in front Toe-out was assumed. Sorry for the poor wording. now, same question again, sorry.
I noticed it mainly in a fairly tight sweeper. It may have been too much speed (if I sawed a little bit at the wheel I massaged it in a bit). I just don't remember it handling like that before. I'm asking to try and learn.
Last time out I ran -1.5 in front, now I'm at -2.3 and a bit more toe-out. I don't have the sheet in front of me (sorry again).
Turn-in was fantastic (I like the toe-out for that) but I'm wondering if I went too far.
I meant front toe-out [space] in front Toe-out was assumed. Sorry for the poor wording. now, same question again, sorry.
I noticed it mainly in a fairly tight sweeper. It may have been too much speed (if I sawed a little bit at the wheel I massaged it in a bit). I just don't remember it handling like that before. I'm asking to try and learn.
Last time out I ran -1.5 in front, now I'm at -2.3 and a bit more toe-out. I don't have the sheet in front of me (sorry again).
Turn-in was fantastic (I like the toe-out for that) but I'm wondering if I went too far.
You still haven't said if this ws an autocross or road course ??? Front toe settings will be different between the two. FWIW I use alot of toe-out in the front for autocross ( helps car change directions rapidly ). Remember too much of anything is bad, including front toe out. Another thing to remember is alot of alignment settings are driver preference oriented.
#9
Le Mans Master
Thread Starter
Originally Posted by RAFTRACER
Sounds like a UIP to me ( user induced push) .
It was a road course, but not a standard de weekend, it was part of a big corvette show at TMS and it was 8 laps and get back in line. It was also open to anyone, and people classified their own experience level - read not too many hot laps so I didn't have a lot of time to try different entry speeds etc.
I was using it mainly as a tune-up of the brain and a quick run on the new alignment settings before my first full out of town weekend of this season coming up.
Thanks!!
#10
Burning Brakes
Originally Posted by yellow01
-2.3* Camber and .12* out (this is between 1/16 and 1/8th, 17" front so probably closer to 1/8th).
Originally Posted by yellow01
Straight line is fine, and turn-in is fantastic (actually feels a bit like a small car and less like a 3400lb gt).
Originally Posted by RAFTRACER
Sounds like a UIP to me ( user induced push) .
#11
Team Owner
Member Since: Sep 2003
Location: Raleigh / Rolesville NC
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Sounds like your finding that one setting can not be use for street, auto-x and track / road racing which is normal.
I use
front
-3.5 camber
1/16" toe out
max caster and equal on both sides ( 7* if i rember corectly - one side could get 7.75* and the other only 7* so made them both 7*)
rear
-2.5 camber
1/16" toe in
equal tire ware across both front and rear tires. Dont have a pyromiter yet to be sure.
Works well for me, so far, but car is not perfectly corner balanced either.
for most multi use vettes
front
-2*
1/16" toe out
max and but equal caster
rear
-1.5*
1/16" toe in
I use
front
-3.5 camber
1/16" toe out
max caster and equal on both sides ( 7* if i rember corectly - one side could get 7.75* and the other only 7* so made them both 7*)
rear
-2.5 camber
1/16" toe in
equal tire ware across both front and rear tires. Dont have a pyromiter yet to be sure.
Works well for me, so far, but car is not perfectly corner balanced either.
for most multi use vettes
front
-2*
1/16" toe out
max and but equal caster
rear
-1.5*
1/16" toe in
Last edited by AU N EGL; 05-22-2006 at 02:27 PM.
#12
Melting Slicks
Originally Posted by dmwhite
at road atlanta this year i was "helped off the track" at T7 in a race, i spun and when i went off it tweaked my right front alignment (significantly more negative camber and subsequently more tow out)...the car did not want to turn left after that (it understeered at corner entry)...
so yes, in my experience, too much tow out in the front can cause understeer
so yes, in my experience, too much tow out in the front can cause understeer
#13
Le Mans Master
Originally Posted by yellow01
I went to a bit more toe in front and experienced some more understeer than I seem to remember (this was my first drive this season).
If you took a car, cornering at constant speed, and aligned the car exactly for that cornering speed, and then returned the steering to dead straight, you would find that the Front tires would be toed-out. A small amount of Front toe-out reduces the scrubbing forces at the front, leaving thses forces for increasing the ability to corner.
Most race cars use Front toe-out because it reduces the scrubbing losses while cornering, and because the race car driver already has great concentration and can tollerate the wander and other negative effects of Front toe-out.
Front Toe-out also increases the sensitivity to steering input, and many cars respond by turing in easier/faster with a bit of toe-out.
Front Toe-out can compensate for agressive camber angles and tone down the wander of the front end when agressive camber angles are used. and enable better wear characteristics by leaving the contact patch more evenly loaded.
#14
Le Mans Master
Thread Starter
Originally Posted by emf
... actually, it's closer to 1/32" out, but who's counting
Originally Posted by AU N EGL
Sounds like your finding that one setting can not be use for street, auto-x and track / road racing which is normal.
UIP - not surprised Always was a distinct possibility in my mind
Mitch, thanks but I worded my post poorly - was always referring to toe-out in front.
#15
Melting Slicks
If you took a car, cornering at constant speed, and aligned the car exactly for that cornering speed, and then returned the steering to dead straight, you would find that the Front tires would be toed-out. A small amount of Front toe-out reduces the scrubbing forces at the front, leaving thses forces for increasing the ability to corner
The car will gain some toe-out or reduce toe-in (depending on static settings) due to Ackerman when the wheels are turned anyways.
#16
Le Mans Master
Originally Posted by RAFTRACER
.The car will gain some toe-out or reduce toe-in (depending on static settings) due to Ackerman when the wheels are turned anyways.
The reason the steering toes-in (with or without Ackerman) is because the inside tire wants to take a smaller radius around the turn then the outer tire. To get toe-zero in a turn, you have to start with a little toe-out straight ahead. Ackerman lets you get away with less toe-out straight ahead.
#17
Melting Slicks
Originally Posted by MitchAlsup
Steering with Ackerman will toe in less than steering without Ackerman.
The reason the steering toes-in (with or without Ackerman) is because the inside tire wants to take a smaller radius around the turn then the outer tire. To get toe-zero in a turn, you have to start with a little toe-out straight ahead. Ackerman lets you get away with less toe-out straight ahead.
The reason the steering toes-in (with or without Ackerman) is because the inside tire wants to take a smaller radius around the turn then the outer tire. To get toe-zero in a turn, you have to start with a little toe-out straight ahead. Ackerman lets you get away with less toe-out straight ahead.
#18
Le Mans Master
Originally Posted by RAFTRACER
.
The car will gain some toe-out or reduce toe-in (depending on static settings) due to Ackerman when the wheels are turned anyways.
The car will gain some toe-out or reduce toe-in (depending on static settings) due to Ackerman when the wheels are turned anyways.
#19
Le Mans Master
Originally Posted by RAFTRACER
Thats what I said in a nutshell wasn't it ???? Ackerman creates toe-out when turning
100% Ackerman causes no toe change when the slip anges on the rear are zero (such as at padock speeds). So if the car is set with toe == zero going straight, it will have toe == zero with the steering turned and the car can be pushed eaily around in the padock.
#20
Team Owner
Originally Posted by Olitho
So where do I find Ackerman and how do I get him to align my car?
Seriously......what is Akerman
DH