GR Yaris Alignment, Camber and handling related talks

[Michael Knight]

Got my alignment done last week (from too much toe in (0.2-0.3) to 0.07 degrees toe out) and noticed the improvement in steering feel.
Given many YT reviews have said GR's steering feel is not the greatest - one could argue it can be caused because of poor front axle setup.
I think the steering feel is now quite good.

On the downside noticed on snowy freeway is that car is quite wiggly to drive - it was constantly turning to either direction. On asphalt it went fine, but on loose surface it was quite much more difficult to keep it going straight. Not that of an biggie but good to notice before you make any setup changes.

All in all have been happy with the setup changes done, and recommend it to whoever gets their GR - check the alignment and add some camber in front!

 

[Yaris San]

looks better now, going from substantial toe in at front to nice toe out guess straight line and turn -in feels bit different now

 

[Onehp]

To add to the confusion, I prefer some toe-in on my Nordic winter tyres. The actual amount I fine tune on feel so no actual measurement

 

[Bronson]

Watching this thread, camber bolts is high up on my list for the next few months.

 

[Yaris San]

To add to the confusion, I prefer some toe-in on my Nordic winter tyres. The actual amount I fine tune on feel so no actual measurement

makes sense going toe IN during winter as maybe not looking for high corner force but better strightline stability

 

[Onehp]

makes sense going toe IN during winter as maybe not looking for high corner force but better strightline stability

Stability comes from caster really and in theory zero toe, but a little toe can remove sidewall slack from the tyres that can cause some wondering.
Toe much toe and the car starts wondering if one tyre gets dominant for whatever reason.

For Nordic winter tyres it's mostly because there is a lot of movement in the thread and soft sidewalls. Slight toe out on summers helps turn in as the inner wheel helps initially to create extra turn-in grip. On Nordics however the moving thread on the outer wheel then 'combs' over to the other side as it gets laterally loaded, and that shifting over of the sipes destroys grip feel imo. But with toe - in the sipes are 'pretentioned' to turn in, meaning it gives move meaningful information on the available grip levels right away, and on low grip surfaces you need this info sooner than later...

Or at least that is how I visualise/understand it....

 

[Michael Knight]

Stability comes from caster really and in theory zero toe, but a little toe can remove sidewall slack from the tyres that can cause some wondering.
Toe much toe and the car starts wondering if one tyre gets dominant for whatever reason.

For Nordic winter tyres it's mostly because there is a lot of movement in the thread and soft sidewalls. Slight toe out on summers helps turn in as the inner wheel helps initially to create extra turn-in grip. On Nordics however the moving thread on the outer wheel then 'combs' over to the other side as it gets laterally loaded, and that shifting over of the sipes destroys grip feel imo. But with toe - in the sipes are 'pretentioned' to turn in, meaning it gives move meaningful information on the available grip levels right away, and on low grip surfaces you need this info sooner than later...

Or at least that is how I visualise/understand it....

I've noticed that. Feels like now track mode is working better on tricky conditions - before it was too understeery.
today I was driving in dead slippery conditions (black ice everywhere) and sport mode without TC was definitely too tail happy..

 

[RSGRY-9Designs]

If I hadn't had my Geo updated and aligned I would have sold the car!

 

[Onehp]

I've noticed that. Feels like now track mode is working better on tricky conditions - before it was too understeery.
today I was driving in dead slippery conditions (black ice everywhere) and sport mode without TC was definitely too tail happy..

Thing is, once one has enough neg camber, one doesn't really need the improved turn-in grip of toe-out and so one can go toe-in for a sharper turn-in...

 

[GRgrampa]

Thing is, once one has enough neg camber, one doesn't really need the improved turn-in grip of toe-out and so one can go toe-in for a sharper turn-in...

I'm not quite sure what you're saying here. I've always used toe-out as a means for sharper turn-in as given that the wheels are aready faced outwards, they are attempting to turn before steering angle is applied.

 

[BlueIn2Red]

Only one wheel is “attempting to turn” of course, the other one is actually trying not to!

 

[Onehp]

I'm not quite sure what you're saying here. I've always used toe-out as a means for sharper turn-in as given that the wheels are aready faced outwards, they are attempting to turn before steering angle is applied.

When turning, weight transfer loads the outer wheel, increasing slip angle, and unloads the inner wheel, decreasing slip angle.

Toe-out is a way to get the inner wheel to 'assist' in turning in, in the initail phase of turn in. As soon as a decent amount of weight is on the outer wheels, the inner wheel has a minor contribution, if any.

With toe-in, one 'pre-loads' the outer wheel with some slip angle, preloading the sidewall and thread. So as one turns-in, the steering will feel sharper in the sense that most grip is coming from the outer wheels from the get-go and you'll feel better, sooner, what is happening there.

Zero toe is good in the sense that the tyres aren't fighting each other, and thus can give the best straight ahead feel. Also when they are driven, they will steer more true independent of variations of grip left/right. Downside is if there is slack in the tyres (soft-sidewalls) the steering can feel unprecise.

Too much toe either way, and the tyres are fighting each other and all you feel is slippage (worst case, thread to surface) irrespective of how you turn, killing feel.

Again, my limited understanding, anyone welcome to contribute

All this is quite subtle and for a stock car sure one can agree on what works best. But as soon as tyres, other alignment, scrub radius, tyre pressures, suspension components, change in balance etc changes, its really a matter of 'set-up' and 'finetuning' to find what works for you and your driving. Hence why I like to set toe to neutral, mark it up and experiment from there. With tools and a blanket in the boot and some practice, 2min job to make adjustments...

 

[GRgrampa]

When turning, weight transfer loads the outer wheel, increasing slip angle, and unloads the inner wheel, decreasing slip angle.

Toe-out is a way to get the inner wheel to 'assist' in turning in, in the initail phase of turn in. As soon as a decent amount of weight is on the outer wheels, the inner wheel has a minor contribution, if any.

With toe-in, one 'pre-loads' the outer wheel with some slip angle, preloading the sidewall and thread. So as one turns-in, the steering will feel sharper in the sense that most grip is coming from the outer wheels from the get-go and you'll feel better, sooner, what is happening there.

Zero toe is good in the sense that the tyres aren't fighting each other, and thus can give the best straight ahead feel. Also when they are driven, they will steer more true indendent of variations of grip left/right. Downside is if there is slack in the tyres (soft-sidewalls) the steering can feel unprecise.

Too much toe either way, and the tyres are fighting each other and all you feel is slippage (worst case, thread to surface) irrespective of how you turn, killing feel.

Again, my limited understanding, anyone welcome to contribute

All this is quite subtle and for a stock car sure one can agree on what works best. But as soon as tyres, other alignment, scrub radius, tyre pressures, suspension components, change in balance etc changes, its really a matter of 'set-up' and 'finetuning' to find what works for you and your driving. Hence why I like to set toe to neutral, mark it up and experiment from there. With tools and a blanket in the boot and some practice, 2min job to make adjustments...

Interesting. I've not considered some of the points you've raised but they certainly seem to make sense.

 

[KTGAZ]

Toe out on the front gives more responsive steering. Toe out on the rear helps the rear turn but reduces stability

Negative camber reduces grip at low speed / load as there’s less rubber in the road. Negative camber improves the car when driven harder.

 

[Michael Knight]

Toe out on the front gives more responsive steering. Toe out on the rear helps the rear turn but reduces stability

Negative camber reduces grip at low speed / load as there’s less rubber in the road. Negative camber improves the car when driven harder.

Though I've noticed that camber improves front end grip even in low grip situations (snow/ice). Hasn't been understeering since..

 

[Onehp]

Well KTGAZ toe statement depends imo as I've tried to explain above.

Neg camber reduces traction straight ahead but that is hardly a major concern on the GRY, and in turns we have LSD's... In bends neg camber tends to help grip as the car leans and reduces load from the outer edge and spreads it to the whole tyre. Proper trackday nerds have IR cameras to see the whole tyre width is heat loaded evenly live as it happens @MagnusT
But needs to be balanced with tyre wear if used on street...

 

[GRWTF]

Toe out on the front gives more responsive steering. Toe out on the rear helps the rear turn but reduces stability

Negative camber reduces grip at low speed / load as there’s less rubber in the road. Negative camber improves the car when driven harder.

Toe out on the front is a subjective feeling, not actual responsive steering. It is very much a placebo effect.

 

[Michael Knight]

Toe out on the front is a subjective feeling, not actual responsive steering. It is very much a placebo effect.

Placebo or not, but too much toe in didn't feel that good.

 

[GRWTF]

Placebo or not, but too much toe in didn't feel that good.

Not surprised it didn't. The main reason front toe-out may feel more responsive (especially on street-legal tyres) is the constant scrub generating more heat in the carcass, so on the street that is fine, on the track, they will overheat.

 

[Onehp]

If tyres are scrubbing against the ground, toe is too much. What happens is a deformation in the sidewall, we're talking fractions of a degree here, there might be some minor heating there but nothing significant. I used to have temp monitors and normal driving temps settled 2 degrees over ambient with aggresive (but not too much) toe.